Tuning Covalent Organic Frameworks via Nucleophilic Aromatic Substitution

TL;DR

Scientists developed a method to modify covalent organic frameworks using nucleophilic substitution, creating materials with new properties like redox activity and extended light absorption.

Contribution

A versatile method for tuning COFs via nucleophilic aromatic substitution with O-, S-, and N-based nucleophiles is introduced.

Findings

COF-EG, COF-Fc, and COF-Cz show unique properties like hydrophilicity, redox activity, and extended absorption.

The optical bandgap of COF-Cz is significantly reduced to 1.9 eV compared to the starting COF-F material.

The method allows for the attachment of bulky functional groups while maintaining the COF's ordered structure.

Abstract

A family of covalent organic frameworks (COFs) with tuned properties has been prepared through nucleophilic aromatic substitution (SNAr) from a fluorinated imine‐linked COF (COF‐F). The method has proved useful for O‐, S‐, and N‐based nucleophiles, including bifunctional molecules, leading to average degrees of substitution (DS) ranging from 34% to 87%. COF‐EG, COF‐Fc, and COF‐Cz containing ethylene glycol (DS = 49%), ferrocene (DS = 23%), or carbazole (DS = 34%) moieties, respectively, have been prepared, showcasing the versatility of the methodology. The introduction of these functional molecules on the framework provides unique properties to the organic material, while maintaining the ordered structure. COF‐EG is highly crystalline, porous, and hydrophilic, while COF‐Fc shows a broad redox profile characteristic of the ferrocene/ferrocenium couple, which is covalently attached to the hexagonal framework. The optical properties of the new family of compounds are also greatly influenced by the substitution, with COF‐Cz featuring a remarkably extended absorption profile beyond 700 nm and an optical bandgap of 1.9 eV, significantly reduced compared to the 2.6 eV of the starting fluorinated COF‐F material and the rest of the substituted materials in the range of 2.1–2.5 eV.

The direct nucleophilic aromatic substitution reaction on a fluorinated covalent organic framework leads to functional materials bearing bulky pendant groups such as carbazole or ferrocene. The method is versatile, suitable for O‐, S‐, and N‐based nucleophiles, and provides a unique conjugated structure containing electron‐withdrawing fluorine atoms and electron‐donating groups.© 2026 WILEY‐VCH GmbH

Figures

COF‐F hexagonal structure with crystallographic pore size (left) and postfunctionalization of COF‐F via SNAr (right). DS: Degree of substitution from elemental analysis.

(Top) Structure of model compounds MF, MSBu, MOBu, and MCz. (Bottom) ORTEP views of MSBu and MCz (thermal ellipsoids at 50% probability). Cz is carbazole.

ATR‐IR spectra of COF‐F, COF‐SBu, COF‐OBu, and COF‐EG. Highlighted with a gray band is the peak corresponding to the C—F stretching in COF‐F.

13C ssNMR of COF‐F, COF‐SBu, COF‐OBu, and COF‐EG. The peaks corresponding to C1 and C2 upon substitution are highlighted with gray bands.

(A) HRTEM images of COF‐F (top) and COF‐EG (bottom). (B) PXRD diffractograms and (C) N2 sorption isotherm of COF‐F (black) and COF‐EG (green).

(A) Ultraviolet–visible diffuse reflectance (UV–vis DRS) spectra of COF‐F, COF‐SBu, COF‐OBu, COF‐EG, and COF‐Cz. The UV–vis DRS data were transformed using the Kubelka–Munk function (K and S are the pseudoabsorption and scattering coefficients, respectively). (B) Tauc plot built from data shown in (A). The dashed lines correspond to the extrapolated linear fit in the region close to the onset, from where the value of the optical bandgap can be obtained.

Cyclic voltammogram (CV) of COF‐F, COF‐Fc, and FcEG in an acetonitrile solution with 0.1  м TBAPF6 as supporting electrolyte. For the CV of COFs, the material was drop‐casted on a glassy carbon disk electrode, which was employed as the working electrode. The CV of FcEG was conducted with a 1 mм FcEG solution using bare glassy carbon as working electrode.

Full text

Introduction

1

The synthesis of covalent organic frameworks (COFs) involves the use of rigid, polyfunctional molecules, often regarded as building blocks, that contain complementary reactive groups. These groups bind through covalent bonds, forming extended well‐ordered lattices [1, 2, 3]. The successful preparation of COFs relies on the correct self‐assembly of the building blocks, leading to the high crystallinity and porosity that characterize this type of material. Although the number of available frameworks has grown exponentially over the last twenty years [1, 4], the restrictions imposed by the reticulation process hinder the preparation of specific structures, such as those that hold pendant groups. In this context, postfunctionalization approaches have become powerful alternatives [5, 6, 7, 8, 9, 10, 11, 12]. Postmodification strategies have also proved useful for introducing metallic centers that bind to specific sites of the COF structure [13, 14, 15], for stabilizing linkage units by functional group interconversion [16, 17, 18], or for building block exchange processes [19, 20, 21]. Despite all these advances, the introduction of bulky functional groups remains a challenging task, particularly with COF materials having small pores.

Postsynthetic modification of COFs via nucleophilic aromatic substitution (S_N_Ar) is an overlooked yet formidable tool for introducing functional pendant groups that are difficult to obtain by other methods [22, 23, 24, 25].

S_N_Ar requires electron‐poor aromatic rings to favor the nucleophilic attack and a good leaving group at the substituted carbon; the C—F bond is one of the best candidates. In this vein, COFs containing fluorine in their structures are ideal platforms for exploiting this type of reactivity. Fluorinated COFs have become popular in the field thanks to the unique properties fluorine provides, including tuned electronic properties, increased crystallinity, and a higher affinity for specific species, such as carbon dioxide [22, 23, 25, 26, 27, 28, 29, 30, 31, 32, 33]. In this work, S_N_Ar strategy is applied for the postfunctionalization of a fluorinated COF (COF‐F in Scheme 1), leading to a new family of COF structures with different degrees of substitution (DS) and unique properties such as extended light absorption, water affinity, or containing redox tags, that would be harder to introduce using other methodologies [24, 34, 35, 36, 37, 38, 39, 40, 41, 42].

COF‐F hexagonal structure with crystallographic pore size (left) and postfunctionalization of COF‐F via SNAr (right). DS: Degree of substitution from elemental analysis.

Results and Discussion

2

Nucleophilic Aromatic Substitution of COF‐F

2.1

To test the S_N_Ar reaction on COFs, COF‐F in Scheme 1 was selected as a model substrate. The synthesis of COF‐F [22, 23], also known as SCF‐FCOF‐1 [27], TFA‐COF [29], TF‐COF [30], or N3F4‐COF [33] involves the condensation of 4,4′,4″‐(1,3,5‐triazine‐2,4,6‐triyl)trianiline and 2,3,5,6‐tetrafluoroterephthalaldehyde monomers, which may form an extended structure in the presence or absence of an acid. In this work, COF‐F was prepared using an optimized methodology based on a 9:1 mixture of 1,4‐dioxane and mesitylene in the presence of acetic acid, enabling batches exceeding 200 mg. The resulting material was characterized by powder X‐ray diffraction (PXRD), elemental analysis, high‐resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET) analysis, and different spectroscopic techniques. All these analyses confirmed the success of the reticulation process and the high crystallinity and surface area (1818  ±  79 m^2^  g^−1^) of the material (see Figures 2–4; and the Supporting Information).

The first attempts to derivatize COF‐F via S_N_Ar were made with butane‐1‐thiol (BuSH) and butan‐1‐ol (BuOH) as nucleophiles. The reaction conditions were adapted from previous reports on tetrafluorophenyl‐containing compounds that use THF and sodium hydride as the base [43]. The best results were obtained using five equivalents of nucleophile in the presence of NaH in THF at 60°C for 24 h, producing COF‐SBu and COF‐OBu (Scheme 1). In addition, the diimine model compound MF shown in Figure 1 was prepared from 2,3,5,6‐tetrafluoroterephthalaldehyde and aniline (90% yield). MF was used to synthesize MSBu using the same S_N_Ar method described above for COF‐F, isolating the desired compound (65% yield). Needle crystals of MSBu suitable for single crystal X‐ray diffraction (SCXRD) analysis were obtained from a DCM/hexane solution. MSBu crystallized in the tetragonal P4/n space group, being the asymmetric unit half of a molecule (Figure 1, bottom). One butyl group exhibits two equally populated disordered orientations. As this occurs at around a quaternary axis, one orientation for the disordered group forces the orientation of the three other neighboring groups (see Section S19). On the other hand, MOBu in Figure 1 could not be isolated from the complex crude mixtures derived from partial substitution on the aromatic ring (Figure S51). These results agree with the lower reactivity of alcohols as compared to thiols in S_N_Ar reactions and suggest that the substitution might also be partial in the COF‐OBu material.

(Top) Structure of model compounds MF, MSBu, MOBu, and MCz. (Bottom) ORTEP views of MSBu and MCz (thermal ellipsoids at 50% probability). Cz is carbazole.

COF‐SBu and COF‐OBu were characterized by infrared (IR) and ^13^C solid‐state nuclear magnetic resonance (ssNMR) spectroscopies to confirm the success of the reaction. As depicted in Figure 2, the C—H stretching bands of the aliphatic chain are clearly visible in the IR spectra at 2956, 2925, and 2868 cm^−1^ for COF‐SBu and at 2959, 2931, and 2871 cm^−1^ for COF‐OBu. More importantly, the decrease in intensity of the C—F stretching band at 995 cm^−1^, characteristic of the starting material COF‐F, supports the success of the substitution reaction and the formation of the new C—S or C—O covalent bonds. This trend is particularly visible for COF‐SBu (red trace in Figure 2, right).

ATR‐IR spectra of COF‐F, COF‐SBu, COF‐OBu, and COF‐EG. Highlighted with a gray band is the peak corresponding to the C—F stretching in COF‐F.

The ^13^C ssNMR spectra in Figure 3 show the characteristic resonances of the α‐carbon bonded to oxygen in COF‐OBu at *δ * =  73.5 ppm (blue trace), which is markedly more deshielded than the sulfur α‐carbon in COF‐SBu (*δ * =  37.2 ppm, red trace). The rest of the carbons of the aliphatic chain appear in the range of *δ * =  12.7–31.7 ppm, as expected. The triazine carbon appears slightly broadened at *δ * =  169 ppm in both cases, while the resonance of the imine carbon shows at *δ * =  150–160 ppm, overlapping with other aromatic carbons. Assignment of the aromatic carbons proved more challenging, and the model compounds MF, MSBu, and MOBu in Figure 1 were essential. Thus, comparing their respective ^13^C ssNMR spectra allowed us to assign the resonances of C1 and C2 in Figure 3, the most affected by the substitution (Figures S45, S49, and S53). As indicated in Figure 3, both carbons shift slightly towards higher fields except for C2 of COF‐SBu, which shifts from 117.9 to 141.0 ppm, in agreement with model compounds MF and MSBu (Table S4).

13C ssNMR of COF‐F, COF‐SBu, COF‐OBu, and COF‐EG. The peaks corresponding to C1 and C2 upon substitution are highlighted with gray bands.

Elemental analyses of COF‐SBu and COF‐OBu were used to estimate the DS, yielding 90% and 60%, respectively, consistent with the reactivity of the model compounds MSBu and MOBu (Scheme 1 and Table S1). Importantly, calculated DS are average values, and it is possible that the DS is higher at the surface and lower in the interior of the bulk material. Indeed, the substituent's bulkiness may block external pores and hinder the diffusion of nucleophiles into the inner part of the material during the substitution reaction. The chemical composition of COF‐SBu and COF‐OBu was further supported by XPS and EDX analyses. Two prominent peaks at 228 and 164 eV related to S 2s and S 2p appear in the XPS spectrum of COF‐SBu (Figure S28). In the case of COF‐OBu, two relevant features are observed. On the one hand, the significant increase in the intensity of the O 1s signal at 533 eV relative to COF‐F is attributed to the successful incorporation of the butoxy fragment. On the other hand, the concomitant decrease of the F 1s peak at 688 eV confirms the substitution of the C—F bond (Figures S27 and S29). Interestingly, the fluorine peak is not detected in the XPS spectrum of COF‐SBu, indicating a high DS and leaving the fluorine signal below the detection limit of the instrument. Analogous trends are observed in the EDX spectra of the materials collected in Figure S26. After the success of the S_N_Ar reaction using BuSH and BuOH, we turned to shorter aliphatic chains and bifunctional nucleophiles, isolating COF‐OEt, COF‐EG, and COF‐SNHBoc from ethanol, ethylene glycol, and Boc‐cysteamine, respectively (Scheme 1). Their chemical structures were confirmed by IR and NMR spectroscopies. In all cases, the decrease of the C—F stretching band in the IR spectra and the consistent appearance of shifted C1 and C2 in the NMR spectra are confirmed. The characteristic resonances of the dangling aliphatic chains corresponding to the Et, EG, 2‐aminoethyl, and ^ t ^Bu groups in COF‐OEt, COF‐EG, and COF‐SNHBoc, respectively, are also clearly identified (Figures 2, 3, S2 and S6–S8). Chemical compositions were also consistent with the expected materials with different DS as estimated by elemental analysis and further confirmed by EDX and XPS analyses (Figures S26 and S30–S32 and Table S1).

Crystallinity, Porosity, and Electronic Properties of the COF Derived from SNAr

2.2

COF postfunctionalization methodologies risks include loss of porosity and crystallinity due to disruption of their ordered structure, pore blockage, or partial decomposition of the organic framework during the reaction. SEM and BET analyses reveal that the morphology of the S_N_Ar‐substituted materials does not change significantly, with characteristic wormlike structures observed in all cases. However, the high porosity of the starting material COF‐F is substantially reduced after substitution, presumably due to the bulkiness of the introduced groups that obstruct the hexagonal pores of the framework (Figures S15–S25). COF‐EG is the only material preserving high porosity (1067  ±  26 m^2^  g^−1^, see Figures 4C and S23–S25), while the pore size distribution is only slightly shifted (inset Figure 4C), a trend that has been observed in previous works [11, 24, 25]. We attribute this phenomenon to the heterogeneous DS along the bulk material, expecting to be very high at the surface (pores completely blocked) and significantly lower in the bulk (empty pore, very similar to that of initial COF‐F). PXRD and HRTEM analyses confirm that the 2D lattice is maintained after the S_N_Ar reaction, e.g. see Figure 4A,B for COF‐EG. The characteristic sharp peak at 2θ = 2.7°–2.9°, corresponding to the (100) and (010) basal planes of the COF hexagonal structure, is clearly visible in all diffractograms, along with additional, less intense peaks at higher degrees (see also Figures S12 and S15–S22). The serrated packing structure of the parent COF‐F [27] with a π–π stacking distance of around 3.5 Å is also maintained, as indicated by the (002) peaks in the PXRD patterns showing around 2θ = 25°, in most cases (Figure S12). In the case of COF‐SBu, broad signals appear in the ranges of 2θ = 5°–12° and 2θ = 15°–25°, which should be attributed to distortions in the crystal structure due to the steric hindrance of vicinal butyl groups. Interestingly, this has also been observed in the crystal structure of MSBu (see Section S19 for a more detailed analysis). Indeed, COF‐SBu is the COF material with the highest DS, close to 90% (Scheme 1). Pawley refinement allowed us to determine the cell parameters of the family of COFs, with slight variation, consistent with minimal structural changes upon substitution (Figures S13 and S14 and Table S2). Among the family of COFs prepared through S_N_Ar, COF‐EG presents the highest crystallinity. The hydroxyl group of the dangling ethylene glycol substituent may play a key role in maintaining the ordered structure through supramolecular interactions based on hydrogen bonding. These groups also determine the macroscopic properties of the material, providing a high affinity for polar solvents, particularly in water (Figure S62). The substitution of the fluorine atoms in the organic framework of COF‐F leads to significant changes in the electronic properties of the potential semiconducting materials as demonstrated by ultraviolet–visible diffuse reflectance (UV–vis DRS) and electrochemical analyses (Figures 5, S35–S37 and Table S3). In particular, the bandgap (BG) values for the partially substituted COF‐OBu (DS = 58%, BG = 2.39 eV), COF‐EG (DS = 49%, BG = 2.28 eV) and COF‐SNHBoc (DS = 54%, BG = 2.09) are significantly lower than that of the parent COF‐F (BG = 2.59 eV). On the other hand, the highly substituted COF‐SBu (DS = 87%) and COF‐OEt (DS = 83%) show larger BGs of 2.47 and 2.48 eV, respectively.

(A) HRTEM images of COF‐F (top) and COF‐EG (bottom). (B) PXRD diffractograms and (C) N2 sorption isotherm of COF‐F (black) and COF‐EG (green).

(A) Ultraviolet–visible diffuse reflectance (UV–vis DRS) spectra of COF‐F, COF‐SBu, COF‐OBu, COF‐EG, and COF‐Cz. The UV–vis DRS data were transformed using the Kubelka–Munk function (K and S are the pseudoabsorption and scattering coefficients, respectively). (B) Tauc plot built from data shown in (A). The dashed lines correspond to the extrapolated linear fit in the region close to the onset, from where the value of the optical bandgap can be obtained.

The partially substituted materials are characterized by the presence of electron‐donating (thio)ether groups in combination with electron‐withdrawing fluorine groups, which are expected to impart a push–pull electronic character that influences their optical and redox properties. The latter can also be affected by the heterogeneous nature of the materials, most likely exhibiting a higher DS at the surface than in the bulk.

Introduction of Redox Tags and Optical Tuning of COF‐F via SNAr

2.3

Taking advantage of the versatility of the S_N_Ar postfunctionalization strategy described here, we next explored the introduction of bulky ferrocene (Fc) or carbazole (Cz) moieties. Fc‐containing COFs have been used as catalytic platforms in the field of artificial photosynthesis [24, 41], or they have shown exceptional adsorption capacity towards organic pollutants through coulombic interactions [42]. On the other hand, similar materials containing Cz groups have been used in photocatalysis for various organic transformations or for producing H_2_O_2_ from water and oxygen [34, 35, 36]. Other examples exploit the unique optical and electronic properties of Cz‐containing materials [37, 38]. In most cases, the Fc or Cz groups are part of the framework that constitutes the COF material, being electronically coupled with the reticular conjugated system. Thus, these materials are prepared via direct synthesis from suitable, polyfunctional building blocks that are not always commercially available. Introducing Fc or Cz via S_N_Ar allows us to access functionalized COF materials of different types from readily available sources, and to modulate the electronic communication between the introduced bulky group (Fc or Cz) and the conjugated framework.

As depicted in Scheme 1, the S_N_Ar method was successful in obtaining COF‐Fc and COF‐Cz with DS of 23% and 34%, respectively, as indicated by elemental analysis and NMR spectroscopy. In the case of COF‐Fc, the ethylene glycol derivative FcEG shown in Figure 6 was used as nucleophile. This compound was found to undergo transesterification in solution, releasing ethylene glycol into the reaction mixture and leading to an additional C—F substitution by free EG of 6% (Scheme S1). This is supported by analysis of the IR spectrum, which presents characteristic OH stretching bands above 3000 cm^−1^, analogous to those of COF‐EG (Figure S2). Thus, the overall DS of COF‐Fc is 29%, accounting for the 23% of Fc and 6% of EG. The presence of the ferrocene moiety was confirmed by inductively coupled plasma optical emission spectroscopy (ICP‐OES) analysis and cyclic voltammetry (CV) of a modified glassy carbon electrode prepared by drop casting an acetone suspension of COF‐Fc. As shown in Figure 6, the typical ferrocene/ferrocenium oxidation feature is observed at the expected potential, similar to that of the precursor FcEG (compare blue and red traces). The Fc oxidation is followed by an additional oxidation event close to that of starting COF‐F (black trace). These results suggest that both redox active species (Fc and conjugated material) are decoupled, as expected considering the EG aliphatic chain linking the two components.

Cyclic voltammogram (CV) of COF‐F, COF‐Fc, and FcEG in an acetonitrile solution with 0.1  м TBAPF6 as supporting electrolyte. For the CV of COFs, the material was drop‐casted on a glassy carbon disk electrode, which was employed as the working electrode. The CV of FcEG was conducted with a 1 mм FcEG solution using bare glassy carbon as working electrode.

On the other hand, to confirm the successful incorporation of the carbazole moiety into the organic framework by covalent bonds, the model compound MCz in Figure 1 was prepared. Single crystals of MCz suitable for SCXRD analysis were obtained, and the ORTEP view of the molecule is shown in Figure 1 (bottom). Interestingly, MCz shows two strong intramolecular interactions between C—H1 and C—H2 and the conjugated carbazole rings, which lay almost perpendicular to each other (Figure S68). Such interaction is manifested in the ^1^H NMR resonance of the aromatic proton in the ortho position of the N‐imine group at an unusually high field of *δ * =  4.86 ppm (Figure S56, labeled as H2) [44]. MCz was key to assigning the resonances in the ^13^C ssNMR spectrum of COF‐Cz and to confirming the substitution pattern of the organic material (Figure S58). The bulkiness of the carbazole group leads to partial substitution in COF‐Cz (DS = 34%), thereby providing a push–pull electronic configuration within the organic material. The presence of the Cz chromophore moiety also results in a significantly reduced BG of 1.9 eV (Figure 5). CV analysis shows that the material also exhibits a low‐lying conduction band, estimated at E CB   =  −0.8 V versus NHE, which is significantly lower than those of the other materials (Figure S37 and Table S3). The significant changes in optical and redox properties of COF‐Cz may not be solely attributed to the push(Cz)–pull(F) electronic structure and the chromophore nature of the Cz group, but also to the heterogeneous nature of the COF‐Cz material having different DS on the surface and within the bulk, as discussed above. In fact, Cz is one of the bulkiest groups used in this work, and its diffusion through the pores on the surface may be limited after the first substitution. Importantly, the crystallinity and morphology of the material are maintained after substitution for both functional materials COF‐Fc and COF‐Cz (Figures S12 and S14 for PXRD and Figures S21 and S22 for SEM/HRTEM) while the surface area is significantly reduced as expected for such bulky substituents (Figures S23–S24).

Conclusion

3

In this work, a versatile methodology for the postfunctionalization of fluorinated COFs, useful for introducing complex and bulky moieties, is described. The strategy is based on the nucleophilic aromatic substitution reaction and allows us to obtain COF materials with unique features that would be difficult or impossible to prepare by direct synthesis. The methodology proved successful with different types of nucleophiles (Nu) such as carbazole, alcohols, and thiols, including bifunctional molecules. The resulting substituted materials show a significant change in the macroscopic properties, such as water affinity in the case of the ethylene glycol substituted COF‐EG, or reduced BG for the partially substituted materials COF‐OBu, COF‐EG, COF‐SBu or COF‐Cz. Partial substitution provides a push–pull electronic configuration, because of the electron‐withdrawing character of the C—F bond combined with the electron‐donating character of the C—Nu bond in the aromatic rings of the organic framework. We expect that this approach can be used in the field of functional materials for a diverse range of applications.

Experimental Section

4

All commercial reagents were used without further purification unless stated otherwise. THF, MeOH, acetone, DCM, EtOAc, 1,4‐dioxane, mesitylene, dry DMF, dry Et_3_N, and NaOH were purchased from Thermo Fischer Scientific. THF was dried by distillation over sodium/benzophenone. 1,4‐dioxane, mesitylene, and DCM were dried over 3 Å molecular sieves. Absolute EtOH and pentane were purchased from VWR. NaH (60% in mineral oil), 1‐butanethiol (BuSH), 1‐butanol (BuOH), ethylene glycol (EG), carbazole (CzH) and oxalyl chloride (2 M in DCM) were purchased from Sigma‐Aldrich. 2,3,5,6‐Tetrafluoroterephthalaldehyde, 4,4′,4″‐(1,3,5‐triazine‐2,4,6‐triyl)trianiline, and ferrocenecarboxylic acid were purchased from BLDpharm. Aniline was purchased from Alfa Aesar and distilled under reduced pressure before use. Boc‐cysteamine (BocCys) was purchased from Fluorochem. The synthesis of COF‐F was performed in a Carousel 12 Plus Reaction Station from Radleys, that allows for up to 12 reactions to be run simultaneously, using 16 mm ø (5 mL) multireactor tubes.

Synthesis of COF‐F

4.1

In four multireactor tubes, 2,3,5,6‐tetrafluoroterephthalaldehyde (33.0 mg, 0.16 mmol, 1.1  equiv) and 4,4′,4″‐(1,3,5‐triazine‐2,4,6‐triyl)trianiline (34.4 mg, 0.10 mmol, 1.0  equiv) were added in each tube under Ar atmosphere. Subsequently, 4 mL of anhydrous 1,4‐dioxane:mesitylene (9:1), followed by 0.1 mL of a 0.3  м acetic acid solution in anhydrous 1,4‐dioxane:mesitylene (9:1), were added. Then, the multireactor tubes were sealed, stirred vigorously by hand, and heated at 120°C for 72 h. After cooling down to room temperature, the contents of the four multireactor tubes were combined and the resulting mixture was filtered and washed with THF, MeOH, and acetone, obtaining an orange solid in 87% yield (216 mg). ^ 13 ^ C ssNMR (101 MHz) δ (ppm): 168.9, 151.9, 147.5, 134.7, 129.0, 120.0, 117.9. Elemental analysis: C: 63.5%, H: 2.5%, N: 13.1%. IR (ATR) ṽ (cm^−1^): 1624 (C=N st), 1594, 1575, 1486, 1410, 1360, 1304, 1172, 1147, 1012, 995 (C—F st), 863, 814. PXRD (Cu Kα) 2θ (°): 2.77 (100), 4.79 (110), 5.57 (200), 7.35 (210), 25.6 broad (002).

General Procedure for the Postfunctionalization of COF‐F via SNAr

4.2

In a 2‐necked round bottom flask, NaH (193 mg, 60% in oil, 4.92 mmol, 5.0  equiv for each F atom, Figure S1) was washed with pentane under N_2_ atmosphere. Then, 20 mL of anhydrous THF and 4.92 mmol of nucleophile (5.0  equiv for each F atom) were added and the mixture was stirred at room temperature. After 30 min, the mixture was purged with N_2_ to remove the H_2_ generated during the deprotonation step. Subsequently, COF‐F (100 mg, 0.16 mmol of COF‐F, 0.98 mmol of F, 1.0  equiv for each F atom) was added. The reaction was stirred at 60°C for 24 h. After cooling down to room temperature, the resulting mixture was filtered and washed with THF, water, MeOH, and acetone.

COF‐SBu

4.2.1

Prepared according to the general procedure from the corresponding nucleophile BuSH (0.53 mL). COF‐SBu was obtained as a light orange solid (135 mg). ^ 13 ^ C ssNMR (101 MHz) δ (ppm): 169.8, 158.9, 154.8, 149.2, 141.0, 132.7, 129.2, 119.7, 37.2, 31.2, 21.6, 13.1. Elemental analysis: C: 65.7%, H: 6.3%, N: 8.6%, S: 16.1%. IR (ATR) ṽ (cm^−1^): 2956 (C—H st), 2925 (C—H st), 2868 (C—H st), 1626 (C=N st), 1599, 1577, 1501, 1409, 1359, 1292, 1172, 1144, 1013, 815. PXRD (Cu Kα) 2θ (°): 2.88.

COF‐OBu

4.2.2

Prepared according to the general procedure from the corresponding nucleophile BuOH (0.45 mL). COF‐OBu was obtained as an orange solid (108 mg). ^ 13 ^ C ssNMR (101 MHz) δ (ppm): 168.9, 151.7, 147.9, 141.9, 133.5, 128.3, 119.9, 115.2, 73.5, 31.7, 18.5, 12.7. Elemental analysis: C: 68.2%, H: 5.7%, N: 9.5%. IR (ATR) ṽ (cm^−1^): 2959 (C—H st), 2931 (C—H st), 2871 (C—H st), 1624 (C=N st), 1596, 1577, 1504, 1412, 1356, 1286, 1172, 1144, 1063 (C—O st), 1035 (C—O st), 1012, 864, 815. PXRD (Cu Kα) 2θ (°): 2.85, 4.94, 5.72, 7.48, 25.6 (broad).

COF‐EG

4.2.3

Prepared according to the general procedure from the corresponding nucleophile EG (0.27 mL). COF‐EG was obtained as an orange solid (89 mg). ^ 13 ^ C ssNMR (101 MHz) δ (ppm): 169.4, 150.5, 148.0, 140.5, 133.4, 129.1, 119.8, 114.8, 74.2, 61.1. Elemental analysis: C: 62.0%, H: 4.1%, N: 10.6%. IR (ATR) ṽ (cm^−1^): 3359 (O—H st), 2945 (C—H st), 2871 (C—H st), 1626 (C=N st), 1605, 1578, 1505, 1412, 1360, 1289, 1175, 1145, 1080 (C—O st), 1047 (C—O st), 1012, 862, 813. PXRD (Cu Kα) 2θ (°): 2.84, 4.94, 5.69, 7.53, 25.9 (broad).

COF‐OEt

4.2.4

Prepared according to the general procedure from the corresponding nucleophile EtOH (0.28 mL). COF‐OEt was obtained as an orange solid (101 mg). ^ 13 ^ C ssNMR (101 MHz) δ (ppm): 169.7, 154.2, 150.4, 147.5, 141.8, 132.9, 129.1, 119.6, 114.3, 69.3, 14.4. Elemental analysis: C: 69.0%, H: 5.5%, N: 11.1%. IR (ATR) ṽ (cm^−1^): 2974 (C—H st), 2928 (C—H st), 2888 (C—H st), 1625 (C=N st), 1595, 1577, 1503, 1412, 1359, 1288, 1175, 1144, 1051 (C—O st), 1035 (C—O st), 1014, 862, 813. PXRD (Cu Kα) 2θ (°): 2.81, 4.84, 5.63, 7.52, 25.3 (broad).

COF‐SNHBoc

4.2.5

Prepared according to the general procedure from the corresponding nucleophile BocCys (0.83 mL). COF‐SNHBoc was obtained as a red‐orange solid (113 mg). ^ 13 ^ C ssNMR (101 MHz) δ (ppm): 169.7, 155.9, 152.4, 149.4, 129.7, 114.8, 80.2, 41.0, 35.7, 28.5. Elemental analysis: C: 59.3%, H: 4.7%, N: 12.0%, S: 7.2%. IR (ATR) ṽ (cm^−1^): 3358 (N—H st), 2977 (C—H st), 2930 (C—H st), 1690 (C=O st), 1625 (C=N st), 1606, 1579, 1503, 1411, 1362, 1291, 1251, 1145, 1013, 861, 812. PXRD (Cu Kα) 2θ (°): 2.91, 5.83.

COF‐Fc

4.2.6

Prepared according to the general procedure from the corresponding nucleophile FcEG (1.21 g). COF‐Fc was obtained as an orange solid (99 mg). ^ 13 ^ C ssNMR (101 MHz) δ (ppm): 169.8, 149.1, 133.9, 129.1, 120.0, 115.9, 70.3, 61.0. Elemental analysis: C: 61.9%, H: 3.8%, N: 10.2%. ICP‐OES: Fe: 3.7%. IR (ATR) ṽ (cm^−1^): 3361 (O—H st), 2944 (C—H st), 2875 (C—H st), 1693 (C=O st), 1623 (C=N st), 1606, 1579, 1500, 1411, 1359, 1292, 1259, 1175, 1145, 1075 (C—O st), 1050 (C—O st), 1013, 863, 812. PXRD (Cu Kα) 2θ (°): 2.86, 5.67.

COF‐Cz

4.2.7

Prepared according to the general procedure from the corresponding nucleophile CzH (0.82 g). COF‐Cz was obtained as a deep red solid (50 mg). ^ 13 ^ C ssNMR (101 MHz) δ (ppm): 169.7, 150.8, 146.6, 141.3, 130.0, 120.1, 115.4. Elemental analysis: C: 69.1%, H: 3.4%, N: 12.4%. IR (ATR) ṽ (cm^−1^): 1626 (C=N st), 1579, 1504, 1413, 1362, 1293, 1178, 1146, 1012, 866, 812. PXRD (Cu Kα) 2θ (°): 2.84, 5.77, 7.54 25.2 (broad).

Synthesis of 1,1′‐(perfluoro‐1,4‐phenylene)bis(N‐phenylmethanimine) (MF)

4.3

In a 25 mL Schlenk tube, a mixture of 2,3,5,6‐tetrafluoroterephthalaldehyde (0.412 g, 2 mmol, 1.0  equiv) and aniline (0.4 mL, 4.4 mmol, 1.1  equiv) in 10 mL of EtOH was stirred at 60°C for 16 h under N_2_ atmosphere. After cooling down to room temperature, the reaction was filtered and washed with abundant EtOH to obtain product MF as a pale white solid in 90% yield (639 mg, 1.79 mmol). ^ 1 ^ H NMR (400 MHz, DMSO‐d_6_) δ (ppm): 8.74 (s, 2H), 7.49 (dd, J = 8.4, 7.1 Hz, 4H), 7.39–7.32 (m, 6H); ^ 13 ^ C NMR (126 MHz, DMSO‐d_6_) δ (ppm): 150.8, 149.9, 145.2 (d, J = 248.8 Hz), 129.4, 127.5, 121.1, 116.8; ^ 19 ^ F NMR (377 MHz, DMSO‐d_6_) δ (ppm): −143.1. Elemental analysis: calcd for C_20_H_12_F_4_N_2_ (C: 67.4%, H: 3.4%, N: 7.9%); found (C: 67.4%, H: 3.5%, N: 7.8%). HRMS (ESI+) m/z: calcd for [C_20_H_13_F_4_N_2_]^+^ [M+H]^+^ 357.1010; found 357.1009.

Synthesis of 1,1′‐(2,3,5,6‐tetrakis(butylthio)‐1,4‐phenylene)bis(N‐phenylmethanimine) (MSBu)

4.4

In a two‐necked round bottom flask, NaH (112 mg, 60% in oil, 2.81 mmol, 2.5  equiv) was added and then washed with dry pentane under N_2_ atmosphere. Then, 10 mL of anhydrous THF and BuSH (0.3 mL, 2.81 mmol, 2.5  equiv) were added and the mixture was stirred at room temperature. After 30 min, the mixture was purged with N_2_ to remove the H_2_ generated during the deprotonation step. Then, MF (100 mg, 0.28 mmol, 1.0  equiv) was added and the reaction was allowed to proceed for 24 h. After completion of the reaction, 2 mL of MeOH were added to the reaction mixture to quench the excess of NaH. The solvent was removed under reduced pressure, and the crude reaction mixture was extracted with DCM/water to obtain 116 mg of a pale‐yellow solid identified as product MSBu, mixed with undetermined impurities in ca. 65% yield, estimated from the ^1^H NMR spectrum. Colorless crystalline needles suitable for SCXRD analysis were obtained from slow evaporation of DCM:hexane solutions. ^ 1 ^ H NMR (500 MHz, DMSO‐d_6_) δ (ppm): 8.81 (s, 2H), 7.48 (t, J = 7.8 Hz, 4H), 7.30 (t, J = 7.6 Hz, 2H), 7.27 (d, J = 7.1 Hz, 4H), 2.91 (t, J = 7.2 Hz, 8H), 1.43 (quint, J = 7.1 Hz, 8H), 1.35–1.29 (m, 8H), 0.79 (t, J = 7.3 Hz, 12H); ^ 13 ^ C NMR (126 MHz, DMSO‐d_6_) δ (ppm): 159.9, 151.3, 148.4, 140.0, 129.4, 126.2, 120.7, 36.7, 30.9, 21.3, 13.4. HRMS (ESI+) m/z: calcd for [C_36_H_49_N_2_S_4_]^+^ [M+H]^+^ 637.2773; found 637.2780.

Synthesis of 1,1′‐(2,3,5,6‐tetrabutoxy‐1,4‐phenylene)bis(N‐phenylmethanimine) (MOBu)

4.5

In a two‐necked round bottom flask, NaH (112 mg, 60% in oil, 2.81 mmol, 2.5  equiv) was added and then washed with dry pentane under N_2_ atmosphere. Then, 10 mL of anhydrous THF and BuOH (0.3 mL, 2.81 mmol, 2.5  equiv) were added and the mixture was stirred at room temperature. After 30 min, the mixture was purged with N_2_ to remove the H_2_ generated during the deprotonation step. Then, MF (100 mg, 0.28 mmol, 1.0  equiv) was added and the reaction was allowed to proceed for 24 h. After completion of the reaction, 2 mL of MeOH were added to the reaction mixture to quench the excess of NaH. The solvent was removed under reduced pressure and the crude reaction mixture was extracted with DCM/water to obtain a dark yellow oil. Product MOBu was obtained as a mixture of different substitution products (Figure S51). HRMS (ESI+) m/z: calcd for the fully substituted compound [C_36_H_49_N_2_O_4_]^+^ [M + H]^+^ 573.3687; found 573.3688.

Synthesis of 1,1′‐(2,3,5,6‐tetra(9H‐carbazol‐9‐yl)‐1,4‐phenylene)bis(N‐phenylmethanimine) (MCz)

4.6

In a two‐necked round bottom flask, NaH (50 mg, 60% in oil, 1.24 mmol, 1.1  equiv) was added and then washed with dry pentane under N_2_ atmosphere. Then, 10 mL of anhydrous THF and CzH (207 mg, 1.24 mmol, 1.1  equiv) were added and the mixture was stirred at room temperature. After 30 min, the mixture was purged with N_2_ to remove the H_2_ generated during the deprotonation step. Then, MF (100 mg, 0.28 mmol, 1.0  equiv) was added and the reaction was allowed to proceed at 60°C for 24 h. After completion of the reaction, 2 mL of MeOH were added to the reaction mixture to quench the excess of NaH. The solvent was removed under reduced pressure and the crude product was filtered and washed with EtOH to obtain product MCz as a yellow solid in 81% yield (215 mg, 0.23 mmol). Small colorless crystals suitable for SCXRD analysis were obtained from slow evaporation of DCM:hexane solutions. ^ 1 ^ H NMR (600 MHz, DMSO‐d_6_) δ (ppm): 7.98 (d, J = 7.7 Hz, 8H), 7.89 (d, J = 8.3 Hz, 8H), 7.23 (t, J = 7.7 Hz, 8H), 7.10 (t, J = 7.7 Hz, 8H), 6.87 (s, 2H), 6.76–6.73 (m, 2H), 6.70 (t, J = 7.5 Hz, 4H), 4.85 (d, J = 7.1 Hz, 4H); ^ 13 ^ C NMR (126 MHz, DMSO‐d_6_) δ (ppm): 153.7, 151.0, 141.0, 138.7, 138.2, 128.4, 125.7, 125.5, 122.8, 120.1, 120.0, 118.4, 111.5. Elemental analysis: calcd for C_68_H_44_N_6_ (C: 86.4%, H: 4.7%, N: 8.9%); found (C: 86.5%, H: 4.7%, N: 8.7%). HRMS (ESI+) m/z: calcd for [C_68_H_45_N_6_]^+^ [M + H]^+^ 945.3700; found 945.3714.

Supporting Information

Additional supporting information can be found online in the Supporting Information section. Additional experimental procedures and equipment details. Spectroscopic, crystallographic, morphological, porosity and electrochemical data. Supporting Scheme. S1: Transesterification reaction of FcEG. Supporting Fig. S1: Repeat unit of COF‐F, corresponding to the formula C_33_H_1_5F_6_N_6_. Supporting Fig. S2: ATR‐IR spectra of COF‐F, COF‐OEt, COF‐NHBoc, COF‐Fc and COF‐Cz. The grey band marks the position of the C‒F stretching band in COF‐F. Supporting Fig. S3: ^13^C CP‐MAS ssNMR (101 MHz) of COF‐F. Supporting Fig. S4: ^13^C CP‐MAS ssNMR (101 MHz) of COF‐SBu. Supporting Fig. S5: ^13^C CP‐MAS ssNMR (101 MHz) of COF‐OBu. Supporting Fig. S6: ^13^C CP‐MAS ssNMR (101 MHz) of COF‐EG. Supporting Fig. S7: ^13^C CP‐MAS ssNMR (101 MHz) of COF‐OEt. Supporting Fig. S8: ^13^C CP‐MAS ssNMR (101 MHz) of COF‐SNHBoc. Supporting Fig. S9: ^13^C CP‐MAS ssNMR (101 MHz) of COF‐Fc. Supporting Fig. S10: ^13^C CP‐MAS ssNMR (101 MHz) of COF‐Cz. Supporting Fig. S11: TGA curves of COF‐F, COF‐SBu, COF‐OBu, COF‐EG, COF‐OEt, COF‐SNHBoc, COF‐Fc and COF‐Cz. Supporting Fig. S12: Comparison of the PXRD diffractograms of COF‐F, COF‐SBu, COF‐OBu, COF‐EG, COF‐OEt, COF‐SNHBoc, COF‐Fc and COF‐Cz. Supporting Fig. S13: Pawley refinement of COF‐F, COF‐OBu, COF‐EG and COF‐OEt. Supporting Fig. S14: Pawley refinement of COF‐SNHBoc, COF‐Fc and COF‐Cz. Supporting Fig. S15: a) SEM and b) HRTEM images of COF‐F. Supporting Fig. S16: a) SEM and b) HRTEM images of COF‐SBu. Supporting Fig. S17: a) SEM and b) HRTEM images of COF‐OBu. Supporting Fig. S18: a) SEM and b) HRTEM images of COF‐EG. Supporting Fig. S19: a) SEM and b) HRTEM images of COF‐OEt. Supporting Fig. S20: a) SEM and b) HRTEM images of COF‐SNHBoc. Supporting Fig. S21: a) SEM and b) HRTEM images of COF‐Fc. Supporting Fig. S22: a) SEM and b) HRTEM images of COF‐Cz. Supporting Fig. S23: N_2_ sorption isotherm of COF‐F, COF‐OBu, COF‐EG, COF‐OEt and COF‐Cz. Supporting Fig. S24: BET plot of COF‐F, COF‐OBu, COF‐EG, COF‐OEt and COF‐Cz. Supporting Fig. S25: Pore size distribution of COF‐F, and COF‐EG. Supporting Fig. S26: EDX spectra of COF‐F, COF‐SBu, COF‐OBu, COF‐EG, COF‐OEt, COF‐SNHBoc, COF‐Fc and COF‐Cz. Supporting Fig. S27: XPS spectra of COF‐F. Supporting Fig. S28: XPS spectra of COF‐SBu. Supporting Fig. S29: XPS spectra of COF‐OBu. Supporting Fig. S30: XPS spectra of COF‐EG. Supporting Fig. S31: XPS spectra of COF‐OEt. Supporting Fig. S32: XPS spectra of COF‐SNHBoc. Supporting Fig. S33: XPS spectra of COF‐Fc. Supporting Fig S34: XPS spectra of COF‐Cz. Supporting Fig. S35: UV‐Vis DRS spectra of COF‐F, COF‐SBu, COF‐OBu, COF‐EG, COF‐OEt, COF‐SNHBoc, COF‐Fc and COF‐Cz. a) The UV‐Vis DRS data was transformed using the Kubelka‐Munk function (K and S are the pseudo‐absorption and scattering coefficients, respectively). b) Tauc plot. The dashed lines correspond to the extrapolated linear fit in theregion close to the onset, from where the value of the optical band gap can be obtained. Supporting Fig. S36: Cyclic voltammogram (CV) of COF‐F and COF‐SBu in an acetonitrile solution with 0.1 м TBAPF_6_ as supporting electrolyte. The corresponding COF‐modified glassy carbon electrode was employed as the working electrode. Supporting Fig. S37: Cyclic voltammogram (CV) of COF‐OBu, COF‐EG, COF‐OEt, COF‐SNHBoc, COF‐Fc and COF‐Cz in an acetonitrile solution with 0.1 м TBAPF6 as supporting electrolyte. The corresponding COF‐modified glassy carbon electrode was employed as the working electrode. Supporting Fig. S38: Cyclic voltammogram (CV) of ferrocene (Fc) and FcEG in an acetonitrile solution with 0.1 м TBAPF_6_ as supporting electrolyte. The CVs were conducted in solution with 1 mм of analyte using bare glassy carbon as working electrode. Supporting Fig. S39: ^1^H NMR (300 MHz, CDCl_3_) of ferrocenecarboxylic acid. Supporting Fig. S40: ^1^H NMR (300 MHz, CDCl_3_) of the crude of reaction of chlorocarbonyl ferrocene. Supporting Fig. S41: ^1^H NMR (400 MHz, CDCl_3_) of FcEG. Supporting Fig. S42: ^13^C NMR (126 MHz, CDCl_3_) of FcEG. Supporting Fig. S43: ^1^H NMR (400 MHz, DMSO‐d_6_) of MF. Supporting Fig. S44: ^13^C NMR (126 MHz, DMSO‐d_6_) of MF. Supporting Fig. S45: Comparison between ^13^C CP‐MAS ssNMR (101 MHz) of COF‐F (black) and ^13^C NMR (126 MHz, DMSOd_6_) of MF (red). Supporting Fig. S46: ^19^F NMR (377 MHz, DMSO‐d_6_) of MF Supporting Fig. S47: ^1^H NMR (600 MHz, DMSO‐d_6_) of MSBu. Supporting Fig. S48: ^13^C NMR (126 MHz, DMSO‐d_6_) of MSBu. Supporting Fig. S49: Comparison between ^13^C CP‐MAS ssNMR (101 MHz) of COF‐SBu (black) and ^13^C NMR (126 MHz, DMSOd_6_) of MSBu (red). Supporting Fig. S50: HSQC (600 MHz, DMSO‐d_6_) of MSBu. Supporting Fig. S51: ^1^H NMR (600 MHz, CDCl_3_) of the mixture of MOBu. Supporting Fig. S52: ^13^C NMR (126 MHz, CDCl_3_) of the mixture of MOBu. Supporting Fig. S53: Comparison between ^13^C CP‐MAS ssNMR (101 MHz) of COF‐OBu (black) and ^13^C NMR (126 MHz, DMSOd_6_) of MOBu (red). Supporting Fig. S54: HSQC (600 MHz, CDCl_3_) of the mixture of MOBu. Supporting Fig. S55: Different patterns of substitution used in Table S4. Supporting Fig. S56: ^1^H NMR (600 MHz, DMSO‐d_6_) of MCz. Supporting Fig. S57: ^13^C NMR (126 MHz, DMSO‐d6) of MCz. Supporting Fig. S58: Comparison between 13C CP‐MAS ssNMR (101 MHz) of COF‐Cz (black) and ^13^C NMR (126 MHz, DMSOd_6_) of MCz (red). Supporting Fig. S59: COSY (600 MHz, DMSO‐d_6_) of MCz. Supporting Fig. S60: HSQC (600 MHz, DMSO‐d_6_) of MCz. Supporting Fig. S61: ^1^H NMR (400 MHz, CDCl_3_) of a mixture of FcEG and Fc‐EG‐Fc. Supporting Fig. S62: A) Vials with 2.5 mg of COF‐F (left) and COF‐EG (right) in 5 mL of water after being sonicated for 1 min and let to settle for 5 min. B) and C) Images corresponding to the contact angle measurements done for films prepared by depositing COF‐F or COF‐EG powders on top of a silicon sample holder by drop casting. In the case of COF‐EG, the powder film immediately absorbs the drop. An approximate measurement has been made in the first milliseconds in which the drop comes in contact with the powder. After that, the contact angle becomes practically negligible, and is considered to be less than 10º, practically out of the measurement range of the equipment. Supporting Fig. S63: ORTEP view of MSBu (thermal ellipsoids at 50% probability). Supporting Fig. S64: Perspective view of the crystal cell of MSBu (disordered carbon positions as dots). Supporting Fig. S65: Intermolecular potentials calculated using the UNI force field for MSBu (kJ/mol). Supporting Fig. S66: Estimated habit of the crystals from the calculated interaction potentials, suggesting the needle observed shape for the MSBu crystals (disordered zone in color). Supporting Fig. S67: ORTEP view of MCz (thermal ellipsoids at 50% probability). Supporting Fig. S68: Representation of intramolecular CH‒π interaction in MCz. In red the plane of the π‐system of the carbazole moiety. In green the distance between the corresponding hydrogen atom and the centroid of the aromatic ring, in light blue the distance between the corresponding hydrogen atom and its projection in the plane (see Table S13). Supporting Table S1: Calculation of the degree of substitution (DS) of the substituted COFs using CHNS elemental analysis and ICP‐OES data. ^a^Substitution by FcEG. ^b^Substitution by ethylene glycol. Supporting Table S2: Cell parameters of the different COFs obtained through Pawley refinement. ^a^The unit cell parameters were obtained manually. A value for c could not be calculated. ^b^A value for c could not be found. The refinement was carried out using the c value obtained for COF‐F. Supporting Table S3: Band analysis of COF‐F, COF‐SBu, COF‐OBu, COF‐EG, COF‐OEt, COF‐SNHBoc, COF‐Fc and COF‐Cz. aEnergy of the valence band and the conduction band vs vacuum calculated using equations (3,4). ^b^Potential of the valence band and the conduction band vs NHE calculated using equations (5,6). Supporting Table S4: Comparison of the change in the ^13^C NMR chemical shifts of C1 and C2 among the different patterns ofsubstitution (Figure S55) for COF‐F, COF‐SBu and COF‐OBu and their corresponding molecular models (MF, MSBuand MOBu, respectively). Results from the differently substituted molecules (in orange) were simulated in MestReNovav12.0.0‐20080 using the MNova Best predictor at 126 MHz in DMSO‐d_6_.[7] Results from the molecular models and theCOFs (in blue) were experimentally obtained. δ_1,X_ refers to the chemical shift of the C1 that is directly bonded to the newsubstituent, while δ_1,F_ refers to the C1 still bonded to F. ^a^This peak appears overlapped, so the precise chemical shift cannotbe assigned. Supporting Table S5: Different patterns of substitution used in Table S4. Supporting Table S6: Atomic coordinates ( x 10^4^ ) and equivalent isotropic displacement parameters (Å^2^ x 10^3^) for MSBu. U(eq) isdefined as one third of the trace of the orthogonalized U^ij^ tensor. Supporting Table S7: Bond lengths (Å) and angles (°) for MSBu. Supporting Table S8: Anisotropic displacement parameters (Å^2^ x 10^3^) for MSBu. The anisotropic displacement factor exponent takesthe form: ‐2π^2^[ h^2^a2U^11^ + … + 2 h k a b* U^12^ ]. Supporting Table S9: Crystal data and structure refinement for MCz. *Supporting Table S10:Atomic coordinates ( x 10^4^ ) and equivalent isotropic displacement parameters (Å^2^x 10^3^) for MCz. U(eq) is defined as one third of the trace of the orthogonalized Uij tensor. Supporting Table S11:Bond lengths (Å) and angles (°) for MCz. Supporting Table S12: Anisotropic displacement parameters (Å^2^ x 10^3^) for MCz. The anisotropic displacement factor exponent takesthe form: ‐2π^2^[ h^2^a^2^U^11^ + … + 2 h k a b U^12^ ]. Supporting Table S13: Geometric parameters of the CH‒π hydrogen bonds of MCz. H‒X is the average distance between thehydrogen atom and the centroid of the neighboring aromatic ring. H‒Y is the average distance between the hydrogenatom and its projection to the plane formed by the neighboring carbazole moiety, θ is the angle between the normal vectorof the plane and the hydrogen‐to‐ring centroid vector, Δδ is the difference in chemical shift between the peak in ^1^H NMRof the corresponding proton of MCz compared to the equivalent proton in MF.

Conflicts of Interest

The authors declare no conflicts of interest.

Supporting information

Supplementary Material