DFT Studies of Dimethylaminophenyl-Substituted Phthalocyanine and Its Silver Complexes

TL;DR

This study uses quantum calculations to explore the electronic properties of a silver phthalocyanine compound and its role in forming silver/polymer nanocomposites.

Contribution

The paper identifies new reaction intermediates and validates the electronic structure of a previously inferred unstable species using quantum chemical calculations.

Findings

The unstable 3[dmaphPcAg]+ species was confirmed through calculations.

Both 1[dmaphPcAg]− and 3[dmaphPcAg]− intermediates coexist in reaction solutions.

Silver nanoparticle formation is energetically and structurally less favorable in the proposed mechanism.

Abstract

The dimethylaminophenyl-substituted silver phthalocyanine [dmaphPcAg] can be used as a UV-vis photoinitiator for in situ preparation of a silver/polymer nanocomposite. To verify early steps of the supposed mechanism of radical polymerization, we performed quantum chemical calculations of m[dmaphPcAg]q complexes with charges q = +1 to −2 in the two lowest spin states m, of a free ligand and its dehydrogenated/deprotonated products m[dmaphPcHn]q, n = 2 to 0, q = 0, −1 or −2, in the lowest spin states m. The calculated electronic structures and electron transitions of all the optimized structures in CHCl3 solutions are compared with experimental EPR and UV-vis spectra, respectively. The unstable 3[dmaphPcAg]+ species deduced only from previous EPR spin trap experiments was identified. In addition to 2[dmaphPcAg]0, our results suggest the coexistence of both reaction intermediates 1[dmaphPcAg]− and 3[dmaphPcAg]− in reaction solutions. Silver nanoparticle formation is a weak point of the supposed reaction mechanism from the energetic, stereochemistry, and electronic structure points of view.

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