# Discrete Heterotrimetallic Assemblies Based on Rod‐Shaped FeII‐Metalloligands and a ZnII‐Porphyrin/RuII‐Metallacycle

## TL;DR

Scientists developed a new method to build stable, complex metal structures using iron, zinc, and ruthenium components.

## Contribution

A novel strategy for constructing stable, discrete heterotrimetallic porphyrin assemblies using FeII-metalloligands and ZnII-porphyrin/RuII-metallacycles.

## Key findings

- The use of FeII-metalloligands improves the stability of the assemblies, enabling solution-based characterization.
- Single crystal X-ray structures revealed strict mutual control over geometrical parameters in the assemblies.

## Abstract

An efficient strategy for the preparation of heterometallic discrete porphyrin assemblies, tuned both in dimensions and number of metal centers, is described. Five rod‐shaped di‐pyridyl FeII‐metalloligands, with varied length (1.5 – 3.2 nm), lateral substituents, and number of iron centers, were used to bridge two RuII‐metallacycles, made of two coplanar ZnII‐porphyrin each. The resulting architectures consist of four RuII complexes, four zinc‐porphyrins, and either two or four FeII‐clathrochelate units. Earlier, geometrically similar sandwich‐like architectures were based on purely organic connectors. Among other novel characteristics, the use of metalloligands was found to be beneficial for the overall stability, thus allowing for a solution‐based characterization of the assemblies. Single crystal X‐ray structures were determined for the complete collection, highlighting additional key features: the two facing ZnII‐porphyrin platforms are set wide apart according to the span of the two connecting metalloligands, while the latter are parallelly aligned by the anchoring ZnII‐porphyrin/RuII‐metallacycles, at fixed inter Fe··Fe distance(s). Mutual control over these geometrical parameters is very strict, as evidenced by self‐sorting experiments. Useful implementation of these systems into functional systems may be envisaged by pairing the peripheral metalloporphyrin photosensitizers with photo/redox/catalytically active inner metal cores.

Modular self‐assembly of extendable porphyrin‐based heterotrimetallic discrete architectures: a new efficient strategy toward the construction of stable multicomponent functional systems.