Bimetallic Copper/Ruthenium/Osmium Complexes: Observation of Conformational Differences Between the Solution Phase and Solid State by Atomic Pair Distribution Function Analysis

Abstract

High-energy X-rays cattering and pair distribution function analysis (HEXS/PDF) is apowerfulmethod to reveal the structure of materials lackingl ong-range order,b ut is underutilized for molecular complexes in solution. We demonstrate the application of HEXS/PDF with 0.26 resolution to uncover the solution structure of five bimetallic Cu I /Ru II /Os II complexes.H EXS/PDF of each complex in acetonitrile solution confirms the pairwise distances in the local coordination sphere of each metal center as well as the metal•••metal distances separated by over 12 .T he metal•••metal distance detected in solution is compared with that from the crystal structure and molecular models to confirm that distortions to the metal bridging ligand are unique to the solid state.T his work presents the first example of observing sub-ngstrçm conformational differences by direct comparison of solution phase and solid-state structures and shows the potential for HEXS/PDF in the determination of solution structure of single molecules.

Photochemical charge accumulation in a heteroleptic copper(i)-anthraquinone molecular dyad via proton-coupled electron transfer

“…62–64 In addition, the almost identical oxidation potential found in both complexes indicates that the Cu centers of Cu + -AnQ and Cu + -DPPZ have similar electronic structure, which is attributed to the negligible electronic influence from the anthraquinone moiety due to the long distance between the Cu center and anthraquinone moiety. Such weak electronic coupling has been observed in other Ru/Os/Cu bimetallic complexes with two metals bridged by TPPHZ-like ligands; 62,65 this further exemplifies that although the π-electrons in the ring system might act as a “wire” for excited state electron transfer, the ground state electronic environment of the metal center remains relatively localized at the first and second coordination sphere.…”

Enhanced Visible Light Absorption in Heteroleptic Cuprous Phenanthrolines

“…This platform facilitates a facile pathway for obtaining heteroleptic Cu­(I) complexes with the generic formula [Cu­(mesPhen)­(L)] + , where L is a second and distinct phenanthroline ligand (Chart ). The secondary phenanthroline moiety can be systematically varied to impart desired photophysical and electrochemical properties. ,− Optically and electronically tuned HETPHEN Cu­(I) complexes have been designed to feature bulky substituents to limit the distortion similar to numerous homoleptic complexes , and have incorporated phenyl groups at the 4,7-positions to increase the absorbance cross-section in the visible MLCT region by promoting π-delocalization of the charge-transfer excited state to increase oscillator strength. ,,− …”