Synthesis, single crystal X-ray, and DFT study of new hybrid-ligand complex [Cu(hfac)2(Me3TTF-CH=CH-Pyr)] and new mixed-valence radical ion salt (Me3TTF-CH=CH-Pyr)2(PF6)3

Abstract

This paper presents a comprehensive study that combines experimental techniques and Density Functional Theory (DFT) to investigate a newly synthesized mixed-ligand complex, [Cu(hfac)2(Me3TTF-CH=CH-Pyr)] (where hfac is hexafluoroacetylacetonate), and a novel mixed-valence radical ion salt (Me3TTF-CH=CH-Pyr)2(PF6)3. Both are constructed using ligands derived from the tetrathiafulvalene (TTF) donor molecule. These materials are meticulously characterized through single-crystal X-ray diffraction analysis. The complex crystallizes in the monoclinic system, specifically in the C2/c space group, with the following lattice parameters: a = 24.583(2) Å, b = 21.613(2) Å, c = 14.2066(13) Å, β = 99.789(5)°, and a volume of V = 7438.3(12) Å3. It exhibits five-coordinate behavior, forming a slightly distorted pyramid with a square base. The paper also provides a detailed account of the crystal structures and reports spectroscopic study results. Electrochemical behavior is explored through cyclic voltammetry in CH2Cl2 as the solvent. Additionally, the reactivity of these compounds is predicted using various theoretical tools, such as Local and Global reactivity descriptors, Hirshfeld charge analyses, and Molecular Electrostatic Potential. To elucidate charge transfer processes, Time-Dependent Density Functional Theory is utilized. Various types of interactions are analyzed through the Quantum Theory of Atoms in Molecules and Non-Covalent Interaction analyses. Finally, conductivity is estimated using frontier molecular orbitals (FMO) and gap energies as crucial parameters.