ChemInform Abstract: Electronic Structure of Cobalt Phthalocyanine: A Charge Density Study.

Abstract

A charge density study of cobalt(II) phthalocyanine based upon 12,163 unique reflections within a (sin /theta/)//lambda/ range 0-10.8 nm/sup /minus/1/, collected by X-ray diffraction at 115 K, was performed. The data was modeled by a conventional multipole analysis as well as by a valence orbital population analysis. When the latter approach was used and data was employed to a (sin /theta/)//lambda/ limit of 8.2 nm/sup /minus/1/, a value of 0.031 was obtained for R/sub w/(I) and 0.015 for R(F). The deformation density maps show bond-centered peaks and lone-pair peaks of ca. 500 e nm/sup /minus/3/ within the phthalocyanine ligand molecule, such as are typical of most good light-atom charge density studies. The rearrangement of the electron density around the cobalt atom is substantial, both in angular function and in radial extent, and suggests a depletion and contraction of the 3d orbitals, combined with a population of more diffuse cobalt-based functions. The valence orbital population analysis quantifies the suggestion, giving a total 3d population of 4.9 (1)e with a radius reduced 35% from the free ion value and a diffuse population (modeled as 4p) of 2.6 (1)e. Those populations are strongly anisotropic: 3d/sub x/sup 2/-y/sup 2///sup 0.0/3d/sub xz,yz//sup 2.4/3d/sub z/sup 2///supmore » 0.8/3d/sub xy//sup 1.8/4p/sub z//sup 1.1/4p/sub xy//sup 1.4/. There seems to be little charge flow from the ligand to the metal atom (0.5 (1)e), but the bonding is obviously quite covalent in character. This is manifest in the distribution of charge between the 3d /pi/ and /sigma/ systems and the diffuse outer regions of the cobalt atom.« less