Premium
Crystal structure and spectroscopic characterization of a cobalt(II) tetraazamacrocycle: completing a series of first‐row transition‐metal complexes
Author(s) -
Van Heuvelen Katherine M.,
Lee Isabell,
Arriola Katherine,
Griffin Rilke,
Ye Christopher,
Takase Michael K.
Publication year - 2017
Publication title -
acta crystallographica section c
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.304
H-Index - 17
ISSN - 2053-2296
DOI - 10.1107/s2053229617010397
Subject(s) - cobalt , crystallography , chemistry , crystal structure , ligand (biochemistry) , transition metal , chloride , square pyramidal molecular geometry , density functional theory , spin states , metal , stereochemistry , inorganic chemistry , computational chemistry , organic chemistry , catalysis , biochemistry , receptor
The tetraazamacrocyclic ligand 1,4,8,11‐tetramethyl‐1,4,8,11‐tetraazacyclotetradecane (TMC) has been used to bind a variety of first‐row transition metals but to date the crystal structure of the cobalt(II) complex has been missing from this series. The missing cobalt complex chlorido(1,4,8,11‐tetramethyl‐1,4,8,11‐tetraazacyclotetradecane‐κ 4 N )cobalt(II) chloride dihydrate, [CoCl(C 14 H 32 N 4 )]Cl·2H 2 O or [Co II Cl(TMC)]Cl·2H 2 O, crystallizes as a purple crystal. This species adopts a distorted square‐pyramidal geometry in which the TMC ligand assumes the trans ‐I configuration and the chloride ion binds in the syn ‐methyl pocket of the ligand. The Co II ion adopts an S = spin state, as measured by the Evans NMR method, and UV–visible spectroscopic studies indicate that the title hydrated salt is stable in solution. Density functional theory (DFT) studies reveal that the geometric parameters of [Co II Cl(TMC)]Cl·2H 2 O are sensitive to the cobalt spin state and correctly predict a change in spin state upon a minor perturbation to the ligand environment.