| Autor: |
Van Heuvelen KM; Department of Chemistry, Harvey Mudd College, 301 Platt Blvd, Claremont, CA 91711, USA., Lee I; Department of Chemistry, Harvey Mudd College, 301 Platt Blvd, Claremont, CA 91711, USA., Arriola K; Department of Chemistry, Harvey Mudd College, 301 Platt Blvd, Claremont, CA 91711, USA., Griffin R; Department of Chemistry, Harvey Mudd College, 301 Platt Blvd, Claremont, CA 91711, USA., Ye C; Department of Chemistry, Harvey Mudd College, 301 Platt Blvd, Claremont, CA 91711, USA., Takase MK; Beckman Institute, California Institute of Technology, 1200 E. California Blvd, Pasadena, CA 91125, USA. |
| Abstrakt: |
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 = 3/2 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. |
