Molecular structures of cobalt complexes of 2-aza-2-[p-methylbenzyl]-5,10,15,20-tetraphenyl-21-carbaporphyrin: [Co(2-NCH2-p-C6H4CH3-21-m-CH2C6H4CH3NCTPP)L] (L = Cl−, N*CS−).

Two experimentally well characterized four-coordinate complexes of the general formula [Co(2-NCH 2 - p -C 6 H 4 CH 3 -21- m -CH 2 C 6 H 4 CH 3 NCTPP)L] (with L = Cl − and N*CS − for 3 and 4 ) are considered for this study. The crystal structures of the paramagnetic chloro(2-aza-2-[ p -methyl benzyl]-5,10,15,20-tetraphenyl-21- m -xylyl-21-carbaporphyrinato-N,N′,N″) cobalt(II) octane solvate [Co(2-NCH 2 - p -C 6 H 4 CH 3 -21- m -CH 2 C 6 H 4 CH 3 NCTPP)Cl]·0.5C 8 H 18 ( 3 ·0.5 C 8 H 18 ) and thiocyanato-N-(2-aza-2-[ p -methylbenzyl]-5,10,15,20-tetraphenyl-21- m -xylyl-21-carbaporphyrinato-N,N′,N″) cobalt(II) [Co(2-NCH 2 - p -C 6 H 4 CH 3 -21- m -CH 2 C 6 H 4 CH 3 NCTPP)(NCS)] ( 4 ) were established. The geometry around the Co 2+ ion in 3 ·0.5 C 8 H 18 (or 4 ) is a distorted tetrahedron, with C 2v symmetry. The magnitude of the zero-field splitting (ZFS) parameter (D) was reported to change from 44.5 cm −1 in 3 to 30.0 cm −1 in 4 through DC magnetic susceptibility determinations. The | D | value can be related to the magnitude of the ligand-field splitting parameter of the axial k-donating Cl − ligand of 3 and the axial π-accepting NCS − ligand of 4 at the cobalt sites. [ABSTRACT FROM AUTHOR]