Preparation and characterization of [M III(SeCH 2CH 2NH 2){N(CH 2CH 2NH 2) 3}] 2+ (M III = Co, Rh) and molecular structure of the perchlorate of the rhodium(III) complex

Abstract

By reaction of [RhCl 2(tren)] + (tren = tris(2-aminoethyl)amine) with CH 3SeCH 2CH 2NH 2 in water in the presence of NaBH 4, or in its absence in ethanol, only one of the two geometrical isomers of [Rh(SeCH 2CH 2NH 2)(tren)] 2+ was formed. Both of the two geometrical isomers of the corresponding Co III complex were formed by the reaction of Co II-tren species with (NH 2CH 2CH 2Se–) 2. The structure of the Rh III complex was determined by the X-ray method. Crystal data [Rh(C 2H 6NSe)(C 6H 18N 4)](ClO 4) 2, monoclinic, space group P2 1/ c, a = 9.012(1), b = 14.438(1), c = 14.550(4) Å, β = 104.81(1)°, and Z = 4. The final R value was 0.026. The complex ion has a distorted octahedral structure with cis(tertiary amine nitrogen, Se) configuration. The RhN bond length for the amine nitrogen bonded trans to the selenium atom is longer by 0.039(6) Å than the average cis RhN distance for the two other primary amine nitrogen of the tren ligand, indicating rans influence of the selenium atom.