Reactions of [RhCl(diene)]2with Bi- and Terdentate Nitrogen Ligands. X-ray Structures of Five-Coordinate Complexes

Abstract

Reaction of [RhCl(diene)]2 (diene = 1,5-cyclooctadiene (COD) or bicyclo[2.2.1] hepta-2,5-diene (NBD)) with the N−N−N nitrogen ligands 2,6-(C(R1)N−R2)2C5H3N in CD2Cl2 or CH2Cl2 yielded the five-coordinate complexes [RhCl(2,6-(C(H)N−R2)2C5H3N)(diene)] (diene = NBD; R2 = i-Pr, t-Bu, and p-anisyl), which has been isolated for NBD but not for COD. A single-crystal X-ray determination showed that [RhCl(2,6-(C(H)N−p-anisyl)2C5H3N)(NBD)] has a distorted trigonal bipyramidal configuration with the pyridyl N-atom, one imine N-atom, and one alkene double bond in the equatorial plane, while the second alkene bond and the chloride atom occupy the axial positions. This conformation containing one noncoordinated imine moiety is clearly retained at 183 K in CD2Cl2, as is also the case for the other complexes. For the COD complexes, the reaction is more complicated, as the intermediates that are observed depend on the substituents R1 and R2 of the N−N−N nitrogen ligand. The five-coordinate complexes [RhCl(2,6-(C(R1)N−R2)2...