REACTION OF 2-((ALPHA-R-BENZYLIDENE)AMINO)PYRIDINES [R = CH3, 4-(CH3O)C6H4] WITH RHCL(L)3 OR RH2CL2(CO)4 - FORMATION AND STRUCTURE OF A RHODIUM(II) DIMER

The reaction of 2-((α-methylbenzylidene)amino)pyridine (L1) with RhCl(PPh3)3 resulted in the formation of cis-[Cl(PPh3)2(L1)RhI]-S (1, S = solvent). The reaction of 2-[(α -(4-methoxyphenyl)benzylidene)-amino]pyridine (L2) with Rh2Cl2(CO)4 (4) under identical conditions resulted in the formation of cis-[Cl(CO)2(L2)RhI] (2). The ligand L1, when treated with the same Rh complex 4 at 90 °C in an autoclave for 18 h resulted in the formation of [Cl(CO)(L1-H)RhII]2 (3), where the benzene ring of the ligand was ortho-metalated to rhodium. Compound 1 crystallized in the triclinic space group PI with Z = 2 and lattice parameters a = 10.9817 (8), b = 12.2447 (12), c = 17.800 (3) Å, α = 94.221 (10), β = 101.770 (9), γ= 92.022 (7)°, V = 2333.8 (4) Å3; final Rw = 3.6%. Compound 2 crystallized in the monoclinic space group P21/c with Z = 4 and lattice parameters a = 10.845 (6), b = 11.161 (6), c = 17.161 (9) Å, β = 86.61 (1)°, V = 2073.58 Å3; final Rw = 4.9%. Compound 3 crystallized in the monoclinic space group P2x/c with ? = 4 and lattice parameters a = 8.0708 (16), b = 20.907 (6), c = 16.373 (2) Å, β = 90.078 (14)°, V = 2762.6 (1.0) Å3; final Rw = 3.2%. The structures of the complexes reported are compared and contrasted with analogous complexes of rhodium. © 1990, American Chemical Society. All rights reserved.