The chelating bis(phosphine) 3,5-bis((diphenylphosphino)methyl)pyridin
e (dppLH, 9) was synthesized from 3,5-lutidine by radical chlorination
, followed by reaction with LiPPh(2). Compound 9 was used to prepare P
h and Pd complexes. The three complexes (dppL)RhL (L = (PPr3)-Pr-r (11
), PPh(3) (12), and CO (13)) are obtained from Rh-2-Cl-2(COE)(4) (COE
= cyclooctene) and HRh(PPh(3))(4). Compound 9 reacts with (PhCN)(2)PdC
l2 to form the Pd(II) complex (dppL)PdCl (14). All complexes are fully
characterized. The X-ray crystal structure of 11 has been determined.
It crystallizes in the triclinic space group <P(1)over bar> (No. 2) w
ith a = 12.242(3) Angstrom, b = 14.384(3) Angstrom, c = 11.653(2) Angs
trom, alpha = 98.61(2)degrees, beta = 96.88(2)degrees, gamma = 106.38(
2)degrees, V = 2023.3(8) Angstrom(3), Z = 2, R = 0.045, and R(W) = 0.0
52. The Rh(I) center is in a square-planar coordination environment wi
th the two phosphines of the dppL Ligand framework being trans to each
other. The pyridine nitrogen is unobstructed and available for bindin
g to other metal centers. Compound 14 acts as a metalloligand toward P
d(II) centers to form the trinuclear complex {(dppL)PdCl}2PdCl2 (16).
N-coordination of a metal moiety and of a Lewis acid influences the el
ectronic properties on the Pd center.