ic301208d_si_001.cif (218.98 kB)
Group 14 Metal Terminal Phosphides: Correlating Structure with |JMP|
dataset
posted on 2012-09-03, 00:00 authored by Eric C.
Y. Tam, Nicola A. Maynard, David C. Apperley, J. David Smith, Martyn P. Coles, J. Robin FultonA series of heavier group 14 element, terminal phosphide
complexes,
M(BDI)(PR2) (M = Ge, Sn, Pb; BDI = CH{(CH3)CN-2,6-iPr2C6H3}2;
R = Ph, Cy, SiMe3) have been synthesized. Two different
conformations (endo and exo) are
observed in the solid-state; the complexes with an endo conformation have a planar coordination geometry at phosphorus (M
= Ge, Sn; R = SiMe3) whereas the complexes possessing an exo conformation have a pyramidal geometry at phosphorus.
Solution-state NMR studies reveal through-space scalar coupling between
the tin and the isopropyl groups on the N-aryl moiety
of the BDI ligand, with endo and exo exhibiting different JSnC values. The
magnitudes of the tin–phosphorus and lead–phosphorus
coupling constants, |JSnP| and |JPbP|, differ significantly depending upon the
hybridization of the phosphorus atom. For Sn(BDI)(P{SiMe3}2), |JSnP| is the largest
reported in the literature, surpassing values attributed to compounds
with tin–phosphorus multiple-bonds. Low temperature NMR studies
of Pb(BDI)(P{SiMe3}2) show two species with
vastly different |JPbP| values, interpreted
as belonging to the endo and exo conformations, with sp2- and sp3-hybridized
phosphorus, respectively.
