Triple bonding to germanium: Characterization of the transition metal germylynes (eta(5)-C5H5)(CO)(2)M Ge-C6H3-2,6-MeS2 (M = Mo, W; Mes = -C6H2-2,4,6-Me-3) and (eta(5)-C5H5)(CO)(2)M Ge-C6H3-2,6-Trip(2) (M = Cr, Mo, W; Trip-C6H2-2,4,6-i-Pr-3) and the related single bonded metallogermylenes (eta(5)-C5H5)(CO)(3)M-Ge-C6H3-2,6-Trip(2) (M = Cr, W)
Lh. Pu et al., Triple bonding to germanium: Characterization of the transition metal germylynes (eta(5)-C5H5)(CO)(2)M Ge-C6H3-2,6-MeS2 (M = Mo, W; Mes = -C6H2-2,4,6-Me-3) and (eta(5)-C5H5)(CO)(2)M Ge-C6H3-2,6-Trip(2) (M = Cr, Mo, W; Trip-C6H2-2,4,6-i-Pr-3) and the related single bonded metallogermylenes (eta(5)-C5H5)(CO)(3)M-Ge-C6H3-2,6-Trip(2) (M = Cr, W), J AM CHEM S, 122(4), 2000, pp. 650-656
The synthesis and characterization of several m-terphenyl stabilized germyl
yne transition metal complexes and related metallogermylenes are reported.
The reaction of Na[M(eta(5)-C5H5)(CO)(3)] (M = Cr, or W) with Ge(Cl)C6H3-2,
6-Trip(2) (Trip = -C6H2-2,4,6-i-Pr-3) below room temperature affords the me
tallogermylenes (eta(5)-C5H5)(CO)(3)M-Ge-C6H3-2,6-Trip(2) (M = Cr, 1; W, 5)
. However, for the analogous reaction with Na[Mo(eta(5)-C5H5)(CO)(3)], the
metallogermylene was not isolated. Instead, the germylyne complex (eta(5)-C
5H5)(CO)(2)Mo drop Ge-C6H3-2,6-Trip(2) (3) was obtained directly with elimi
nation of carbon monoxide. The corresponding chromium and tungsten compound
s (eta(5)-C5H5)(CO)(2)M drop Ge-C6H3-2,6-Trip(2) (M = Cr, 2; W, 6) could be
obtained by refluxing 1 or 5 in toluene or by photolysis. The related germ
ylyne (eta(5)-C5H5)(CO)(2)W drop Ge-C6H3-2,6-Mes(2) (7), as well as the rec
ently reported molybdenum analogue (eta(5)-C5H5)(CO)(2)Mo drop Ge-C6H3-2,6-
Mes(2) (4), which was the first example of a triply bonded germanium specie
s? are also described. All compounds were characterized by H-1 and C-13 NMR
, UV-vis, and IR spectroscopy, and by 6, H analysis. The X-ray crystal stru
ctures of 1-3, 5, and 7 have also been determined. The M drop Ge (M = Cr, M
o, W) triple bonds in the germylynes are typically ca. 0.4 ti shorter than
the hl-Ge single bonds in the metallogermylenes. In addition, angles at ger
manium in the germylynes are nearly linear (range 170.9(3)-175.99(6)degrees
) whereas in the metallogermyleness the corresponding angles are 114.7(6) a
nd 117.8(2)degrees, consistent with the presence of a lone pair at germaniu
m. The synthesis of the series of compounds 1-7 has enabled, for the first
time, a comparison of single and triple bond lengths between closely relate
d species involving the same coordination number and substituents at the he
avier group 14 element.