η²-Alkynyl and Vinylidene Transition Metal Complexes. 6.¹ Reaction of Tungsten Vinylidene Complexes with Chlorophosphines as Nucleophile. Preparation and Crystal Structural Analysis of Neutral η²-Phosphinovinyl Complexes

Abstract

The reaction of vinylidene complexes [(η 5-C5H5)(CO)(NO)WCCHR] [R = H (1a), CH3 (1b), C6H5 (1c)] with chlorodiphenylphosphine (2) leads to neutral [R = H (3a), CH3 (3b), C6H5 (3c)]. Analogously the reaction of chlorodi-tert-butylphosphine (4) with [(η 5-C5H5)(CO)(NO)WCCH2] (1a) gives rise to chloro(η 5-cyclopentadienyl)nitrosyl(η 2-di-tert-butylphosphinovinyl)tungsten (5). The formation of these metallacyclopropane rings is rationalized by the nucleophilic attack of chlorophosphine on the Cα carbon of the vinylidene, followed by substitution of the carbonyl ligand. Single-crystal X-ray diffraction data of 3a−c and 5 are reported.

Reactivity of the Inversely Polarised Arsaalkenes R–As=C(NMe2)2 {R = [(η5‐C5Me5)(CO)2Fe], tBuC(O)} Towards Vinylidene Complexes [η5‐(C5H5)(CO)(NO)W=C=C(H)R] (R = Ph, tBu)

“…The signal of the hydrogen atom at the C=C double bond was observed as a singlet at δ = 5.65 ppm. 13 C NMR singlets at δ = 140.6 and 118.8 ppm are due to the carbon atoms β-C and γ-C, respectively, of this double bond. A 13 C NMR singlet at δ = 233.2 ppm is attributed to the carbonyl ligand.…”

“…13 C NMR singlets at δ = 140.6 and 118.8 ppm are due to the carbon atoms β-C and γ-C, respectively, of this double bond. A 13 C NMR singlet at δ = 233.2 ppm is attributed to the carbonyl ligand. This resonance is markedly low-field shifted in comparison to those of precursor 10b and complex 15, which reflects the pronounced donor capacity of the aminocarbene ligand.…”

“…In the precursor molecule 10a the protons of the C 5 H 5 ring are much more deshielded (δ = 5.81, 5.83 ppm), whereas the signal of the hydrogen atom at the vinylidene unit was observed at significantly higher field (δ = 5.69, 5.73 ppm). In the 13 C{ 1 H} NMR spectrum of 13, singlets at δ = 174.8 and 158.3 ppm were assigned to the carbon atoms in β and α positions, respectively, of the arsaallene ligand. In 10a these carbon atoms give rise to resonances at δ = 139.5, 140.0 and 338.4, 338.7 ppm.…”

“…The strong high-field shift of the α-C signal in going from 10a to 13 points to the η 2 -ligation of the As=C bond to the metal atom. The 13 C NMR signals of the terminal CO ligand and the acylic carbonyl group were observed at δ = 216.7 and 227.5 ppm, respectively. The significant low-field shift of the resonance of the CO ligand compared to precursor 10a (δ = 210.8, 211.8 ppm) points to an improved donor capacity of the heteroallene ligand over the vinylidene system.…”

“…The analysis ( Figure 1, Table 1) displays a molecule with a distorted piano-stool geometry [As (1) The bond length W(1)-C(7) is comparable to that in complex 19 [2.178(7) Å] [13] but much smaller than in the (η 3 -2-phospha-1-arsaallyl)tungsten complex 7d [2.439(2) Å].…”