Reactivity of the Inversely Polarized Phosphaalkene HPC(NMe₂)₂Toward Carbene Tungsten Complexes [(CO)₅WC(R¹)OR²] (R¹=c-C₃H₅,c-C₅H₉; R²= Me, Et, Me₃Si):  A Novel Access to η¹-Phosphaalkene Complexes [(CO)₅W−P(R²)C(H)NMe₂]

Abstract

Reaction of equimolar amounts of the phosphaalkene HPdC(NMe 2 ) 2 (6c) and carbene complex [(CO) 5 WdC(OSiMe 3 )(c-C 3 H 5 )] (11a) in n-pentane afforded the novel phosphaalkene complex [(CO) 5 W-κ-P{Me 3 SiPdC(H)NMe 2 }] (12). Under comparable conditions carbene complexes ,c). In contrast with this, treatment of [(CO) 5 WdC(OEt)(c-C 5 H 9 )] (11d) with XPdC(NMe 2 ) 2 (X ) H, D) gave rise to the formation of a bis(pentacarbonyltungsten) complex of a PH-functionalized 1,3-diphosphetane [{(CO) 5 W} 2 -κ-P{HP-C(X)(NMe 2 )-P(H)-C(X)NMe 2 }] (14). The novel products were characterized by elemental analyses and IR and 1 H, 13 C, and 31 P NMR spectra. Moreover, the molecular structures of 12, 13c, and 14 were elucidated by X-ray structural analyses.

From P‐Functional Thiazol‐2‐thione Derivatives to Phosphaalkenes

“…This assignment is further supported by a comparison with NMR data of the head‐to‐head dimer of W(CO) 5 (PhP=CMe 2 ) ( IV ) (Figure ) showing a doublet for the C Me 2 nuclei (36.9 ppm, d, 1 J P,C = 28.2 Hz). So far, there is only one report of a dinuclear 1,3‐diphosphetane tungsten(0) complexes having P ‐alkyl substituents (complexes V , R = Me, Et) (Figure ) which has 31 P resonances at 8.9 (R = Me) ( 1 J W,P = 188.2 Hz) and 51.1 ppm (R = Et) ( 1 J W,P = 218.1 Hz). But most importantly, derivatives V possess 13 C{ 1 H} NMR features of the NMe 2 ‐substituted ring carbon nuclei [60.5 (R = Me) and 62.7 (R = Et) ppm] displaying both a triplet splitting pattern ( 1 J P,C = 29.7 Hz and 28.7 Hz, respectively).…”

13 Chromium, molybdenum, and tungsten

“…3 H 5 , c-C 5 H 9 ; R2 ~Me, Et, Me 3 Si) has been studied. 148 These studies revealed a novel synthetic protocol to access g 1 -phosphaalkene complexes of the type [(CO) 149 The electron-rich carbene carbons in these complexes show some of the most highly shielded values of dC carbene so far observed. Facile migration of tungsten pentacarbonylmetal fragments W(CO) 5 in carbene complexes have produced mono-and bi-nuclear 3-amino cyclobuten-2-one complexes (Fig.…”

Phospha‐ and Arsaalkenes RE=C(NMe2)2 (E = P, As) as Novel Phosphinidene‐ and Arsinidene‐Transfer Reagents

“…Scheme 47. In contrast to this, cyclopropyl(methoxy)-and cyclopropyl(ethoxy)carbene complexes 115b and 115c were converted by HP=C(NMe 2 ) 2 (82g) into the 1,3-bis(pentacarbonyltungsten)-1,3-diphosphetane complexes 117b and 117c, which separated from pentane solutions at -16°C as yellow-to-orange crystals in 60 % and 72 % yields, respectively. [66] In many cases 1,3-diphosphetanes result from a [2+2] head-to-tail dimerization of relatively unhindered phosphaalkenes. Accordingly, it is most likely that phosphaalkene complexes analogous to 116 were initially generated and subsequently suffered from self-dimerization [66] (Scheme 48).…”

“…[66] In many cases 1,3-diphosphetanes result from a [2+2] head-to-tail dimerization of relatively unhindered phosphaalkenes. Accordingly, it is most likely that phosphaalkene complexes analogous to 116 were initially generated and subsequently suffered from self-dimerization [66] (Scheme 48). Cyclopentyl(ethoxy)carbene complex 115d and XP=C(NMe 2 ) 2 (X = H, D) did not react to afford the expected 1,3-diphosphetane 117c.…”