η¹-Ligation versus Pnictogen−Carbon Double Bond Cleavage:  The Contrasting Behavior of Phospha- and Arsaalkenes [Tp*(CO)₂M⋮C−EC(NMe₂)₂] [E = P, As; M = Mo, W; Tp* = HB(3,5-Me₂pz)₃] toward [Au(CO)Cl]

Abstract

Reaction of [Tp*(CO) 2 MtC-PdC(NMe 2 ) 2 ] [1a, M ) Mo; 1b, W; Tp* ) HB(3,5-Me 2 pz) 3 ] with 2 molar equiv of [Au(CO)Cl] afforded the trinuclear complexes [Tp*(CO) 2 MtC-P(AuCl) 2 C(NMe 2 ) 2 ] 2a (M ) Mo) and 2b (M ) W). In marked contrast to this the arsenic analogues [Tp*(CO) 2 MtC-AsdC(NMe 2 ) 2 ] (3a, M ) Mo; 3b, M ) W), when treated with the gold complex, give rise to AsdC cleavage with formation of the gold carbene complex [ClAuC-(NMe 2 ) 2 ] (5) and the functionalized cyclotriarsanes [{Tp*(CO) 2 MtC-As} 3 ] 4a (M ) Mo) and 4b (M ) W). Compounds 2a,b and 4a,b have been characterized by IR and 1 H and 13 C NMR spectroscopy. In addition, the molecular structures of 2a, 2b, and 5 have been determined by single-crystal X-ray structural analyses.

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 previously observed transition-metal-induced cleavages of inversely polarised arsaalkenes to give cyclotriarsanes, [18] an η 2 -diarsene complex [19] or η 3 -1-arsa-2-phosphaallyl complexes [9] were extended to the smooth generation of η 2 -1-arsaallene complexes 13, 14 and 15, which underline the ability of arsaalkenes to act as convenient sources for arsanediyl (arsinidene) units under mild conditions.…”

Reactivity of the Inversely Polarized Arsaalkenes R–As=C(NMe2)2 {R = [(η5‐C5Me5)(CO)2Fe], tBuC(O), 4‐Et–C6H4C(O)} towards Phosphavinylidene Complexes [η5‐(C5H5)(CO)2M=P=C(SiMe3)2] (M = Mo, W)

“…Transition-metal-induced cleavages of inversely polarized arsaalkenes to give cyclotriarsanes [35] or an η 2 -diarsene complex [36] were observed. Here the smooth generation of η 3 -2-phospha-1-arsaallyl complexes 4a, 5a, 5b, and complex 6 featuring the 1,2,4-oxaphospharsolenium ligand underlines the ability of arsaalkenes to act as convenient sources for arsanediyl (arsinidene) units under mild conditions.…”

Aryl-substituted Triarsiranes: Synthesis and Reactivity

“…[8] In addition, a metal-carbine-substituted triarsirane [Tp*(CO) 2 M≡C−As] 3 (M = Mo, W; Tp* = HB(3,5-Me 2 pz) 3 ; Figure 1, E) was afforded, in the cyclo-trimerization of arsanediyls of the type [Tp*(CO) 2 M≡C−As]. [9] Recently, Kilian and co-workers constructed stable arsanylidenephosphoranes through peri-substitution of an acenaphtene-unit. [10] Upon exposure to oxygen, the intramolecular phosphine-stabilization is removed and the free arsinidenes oligomerize to afford the respective cyclic tri-and tertraarsanes ( Figure 1, F).…”