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)

Abstract

The reaction of the phosphavinylidene complexes [Cp(CO)2M=P=C(SiMe3)2] [Cp = C5H5, M = Mo (2), W (3)] with the ferrioaarsaalkene [Cp*(CO)2Fe–As=C(NMe2)2] (1a) (Cp* = C5Me5) afforded the novel η3‐2‐phospha‐1‐arsaallyl complexes [η3‐{[Fe]–As–P–C(SiMe3)2}M(CO)2Cp] {M = Mo, [Fe] = [Cp*(CO)2Fe] (4a);W (5a)}. Similarly, treatment of equimolar amounts of 3 with arsaalkene tBu–C(O)–As=C(NMe2)2 (1b) gave rise to the formation of [η3‐{tBuC(O)–As–P–C(SiMe3)2}W(CO)2Cp] (5b) by an arsinidene transfer process. In contrast to this, the more reactive arsaalkene 4‐Et–C6H4C(O)–As=C(NMe2)2 (1c) and complex 3 underwent reaction to give the cyclic phosphenium complex [Cp(CO)2W=P–O–Ca(4‐Et–C6H4)=As–Cb(SiMe3)2(P–Cb)] (6). The novel compounds 4a, 5a, 5b, and 6 were characterized by elemental analyses and by means of spectroscopy (IR, 1H, 13C, 31P NMR). Moreover, the molecular structures of 4a, 5b, and 6 were elucidated by X‐ray diffraction analyses.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)

Synthesis of the η2‐1‐Phosphaallene Complexes [(η5‐C5H5)(CO)(NO)W{η2‐R1P=C=C(R2)H}] (R1 = tBu, Cy; R2 = Ph, H) from [(η5‐C5H5)(CO)(NO)W=C=C(R2)H] (R2 = Ph, H) and Inversely Polarized Phosphaalkenes R1P=C(NMe2)2 (R1 = tBu, Cy), and Their Structure

“…The analysis (Figure 1 [13] but much smaller than in the (η 3 -2-phospha-1-arsaallyl)tungsten complex 20 [2.439(2) Å]. [6] Thus, the situation of a π complex involving the W atom and the P=C double bond is not reflected satisfactorily by the structural data of 14. Moreover, inspection of the W=C bond lengths in a series of carbene-tungsten complexes [1.859(4)-2.23(2) Å] [14] reveals some degree of WC multiple bonding in our new complex.…”

“…[5] Similar transformations have been effected with inversely polarized arsaalkenes. [6] Synthesis and Structure of η 2 -1-Phosphaallene Complexes FULL PAPER Scheme 3. Formation of 1,2-diphosphaallyl complexes 8a-c.…”

meta‐Terphenyl Phosphaalkenes Bearing Electron‐Donating and ‐Accepting Groups

“…In some cases, directly attaching electron‐donating groups can even reverse the slight polarization of the P=C bond to create inversely polarized phosphaalkenes having very different chemistries 21…”

Arsaalkenes R−AsC(NMe2)2 [R = PhC(O), 4-EtC6H4C(O), 2,4,6-Me3C6H2C(O), tBuC(O), Me3Si]: Versatile Reagents in the Chemistry of Heterocumulenes

“…Recently, we described the generation of η 3 -2-phospha-1-arsaallyl complexes 4a − d by the formal transfer of arsanediyl units from arsaalkenes onto the organophosphorus ligand of phosphavinylidene complexes 3a , b (Scheme ) 2 Formation of 2-Phospha-1-arsaallyl Complexes 4 a a R = t BuC(O), M = Mo (a), W (b); R = Cp*(CO) 2 Fe, M = Mo (c), W (d). …”

“…In contrast to the reactivity of the pivaloylarsaalkene the employment of the related p -ethylbenzoylarsaalkene 4-EtC 6 H 4 C(O)−AsC(NMe 2 ) 2 gave rise to the formation of the cyclic phosphenium complex 5 (Scheme ) 3 Formation of Complex 5 …”