Synthese, Struktur und Reaktivität von η 3 ‐1,2‐Diphosphaallylkomplexen sowie von [{(η 5 ‐C 5 H 5 )(CO) 2 W–Co(CO) 3 }{μ‐AsCH(SiMe 3 ) 2 }(μ‐CO)]

Syntheses, Structure and Reactivity of η 3 ‐1,2‐Diphosphaallyl Complexes and [{(η 5 ‐C 5 H 5 )(CO) 2 W–Co(CO) 3 }{μ‐AsCH(SiMe 3 ) 2 }(μ‐CO)] Reaction of ClP=C(SiMe 2 i Pr) 2 ( 3 ) with Na[Mo(CO) 3 (η 5 ‐C 5 H 5 )] afforded the phosphavinylidene complex [(η 5 ‐C 5 H 5 )(CO) 2 Mo=P=C(SiMe 2 i Pr) 2 ] ( 4 ) which in situ was converted into the η 1 ‐1,2‐diphosphaallyl complex [η 5 ‐(C 5 H 5 )(CO) 2 Mo{η 3 ‐ t BuPPC(SiMe 2 i Pr) 2 ] ( 6 ) by treatment with the phosphaalkene t BuP=C(NMe 2 ) 2 . The chloroarsanyl complexes [(η 5 ‐C 5 H 5 )(CO) 3 M–As(Cl)CH(SiMe 3 ) 2 ] [where M = Mo ( 9 ); M = W ( 10 )] resulted from the reaction of Na[M(CO) 3 (η 5 ‐C 5 H 5 )] (M = Mo, W) with Cl 2 AsCH(SiMe 3 ) 2 . The tungsten derivative 10 and Na[Co(CO) 4 ] underwent reaction to give the dinuclear μ‐arsinidene complex [(η 5 ‐C 5 H 5 )(CO) 2 W–Co(CO) 3 {μ‐AsCH(SiMe 3 ) 2 }(μ‐CO)] ( 11 ). Treatment of [(η 5 ‐C 5 H 5 )(CO) 2 Mo{η 3 ‐ t BuPPC(SiMe 3 ) 2 }] ( 1 ) with an equimolar amount of ethereal HBF 4 gave rise to a 85/15 mixture of the saline complexes [(η 5 ‐C 5 H 5 )(CO) 2 Mo{η 2 ‐ t Bu(H)P–P(F)CH(SiMe 3 ) 2 }]BF 4 ( 18 ) and [Cp(CO) 2 Mo{F 2 PCH(SiMe 3 ) 2 }( t BuPH 2 )]BF 4 ( 19 ) by HF‐addition to the PC bond of the η 3 ‐diphosphaallyl ligand and subsequent protonation ( 18 ) and/or scission of the PP bond by the acid ( 19 ). Consistently 19 was the sole product when 1 was allowed to react with an excess of ethereal HBF 4 . The products 6 , 9 , 10 , 11 , 18 and 19 were characterized by means of spectroscopy (IR, 1 H‐, 13 C{ 1 H}‐, 31 P{ 1 H}‐NMR, MS). Moreover, the molecular structures of 6 , 11 and 18 were determined by X‐ray diffraction analysis.