Darstellung und Eigenschaften von und Reaktionen mit metallhaltigen Heterocyclen, LXXVII Synthese, Struktur und Reaktivität von Phosphametallacyclopropanen mit isolobalen ER‐ (E = N, P, As, Sb) und Fe(CO) 4 ‐Bausteinen

Metal‐Containing Heterocycles: Preparation, Properties, Reactions, LXXVII. – Synthesis, Structure and Reactivity of Phosphametallacyclopropanes with Isolobal ER (E = N,P,As,Sb) and Fe(CO) 4 Building Blocks The phosphidometallates \documentclass{article}\usepackage{amsmath}\pagestyle{empty}\begin{document}$ Li_2 \left\{ {\left[ M \right]\dddot - PPh_2 } \right\} $\end{document} {[M] = (η 5 ‐C 5 H 5 )M‐(CO) 2 }, resulting from the metal hydride complexes H[M]PPh 2 H [M = Cr ( 1 ), Mo ( 2 ), W ( 3 )] by reduction with n BuLi, react with the geminal dihalides RECl 2 to give the three‐membered phosphametallacyclopropanes [ER = NC 6 F 5 (M = Cr ( 1a ), Mo ( 2a ), W ( 3a )), PPh (M = Cr ( 1b ), Mo ( 2b ), W ( 3b )), PC 6 H 11 (M = Cr ( 1c ), Mo ( 2c ), W ( 3c )), P‐ t Bu (M = Cr ( 1d ), Mo ( 2d ), W ( 3d )), P(2,4,6‐( t Bu) 3 C 6 H 2 ) (M = Cr ( 1e ), Mo ( 2e ), W ( 3e )), As(2,4,6‐( t Bu) 3 C 6 H 2 ) (M = Cr ( 1f ), Mo ( 2f ), W ( 3f )), Sb‐ t Bu (M = Cr ( 1g ), Mo ( 2g ))]. Reaction of Br 2 Fe(CO) 4 with the corresponding dilithium compounds \documentclass{article}\usepackage{amsmath}\pagestyle{empty}\begin{document}$ Li_2 \left\{ {\left[ M \right]\dddot - PPh_2 } \right\} $\end{document} affords the phosphido‐bridged heterodimetallic complexes . According to X‐ray structural analyses in 2a and 2f the P – E bond distances are shortened while the Mo – E bonds are significantly elongated compared to a single bond. (OC) 5 CrTHF is added to the Lewis basic E atom in 2b , 2d , and 2g with loss of THF to give P‐ t Bu ( 4d ), Sb‐ t Bu ( 4g )]. By this reaction the antimony‐containing ring 2g is kinetically stabilized. Because of the low basicity of the N atom in 2a no addition was observed. The ring skeleton of 4b and 4g , undergoes no change by Cr(CO) 5 coordination as shown by X‐ray structural analyses.