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

Abstract

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 BlocksThe phosphidometallates \documentclass{article}\usepackage{amsmath}\pagestyle{empty}\begin{document}$ Li_2 \left\{ {\left[ M \right]\dddot - PPh_2 } \right\} $\end{document} {[M] = (η5‐C5H5)M‐(CO)2}, resulting from the metal hydride complexes H[M]PPh2H [M = Cr (1), Mo (2), W (3)] by reduction with nBuLi, react with the geminal dihalides RECl2 to give the three‐membered phosphametallacyclopropanes [ER = NC6F5 (M = Cr (1a), Mo (2a), W (3a)), PPh (M = Cr (1b), Mo (2b), W (3b)), PC6H11 (M = Cr (1c), Mo (2c), W (3c)), P‐tBu (M = Cr (1d), Mo (2d), W (3d)), P(2,4,6‐(tBu)3C6H2) (M = Cr (1e), Mo (2e), W (3e)), As(2,4,6‐(tBu)3C6H2) (M = Cr (1f), Mo (2f), W (3f)), Sb‐tBu (M = Cr (1g), Mo (2g))]. Reaction of Br2Fe(CO)4 with the corresponding dilithium compounds \documentclass{article}\usepackage{amsmath}\pagestyle{empty}\begin{document}$ 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)5CrTHF is added to the Lewis basic E atom in 2b, 2d, and 2g with loss of THF to give P‐tBu (4d), Sb‐tBu (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.