Notes. Complexes containing mercury–molybdenum bonds: new compounds of the type [HgX{trans-Mo(CO)2L(η5-C5H5)}](L = arsine or phosphine). Crystal and molecular structure of the complex [Hg(CN){trans-Mo(CO)2(AsMe2Ph)(η5-C5H5)}]

Abstract

The series of Hg–Mo bonded complexes [Hg(CN){trans-Mo(CO)₂L(η⁵-C₅H₅)}](where L = AsMe₂Ph, PMe₂Ph, PMePh₂, or PPh₃) have been prepared from Hg(CN)₂ and the salts Na[Mo(CO)₂L(η⁵-C₅H₅)] or dimers [Hg{trans-Mo(CO)₂L(η⁵-C₅H₅)}2]. The cyanomercury complexes are extremely useful intermediates for the facile synthesis of the derivatives [HgX{trans-Mo(CO)₂L(η⁵-C₅H₅)}](where X = Cl, Br, I, NO₃, O₂CMe, OCN, SCN, or S₂CNEt₂). The molecular structure of the complex [Hg(CN){trans-Mo(CO)₂(AsMe₂Ph)(η⁵-C₅H₅)}] has been determined by single-crystal X-ray analysis. The crystals are monoclinic, space group P2₁/c, with a= 14.570(4), b= 12.457(3), c= 10.783(3)Å, β= 114.04(2)°, and Z= 4. The structure was solved by heavy-atom methods and refined by least squares to a residual of 0.037 for 2 218 reflections with |I₀| > 3σ(I). The Hg–Mo bond length [2.654(1)Å] is the shortest hitherto observed.