The synthesis and reactivity of pnictogen ligand complexes of transition metal carbonyls : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science, Chemistry/Biochemistry/Biophyisics Department, Massey University

Abstract

Metal carbonyl complexes of the type M(CO)₅L, M(CO)₄L and (M(CO)₅)₂L where M is Cr, Mo and W, and L is a pnictogen ligand ((I) or (II)). have been synthesised by the addition of L to UV-irradiated tetrahydrofuran solutions of the appropriate metal carbonyl. Complexes of the type M(CO)₃L Br (III) and M(CO)₂L₂ Br (IV) where M = Mn and L = (I) or (II) have also been synthesised by refluxing Mn(CO)₅ Br and L in a 1:1 molar ratio to form (III) and in: a 1:2 molar ratio to form (IV). The W(CO)₅L complexes react with acids HX (where X¯ = Cl¯, Br¯, I¯, BF₄¯ or PF₆¯) to give the cationic ligand complexes, W(CO)₅L HX. The conductivity of the complexes is anion dependent. The complexes were characterised by Infra-Red spectroscopy, Visible-UV spectroscopy, ³¹P nmr, ¹H nmr, ¹³C nmr, and Mass-spectra. Excess acid (e.g. HBr) cleaves the P-N bond yielding primarily W(CO)₅P(C₆H₅)₂Br and the protonated amine. The complex W(CO)₅L (where L = (I)) acts as a ligand towards CoCl₂ in the complex (W(CO)₅L)₂CoCl₂ as well as in the bridging complex (W(CO)₅)₂L.