[LM(CO)3,4X] complexes of manganese(I) and rhenium(I) with phosphino- and thiophosphinatopyrazole ligands

Abstract

A series of complexes [LM(CO)3X] [Formula: see text] R2pz = pyrazolyl, or 3,5-dimethylpyrazolyl, x = 0–2; M = Mn, X = Cl; M = Re, X = Br) and [Formula: see text] were prepared by the reaction of the appropriate ligand with [M(CO)5X] or [M(CO)4X]2, and were characterized by elemental analysis, solution molecular weight, and infrared, mass, and nmr spectroscopic data. The products are formed via tetracarbonyl intermediates, of which the phosphorus bonded derivative [Formula: see text] was isolated and characterized. The tricarbonyl complexes [LM(CO)3X] and [Formula: see text] adopt a cis-octahedral configuration, in which the ligands form four-, five-, or six-membered chelate structures, via (i) the P atom and the 2-N site of the pyrazolyl moiety, with [Formula: see text], (ii) the sulphur and 2-N atoms, with [Formula: see text], (iii) the 2-N atoms of two pyrazolyl rings, with [Formula: see text] and (iv) the 2-N atoms of three pyrazolyl rings, resulting in a bicyclic system, with P(R2pz)3.The reactions of [CH3Re(CO)5] with [Formula: see text] require forcing conditions, resulting in the simultaneous elimination of carbon monoxide and methane, and yielding a variety of products, including tetracarbonyl, tricarbonyl, and ring-metalated species.