Trirhenium(III) cluster alkyls. Synthesis of tertiary phosphine adducts; cleavage to rhenium-(III) and -(II) dimers; reactions with carbon monoxide, nitric oxide, and hydrogen chloride. X-Ray structural determinations of hexamethylbis(diethylphenylphosphine)tri-µ-methyl-triangulo-trirhenium(III) and tri-µ-chloro-(N-nitroso-N-trimethylsilyl-methylhydroxylaminato)pentakis(trimethylsilylmethyl)-triangulo-tri-rhenium(III)

Abstract

Listen

Translate article

A new cluster benzyl, Re3Cl3(CH2Ph)6, and tertiary phosphine (L) adducts of the corresponding cyclohexyl, Re3Cl3(C6H11)6L3, and of the permethyl, Re3Me3L2,3, have been prepared. The structure of the diethylphenylphosphine derivative Re3Me9(PEt2Ph)2 has been confirmed by a single-crystal X-ray structure determination. Crystals are monoclinic, space group C2/c, with dimensions a= 27.220(4), b= 9.817(1), c= 26.051(5)A, and β= 102.65(2)° and the structure was solved by direct methods and refined by least squares to an R of 0.043 using 4 982 unique observed intensities. The Re3Me9 unit present in the trinuclear molecule is considerably distorted as a result of steric compression from the two strongly bound phosphines. The trinuclear rhenium(III) phosphine adducts undergo cleavage reactions to give dimeric compounds of rhenium(III) or rhenium(II), examples being Re2Me6(PMe2Ph)2 and Re2Cl2(CH2SiMe3)2(PMe3)4. The reactions of the blue trimethylsilylmethyl cluster Re3Cl3(CH2SiMe3)6 with CO, NO, and HCl are described. Nitric oxide is shown to give an insertion product with an N-(trimethylsilylmethyl)-N-nitrosohydroxylaminato-chelate ring, of formula Re3Cl3(CH2SiMe3)5{ON(CH2SiMe3)-NO} whose structure has also been confirmed by X-ray structure determination. Crystals are monoclinic, space group P21/a, with a= 33.33(4), b= 11.733(5), c= 11.947(6)A, and β= 92.93(4)°. The structure was solved by direct methods and refined by least squares to an R of 0.067 using 4 360 observed data. The nitrosohydroxylaminato-ligand chelates symmetrically (Re-O 2.10 A× 2) to one of the metal atoms, using one out-of-plane and the in-plane terminal sites.