R. R. Ryan

Synthesis and X-ray structure of (C/sub 5/Me/sub 5/)/sub 2/Th(. mu. -PPh/sub 2/)/sub 2/Pt(PMe/sub 3/): a complex with a thorium-platinum bond

The synthesis of Cp/sub 2/*Th(PPh/sub 2/)/sub 2/ (1), and the preparation (eq 1) of Cp/sub 2/*Th(..mu..-PPh/sub 2/)/sub 2/Ni(CO)/sub 2/ (2), Cp/sub 2/*Th(PPh/sub 2/)/sub 2/ + Ni(COD)/sub 2/ + 2CO ..-->.. Cp/sub 2/*Th(..mu..-PPh/sub 2/)/sub 2/Ni(CO)/sub 2/ + 2COD (1) the first phosphido-bridged heterobimetallic complex incorporating an actinide element have been reported. The X-ray structure of 2 revealed distorted tetrahedral environments about both metal centers, as well as two unexpected features: (1) acute Th-P-Ni angles which average 76.2 (4)/sup 0/ and (2) a short thorium-nickel separation of 3.206 (2) A. These data led to postulation of the existence of a direct, albeit weak, thorium-nickel interaction, one that could be formulated as a donor-acceptor bond from Ni(0) to the electron-deficient Th(IV) center. Because bonding interactions between actinides (An) and transition metals (M) were unprecedented in discrete complexes, additional experimental evidence was sought for donor-acceptor bonding in Cp/sub 2/*An(..mu..-PR/sub 2/)/sub 2/ML/sub n/ systems. Replacement of the Ni(CO)/sub 2/ fragment of 2 with an electron-rich transition-metal donor was a logical first step toward providing that evidence. Here the synthesis, properties and structure of a new thorium-platinum complex are described and some theoretical insight is provided on the nature of the Th-Pt bond contained therein. 30morexa0» references, 2 figures.«xa0less

A new bridging geometry for sulphur dioxide in [Mo(CO)2(PPh3)-(pyridine)(µ-SO2)]2·2CH2Cl2; X-ray crystal structure

In CH2Cl2 solution the complex cis, trans-Mo(CO)2(PPh3)2(pyridine)(η2-SO2)(1) reacts to give a dinuclear complex (2); an X-ray crystal structuree determination shows that the moly-bdenum atoms are bridged by two SO2 ligands that are co-ordinated to one metal through the sulphur atom and one oxygen atom and to the second metal via thee remaining oxygen atom.

Tetrahydroborate complexes of uranium with 2-(diphenylphosphino)pyridine

U(BH4)3(THF)x, (THF = tetrahydrofuran,) and (η5-C5H5)UCl3 react with 2-(diphenylphosphino)pyridine, (Ph2Ppy), producing 1:2 and 1:1 adducts, respectively; and X-ray crystal structure of U(BH4)3(Ph2Ppy)2·1/2C6H6 shows U–P = 3.162(1) and U–N = 2.659(4)A.

Tertiary phosphine complexes of trivalent uranium: preparation and structure of U(BH4)3(dmpe)2(dmpe = Me2PCH2CH2PMe2)

U(BH4)3(THF)x(THF = tetrahydrofuran) reacts cleanly with excess of dmpe (dmpe = Me2PCH2CH2PMe2) producing U(BH4)3(dmpe)2; an X-ray structural analysis of this molecule has been carried out revealing U-P(1)= 3.1139(8) and U-P(2)= 3.051(9)A.