98576-44-4Relevant academic research and scientific papers
Preparation of Four-membered Phosphonickelocycles. Unusual Facile Stabilization of Five-co-ordinate Complexes
Font-Bardia, Merce,Gonzalez-Platas, Javier,Muller, Guillermo,Panyella, David,Rocamora, Merce,Solans, Xavier
, p. 3075 - 3084 (2007/10/02)
Three different types of organometallic compounds (R = Ph 1 or Et 1'), (R = Ph 2 or Et 2') and (R = Ph 3 or Et 3') have been obtained from 1 equivalent of PR2(C6Cl5) (R = Ph or Et), (cod = cis,cis-cycloocta-1,5-diene), and L = PMe2Ph a, PEt3 b, P(CH2Ph)3 c or PPh3 d.Complexes 2 evolve in solution, either to 1 and , or to 3 by breaking of the Ni-P bond of the four-membered ring by free phosphine.The selective preparation of compounds 1 or 3 can be achieved by performing the oxidative-addition reaction in the absence or with 2 equivalents of L respectively.When 1 equivalent of a diphosphine was used in the oxidative-addition reaction a mononuclear five-co-ordinate complex was obtained, 4 .However, dppm (Ph2PCH2PPh2) acts as a monodentate ligand to give the five-co-ordinate compound .Complexes 2, 2' show preferentially a cis geometry, 1' is trans, and 3, 3' have the L ligands in trans position.Insertion of CO or alkynes into the Ni-C bond was not observed.Compounds 1 and 1' in the presence of neutral ligands L = CO or PR3 (PR3 = PMe2Ph a or PEt3 b) gave five-co-ordinate complexes without cleavage of the Ni-P bond of the ring.Stabilization of the four-membered ring is achieved when two bidentate ligands are present or in the five-co-ordinate compound .Two bidentate ligands are also needed to stabilize the formation of five-co-ordinate complexes.The molecular structures of complexes 1', 3b, and were determined by single-crystal X-ray diffraction.
Simultaneous conversion of Ni-PR3 and B-H to Ni-H and B-PR3 linkages by thermal rearrangement of d8 closo-bis(triarylphosphine)nickelacarboranes. Crystal and molecular structure of [closo-3-(μ-CO)-8-PPh3-3,1,2-NiC2B9H 10]2: A dimeric nickelacarborane complex containing a metal-metal bond
King III,Miller, Steven B.,Knobler, Carolyn B.,Hawthorne, M. Frederick
, p. 3548 - 3554 (2008/10/08)
The reaction of L2NiCl2 (L = PR3) species with nido-7,8-, nido-7,9-, or nido-2,9-C2B9H112- ions led to the formation of the corresponding icosahedral bis(phosphine)nickelacarboranes in high yield. Heating members of the closo-3,3-(triarylphosphine)2-3,1,2-NiC2B 9H11 series at 80°C in benzene solution led to the formation of the corresponding [closo-3,8-(triarylphosphine)2-3-H-3,1,2-NiC2B 9H11] by interchange of phosphine and hydrido ligands. No intermediates were observed, and the reaction was specific for the bis(triarylphosphine)-3,1,2-NiC2 icosahedral system among those investigated. The dimeric nickelacarborane carbonyl [closo-(3-(μ-CO)-8-PPh3-3,1,2-NiC2B9H 11)2] was prepared by a variety of routes such as the reaction of [closo-3,3-(PPh3)2-3,1,2-NiC2B 9H11] (1a) with CO in benzene at 80°C. A variety of ligand substitution reactions were carried out with 1a. The mechanism of the phosphine-hydride ligand interchange is discussed. The dimeric nickelacarborane complex was characterized by an X-ray diffraction study. Amber crystals were triclinic, space group P1, with a = 13.319 (4) A?, b = 10.039 (3) A?, c = 9.813 (3) A?, α = 80.00 (1)°, β = 82.91 (1)°, γ = 110.32 (1)°, and Z = 1. The structure was solved by conventional heavy-atom methods to a final discrepancy index of R = 0.057 for 2233 independent observed reflections. The complex contains a metal-metal bond (2.477 (2) A?) and two metal-bridging carbon monoxide groups.
