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Lookup NU author(s): Professor William Clegg, Dr Keith Izod, Dr Stephen Liddle, Paul O'Shaughnessy, Dr Joanne Sheffield
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The two new sterically demanding secondary phosphines (C6H4-2-OMe)RPH (1a) and (C6H3-2-OMe-S-Me)RPH (1b) [R = CH(SiMe3)2] are synthesized by the reaction of RPCl2 with 1 equiv of LiC6H4-2-OMe or LiC6H3-2-OMe-3-Me, respectively, followed by in situ reduction with LiAlH4. Metalation of 1 with BunLi, followed by metathesis with KOBut, yields the potassium salts K{PR(C6H4-2-OMe)} (2a) and K{PR(C6H3-2-OMe-3-Me)} (2b). The reaction of K{PR(C6H3-2-OMe-3-Me)} with YbI2 yields the diphosphide complex [YbII{PR(C6H3-2 OMe-S-Me)}2(THF)2] (3), in which the phosphides act as P,O-chelating ligands. In contrast, reaction of K{PR(C6H4-2-OMe)} with YbI2 under similar conditions yields the unexpected alkoxophosphide complex [YbII{PR(C6H4-2-O)}(THF)] 4ยท4Et2O (4), via an unusual ligand cleavage reaction involving the transfer of a methyl group from oxygen to phosphorus. Compounds 1-4 have been characterized by elemental analyses and multinuclear NMR spectroscopy and compounds 3 and 4 by X-ray crystallography. Compound 3 is monomeric in the solid state, with a distorted all-trans-octahedral geometry about the Yb center; compound 4 crystallizes as an unprecedented tetrameric cluster containing a Yb4O4 cuboidal core. Multi-element NMR spectroscopy suggests that 4 maintains an oligomeric structure in THF solution. The P-containing side product formed in the synthesis of 4 has been isolated and identified as (Me)PR(C6H4-2-OMe) by comparison of its NMR and mass spectra with those of an authentic sample.
Author(s): Clegg W, Izod K, Liddle ST, O'Shaughnessy P, Sheffield JM
Publication type: Article
Publication status: Published
Journal: Organometallics
Year: 2000
Volume: 19
Issue: 11
Pages: 2090-2096
Print publication date: 29/05/2000
ISSN (print): 0276-7333
ISSN (electronic): 1520-6041
Publisher: American Chemical Society
URL: http://dx.doi.org/10.1021/om000057u
DOI: 10.1021/om000057u
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