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Reactions of Sn(NMe 2 ) 2 with MPHCy: The Effects of Alkali Metal Phosphide Coupling (Cy=Cyclohexyl; M=Li, Na, K, Rb)
Author(s) -
Alvarez Paula,
García Felipe,
Hehn Jörg P.,
Kraus Florian,
Lawson Gavin T.,
Korber Nikolaus,
Mosquera Marta E. G.,
McPartlin Mary,
Moncrieff David,
Pask Christopher M.,
Woods Anthony D.,
Wright Dominic S.
Publication year - 2007
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200600633
Subject(s) - phosphide , chemistry , alkali metal , natural bond orbital , stoichiometry , medicinal chemistry , base (topology) , metal , lewis acids and bases , crystallography , stereochemistry , computational chemistry , organic chemistry , catalysis , density functional theory , mathematical analysis , mathematics
The reactions of the Sn II base Sn(NMe 2 ) 2 with CyPHM (Cy=cyclohexyl) produce a range of products, depending primarily on the alkali metal (M) involved. The 1:3 stoichiometric reaction of Sn(NMe 2 ) 2 with CyPHNa in the presence of the Lewis base donor PMDETA (PMDETA=(Me 2 NCH 2 CH 2 ) 2 NMe) gives [(Na⋅PMDETA) 2 {Sn(μ‐PCy)} 3 ] ( 3 ), containing the electron‐deficient [{Sn(μ‐PCy)} 3 ] 2− dianion. Natural bond order (NBO) and electron localisation function (ELF) calculations show that this species is described most appropriately by a two‐electron, three‐centre Sn 3 bonding model. Evidence that 3 results from phosphide coupling is provided by the 1:1 reaction of Sn(NMe 2 ) 2 with CyPHNa in the presence of PMDETA, which gives 3 and trace amounts of (Na⋅PMDETA) 2 [{Sn(μ‐PCy)} 2 (μ‐PCyPCy)] ( 4 ) (containing one PCyPCy 2− dianion). Greater extents of phosphide coupling are observed as the size of the Group 1 metal is increased. Thus, the 1:3 reaction of Sn(NMe 2 ) 2 with CyPHK in THF gives the co‐crystalline product {(K⋅2 THF) 2 [{Sn(μ‐PCyPCy)} 2 (μ‐PCy)]} 0.9 {(K⋅2 THF) 2 [{Sn(μ‐PCy)} 2 (μ‐PCyPCy)]} 0.1 ( 5 ) (containing [{Sn(μ‐PCyPCy)} 2 (μ‐PCy)] 2− and [{Sn(μ‐PCy)} 2 (μ‐PCyPCy)] 2− dianions), whereas the analogous reaction of Sn(NMe 2 ) 2 with RbPHCy gives [Rb⋅PMDETA{(CyP) 3 SnP(H)Cy}] ( 6 ) (containing a cyclic {(CyP) 3 Sn} unit).