Citation:
Abstract:
The reaction of ((BuNH)-Bu-1)(3)PNSiMe3 (1) with 1 equiV of (BuLi)-Bu-n results in the formation of Li[P((NHBU)-B-1)(2)((NBu)-Bu-t)(NSiMe3)] (2); treatment of 2 with a second equivalent of nBuLi produces the dilithium salt Li-2[P((NHBu)-Bu-t)((NBU)-B-t)(2)(NSiMe3)] (3). Similarly, the reaction of 1 and (BuLi)-Bu-n in a 1:3 stoichiometry produces the trilithiated species Li-3[P((NBU)-B-t)(3)(NSiMe3)] (4). These three complexes represent imido analogues of dihydrogen phosphate [H2PO4](-), hydrogen phosphate [HPO4](2-), and orthophosphate [PO4](3-), respectively, Reaction of 4 with alkali metal alkoxides MOR (M = Li, R = SiMe3; M = K, R = Bu-t) generates the imiclo-alkoxy complexes {Li-3[P((NBU)-B-t)(3)(NSiMe3)](MOR)(3)} (8, M = Li; 9, M = K). These compounds were characterized by multinuclear (H-1, Li-7, C-13, and P-31) NMR spectroscopy and, in the cases of 2, 8, and 9-3THF(1) by X-ray crystallography. In the solid state, 2 exists as a dimer with Li-N contacts serving to link the two Li[P((NHBu)-Bu-t)(2)((NBu)-Bu-t)(NSiMe3)] units. The monomeric compounds 8 and 9-3THF consist of a rare M3O3 ring coordinated to the (LiN)(3) unit of 4. The unexpected formation of the stable radical {(Me3SiN)P(mu(3)-(NBU)-B-t)(3)[mu(3)-Li(THF)](3)((OBu)-Bu-t)} (10) is also reported. X-ray crystallography indicated that 10 has a distorted cubic structure consisting of the radical dianion [P((NBU)-B-t)(3)(NSiMe3)](*2-), two lithium cations, and a molecule of (LiOBu)-Bu-t in the solid state. In dilute THF solution, the cube is disrupted to give the radical monoanion [(Me3SiN)((BuN)-Bu-t)P-(mu-(NBu)-Bu-t)(2)Li(THF)(2)](*-), which was identified by EPR spectroscopy.
Notes:
Times Cited: 13Armstrong, A Chivers, T Parvez, M Schatte, G Boere, RT