509084-48-4Relevant articles and documents
Transition-metal imido-boroxide complexes: A structural and spectroscopic investigation of the influence of boron
Cole, Sarah C.,Coles, Martyn P.,Hitchcock, Peter B.
, p. 4168 - 4174 (2002)
The four coordinate compounds Mo(NR)2[OB(mes)2]2 (1, R = tBu; 2, R = Ar = 2,6-iPr2C6H3) have been obtained from the reaction of [(mes)2BOLi(Et2O)n]x with the corresponding Mo(NR)2Cl2(dme) starting material; for structural comparison, Mo(NtBu)2[OCH(mes)2]2 (3) was also synthesised. The related five-coordinate complexes Ti(NtBu)-[OB(mes)2]2(py)2 (4) and Ti(NtBu)[OCH(mes)2]2(py)2 (5) were made using analogous procedures. X-Ray structural investigations of 1-5 were performed to assess the effect that the boron atom has on the metal-oxygen and metal-nitrogen(imido) bond lengths and angles. On average, both classes of compound displayed longer metal-oxygen bonds and shorter metal-nitrogen(imido) bonds for the boroxide derivatives. Spectroscopic investigation of the Δδ values for the tert-butylimido derivatives revealed that complexes incorporating the [OB(mes)2]-anion exhibit a reduction in the electron density at the imido nitrogen atom, in agreement with the observations from the solid state structures.
