Boratropic rearrangements in tris(pyrazolyl)borate molybdenum mononitrosyl complexes: effects of co-ligands
Abstract
The complexes [Mo(NO){HB(impz)3}I(ER)][impz = isopropylmethylpyrazol-1-yl; E = O; R = Pri, But, CH2SiMe3, (CH2)4I, Ph or C6H4Me-4: E = NH; R = Ph or C6H4Me-4] have been prepared from a mixture of isomers of [Mo(NO){HB(impz)3}I2]; in the cases where ER = OPh, O(CH2)4I or OCH2SiMe3 the products could only be obtained as mixtures of isomers, but where ER = OPri, OBut, NHPh or NHC6H4Me-4 the products could be thermally converted into compounds containing a single isomer of the ligand HB(impz)3. Reactions involving REH (E = O; R = Me, Pri or But; E = NH; R = Et, CH2Ph or Ph) and a single isomer of [Mo(NO){HB(impz)3}I2] produced [Mo(NO){HB(impz)3}I(ER)] containing a single isomer of the ligand HB(impz)3 and which did not rearrange on heating. The locations of the methyl and isopropyl groups in the HB(impz)3 ligand in [Mo(NO){HB(3-Pri-5-Me-C3N2H)3}(OPri)2] have been determined by X-ray crystallographic methods.