Dioximate‐ and Bis(salicylaldiminate)‐Bridged Titanium and Zirconium Alkoxides: Structure Elucidation by Mass Spectrometry

Abstract

The treatment of titanium alkoxides with 1,5-pentanedioxime or 2,5-hexanedioxime resulted in the formation of complexes [{TiL(OR)2}2] in which the dioximate ligands (L) bridge a dimeric Ti2(μ2-OR)2 unit. The structures of the complexes were determined by single-crystal structure analysis, ESI mass spectrometry, and 1D and 2D solution NMR spectroscopy. In contrast, the treatment of titanium alkoxides with dioximes bearing cyclic linkers, such as cyclohexyl or aryl groups, resulted in insoluble polymeric compounds. The treatment of various bis(salicylaldiminates) with titanium and zirconium alkoxides resulted in compounds with the same composition [{TiL(OR)2}2], in which, however, two monomeric Ti(OR)2 units are bridged by the ligands L. The two structural possibilities can be distinguished by low-energy collision-induced dissociation owing to their different fragmentation patterns.

Novel enantiopure cyclopentadienyl Ti(IV) oximato compounds as potential anticancer agents

“…4. The X-ray diffraction structure confirms a dihapto κ 2 NO coordination of the oximato unit to the titanium centre, which is the usual coordination mode found for other titanium(IV) oximato derivatives [52,55–57,59,62,81]. N, O and C atoms of the ON=C unit are coplanar, and the plane that contained them bisects the angle Cl(2)-Ti-Cl(3) along the Ti-Cp centroid vector.…”

Structural clues to UO22+/VO2+competition in seawater extraction using amidoxime-based extractants

“…Of the two papers in which crystal structures of 1,4-dioxime ligands bonded to metal ions are reported, in one case the two oximes are on the opposite ends of a six-membered ring and cannot interact with the same metal 16 while the other involves an aliphatic dioxime which is associated with a multi-nuclear complex bridged by other ligands. 17 The structures reported here are thus the first direct evidence of 1,2-diamidoxime ligands coordinating as the amidoxime tautomer.…”

A complete series of halocarbonyl molybdenum PNP pincer complexes – Unexpected differences between NH and NMe spacers

“…Mass calibration was done with a commercial mixture of perfluorinated trialkyl-triazines (ES Tuning Mix, Agilent Technologies, Santa Clara, CA, USA). All analytes were dissolved in methanol hypergrade for LC–MS Lichrosolv (Merck, Darmstadt, Germany) to a concentration of roughly 1 mg/mL and doped with sodium fluoride, sodium chloride, sodium bromide or sodium iodide (Merck, Darmstadt, Germany) to promote [M + Na] + -adduct ion formation of the neutral molybdenum complexes as previously described for titanium and zirconium complexes [17,18] . Direct infusion experiments were carried out using a Cole Parmer model 74900 syringe pump (Cole Parmer Instruments, Vernon Hills, IL, USA) at a flow rate of 2 μL/min.…”