Heteroallene Insertions into Tin(II) Alkoxide Bonds.

A series of iso-carbamate complexes have been synthesized by the reaction of [Sn(OPr)] or [Sn(OBu)] with either aryl or alkyl isocyanates, ONC-R (R = 2,4,6-trimethylphenyl (Mes), 2,6-diisopropylphenyl (Dipp), isopropyl (Pr), cyclohexyl (Cy) and -butyl (Bu)). In the case of aryl isocyanates, mono-insertion occurs to form structurally characterized complexes [Sn{κ--R-NC(OPr)O}(μ-OPr)] (: R = Mes, : R = Dipp) and [Sn{κ--R-NC(OBu)O}(μ-OBu)] (: R = Mes, : R = Dipp). The complicated solution-state chemistry of these species has been explored using H DOSY experiments.

Green Alternatives to Zinc Dialkyldithiophosphates: Vanadium Oxide-Based Additives.

A functionalized vanadyl(IV) acetylacetonate (acac) complex has been found to be a superior and highly effective antiwear agent, affording remarkable wear protection, compared to the current industry standard, zinc dialkyldithiophosphates (ZDDPs). Analysis of vanadium speciation and the depth profile of the active tribofilms by a combination of X-ray absorption near-edge structure (XANES), X-ray photoelectron spectroscopy (XPS), and near-edge X-ray absorption fine structure (NEXAFS) analyses indicated a mixed-valence oxide composite, comprising V(III), V(IV), and V(V) species. A marked difference in composition between the bulk and the surfaces of the tribofilms was found.

Exploration of Solid-State Solution-State Structure in Contact Ion Pair Systems: Synthesis, Characterization, and Solution-State Dynamics of Zinc Diphenyl Phosphate, [Zn{OP(OPh)}], Donor-Base-Supported Complexes.

A family of zinc phosphate complexes supported by nitrogen donor-base ligands have been synthesized, and their molecular structures were identified in both the solid (X-ray crystallography) and solution state (DOSY NMR spectroscopy). [Zn{OP(OPh)}] (), formed from the reaction of Zn[N(SiMe)] with HO(O)P(OPh) coordinates to donor-base ligands, , pyridine (Py), 4-methylpyridine (4-MePy), 2,2-bipyridine (bipy), tetramethylethylenediamine (TMEDA), pentamethyldiethylenetriamine (PMDETA), and 1,3,5-trimethyl-1,3,5-triazacyclohexane (Me-TAC), to produce polymeric 1D structures, [(Py)Zn{OP(OPh)}] () and [(4-MePy)Zn{OP(OPh)}] (), the bimetalic systems, [(Bipy)Zn{OP(OPh)}] (), [(TMEDA)Zn{OP(OPh)}] (), and [(Me-TAC)Zn{OP(OPh)}] (), as well as a mono-nuclear zinc bis-diphenylphosphate complex, [(PMDETA)Zn{OP(OPh)}] (). H NMR DOSY has been used to calculate averaged molecular weights of the species.

Lithium, Tin(II), and Zinc Amino-Boryloxy Complexes: Synthesis and Characterization.

Analogous to the ubiquitous alkoxide ligand, metal boroxide and boryloxy complexes are an underexplored class of hard anionic O ligand. A new series of amine-stabilized Li, Sn(II), and Zn boryloxy complexes, comprising electron-rich tetrahedral boron centers have been synthesized and characterized. All complexes have been characterized by one-dimensional (1D), two-dimensional (2D), and DOSY NMR, which are consistent with the solid-state structures unambiguously determined via single-crystal X-ray diffraction.