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.

Tin(II) Ureide Complexes: Synthesis, Structural Chemistry, and Evaluation as SnO Precursors.

In an attempt to tailor precursors for application in the deposition of phase pure SnO, we have evaluated a series of tin (-) ureide complexes. The complexes were successfully synthesized by employing ,'-trialkyl-functionalized ureide ligands, in which features such as stability, volatility, and decomposition could be modified with variation of the substituents on the ureide ligand in an attempt to find the complex with the ideal electronic, steric, or coordinative properties, which determine the fate of the final products. The tin(II) ureide complexes - were synthesized by direct reaction [Sn{NMe}] with aryl and alkyl isocyanates in a 1:2 molar ratio.

Evaluation of Sn(II) aminoalkoxide precursors for atomic layer deposition of SnO thin films.

We have successfully prepared and structurally characterized a family of eight tin(II) heteroleptic complexes, [Sn(NR)(ON)] (NR = NMe (1a-d) or N(SiMe) (2a-d); = 1 or 2) and four homoleptic systems, [Sn(κ-ON)] (3a-d) from a series of aminoalcohols and fluorinated aminoalcohols (H{ON}) having a different number of methyl/trifluoromethyl substituents at the α-carbon atom, [HOC(R)(R)CHNMe] (R = R = H (H{dmae}) (a); R = H, R = Me (H{dmap}) (b); R = R = Me (H{dmamp}) (c); R = R = CF (H{Fdmamp}) (d)). The synthetic route used reactions of either [Sn{N(SiMe)}] or [Sn(NMe)] with one or two equivalents of the aminoalcohols (a-d) in dry aprotic solvents leading to elimination of amines and formation of the Sn(II) species 1a-d, 2a-d and 3a-d respectively. All complexes were thoroughly characterized by NMR spectroscopy (H, C, F, and Sn) as well as single-crystal X-ray diffraction studies.

Synthetic, Structural, and Computational Studies on Heavier Tetragen and Chalcogen Triazenide Complexes.

The syntheses of the triazenide complexes [{N(N)}M] (Dipp = 2,6-di-isopropylphenyl; M = Ge(II) (), Sn(II) (), Pb(II) (), and Te(II) ()) are described for the first time. These compounds have been characterized by single-crystal X-ray diffraction and heteronuclear NMR spectroscopy. Density functional theory calculations were employed to confirm the presence and nature of the stereochemically active lone pairs in -, alongside the Gibbs energy changes for their general synthesis, which enable the rationalization of observed reactivities.

Aerosol-Assisted Chemical Vapor Deposition of ZnS from Thioureide Single Source Precursors.

A family of 12 zinc(II) thoureide complexes, of the general form [{L}ZnMe], [{L}Zn{N(SiMe)}], and [{L}Zn], have been synthesized by direct reaction of the thiourea pro-ligands PrN(H)CS(NMe) H[L], CyN(H)CS(NMe) H[L], BuN(H)CS(NMe) H[L], and MesN(H)CS(NMe) H[L] with either ZnMe (1:1) or Zn{N(SiMe)} (1:1 and 2:1) and characterized by elemental analysis, NMR spectroscopy, and thermogravimetric analysis (TGA). The molecular structures of complexes [{L}ZnMe] (1), [{L}ZnMe]] (2), [{L}ZnMe] (3), [{L}ZnMe]] (4), [{L}Zn{N(SiMe)}] (5), [{L}Zn{N(SiMe)}] (6), [{L}Zn{N(SiMe)}]] (7), [{L}Zn{N(SiMe)}]] (8), [{L}Zn] (9), and [{L}Zn] (12) have been unambiguously determined using single crystal X-ray diffraction studies. Thermogravimetric analysis has been used to assess the viability of complexes 1-12 as single source precursors for the formation of ZnS.

Synthesis, characterisation and thermal properties of Sn(ii) pyrrolide complexes.

SnO is a rare example of a stable p-type semiconductor material. Here, we describe the synthesis and characterisation of a family of Sn(ii) pyrrolide complexes for future application in the MOCVD and ALD of tin containing thin films. Reaction of the Sn(ii) amide complex, [{(Me3Si)2N}2Sn], with the N,N-bidentate pyrrole pro-ligand, L1H, forms the hetero- and homoleptic complexes [{L1}Sn{N(SiMe3)2}] (1) and [{L1}2Sn] (2), respectively, bearing the 2-dimethylaminomethyl-pyrrolide ligand (L1).

Aerosol-assisted CVD of SnO from stannous alkoxide precursors.

The stannous alkoxides [Sn(OR)] [R = i-Pr, t-Bu, C(Et)Me, CHPh, CPh] have been synthesised by reaction of Sn(NR') with two equivalents of HOR [R' = Me, R = i-Pr; R' = SiMe, R = t-Bu, C(Et)Me, CHPh, CPh]. Single crystal X-ray diffraction analysis of the bis(diphenylmethoxide) (4) and bis(triphenylmethoxide) (5) species have shown them to comprise three-coordinate Sn(ii) centres through dimerisation in the solid state with the alkoxide units adopting transoid and cisoid configurations across the {SnO} cores respectively. Thermogravimetric analysis indicates clean decomposition and some evidence of volatility at temperatures >200 °C for all three aliphatic alkoxides, whereas both the diphenyl- and triphenylmethoxide compounds provide higher decomposition temperatures and, for the triphenylmethoxide derivative, a residual mass consistent with the formation of a carbon-containing residue.