Tris(phosphino)borato Silver(I) Complexes as Precursors for Metallic Silver Aerosol-Assisted Chemical Vapor Deposition

Inductive modulation of tris(phosphinomethyl)phenylborate donation at group VI metals via borate phenyl substituent modification

New tris(phosphinomethyl)phenylborate ligands were synthesized to examine tuning of PhBP^Ph₃ donation via inductive modulation of the borate charge. Cyclic voltammetry suggests that rational tuning of this type occurs in complexes of zerovalent metals.

Oil-Soluble Silver-Organic Molecule for in Situ Deposition of Lubricious Metallic Silver at High Temperatures

A major challenge in lubrication technology is to enhance lubricant performance at extreme temperatures that exceed conventional engine oil thermal degradation limits. Soft noble metals such as silver have low reactivity and shear strength, which make them ideal solid lubricants for wear protection and friction reduction between contacting surfaces at high temperatures. However, achieving adequate dispersion in engine lubricants and metallic silver deposition over predetermined temperatures ranges presents a significant chemical challenge. Here we report the synthesis, characterization, and tribological implementation of the trimeric silver pyrazolate complex, [Ag(3,5-dimethyl-4-n-hexyl-pyrazolate)]3 (1). This complex is oil-soluble and undergoes clean thermolysis at ∼310 °C to deposit lubricious, protective metallic silver particles on metal/metal oxide surfaces. Temperature-controlled tribometer tests show that greater than 1 wt % loading of 1 reduces wear by 60% in PAO4, a poly-α-olefin lubricant base fluid, and by 70% in a commercial fully formulated 15W40 motor oil (FF oil). This silver-organic complex also imparts sufficient friction reduction so that the tribological transition from oil as the primary lubricant through its thermal degradation, to 1 as the primary lubricant, is experimentally undetectable.

Group VI metal complexes of tris(diphenylphosphinomethyl)phenylborate: modulation of ligand donation via coordination of M(CO)3 units at the borate phenyl substituent

A series of d(6) metal complexes of tris(diphenylphosphinomethyl)phenylborate ([PhB(CH2PPh2)3](-), PhBP3), including [Et4N][M(CO)3(PhBP3)] (M = Cr, Mo, W), inaugural group VI metal tris(phosphino)borate complexes, and zwitterionic Mn(CO)3(PhBP3) have been synthesized and fully characterized. An analysis of IR ν(CO) data for [Et4N][M(CO)3(PhBP3)] indicates that PhBP3 is significantly less strongly donating than Tp towards zerovalent M(CO)3 fragments; PhBP3 does not function as a strongly donating scorpionate in this system as its does towards cationic metal fragments suggesting that PhBP3 may not function as an effective surrogate of hydrotris(1-pyrazolyl)borate towards zerovalent metals. While the metal centers of [Et4N][M(CO)3(PhBP3)] are very likely still more electron-rich than those of M(CO)3(triphos), the anions of [Et4N][M(CO)3(PhBP3)] do not provide robust oxidative addition products analogous to those of M(CO)3(triphos). A new bi-functional role for PhBP3 was investigated via the synthesis of seven structurally characterized bimetallics in which zerovalent M(CO)3 and monovalent [Mn(CO)3](+) fragments bind the three phosphine atoms and the borate phenyl substituent. IR ν(CO) data support modest attenuation of PhBP3 donor ability at phosphorus upon η(6)-phenyl substituent binding, representing a new inductive strategy for tuning tris(phosphino)phenylborate donation at the κ(3)-phosphine-bound metal fragment.

The AACVD of Cu2FeSn(SxSe1−x)4: potential environmentally benign solar cell materials

Films of Cu₂FeSn(S_xSe_1−x) have been deposited by aerosol assisted chemical vapour deposition using mixtures of molecular precursors.

Syntheses of a novel fluorinated trisphosphinoborate ligand and its copper and silver complexes. Catalytic activity toward nitrene transfer reactions

A novel fluorinated ligand, the anionic PhB(CH2P(p-CF3C6H4)2)3 (PhBP3 (p-CF3Ph)), has been synthesized and characterized, as well as its corresponding thallium, copper, and silver derivatives. The presence of fluorine atoms in the ligand structure induced the desired effect of enhancing electrophilic character at the metal center, without promoting substantial changes in the ligand skeleton compared with the parent ligand PhB(CH2PPh2)3(-) (PhBP3). Olefin aziridination and C-H amidation reactions have been induced with those complexes as catalyst precursors. The copper derivative catalyzed the olefin aziridination of an array of olefins bearing either electron-donating or electron-withdrawing groups. The silver analogue was found to promote the C-H amidation of a series of substrates in moderate to high yields.

Synthesis of ZnO and Zn nanoparticles in microwave plasma and their deposition on glass slides

This work represents a new method to synthesis of ZnO and/or Zn nanoparticles by means of microwave plasma whose electrons are the reducing agents. Glass quadratic slides sized 2.5 x 2.5 cm were coated by ZnO and/or Zn particles whose sizes ranged from a few micrometers to approximately 20 nm. The size of the particles can be controlled by the type of the precursor and its concentration. In the current paper, the mechanism of the reactions of ZnO and/or Zn formation was proposed. Longer plasma irradiation and lower precursor concentration favor the fabrication of metallic Zn nanoparticles. The nature of the precursor's ion (acetate, nitrate, or chloride) is also of importance in determining the composition of the product. The glass slides coated by ZnO and/or Zn nanoparticles were characterized by HR-SEM, HR-TEM, AFM, XRD, ESR, contact angle and diffuse reflectance spectroscopy (DRS).