Hypercoordination in Organotin Chemistry – A Novel O,C,O-Coordinating Ligand

Recent results are reported on the application of the novel O,C,O-coordinating pincer ligand {2,6-[P(O)(OEt)₂]₂-4-tert-Bu-C₆H₂} (A) for the synthesis of hypercoordinate organotin(IV) compounds ASnR₃ (R = Ph, Cl), heteroleptic stannylenes ASnR (R = Cl, CH₂SiMe3) and intramolecularly coordinated 1,2,5-oxaphosphastannolanes.     

Synthesis of Some Polymer‐Metal Complexes and Elucidation of their Structures

In this study, the nine coordination polymers of Fe(III), Co(II) and Ni(II) salts have been synthesized using polyacrylamide (PAA), polt(ethylene glycol) (PEG) and poly(vinyl alcohol) (PVA) and their structures were characterized by magnetic and conductivity measurements, ultraviolet‐visible (UV‐VIS), FTIR spectroscopy and thermogravimetric analysis (TGA). The structures of Fe(III) complexes in the all coordination polymers were found as tetrahedral. The structures of PAA‐Co(II) coordination polymer was determined as octahedral geometry whereas PEG‐Co(II) and PVA‐Co(II) complexes showed as tetrahedral structure. PAA‐Ni(II) and PEG‐Ni(II) complexes have octahedral geometry, whereas PVA‐Ni(II) has a square planar structure. Besides, the stress‐strain experiments of PVA‐metal coordination polymers obtained rubber‐like structure were carried out and the value of breaking‐strain of PVA‐Ni(II) complex was found to be about 17% of vulcanized natural rubber. The conductivities of the resulting polymer‐metal complexes were measured by four‐probe technique and were found in the range 10^?5?10^?6 Scm^?1. Thus, it was suggested that they can be used in the field potential application of conducting polymers. TGA results revealed that among the complexes PEG‐Fe(III) and PVA‐Fe(III) complexes have the highest thermally stable.     

Synthesis and Characterization of Aminophosphines,Bis(amino)phosphine Derivatives,and Their Molybdenum(0) Complexes

Functionalized bis(amino)phosphines of the type PhP(NHR)₂ ( 1a–c ) and aminophosphines of the type Ph₂PNHR ( 2a–c ) have been synthesized by treating PhPCl₂ or Ph₂PCl with corresponding primary amines of H₂N-R where R = -CH₂SO₃H, -C₆H₄SO₃H, and benzo-15-crown-5. The molybdenum(0) complex of the aminophosphine ( 3 ) has been obtained by reacting cis-[Mo(CO)₄(bipy)] with aminophosphine ( 2c ). The synthesized aminophosphines, bis(amino)phosphines, and the molybdenum(0) complex have been characterized by IR, ¹H NMR, ³¹P NMR, and MS spectroscopic techniques and by elemental analysis.     

Alternative Synthesis of A C,C-Diacetylenic Phosphaalkene

Abstract

Bis(trimethylsilyl)-terminated C,C-diacetylenic phosphaalkene was prepared from Mes*PCl₂ and a propargylic Grignard reagent that in turn was formed from 3-bromo-1,5-bis(trimethylsilyl)penta-1,4-diyne and Rieke-Mg.     

Preparation,Characterization and Electromagnetic Shielding Effectiveness of Conductive Polythiophene/Poly(ethylene terephthalate) Composite Fibers

Conductive polythiophene (PTh)/poly(ethylene terephthalate) (PET) composite fibers were prepared by polymerization of thiophene in the presence of PET fibers in acetonitrile medium using FeCl₃. The effects of polymerization conditions such as oxidant/monomer mol ratio and polymerization temperature and time on PTh content and surface electrical resistivity of PTh/PET composite fiber were investigated in detail. It was observed that the usage of preswelled PET fibers in dichloromethane increased the PTh content and decreased surface resistivity of composite fiber. Composite fiber having the highest PTh content (5.7%) and the lowest surface resistivity (80 kΩ) was obtained at 20°C with 1.25 M FeCl₃ and 0.42 M thiophene concentrations. The washing effects of laundering detergent and dry cleaning liquid on surface resistivity of composite fibers were investigated. The electromagnetic shielding effectiveness (EMSE) and relative shielding efficiency by absorption and reflection of composite fibers were measured in the radio and microwave frequency range. The results show that the EMSE values decreased with increasing frequency from radio waves to microwaves with an attenuation of 21 dB to 4 dB.     

PEPPSI-Pd-NHC catalyzed Suzuki-Miyaura cross-coupling reactions in aqueous media

A series of unsymmetrical 1,3-disubstituted benzimidazolium chlorides were synthesized as N-heterocyclic carbene (NHC) precursors. These compounds were used to synthesize of the PEPPSI-type palladium NHC complexes. The structures of all compounds were characterized by ¹H NMR, ¹³C NMR, FT-IR spectroscopy and elemental analyses. The catalytic activity of the PEPPSI-type palladium–NHC complexes has been evaluated with respect to the Suzuki-Miyaura cross-coupling reactions of phenyl boronic acid with various aryl halides in aqueous media.     

The mixed ligand complexes of Co(II), Ni(II), Cu(II) and Zn(II) with coumarilic acid/1,10-phenanthroline

Journal of Thermal Analysis and Calorimetry - The coumarilate (coum?) and 1,10-phenanthroline (phen) mixed ligand complexes of Co(II) (1), Ni(II) (2) Cu(II) (3) and Zn(II) (4) were...