Reactions of [Pt2(μ-Cl)2(C∩P)2] (C∩P = CH2C(Me2)PBut2-C,P) with various anionic ligands differing in ligand bite and denticity have been investigated and the resulting products have been characterized by elemental analyses and NMR (1H, 13C, 31P, 195Pt) spectroscopy. Stereochemistry of the complexes has been deduced by NMR spectroscopy. Structures of [Pt2(μ-SPh)2(C∩P)2], [Pt2(μ-pz)2(C∩P)2], [PtCl(Spy)(PBut3)], [Pt2(μ-SCOPh)2(C∩P)2] and [Pt{S2P(OPri)2}(C∩P)] have been established by single crystal X-ray diffraction analyses. The complex [Pt2(μ-SPh)2(C∩P)2] adopts a sym cis configuration while other binuclear complexes exist in a sym trans configuration. The molecular structure of [Pt{S2P(OPri)2}(C∩P)] revealed that complex comprises of two four-membered chelate rings but in solution a dimeric structure based on 195Pt NMR data has been suggested. 相似文献
A variety of single component rare earth aryloxides substituted by various alkyl groups [Ln(OAr)3] such as methyl, isopropyl, tert‐butyl have been surveyed in the ring‐opening copolymerization of 2,2‐dimethyltrimethylene carbonate (DTC) and ε‐caprolactone (ε‐CL). It was worthwhile to note that activity of the catalyst varied with both the ligands' structure and the number of alkyl groups on phenyl ring. The stronger ability of electron‐donation of alkyl groups on phenyl ring, and the more numbers of alkyl groups on phenyl ring, the higher catalytic activity. The experimental results show that lanthanum tris(2,4,6‐tri‐tert‐butylphenolate) [La(OTTBP)3] exhibits highest activity in all lanthanum aryloxides. 1H NMR spectral data of copolymer obtained showed that the polymerization mechanism is in agreement with the coordination insertion mechanism. 相似文献
An amphiphilic biodegradable polymer, poly(aspartic acid‐co‐lactic acid) (PAL), was synthesized by simply heating a mixture of aspartic acid (Asp) and L ‐lactide without additional catalysts or solvents. The unique branched architecture comprising succinimide units and lactic acid units was confirmed by IR and NMR spectroscopy. A copolymer of sodium aspartate and lactic acid (PALNa) was prepared by reacting PAL with an aqueous sodium hydroxide solution. The PAL was soluble in many organic solvents, while the PALNa was soluble in methanol and water. The hydrolytic degradation behavior of PAL varied with the copolymer composition. A higher Asp content resulted in a faster molecular weight decrease, and introducing glycolic acid units accelerated the degradation rate.
