Synthesis of Aliphatic Polyanhydrides with Controllable and Reproducible Molecular Weight.

Polyanhydrides have been synthesized for decades by melt-polycondensation of diacid monomers and 5 to >10 times mole excess acetic anhydride to diacid monomers to form polymers with a polydispersity ranging from 2.5 to 6 and low reproducibility. Hydrophobic segments in polyanhydrides are beneficial to hinder the characteristic hydrolytic cleavage of an anhydride bond that provides stable polyanhydrides at room temperature.

Poly(ester-anhydrides) Derived from Esters of Hydroxy Acid and Cyclic Anhydrides.

The alternating architecture and hydrophobic side chains hinder hydrolytic cleavage and anhydride interchange in poly(sebacic acid-ricinoleic acid) (P(SA-RA)), which provides stable polyanhydrides at room temperature. In this report, a series of polyanhydrides were designed to investigate the effect of ester bonds, hydrophobic side chains, phenyl moieties, and their distance from anhydride bonds on their stability and properties. Polyanhydrides with alternating architecture are constructed by the polymerization of ester-diacids prepared from ricinoleic or other hydroxy acids with anhydrides such as succinic, maleic, and phthalic anhydrides.

Unprecedented formation of palladium(II)-pyrazole based thiourea from chromone thiosemicarbazone and [PdCl(PPh)]: Interaction with biomolecules and apoptosis through mitochondrial signaling pathway.

Two novel pyrazole based thiourea palladium(II) complexes, [PdCl(PPh)(CHNOS-pz)] (1) and [PdCl(PPh)(CHNOS-pz)] (2) [pz = pyrazole (CHN)] have been obtained unexpectedly from chromone thiosemicarbazones (L1 and L2) and [PdCl(PPh)]. The compounds have been fully characterized by physicochemical studies. The single crystal X-ray diffraction and spectral studies revealed square planar geometry for the complexes.