Poly(9-phenyl-2,4,8,10-tetraoxaspiro-[5,5]undcane-3-one)(PPTC) was synthesized by the microwave-assisted ring-opening polymerization(MROP) of a six-membered cyclic carbonate monomer 9-phenyl-2,4,8,10-tetraoxaspiro-[5,5]undcane-3-one(PTC) with tin(Ⅱ) 2-ethylhexanoate(Sn(Oct)_2) or aluminum isopropoxide(Al(O^iPr)_3) as the catalysts. The obtained polycarbonates were further reduced by apalladium/carbonate catalyst(10% Pd/C) to afford partly deprotected polycarbonates containing hydroxyl groups(HPPTC). These two types of polycarbonates were characterized by ~1H-NMR, Fourier transform infrared spectroscopy(FTIR), UV, gel permeation chromatography(GPC), differential scanning calorimetry(DSC), and automatic contact-angle measurements. The influence of the feed molar ratio of monomer-to-catalyst, the microwave irradiation power and the reaction time on the polymerization was also studied. The experimental results showed that HPPTC possessed significantly higher hydrophilicity and water absorption rate than PPTC.
Fan LiuLi-li MeiZhi-lin Tan鄢国平Jun-fang GuoQiao ZhangHui LiuJun Yang
Gadolinium diethylenetriamine-pentaacetic bisdopamide (Gd-DTPA-2DA) was synthesized by the incorporation of dopamine to diethylenetriaminepentaacetic acid (DTPA) and further reaction with gadolinium chloride. In vitro and in vivo properties were also evaluated. Gadolinium complex Gd-DTPA-2DA possessed higher relaxation effectiveness and less cytotoxicity to HeLa cells than that of Gd-DTPA. Moreover, Gd-DTPA-2DA greatly enhanced the contrast of MR images of the brains, provided prolonged intravascular duration, and produced highly contrasted visualization of the brain.
