| Summary: | 碩士 === 國立中興大學 === 化學系所 === 106 === Ten novel di-nuclear metal complexes bearing diamine-bis(benzotriazole phenolate)(DiBTP) ligands, [(C83CHDiBTP)Ni2(OAc)2(MeOH)] (1), [(C83CHDiBTP)Ni2(OAc)2(DMAP)] (2), [(C85CHDiBTP)Ni2(OAc)2(MeOH)] (3), [(C85CHDiBTP)Ni2(OAc)2(H2O)] (4), [(C85CHDiBTP)Ni2(OAc)2(DMAP)] (5), [(C85CHDiBTP)Ni2(O2CCF3)2(H2O)] (6), [(C85CHDiBTP)Ni2(O2CC6F5)2(MeOH)] (7), [(C85CHDiBTP)Ni2(NP)2(H2O)] (8), [(C85CHDiBTP)Ni2(DNP)2(H2O)] (9), [(C85CHDiBTP)Co2(OAc)2(H2O)] (10) have been synthesized and structurally characterized. Their catalytic performances of carbon dioxide/epoxides coupling and copolymerization were systematically studied.
Experimental results indicated that these nickel complexes (1)-(9) are all active for the copolymerization of cyclohexene oxide with carbon dioxide. Among them, complex 3 shows the highest catalytic activity (TOF> 1040 h-1) and illustrates a characteristic that the molecular weight of PCHC almost increases linearly with the gradually enlarged conversion. Complex 3 was able to efficiently copolymerize not only CO2/CHO copolymerization, but also was applied to catalyze the copolymerization of 4-vinyl-1,2-cyclohexene oxide (VCHO) and cyclopentene oxide (CPO) or coupling of hexene oxide (HO) with CO2 to obtain the corresponding polycarbonate or cyclic carbonate. Upon addition of excess of chain transfer agents (CTA), like water, small molecular weight polycarbonate polyols could be produced with almost the same CHO or VCHO conversion yield compare to that without the addition of CTA. A unimodal molecular weight distribution was observed by GPC, and the resulting polymer microstructure contains two –OH end-chains, which was identified by MALDI-TOF. In addition, complex 3 could effectively catalyze the copolymerization of unpurified CHO with CO2 to obtain small molecular weight with the remaining activity.
DiBTP-ligand cobalt complex 10 towards the copolymerization of cyclohexene oxide with carbon dioxide also displayed a high catalytic performance as good as di-nickel complex 3. In addition, both complexes 3 and 10 enabled to efficiently catalyze the copolymerization of cyclohexene oxide at 1 atm CO2 to obtain the alternating polycarbonate.
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