摘要
合成并表征了由一定长度烷氧链桥连的新型双核 Salen Zn配合物 [简记为 C1 0 -(Salen Zn) 2 ],用紫外 -可见光谱滴定方法测定了主体 C1 0 -(Salen Zn) 2 与单齿客体咪唑 (Im)、吡啶 (Py)、双齿客体 DABCO(1 ,4-重氮双环 [2 .2 .2 ]辛烷 )及吡嗪 (Pyrazine)等 4种含氮客体间的轴向配位反应的配位数及缔合常数 .结果表明 ,双核主体与咪唑、吡啶和吡嗪的配位数均为 2 ,与 DABCO的配位数为 1 ;各主客体体系的缔合常数按K0 (Im) >K0 (DABCO) >K0 (Pyrazine) >K0 (Py)顺序递减 .各主客体缔合反应的热力学参数Δr H0m,Δr S0m和Δr G0m 结果表明 ,此类识别过程均为放热和熵减少的过程 .采用 1 H NMR方法和分子动力学构象搜索方法对主体 C1 0 -(Salen Zn) 2 与双齿客体 DABCO间的分子识别行为及产物构型作了合理解释 .通过量子化学计算进一步解释了主客体识别过程中光谱性质的变化 .
A novel dinuclear Salen zinc complex was synthesized and characterized. The coordination number and association constants of axial coordination reaction of complex C_ 10-(Salen Zn)_2 towards imidazole, pyridine, DABCO and Pyrazine were measured by means of spectra technique. The coordination number for Im, Py and pyrazine were all 2, but for DABCO was only 1. The association constants of host-vip system decreased in the order of K 0(Im)>K 0(DABCO)>K 0(Pyrazine)> K 0(Py). The thermodynamic parameters Δ_rH 0_m, Δ_rS 0_m and Δ_rG 0_m were determined. The results showed that recognition process was exothermic and entropy decrease. In addition, the studies by means of 1H NMR and the conformations with minimal energy of the host-vip were sought by simulated annealing method, which gave the reasonable explanation for the conformation of the host C_ 10-(Salen Zn)_2 and DABCO forming complex, the spectral changes of host-vip systems were explained by quantum chemical calculations.
出处
《高等学校化学学报》
SCIE
EI
CAS
CSCD
北大核心
2005年第3期412-417,共6页
Chemical Journal of Chinese Universities
基金
国家自然科学基金 (批准号 :2 0 1710 2 4
2 0 2 710 3 0 )
天津市自然科学基金 (批准号 :0 2 3 60 40 11)
教育部留学回国人员科研基金资助 .
