冠醚配合物热力学性质的研究 Ⅹ.用NMR研究15-冠-5衍生物与钠离子的配位反应  

Studies on Thermedynamic Properties of Crown Compounds——X. Coordination Reaction of Methyl Derivaties of 15-Crown-5 with Sodium Ion by ^(23)Na NMR

作　　者：罗勤慧[1] 冯旭东[1] 沈孟长[1] 屠庆云 

机构地区：[1]南京大学配位化学研究所

出　　处：《化学学报》1989年第8期727-730,共4页Acta Chimica Sinica

基　　金：国家自然科学基金

摘　　要：用^(23)Na NMR研究了15-冠-5(15C5),2,3-苯并-15-冠-5(B-15C5),2,3-苯并-6-甲基-15冠-5(BC1-15C5),2,3-苯并-8,12-二甲基-15-冠-5(BC2-15C5)在丙酮中与Na^+的配位反应,由此探索甲基的影响。实验结果表明,当在金属盐溶液中加入冠醚,配体为15C5时,体系表观化学位移移至低场,配体为B-15C5,BC1-15C5,BC2-15C5时,体系的表现化学位移移至高场。后者与苯并-18-冠-6及其甲基衍生物不同,这是由于苯环在空间排布不同所致,用Newton-Raphson法和描坑法(Pit-mapping)拟合实验数据,发现BC1-15C5和BC2-15C5除形成NaL^+和NaL_2^+外还有不稳定的Na_3L_2^(3+)形成。本文对形成过程和生成NaL^+反应的平衡常数lgK_(11)与甲基数的关系亦作了讨论,lgK_(11)与甲基数目n近似成直线关系,可用下式表示:lgK_(11)=3.50-0.480n,n=0,1,2。The coordination reaction of 2, 3-benzo-6-methyl-15-crown-5, 2, 3-benzo-8, 12- dimethyl-15-crown-5, 2, 3-benzo-15-crown-5 and 15-crown-5 with sodium ion was studied by NMR in acetone to probe the effect of methyl at crown ring on coordination ability and some regularities. The experimental results show that adding NaI fo the solution of crown, the chemical shift of ^(23)Na shifted toward low field for 15C5 similar to that of benzo-derivatives of 18C6 but it shifted toward high field for 15C5 with benzo- ring. The difference may be due to orientation of benzo-ring in crowns. Fitting the data by Newton-Raphson method and pit-mapping method, we found that unstable species Na_3L_2^(3+) formed (L=BC1-15C5 and BC2-15C5) besides NaL^+ and NaL_2^+ In this paper we discussed the formation reaotion of Na_3L_2^(3+) and found the relationship between formation constants lg K_(11) of NaL and n, the number of methyl, that is lgK(11)=3.50-0.480n (n=0, 1, 2).

关 键 词：热力学性质 钠离子 配位反应 15-冠5 冠醚 配合物 衍生物 

分 类 号：O614.112[理学—无机化学] O623.423[理学—化学]