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二环己基-18-冠-6异构体A(dcc)在从盐酸体系中萃取UO_2Cl_2和UCl_4时,形成的配合物晶体的组成分别为(C_(20)H_(36)O_6·H_3O)_2UO_2Cl_4·2C_6H_6(1)和(C_(20)H_(36)O_6·H_3O)_2UCl_6(2).前者结晶学参数为C2/c,a=32.464(1),b=10.207(3),c=21.616(10)(?),β=119.73(5)°,Z=4.后者为:P2_1/c,a=12.746(1),b=29.898(4),c=14.573(3)(?),β=108.08(10)°,Z=4.最终的偏离因子 R 分别为0.044和0.047.结构分析证实,在1和2中,U(Ⅵ)和U(Ⅳ)均未与冠醚直接配位,而是分别形成配阴离子 UO_2Cl_4~(2-)和 UCl_6~(2-).而配阳离子均由冠醚环的三个氧原子与 H_3~+O 以较强的氢键键合,将H_3O~+稳定于冠醚环中,成为配阳离子 dcc·H_3O~+.由静电吸引及 Vander Waals 力形成稳定的晶体,因此 dcc 在二氯乙烷中萃取盐酸体系中 UO_2~(2+)和 U(Ⅳ)的过程分别为:UO_2~(2+)+2dcc+2H_3O~++4Cl~-=(dcc·H_3O)_2UO_2Cl_4和 U~(4+)+2dcc+2H_3O~++6Cl~-=(dcc·H_3O)_2UCl_6.
The composition of dicyclohexyl-18-crown-6 isomer A (dcc) in the extraction of UO_2Cl_2 and UCl_4 from the hydrochloric acid system were (C_ (20) H_ (36) O_6 · H_3O) _2UO_2Cl_4 The crystallographic parameters of the former were C2 / c, a = 32.464 (1), b = 10.207 (3), c = 21.616 (10) (?), Β = 119.73 (5) ° and Z = 4. The latter are: P2_1 / c, a = 12.746 (1), b = 29.898 (4), c = 14.573 (3) , β = 108.08 (10) ° and Z = 4. The final deviation factors R were 0.044 and 0.047, respectively. Structural analysis confirmed that U (Ⅵ) and U (Ⅳ) But with the formation of anion UO_2Cl_4 ~ (2-) and UCl_6 ~ (2-), respectively, while the cations are all bonded to the H_3 ~ + O by the three oxygen atoms of the crown ether ring with strong hydrogen bonds. H_3O ~ + is stable in the crown ether ring and becomes a cation dcc · H_3O ~ +. The electrostatic attraction and Vander Waals force form a stable crystal, so dcc is extracted from the system of hydrochloric acid by dichloroethane. The processes of U (Ⅳ) are as follows: UO_2 ~ (2 +) + 2dcc + 2H_3O ~ + 4Cl ~ - = (dcc · H_3O) _2UO_2Cl_4 and U ~ (4 +) + 2dcc + 2H_3O ~ (dcc · H_3O) _2UCl_6.