Anion-induced structural diversity in 12-crown-4 complexes of transition metal salts

The synthesis and X-ray crystal structures of eight transition metal comple xes of 12-crown-4 are reported. These are: [Mn(H2O)(6)][Mn(12-crown-4)(2)]( 2)(ClO4)(6). 6H(2)O (1), [Ni(H2O)(6)](ClO4)(2). 12-crown-4 (2), [Zn(12-crow n-4)(2)](2)[Zn(H2O)(6)](ClO4)(6). (12-crown-4)(2). (H2O)(2) (3), [Mn(12-cro wn-4)(2)][MnCl4].H2O (4), [Co(12-crown-4)CI(H2O)](2)(ClO4).H2O (5), [Zn(12- crown-4)(2)][ZnCl3(H2O)](2) (6), [Cu(Br)(2)(12-crown-4)] (7) and [Cd(12-cro wn-4)(NO3)(2)] (8). Depending on the identity of the counter anion, the str uctures fall into three groups: (1) hydrogen bonded polymers; (2) sandwich M(12-crown-4)2 cations alternating with transition metal containing anions; and (3) neutral molecular species incorporating 12-crown-4. (C) 2001 Elsev ier Science Ltd. All rights reserved.