Interconversion of a monomer and two coordination polymers of a copper(II)-reduced Schiff base...

Two compounds, [Cu(3)(Sbal)(2)(phen)(H(2)O)(2)](ClO(4))(2)-3H(2)O (1) and [Cu(H(2)Sbal)(2)(phen)](ClO(4))(2) (2), were isolated in successive steps from the reaction mixture containing Cu(ClO(4))(2)-6H(2)O, 1,10-phenanthroline, N-(2-hydroxybenzyl)-beta-alanine (H(2)Sbal), and LiOH in the ratio of 1:1:1:1. When the ratio of the base was doubled, the neutral monomer [Cu(Sbal)(phen)]-2H(2)O (3) was obtained. The cation in 1 exists as a one-dimensional polymer in the solid state, while weak O--H...O hydrogen bonds in the cation of 2 generate Delta Lambda Delta Lambda. type one-dimensional spiral chains. Addition of HClO(4) to 3 furnished 1 and 2, and this mixture can be converted back to 3 by the addition of a base. This conversion of a monomer to two 1-D polymers was found to be reversible. Crystal data for 1: triclinic space group P one macro, a = 12.0353(5) A, b = 12.2848(5) A, c = 15.3185(6) A, alpha = 84.993(1) degrees, beta = 89.411(1) degrees, gamma = 67.414(1) degrees, V = 2082.5(2) A(3), Z = 2, rho(calcd) = 1.668 g cm(-3). Crystal data for 2: tetragonal space group P4(1)/a, a = 10.8095(1) A, c = 59.0159(4) A, V = 6895.7(1) A(3), Z = 8, rho(calcd) = 1.605 g cm(-3). Crystal data for 3: monoclinic space group Pn, a = 10.6344(3) A, b = 5.3953(1) A, c = 18.1983(1) A, V = 1029.26(4) A(3), Z = 2, rho(calcd) = 1.526 g cm(-3). When Cu(NO(3))(2) was used in the place of Cu(ClO(4))(2), [Cu(2)(Sbal)(phen)(3)](NO(3))(2)-2.5H(2)O (4) was the only isolable product for the 1:1:1:1 ratio, and 3 was the only isolable product for the 1:1:1:2 ratio. Crystal data for 4: triclinic space group P one macro, a = 10.8063(8) A, b = 13.919(1) A, c = 16.564(1) A, alpha = 88.957(2) degrees, beta = 71.008(1) degrees, gamma = 69.829(2) degrees, V = 2198.9(3) A(3), Z = 2, rho(calcd) = 1.556 g cm(-3). Variable temperature magnetic measurements showed that the polymeric structure in 1 behaves, magnetically, as a strongly coupled micro-phenoxo dimer (2J = -390 cm(-1)) plus an isolated monomer.