Cyanide-bridged lanthanide(III)-transition metal extended arrays: interconversion of one-dimensional arrays from single-strand (type A) to double-strand (type B) structures. Complexes of a new type of single-strand array (type C)

A series of one-dimensional arrays of lanthanide-transition metal complexes has been prepared and characterized. These complexes, (DMF)(10)Ln(2)Ni(CN)(4)](3)](infinity), crystallize as linear single-strand arrays (structural type A) (Ln = Sm, 1a; Eu, 2a) or double-strand arrays (structural type B) (Ln = Sm, 1b; Eu, 2b) depending upon the conditions chosen, and they are interconvertible. The single-strand type A structure can be converted to the double-strand type B structure. When the 1b and 2b type B crystals are completely dissolved in DMF, their infrared spectra are identical to the infrared spectra of 1a and 2a type A crystals dissolved in DMF. These solutions produce type A crystals initially. It is believed that formation of the type A structure is kinetically favored while the type B structure is thermodynamically favored for lanthanide-nickel complexes 1 and 2. On the other hand the complex (DMF)(10)Y(2)Pd(CN)(4)](3)](infinity), 3, appears to crystallize only as the double-strand array (type B). The complexes (DMF)(12)Ce(2)Ni(CN)(4)](3)](infinity), 4, and (DMF)(12)Ce(2)Pd(CN)(4)](3)](infinity), 5, crystallize as a new type of single-strand array (structural type C). This structural type is a zigzag chain array. Crystal data for 1a: triclinic space group P1, a = 10.442(5) A, b = 10.923(2) A, c = 15.168(3) A, alpha = 74.02(2) degrees, beta = 83.81(3) degrees, gamma = 82.91(4) degrees, Z = 2. Crystal data for 1b: triclinic space group P1, a = 9.129(2) A, b = 11.286(6) A, c = 16.276(7) A, alpha = 81.40(4) degrees, beta = 77.41(3) degrees, gamma = 83.02(3) degrees, Z = 2. Crystal data for 2a: triclinic space group P1, a = 10.467(1) A, b = 10.923(1) A, c = 15.123(1) A, alpha = 74.24(1) degrees, beta = 83.61(1) degrees, gamma = 83.13(1) degrees, Z = 2. Crystal data for 2b: triclinic space group P1, a = 9.128(1) A, b = 11.271(1) A, c = 16.227(6) A, alpha = 81.36(2) degrees, beta = 77.43(2) degrees, gamma = 82.99(1) degrees, Z = 2. Crystal data for 3: triclinic space group P1, a = 9.251(3) A, b = 11.193(4) A, c = 16.388(4) A, alpha = 81.46(2) degrees, beta = 77.18(2) degrees, gamma = 83.24(3) degrees, Z = 2. Crystal data for 4: triclinic space group P1, a = 11.279(1) A, b = 12.504(1) A, c = 13.887(1) A, alpha = 98.68(1) degrees, beta = 108.85(1) degrees, gamma = 101.75(1) degrees, Z = 2. Crystal data for 5: triclinic space group P1, a = 11.388(3) A, b = 12.614(5) A, c = 13.965(4) A, alpha = 97.67(3) degrees, beta = 109.01(2) degrees, gamma = 101.93(2) degrees, Z = 2.