Manifestations of noncovalent bonding in the solid state. 6. [H4(cyclam)]4+ (cyclam = 1,4,8,11-tetraazacyclotetradecane) as a template for crystal engineering of network hydrogen-bonded solids

Abstract

A series of salts of composition [H4(cyclam)]X•nH2O, where cyclam = 1,4,8,11-tetraazacyclotetradecane and X = 4Cl− (1−, n = 4), 4Br− (2, n = 4), 4I− (3, n = x), 4ClO4−(4, n = 2), 4CNS− (5, n = 2), 2SO42−(6, n = 6), and (p-CH3C6H4SO3−) (7, n = 0) have been prepared and crystal structures of 1, 2, 4, 5, 6, and 7 have been determined by single crystal X-ray crystallography. 1, 2, 3, 4, and 7 were prepared by crystallizing cyclam with a large excess of the corresponding acid whereas the thiocyanate, 5, and the sulphate, 6, salts were prepared by metathesis of the perchlorate salt, 4, with KCNS and K2SO4, respectively. Crystal data: 1: orthorhombic, Pnnb, a = 7.7962(16), b = 14.278(4), c = 17.787(4) Å, V = 1979.9(8) Å3, Z = 4, Dc = 1.39 Mg m−3, Rf = 0.051, and Rw = 0.069 for 1176 reflections with I > 3σ(I). 2: triclinic. [Formula: see text]a = 7.6860(8), b = 7.8848(9), c = 9.6385(11) Å, α = 105.111(16)°, β = 95.495(18)°, γ = 102,464(17)°, V = 543.43(12) Å3, Z = 1, Dc = 1 1.82 Mg m−3,Rf = 0.034, and Rw = 0.041 for 1530 reflections with I > 3σ(I). 4: monoclinic, P21/n, a = 8.4519(11), b = 15.9248(12), c = 9.2981(17) Å, β = 106.243(18)°, V = 1201.5(3) Å3, Z = 2, Dc, = 1.76 Mg m−3, Rf = 0.052, and Rw = 0.068 for 1902 reflections with I > 3.0σ(I). 5: triclinic, [Formula: see text] a = 8.2996(7), b = 9.0061(15), c = 9.2015(15) Å, α = 107.60(3)°, β = 97.738(14)°, γ = 108.863(9)°, V = 599.44(15) Å3, Z = 1, Dc = 1.309 Mg m−3Rf = 0.038 and Rw = 0.049 for 1856 reflections with I > 4σ(I). 6: triclinic, [Formula: see text] a = 7.8687(5), b = 8.8396(12), c = 9.0405(25) Å, α = 68.547(16), β = 85.332(9), γ = 78.473(7)°, V = 573.43(18) Å3, Z = 1, Dc = 1.693 Mg m−3, Rf = 0.053 and Rw = 0.076 for 1441 reflections with I > 3σ(I). 7: triclinic, [Formula: see text] a = 8.533(3), b = 9.110(3), c = 15.3605(21) Å, α = 82.475(17)°, β = 74.307(20)°, γ = 73.26(3)°, V = 1099.0(5) Å3, Z = 1, Dc = 1.343 Mg m−3, Rf = 0.042 and Rw = 0.052 for 2460 reflections with I > 2.5σ(I). 1, 2, 4, 5, 6, and 7 exhibit extensive network hydrogen bonding between the anions, cations, and, if appropriate, water molecules of crystallization. The dimensionality of the hydrogen-bonded networks is dependent upon the nature of the anion and the number of water molecules of crystallization since the cation adapts a centrosymmetric exodentate conformation in all six salts. Keywords: crystal engineering, cyclams, network hydrogen bonding.