MANIFESTATIONS OF NONCOVALENT INTERACTIONS IN THE SOLID-STATE .3. X-RAY CRYSTAL-STRUCTURES OF [H4(CYCLAM)][FECL5(OH2)](CL)2 AND [H4(CYCLAM)][CF3COO]4, 2 NETWORK HYDROGEN-BONDED SOLIDS

FeCl2 or FeCl3 react with cyclam (cyclam = 1,4,8,11-tetraazacyclotetra decane) in an acidic medium (4 M HCl) to afford dark orange-red plates of [H-4(cyclam)][FeCl5(OH2)](Cl)2 (1). 1 crystallizes in a polar spac e group (orthorhombic, Pc2(1)b) with a = 10.7730(6), b = 13.3418(10), c = 14.4564(10) angstrom, V = 2077.84(24) angstrom3, and D(calc) = 1.6 8 g cm-3 for Z = 4. Final values of R = 0.031 and Rw = 0.034 were obta ined for 1950 independent observed (1 > 3sigma(I)) reflections. Cyclam reacts with neat trifluoroacetic acid to afford a colourless salt, [H -4(cyclam)][CF3COO]4 (2). 2 crystallizes in a centric space group (mon oclinic, P2(1)/c), with a = 8.7442(11), b = 10.5121(11), c = 15.2469(2 0) angstrom, beta = 102.526(15)degrees, V = 1368.1(3) angstrom3, and D (calc) = 1.593 g cm-3 for Z = 2. Final values of R = 0.059 and Rw = 0. 067 were obtained for 1336 independent observed (I > 3sigma(I)) reflec tions. Extensive interionic hydrogen bonding between the cyclam cation s, which adopt exodentate conformations, and anions results in network polymeric hydrogen bonding (1-D for 1, 2-D for 2). The networking in 1 is intrinsically polar because one chloride anion and the [FeCl5(OH2 )]2- complex anion are involved in networking between the H-4(cyclam)4 + cations. The implications of the crystal structures are discussed fr om the perspective of rational design of polar solids.