Synthesis and structural systematics of nitrogen base adducts of group 2 salts .7. Some complexes of group 2 metal halides with aromatic N,N'-bidentate ligands

Syntheses and room-temperature single-crystal X-ray structural characterizations are recorded for a number of adducts of Group 2 halides with the aromatic N,N'-bidentate ligands L = 2,2'-bipyridine (bpy) and 1,10-phenanthroline (phen). One adduct of 1 : 1 MX(2)/L stoichiometry is recorded: [(bpy)Ca(mu-Br)((4/2))]((infinity\infinity)) (1) is monoclinic, C 2/c, a 17.102(5), b 9.845(1), c 7.600(2) Angstrom, beta 107.65(2)degrees, Z = 4 f.u.; conventional R on \F\ at convergence was 0.057 for N-o 817 independent 'observed' (I > 3 sigma(I)) reflections, the compound being a one-dimensional polymer...CaL(mu-Br)(2)CaL(mu-Br)(2)..., with six-coordinate calcium, cis-CaN2(mu-Br)(4), on a twofold axis. 1 : 2 MX(2)/L systems have been described for two types of array: [(bpy)(2)CaI2] (2), orthorhombic, Pnca, a 16.914(4), b 13.80(1), c 9.290(4) Angstrom, Z = 4 f.u.; R 0.039 for N-o 1738, is discrete mononuclear, containing cis-CaN4I2 six-coordinate calcium, whereas the barium analogue is an infinite one-dimensional polymer, [(bpy)(2)Ba(mu-I)((4/2))]((infinity\infinity)) (3), triclinic, <P(1)over bar>, a 11.318(2), b 11.078(2), c 9.206(4) Angstrom, alpha 80.87(2), beta 77.52(2), gamma 87.53(1)degrees, Z = 2 f.u.; R 0.032 for N-o 4154, with eight-coordinate (N-2)(2)Ba(mu-I)(4) The perchlorate analogue, [(bpy)(2)Ba(mu-OClO2O)((4/2))]((infinity\infinity)) (4), although of similar stoichiometry, has a trans- rather than a cis-linked chain; it is monoclinic, P 2(1)/c, a 6.606(2), b 18.661(7), c 19.440(8) Angstrom, beta 109.45(4)degrees, Z = 4 f.u.; R 0.044 for N-o 4060, with mu-I replaced by O,O'-ClO4 bridging units and eight-coordinate barium, (N-2)(2)BaO4. The 1 : 3 MX(2)/L system is represented (as its hemi(bipyridine) 'solvate') by mononuclear [(bpy)(3)SrI2].0.5bpy (5), monoclinic, P 2(1)/c, a 20.834(8), b 9.735(4), c 18.460(7) Angstrom, beta 114.87(3)degrees, Z = 4 f.u.; R 0.039 for N-o 3711, containing eight-coordinate strontium, [(N-2)(3)SrI2]; there is also an isomorphous calcium/perchlorate analogue [(bpy)(3)Ca(OClO3)(2)].0.5bpy (6), a 21.413(6), b 9.813(4), c 18.659(2) Angstrom, beta 115.67(2)degrees, R 0.057 for N-o 3090, in which unidentate O-ClO4 ligands replace the iodine about the metal atom. A 1 : 4 adduct is obtained with CaI2/phen; ionic [Ca(phen)(4)]I-2 (7), triclinic, <P(1)over bar>, a 14.703(3), b 13.292(3), c 11.38(1) Angstrom, alpha 92.78(4), beta 96.15(4), gamma 105.22(2)degrees, Z = 2 f.u., R 0.053 for N-o 3658, contains eight-coordinate Ca(N-2)(4) arrays, while the novel 1 : 5 adduct [Ba(phen)(5)]I-2.MeCN (8) is triclinic, <P(1)over bar>, a 12.170(6), b 13.760(7), c 18.254(8) Angstrom, alpha 77.05(9), beta 71.96(4), gamma 70.83(9)degrees, Z = 2 f.u., R 0.040 for N-o 4447, containing 10-coordinate barium, [Ba(N-2)(5)]. A 1 : 4 adduct formed with BaBr2 is [BrBa(phen)(4)] Br.MeOH (9), triclinic, <P(1)over bar>, a 17.748(4), b 17.418(2), c 15.535(7) Angstrom, alpha 91.63(2), beta 100.53(3), gamma 115.39(1)degrees, Z = 4 f.u., R 0.062 for N-o 4092, containing nine-coordinate barium, [BrBa(N-2)(4)].