Synthesis and Structural Systematics of Nitrogen Base Adducts of Group 2 Salts. VII. Some Complexes of Group 2 Metal Halides With Aromatic N,N'-Bidentate Ligands

Abstract

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 MX2/L stoichiometry is recorded: [( bpy )Ca(µ-Br)(4/2)](8 ? 8) (1) is monoclinic, C 2/c, a l7.102(5), b 9.845(1), c 7.600(2) ?, ß 107.65(2)°, Z = 4 f.u .; conventional R on #1472; F ? at convergence was 0.057 for No 817 independent 'observed' ( I > 3s(I)) reflections, the compound being a one-dimensional polymer… CaL (µ-Br)2CaL(µ-Br)2…, with six-coordinate calcium, cis-CaN2(µ-Br)4, on a twofold axis. 1 : 2 MX2/L systems have been described for two types of array: [( bpy )2CaI2] (2), orthorhombic, Pnca, a 16.914(4), b 13.80(1), c 9.290(4) ?, Z = 4 f.u .; R 0.039 for No 1738, is discrete mononuclear, containing cis-CaN4I2 six-coordinate calcium, whereas the barium analogue is an infinite one-dimensional polymer, [( bpy )2Ba(µ-I)(4/2)](8? 8) (3), triclinic, Pi, a 11.318(2), b 11.078(2), c 9.206(4) ?, a 80.87(2), ß 77.52(2), ? 87.53(1)°, Z = 2 f.u .; R 0.032 for No 4154, with eight-coordinate (N2)2Ba(µ-I)4. The perchlorate analogue, [( bpy )2Ba(µ-OClO2O)(4/2)](8 ? 8) (4), although of similar stoichiometry, has a trans-rather than a cis-linked chain; it is monoclinic, P 21/c, a 6.606(2), b 18.661(7), c 19.440(8) ?, ß 109.45(4)°, Z = 4 f.u .; R 0.044 for No 4060, with µ-I replaced by O,O'-ClO4 bridging units and eight-coordinate barium, (N2)2BaO4. The 1 : 3 MX2/L system is represented (as its hemi( bipyridine ) 'solvate') by mononuclear [( bpy )3SrI2].0.5bpy (5), monoclinic, P 21/c, a 20.834(8), b 9.735(4), c 18.460(7) ?, ß 114.87(3)°, Z = 4 f.u .; R 0.039 for No 3711, containing eight-coordinate strontium, [(N2)3SrI2]; there is also an isomorphous calcium/ perchlorate analogue [( bpy )3Ca(OClO3)2].0.5bpy (6), a 21.413(6), b 9.813(4), c 18.659(2) ?, ß 115.67(2)°, R 0.057 for No 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] I2 (7), triclinic, Pi , a 14.703(3), b 13.292(3), c 11.38(1) ?, a 92.78(4), ß 96.15(4), ? 105.22(2)°, Z = 2 f.u ., R 0.053 for No 3658, contains eight-coordinate Ca(N2)4 arrays, while the novel 1 : 5 adduct [ Ba ( phen )4] I2.MeCN (8) is triclinic, Pi , a 12.170(6), b 13.760(7), c 18 254(8) ?, a 77.05(9), ,ß 71.96(4), ? 70.83(9)°, Z = 2 f.u ., R 0.040 for No 4447, containing 10-coordinate barium, [ Ba (N2)5]. A 1 : 4 adduct formed with BaBr2 is [ BrBa( phen )4] Br.MeOH (9), triclinic, Pi , a 17.748(4), b 17.418(2), c 15.535(7) ?, a 91.63(2), ß 100.53(3), ? 115.39(1)°, Z = 4 f.u ., R 0.062 for No 4092, containing nine-coordinate barium, [ BrBa (N2)4].