Syntheses and single-crystal X-ray structural characterizations (at c. 295 K) are recorded for the 1 : 1 adducts of copper(I) chloride, bromide and iodide with L = 2,2′-bipyridine. The chloride is triclinic, Pī , a 14.069(5), b 10.520(3), c 7.872(2)Ǻ, α 69.00(2), β 88.62(3), γ 70.70(2)°, Z = 4 formula units; R was 0.041 for No 1805 'observed' [I > 3σ(I)] reflections. The bromide is monoclinic, P21/c, a 8.788(3), b 13.206(6), c 9.895(3)Ǻ, β 117.90(2)°, Z = 4 formula units; R 0.036 for No 1007. The iodide is monoclinic, C2/c, a 17.571(3), b 8.587(7), c 16.796(3)Ǻ, β 120.17(2)°, Z = 8 formula units; R 0.041 for No 1038. The chloride is ionic, [CuL2]+ [ ClCuCl ]-; in the cation, Cu-N are 2.005(6)-2.039(6)Ǻ with interligand N-Cu-N 114.4(3)-132.4(2)°, while, in the anion, Cl-Cu-Cl is 177.3(1)°, with Cu-Cl 2.086(2) and 2.091(2)Ǻ. The bromide (unlike its 1,10-phenanthroline counterpart, which is ionic) is a centrosymmetric dimer , as also is the iodide. In the bromide, Cu-N are 2.083(6), 2.099(5), and Cu-Br 2.428(2), 2.463(1)Ǻ, Cu…Cu and Br…Br being 2.850(1) and 3.975(2)Ǻ respectively. In the iodide, Cu-N are 2.070(8), 2.08(1), and Cu-I, 2.583(3)Ǻ (×2), and Cu…Cu and I…I are 2.610(2) and 4.420(1)Ǻ.

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)](∞ ׀ ∞) (1) is monoclinic, C 2/c, a l7.102(5), b 9.845(1), c 7.600(2) Ǻ, β 107.65(2)°, Z = 4 f.u .; conventional R on #1472; F ׀ at convergence was 0.057 for No 817 independent 'observed' ( I > 3σ(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) Ǻ, 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)](∞׀ ∞) (3), triclinic, Pī, a 11.318(2), b 11.078(2), c 9.206(4) Ǻ, α 80.87(2), β 77.52(2), γ 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)](∞ ׀ ∞) (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) Ǻ, β 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) Ǻ, β 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) Ǻ, β 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, Pī , a 14.703(3), b 13.292(3), c 11.38(1) Ǻ, α 92.78(4), β 96.15(4), γ 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, Pī , a 12.170(6), b 13.760(7), c 18 254(8) Ǻ, α 77.05(9), ,β 71.96(4), γ 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, Pī , a 17.748(4), b 17.418(2), c 15.535(7) Ǻ, α 91.63(2), β 100.53(3), γ 115.39(1)°, Z = 4 f.u ., R 0.062 for No 4092, containing nine-coordinate barium, [ BrBa (N2)4].

Adducts (1 : 1) of copper(I) chloride, bromide and thiocyanate with quinoline have been synthesized and have been the subject of single-crystal X-ray structure determinations at 295 K. Crystals of the chloride are orthorhombic, P 212121, a 15.358(7), b 14.309(6), c 3.801(2)Ǻ, Z 4; R was 0.055 for 541 'observed' reflections. Crystals of the bromide are monoclinic, C2/c, a 19.417(5), b 14.048(4), c 15.753(6) Ǻ, β 125.31(2)°, Z 4 tetramers; R was 0.049 for 1138 'observed' reflections. Crystals of the thiocyanate are monoclinic, P 21/c, a 5.682(1), b 10.412(2), c 16.838(5)Ǻ, β 97.48(2)°, Z 4 f.u .; R was 0.045 for 914 'observed' reflections. The chloride takes the form of the common 'stair' polymer, unexpectedly, while the thiocyanate is an expanded version of the same. The bromide provides a second example of a novel tetrameric 'basket' structure exemplified previously by the iodide analogue.

Room-temperature single-crystal X-ray structural characterizations are recorded for a variety of adducts of Group 2 metal halides with 2,2':6',2?-terpyridine ( tpy ) from various hydroxylic solvents. [Mg( tpy )2][Mg( tpy )(OH2)3] Br4.PriOH (1) is triclinic, Pī, a 19.352(6), b 12.852(5), c 11.463(3) Ǻ, α 110.95(3), β 99.04(2), γ 98.81(3)°, Z = 2 f.u .; conventional R on ׀ F ׀ at convergence was 0.056 for No 4398 independent 'observed' (I > 3σ(I)) reflections. In the [Mg( tpy )2]2+ ion, Mg-N(central; distal) are 2.099(9), 2.09(1); 2.152(9)-2.212(8) Ǻ, while in [Mg( tpy )(OH2)3]2+, Mg-N(central; distal) are 2.139(7); 2.206(9), 2.222(9) Ǻ, while Mg-O trans to these are 2.042(6); 2.082(9), 2.097(8) Ǻ. [Mg( tpy )(OH2)2( MeOH )] Cl2 (2) is triclinic, Pī, a 14.049(7), b 8.354(4), c 8.301(2) Ǻ, α 74.25(3), β 73.05(3), γ 80.37(4)°, Z = 2 f.u., R 0.064 for No 2417. In the cation, Mg-N(central; distal) are 2.125(4); 2.203(4), 2.218(4) Ǻ; Mg-O( MeOH ) is trans to Mg-N(central), being 2.013(4) Ǻ; Mg-O(OH2) are 2.067(4) and 2.063(4) Ǻ. [CaCl2( tpy )( dmf )2 (3) ( dmf = N,N- dimethylformamide ) is monoclinic, C2/c, a 23.27(2), b 11.225(6), c 16.517(8) Ǻ, β 109.56(5)°, Z = 4 centrosymmetric dimers, R 0.061 for No 985. The calcium atoms are linked by a pair of μ-chlorines, CaCl2Ca, and are seven-coordinate, N3Ca(μ-Cl )4 being broadly coplanar in the equatorial plane of a pentagonal bipyramidal array, with the other chlorine and the dmf oxygen trans and axial.

Recrystallization of anhydrous Group 2 halides from anhydrous acetonitrile has yielded, in a number of cases, adducts MX2.nMeCN suitable for characterization by room-temperature single-crystal X-ray studies, which revealed novel stereochemical types. Magnesium(II) bromide yields a trisolvate, ionic with disproportionated ligand arrays, as [Mg(NCMe)6][MgBr4] (1), an unusual combination of homoleptic cationic and anionic species. Crystals are triclinic, Pī , a 19.129(1), b l6.870(8), c 8.737(7) Ǻ,α 83.96(3), β 87.93(4), γ 65.24(2)�, Z=4 f.u .; R was 0.068 for N o 3181 'observed' (I > 3σ(I)) reflections. Mg-N are 2.12(2)-2.18(2) Ǻ, and Mg-Br are 2.452(7)-2.481(6) Ǻ. Calcium(II) bromide, by contrast, yields a disolvate , an infinite polymer, with the two MeCN ligands trans in a quasi-octahedral coordination sphere, and the polymer comprising a ... Ca(μ-Br)2Ca(μ-Br)2... linear array. Crystals of 1:2 CaBr2/MeCN (2) are orthorhombic, Pbam , a l4.252(3), b 8.539(2), c 4.2088(6) Ǻ, Z=2 f.u .; R 0.043 for N o 352. Ca-N is 2.46(1) Ǻ, and Ca-Br 2.8765(9) Ǻ. CaI2 and SrI2 yield pentasolvates as neutral, molecular species [( MeCN )5MX2] (3) and (4), with the halides trans in a pentagonal bipyramidal coordination sphere. They are isomorphous . orthorhombic, Pcab , a ≈ 18.4, b ≈ 14.6, c ≈ 14.3 Ǻ, Z = 8 f.u .; R were 0.042 and 0.059 for N o 2297 and 1489 respectively. Ca-I are 3.132(2), 3.116(2) Ǻ and Sr -I are 3.265(3), 3.238(3) Ǻ, while Ca-N are (range) 2.518(8)-2.566(8) Ǻ and Sr -N 2.68(2)-2.73(2) Ǻ.