Synthesis and structural systematics of nitrogen base adducts of group 2 salts .3. Some mixed-ligand complexes with pyridine base and oxygen donors

In association with the report of a number of homoleptic pyridine base adducts of Group 2 salts in the preceding paper, a number of mixed-ligand compounds have been synthesized and characterized by room-temperature single-crystal X-ray studies. MgI2.2H(2)O.6py=[trans(py)(4)Mg(OH2)(2)]I-2.2py (1) is monoclinic, P2(1)/c, a 10.47(1),b 10.0400(8), c 32.77(1) Angstrom, beta 92.34(6)degrees, Z=4; R was 0.053 for N-o=2990 independent, observed (I>3 sigma(I)) diffractometer reflections. Mg-O are 2.063(8) and 2.061(8), Mg-N ranging between 2.19(1) and 2.23(1) Angstrom. MgI2.4H(2)O.8(3,5-dmpy)=[trans-(3,5-dmpy)(2)Mg(OH2)(4)]I-2.6(3,5-dmpy) (2) is orthorhombic, Pcab, a 22.2.3(6), b 17.023(8), c 16.548(7) Angstrom, Z=4 f.u.; R 0.045 for N-o 2457. Mg-O are 2.026(5) and 2.082(5), and Mg-N 2.267(6) Angstrom in the centrosymmetric cation, with which the aggregate of anions and solvent form a discrete hydrogen-bonded cluster. CaBr2.2H(2)O.4(2-mpy)=[trans-CaBr2(OH2)(2)(2-mpy)(2)].2(2-mpy) (3) is monoclinic, P2(1)/c, a 7.076(1), b 9.329(3), c 21.957(2) Angstrom respectively, its 3-mpy counterpart (4) has a very similar cell but with b and c transposed; R was 0.047 for N-o 2116, and Ca-BR, N, O 2.8902(6), 2.500(5), 2.344(3) Angstrom. Sr(ClO4) are 2.644(8)-22.69(1), Sr-N 2.64(1)-2.69(1), Sr-O(dmf) 2.417(9) Angstrom. The other two compounds, Ba(ClO4)(2).H2O.L (L=py (6), 3-mpy (7)), are two-dimensional polymers, linked by bridging perchlorate ions and water molecules. Compound (6) is orthorhombic, Pnna, a 24.098(3), b 10.444(1), c 4.871(3) Angstrom, Z=4 f.u., R 0.025 for N-o 688; the barium is 11-coordinate Ba(O(H2O))(2)(O(ClO4))(8)N with m symmetry, Ba-N 2.889(7), Ba-O(H2O) 2.943(4), Ba-O(ClO4) 2.844(6)-2.942(5) Angstrom. Compound (7) is monoclinic, P2(1)/c, a 7.421(4), b 24.479(8), c 7.293(7) Angstrom, beta 104.80(6)degrees, Z=4 f.u., R 0.041 for N-o 2033; the barium is nine-coordinate Ba(O(H2O))(2)(O(ClO4))(6)N, Ba-N 2.839(7), Ba-O(H2O) 2.791(5), 3.049(5), Ba-O(ClO4) 2.753(6)-2.936(6) Angstrom.