Synthesis and Structural Systematics of Nitrogen Base Adducts of Group 2 Salts. VI. Mixed Oligodentate-Aliphatic-Base/Oxygen Ligand Adducts

Abstract

In the course of synthesizing oligodentate aliphatic nitrogen base adducts of Group 2 metal salts, a number of mixed- ligand species have been isolated with oxygen ligands , and characterized by room-temperature single-crystal X-ray studies. BaCl₂.4en.H₂O ≡[(en)₄Ba(OH₂)] Cl₂ (1) is monoclinic, P 2₁/c, a 9.456(4), b 14.953(6), c 14.82(1) Ǻ, β 100.78(6)°, Z = 4 f.u ., R 0.043 for No 1862 independent 'observed' (I > 3σ(I)) diffractometer reflections. Ba -N range between 2.900(9) and 2.97(1) Ǻ, and Ba-O is 2.779(8) Ǻ in the nine-coordinate BaN₈O environment. CaCl₂.2dien.H₂O ≡ [( dien )₂Ca(OH₂) Cl ] Cl (2) is monoclinic, P 2₁/c, a 10.808(4), b 11.999(4), c 15.71(1) Ǻ, β 123.58(4)°, Z = 4 f.u ., R 0.050 for No 3134; CaBr₂.2dien.2H₂O ≡ [( dien )₂Ca(OH₂)₂] Br₂ (3) is monoclinic, P 21/c, a 18.001(3), b 11.983(6), c 21.562(5) Ǻ, β 124.97(2)°, Z = 8 f.u ., R 0.045 for No 2858; CaBr₂.2dien.2MeOH ≡ [( dien )₂Ca( HOMe )₂] Br₂ (4) is orthorhombic, P2₁2₁2₁, a 16.620(8), b 12.78(1), c 9.765(4) Ǻ, Z = 4 f.u ., R 0.073 for No 878. In (2)-(4), the cation configurations are similar, being of the form [L₂Ca( dien )2], L (L') being the unidentate ligand, with the eight-coordinate calcium environments [L₂Ca(N₃)₂] in a common isomeric configuration, the two ligands L being cis in an array of quasi-2 symmetry. Ca- Cl in (2) is 2.834(1) Ǻ; Ca-N generally range between 2.52(5) and 2.64(1) Ǻ; Ca-O(H₂O) is 2.418(2) in (2), 2.434(7)-2.496(7) Ǻ in (3), while Ca-O( MeOH ) in (4) are 2.43(2) and 2.43(2) Ǻ. [Mg(HOMe)₆] I₂.2tmeda (5) ( tmeda = Me₂N(CH₂)₂NMe₂), orthorhombic, Pbca, a 23.423(8), b 15.306(4), c 9.345(1) Ǻ, Z = 4 f.u ., R 0.052 for No 1928, provides a usefully precise description for the centrosymmetric cation, Mg-O being 2.069(4), 2.080(4), 2.096(5) Ǻ, with Mg-O-C 128.4(4) l28.9(4), l29.7(4)°. [( tmeda )SrI₂ ( HOMe )₃].½tmeda (6), monoclinic, P 2₁/c, a 7.730(1), b 35.493(9), c 11.081(2) Ǻ, β 126.49(1)°, R 0.042 for No 3161, has a seven-coordinate, quasi-pentagonal bipyramidal SrN₂I₂O₃ array about the metal with trans-iodines.