Synthesis and Structural Systematics of Nitrogen Base Adducts of Group 2 Salts. X. Some Mixed-Ligand Complexes of Group 2 Metal Halides With 2,2':6',2"-Terpyridine and Oxygen Donors

Abstract

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.