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

Abstract

Syntheses and room-temperature single-crystal X-ray structure determinations are recorded for a number of adducts of MX₂.ntpy stoichiometry of salts of Group 2 metals, MX₂, with 2,2':6',2"-terpyridine ( tpy ). ' Homoleptic' adducts, [M( tpy )₃] X₂, are found in space groups with trigonal symmetry, with M located on a site of at least 3 symmetry, the structures being derivative of the P 62c array found in [ Pb ( tpy )₃] (ClO₄)₂, but with variations in anion and cation stackings . [M( tpy )₃] I₂.~1.7MeOH, M = Ca (1), Sr (2), are trigonal , P3c1, a ≈ 13, c ≈ 15.3 Ǻ, Z = 2 f.u., conventional R on ׀ F ׀ being 0.050, 0.086 for No 894, 865 independent 'observed' (I > 3σ(I)) reflections respectively. [ Sr ( tpy )₃] Br₂.2MeOH (3), although similar, is modelled in space group P3c1, a 13.040(4), c 15.13(1) Ǻ, Z = 2 f.u ., R 0.041 for No 447. [( tpy )₂BaI₂] (4) is monoclinic, P 2₁/c, a 10.812(4), b 16.740(5), c 17.458(4) Ǻ, β 109.39(2)°, Z = 4 f.u ., R 0.042 for N_o 3256. [( tpy )₂Ba(O₂ClO₂)₂] (5) is triclinic, Pī , a 14.220(4), b 11.212(2), c 10.511(2) Ǻ, α 65.66(2), β 87.32(2), γ 88.92(2)°, Z = 2 f.u ., R 0.029 for N_o 4676.