SYNTHESIS AND STRUCTURAL SYSTEMATICS OF NITROGEN BASE ADDUCTS OF GROUP-2 SALTS .9. SOME COMPLEXES OF GROUP-2 METAL-HALIDES WITH 2,2' 6',2''-TERPYRIDINE/

Syntheses and room-temperature single-crystal X-ray structure determin ations are recorded for a number of adducts of MX(2).ntpy stoichiometr y of salts of Group 2 metals, MX(2), with 2,2':6',2 ''-terpyridine (tp y). 'Homoleptic' adducts, [M(tpy)(3)]X(2), are found in space groups w ith trigonal symmetry, with M located on a site of at least 3 symmetry , the structures being derivative of the <P(6)over bar 2c> array found in [Pb(tpy)(3)] (ClO4)(2), but with variations in anion and cation st ackings. [M(tpy)(3)]I-2.similar to 1.7MeOH, M = Ca (1), Sr (2), are tr igonal, P3c1, a approximate to 13, c approximate to 15.3 Angstrom, Z = 2 f.u., conventional R on \F\ being 0.050, 0.086 for N-o 894, 865 ind ependent 'observed' (I > 3 sigma(I)) reflections respectively. [Sr(tpy )(3)]Br-2.aMeOH (3), although similar, is modelled in space group <P(3 )over bar c1>, a 13.040(4), c 15.13(1) Angstrom, Z = 2 f.u., R 0.041 f or N-o 447. [(tpy)(2)BaI2] (4) is monoclinic, P2(1)/c, a 10.812(4), b 16.740(5), c 17.458(4) Angstrom, beta 109.39(2)degrees, Z = 4 f.u., R 0.042 for N-o 3256. [(tpy)(2)Ba(O2ClO2)(2)] (5) is triclinic, <P(1)ove r bar>, a 14.220(4), b 11.212(2), c 10.511(2) Angstrom, alpha 65.66(2) , beta 87.32(2), gamma 88.92(2)degrees, Z=2 f.u., R 0.029 for N-o 4676 .