Lewis-Base Adducts of Lead (II) Compounds. XI. Synthetic and Structural Studies of Some 1:1 Adducts of 2,2'-Bipyridine and 1,10-Phenanthroline With Lead(II) Oxoanion Salts

Abstract

Syntheses and room-temperature single-crystal X-ray structure determinations are recorded for 1 : 1 adducts of 1,10-phenanthroline ('phen') with lead(II) nitrate (as a monohydrate; the structure of the isomorphous 2,2'-bipyridine (' bpy ') analogue is also recorded) and of its lead(II) acetate ('ac') analogue (as a dihydrate ). [( bpy ) Pb (NO₃)₂](∞|∞).H₂O is monoclinic, P 2₁/c; a 7.244(9), b 9.872(2), c 20.395(5) Ǻ, β 109.08(7)°, Z = 4 f.u ., R being 0.048 for N_o = 3447 independent 'observed' (I > 3σ(I)) reflections. [( phen ) Pb (NO₃)₂](∞|∞).H₂O has a 7.168(2), b 9.972(1), c 21.069(3) Ǻ, β 99.47(1)°, R 0.034 for N_o 3596. [( phen ) Pb (ac)₂]₂.4H₂O is triclinic, Pī , a 13.932(3), b 12.904(4), c 12.716(5) Ǻ, α 62.37(2), β 71.16(2), γ 60.55(2)°, Z = 2 ( dimers ); R was 0.029 for N_o 5457. The nitrates are one-dimensional polymers along b, successive lead atoms being linked by one oxygen of one of the nitrate groups, each of the other oxygen atoms completing a chelate to either side; the lead environment is completed as N₂PbO₇ by the other nitrate (as a chelate ), the bidentate base, and the water molecule. In the acetate which is a centrosymmetric dimer (manifested in two distinct independent dimers ) the two lead atoms are linked by bridging oxygen atoms derived from pairs of chelating acetate moieties about each lead atom. The coordination sphere of each lead atom is completed by the bidentate aromatic base. The two dimers differ significantly in parallel comparison of their geometrical descriptors.