Lewis-base adducts of lead(II) compounds .15. Synthesis and structure of some adducts of bis(2-pyridyl)amine with lead(II) salts

Several complexed of bis(2-pyridyl)amine ('dpa') with lead(II) salts have been synthesized and subjected to room-temperature single-crystal X-ray studies. 1:1 Adducts have been obtained with lead(II) bromide and iodide. They have similar unit cells, also similar to those of a variety of other N,N'-heteroaromatic bidentate ligand adducts with metal(II) halides, and the C2/c cell described elsewhere in this series may be regarded as archetypical. [(dpa)PbBr2]((infinity/infinity)) is monoclinic, P2(1)/a, a 9.791(4), b 9.720(4), c 16.498(4) Angstrom, beta 95.96(4)degrees, Z = 4 f.u.; conventional R on \F\ at convergence was 0.066 for N-o = 2717 'observed' (I > 3 sigma(I)) reflections. [(dpa)PbI2]((infinity/infinity)) is monoclinic, P2(1)/c, a 8.299(2), b 10.229(3), c 16.905(5) Angstrom, beta 101.47(2)degrees, Z = 4 f.u.; R was 0.044 for N-o 2140. Both complexes, like their 2,2'-dipyridine and 1,10-phenanthroline analogues, are linear polymers with six-coordinate (cis-N-2)Pb(mu-X)(4) environments linked in infinite ...(mu-X)(2)Pb(mu-X)(2)... one-dimensional chains,and with dpa being bidentate. A 2:1 adduct of bis(2-pyridyl)amine with lead(II) acetate ('Pb(ac)(2)') is also described. [(dpa)(2)Pb(ac)(2)]((infinity/infinity)) is monoclinic, C2/c, a 28.835(5), b 10.868(3), c 7.665(2) Angstrom, beta 94.21(2)degrees, Z = 4; R was 0.029 for N-o 1854. The complex is a linear polymer along c; the lead atom lies on a crystallographic twofold axis with a coordination environment comprising a pair of symmetry-related dpa ligands, in this case unidentate (Pb-N 3.092(6) Angstrom), and a pair of symmetry-related bidentate acetate ligands (Pb-O 2.465(4) and 2.567(5) Angstrom) with the first oxygen atom performing an additional bridging function to adjacent symmetry-related lead atoms (Pb-O 2.663(4) Angstrom).