Lewis-Base Adducts of Lead(II) Compounds. VII. Synthetic and Structural Studies of Some 1:1 Adducts of Linear Polyamines With Lead(II) Nitrate

Abstract

Syntheses and room-temperature single-crystal X-ray structure determinations are recorded for 1 : 1 adducts of lead(II) nitrate with the linear multidentate polyamines ethane-1,2-diamine ('en'(= '2')), H₂N(CH₂)₂NH(CH₂)₂NH₂(' dien ' = '22') and H₂N(CH₂)_xNH(CH₂)_yNH(CH₂)_zNH₂ ( xyztet = '222tet' (= ' trien '), '232tet', '323tet'). Crystal/refinement data are as follows: [(en) Pb (NO₃)₂]_(∞|∞) is monoclinic, P 2₁/c, a 5.388(2), b 12.440(5), c 13.123(3) Ǻ, β 102.33(3)°, Z = 4 f.u .; R 0.037 for N_o 2698 'observed' (I > 3σ(I)) reflections. [( dien ) Pb (NO₃)₂]_(∞|∞) is orthorhombic, Ccma , a 9.800(2), b 10.840(2), c 20.521(5), Z = 8; R 0.045, N_o 991. [( trien ) Pb (NO₃)₂]_(∞|∞) is orthorhombic, P 2₁2₁2₁, a 14.815(3), b 10.975(3), c 8.410(2) Ǻ, Z = 4; R 0.050, N_o 1360; [(232tet) Pb (NO₃)₂]_(∞|∞) is isomorphous, a 14.524(6), b 11.221(1), c 8.860(2) Ǻ, R 0.036, N_o 2371. [(323tet) Pb (NO₃)₂]_(∞|∞) is monoclinic, P2₁/c, a 8.195(4), b 14.407(7), c 13.312(4) Ǻ, β 91.05(3)°, Z = 4; R 0.049, N_o 1644. In general, the degree of complexity of the adduct diminishes as the ligand size increases: whereas the en adduct is a compact one-dimensional two stranded polymer with nearly all nitrate oxygens involved in tight bridging interactions, the extent of bridging diminishes in the adducts of the larger amines, until, for the 323tet species, a monomer is obtained involving a lead coordination sphere containing the ligand and a pair of bidentate nitrate groups. The 1 : 2 adduct with en is also recorded, and is a dimer with quasi-i internal symmetry. [(en)₂Pb(NO₃)₂]₂ is monoclinic, P2₁, a 6.661(2), b 14.226(8), C 13.618(4)Ǻ, β 96.51(2)°; R 0.072, N_o 1713.