Diaqua(nitrato-κ2O,O′)bis(L-valine-κO)lead(II) nitrate at 296 K

Abstract

The structure of the title complex, [Pb(NO3)(C5H11NO2)2(H2O)2]NO3, had been determined previously at 173 and 193 K, and is now reported at 296 K, in the same space group. The main difference with the low-temperature structures is that a methyl group of one valine ligand is clearly disordered over two positions, for which the occupancies converged to 0.56 (3) and 0.44 (3). Bond-length variations within the coordination sphere of PbIIas a function ofTare difficult to assess because uncertainties on these parameters are high. On the other hand, Pb...O distances above 2.9 Å cannot be assigned unambiguously to formal Pb—O bonds. As a consequence, the polymeric nature of the complex previously described at 173 K is uncertain, as well as the actual coordination number of PbII, and it is thus not possible to determine if the metal environment is holo- or hemidirected.