catena-Poly[[(1,10-phenanthroline-κ2 N,N′)lead(II)]-μ-azido-κ2 N 1:N 3-μ-nitrito-κ3 O,O′:O′-[(1,10-phenanthroline-κ2 N,N′)lead(II)]-di-μ-azido-κ4 N 1:N 1]

The title coordination polymer, [Pb2(N3)3(NO2)(C12H8N2)2]n, has as the repeat unit a centrosymmetric dinuclear molecule having azide and nitrite groups that bridge adjacent heterocycle-coordinated metal centers. One of the azide group uses its terminal ends to bridge whereas the nitrite group chelates to one metal atom and uses one of its O atoms to bridge. The azide and nitrite groups are disordered with respect to each other in a 1:1 ratio. Adjacent dinuclear molecules are further bridged by the other two azide groups, generating a linear chain motif parallel to [010]. Half of the Pb atoms show a Ψ-dodecahedral coordination and the other half show a Ψ-pentagonal-bipyramidal coordination.

The title coordination polymer, [Pb 2 (N 3 ) 3 (NO 2 )(C 12 H 8 -N 2 ) 2 ] n , has as the repeat unit a centrosymmetric dinuclear molecule having azide and nitrite groups that bridge adjacent heterocycle-coordinated metal centers. One of the azide group uses its terminal ends to bridge whereas the nitrite group chelates to one metal atom and uses one of its O atoms to bridge. The azide and nitrite groups are disordered with respect to each other in a 1:1 ratio. Adjacent dinuclear molecules are further bridged by the other two azide groups, generating a linear chain motif parallel to [010]. Half of the Pb atoms show a É-dodecahedral coordination and the other half show a É-pentagonal-bipyramidal coordination.

Related literature
For the crystal structure of a related lead azide complex, see: Marandi et al. (2007).

Comment
There are a number of 1,10-phenanthroline-chelated lead(II) compounds having inorganic anions (having only few atoms) as counterions whose crystal structures have been reported. For some, two counterions exist in the crystal structure that originally came from the reactants used in the synthesis.
The azide derivative is a polymeric dinuclear chain compound in which the lead atoms show PbN 8 and PbN 6 O 2 dodecahedral coordination. In lead azide nicotinate, the azide unit engages in µ 3 bridging (Marandi et al., 2007). In Pb 2 (N 3 ) 3 (NO 2 )(C 12 H 8 NO) 2 (Scheme I, Fig. 1), the azide groups bridge adjacent heterocycle-coordinated metal centers through one nitrogen atom and the third bridging through two nitrogen atoms. The nitrite group chelates to one metal atom and uses one oxygen atom to bind to the inversion-related lead atom. The bridging interactions lead to the formation of a linear chain motif. One of the azide groups that uses its terminal nitrogen atoms to bridge is disordered with respect to the nitrite group in a 1:1 ratio. The disorder gives rise to a Ψ-dodecahedral geometry for 50% of the lead atoms and a Ψpentagonal bipyramidal geometry for the other 50% of the lead atoms.
Experimental 1,10-Phenanthroline (0.36 g, 2 mmol) and sodium azide (0.13 g, 1 mmol) were placed in one arm of a convection tube, and lead(II) nitrate (0.33 g, 1 mmol) and sodium nitrite (0.07 g, 1 mmol) in the other. Methanol was then added to fill both arms and the tube was sealed. The ligand-containing arm was immersed in an oil bath at 333 K, whereas the other was left at ambient temperature. After 1 day, crystals deposited in the arm that was kept at ambient temperature.

Refinement
Carbon-bound H-atoms were placed in calculated positions [C-H = 0.95 Å; U(H) = 1.2U eq (C)] in the riding model approximation.
The N1 and O1 atoms occupy the same site; the atoms are give half occupancy and the same temperature factors. The N2 atom is disordered with respect to the O2 atom but they do not occupy the same site; their temperature factors were also restrained to be identical.
The final difference fourier map had a large peak/deep hole in the vicinity of the lead atom.