C 25 H 18 ClFN 4 O 4 Pb, monoclinic, P12 1 /c1(no. 14), a =13.056(2) Å, b =9.290(2) Å, c =19.126(3) Å, b =100.682(2)°, V =2279.5 Å 3 , Z =4,R gt (F) =0.040, Source of materialThe pH value of amixture of Pb(NO 3 ) 2 (0.5 mmol), adipic acid (H 2adip, 0.5 mmol) and 2-(2-chloro-6-fluorophenyl)-1H-imidazo[4,5-f][1,10]phenanthroline (L, 0.5 mmol) in 12 mL distilled water was adjusted to between 5a nd 6b ya ddition of triethylamine. The resultant solution was heated at 458 Ki na Teflon-lined stainless steel autoclave for four days. The reaction system was then slowly cooled to room temperature. Pale yellow crystals suitable for single crystal X-ray diffraction analysis were collected from the final reaction system by filtration, washed several times with distilled water and dried in air at ambient temperature (yield 56 %based on Pb). Experimental detailsAll Hatoms were positioned geometrically (d(C-H) =0.93 Å) and refined as riding, with U iso (H) =1 .2 U eq (carrier). The H atoms of the water molecules were located in adifference Fourier map and refined freely. The disorder of the carboxylate O1 atoms was describe by two sites (O1 and O1'), with aoccupancy of 0.50 for each. DiscussionSo far, coordination polymers based on s-, d-, and even f-block metal ions as coordination centers have been widely studied. Less consideration has been given to the metals of the p-block [1]. In contrast to transition metals, the main group metals possess unique coordination preferences and electronic properties observed rarely in the rest of the periodic table, and presenting unique opportunities for the preparation of novel structures with new and interesting characteristics. Among the main group metals, lead, as aheavy toxic metal, is commonly found in critical life cycles due to its widespread use in numerous industrial appli-

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Source of materialAmixture of Pb(NO 3 ) 2 (0.5 mmol), naphthalene-1,4-dicarboxylic acid (1,4-H 2 ndc, 0.5 mmol) and bis(2-(2-chloro-6-fluorophenyl)-1H-imidazo[4,5-f][1,10]phenanthroline (L, 0.5 mmol) in 12 .mL distilled water was heated at 455 Ki naT eflon-lined stainless steel autoclave for seven days. The reaction system was then slowly cooled to room temperature. Pale yellow crystals of the title compound suitable for single crystal X-ray diffraction analysis were collected by filtration, washed several times with distilled water and dried in air at ambient temperature (yield 62 % based on Pb(II)). Experimental detailsAll Hatoms were positioned geometrically (d(C-H) =0.93 Å) and refined as riding, with U iso (H) =1.2 U eq (carrier). The Hatoms of the water molecules were not located. The disordered carboxylate Oatoms (O2 and O2') were refined using Oatoms split over two sites, with atotal occupancy of 1. DiscussionLead(II), as aheavy toxic metal, is commonly found in critical life cycles due to its widespread use in numerous industrial applications [1]. The possible molecular mechanisms of lead(II) toxicity may be involved in several different types of proteins. Therefore, ag ood knowledge of the lead(II) coordination properties, including aspects such as the lone pair of electrons, coordination number, and coordination geometry, is crucial for understanding of the toxicological properties of lead(II) [2]. Each Pb(II) atom is seven-coordinated by four nitrogen atoms from two different Lligands, and three carboxylate oxygen atoms from two different 1,4-ndc ligands. The 1,4-ndc dianions link neighboring Pb(II) atoms to an one-dimensional chain structure. The Lligands are attached on both sides of the chains. Further, the aromatic p-p stacking interactions between Lligands of neighbouring chains extended the adjacent chains into an interesting two-dimensional supramolecular architecture.

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