C 22 H 16 N 2 O 9 ,triclinic, P 1 (no. 2), a =8.015(2) Å, b =9.836(2) Å, c =12.274(3) Å, a =94.900(3)°, b =92.085(4)°, g =94.697(3)°, V =959.9 Å 3 , Z =2, R gt(F) =0.035, wRref(F 2 ) =0.100, T =293 K.Source of material 1,10-phenanthroline( 0.1 g, 0.5 mmol), 1,2,4,5-benzenetetracarboxylic acid (0.12 g, 0.5 mmol; H 4 btec), and NaOH (0.02 g, 0.5 mmol) were added to aH 2 Osolution( 12 mL)i naT eflonlined stainless steel reactor. The mixture washeated at438 Kfor 3d,and then slowly cooled down to room temperature. Colorless crystals of the title compound were obtained. Elementalanalysis -found: C,58.48 %; H,3.51 %, N,6.27 %, calc. for C 22H 16N 2 O 9 :C,58.41 %; H,3.57 %; N,6.19 %.
DiscussionThe design and synthesis of supramolecularcoordination polymeric networks, especially those constructed by hydrogen bonding and intermolecularw eaki nteractions have been afield of rapid growth due to their specialphysicalproperties and potential application in functionalmaterials. Ofparticularinterest are compounds thatare capable of forming very strong hydrogen bonds like some salts of pyromellitic acid. The 1,2,4,5-benzenetetracarboxylic acid, also known aspyromelliticacid, possesses severali nteresting characteristics: (a)i th asf our carboxyl groups which maybecompletely or partially deprotonated, inducing rich coordination modes and allowing interesting structures with higher dimensions; (b) it canact not only ashydrogen-bond acceptor but also ash ydrogen-bond donor, depending upon the numbers of deprotonated carboxyl groups [1][2][3][4][5][6][7][8][9][10]. The crystalstructure of the title compound (figure, top) comprises a1,10-phenanthrolinium cation, atrihydrogen-1,2,4,5-benzenetetracarboxylate anion and awater molecule.Three carboxyl groupso f1 ,2,4,5-benzenetetracarboxylic acid are deprotonated and apyridine-ring accepts aproton coming from a1,2,4,5-benzenetetracarboxylic acid molecule to produce the pyridinium cation. Hydrogen bonding and intermolecularw eaki nteractions playanimportant role in the crystalstructure. Ashort intermoleculardistancebetween N2···O1of2.