The different complexation methods of a proton transfer compound, (phenH)2(pydc) (phen=1,10‐phenanthroline; pydcH2= pyridine‐2,6‐dicarboxylic acid), are discussed and formation of [Sn(pydc)(phen)(OH)2]·3H2O (1), {[Sb(pydc)(phen)]2O}·2DMSO·4H2O(2) and [(Tl(pydcH)]n (3) complexes are reported. The characterization was performed using IR spectroscopy and X‐ray diffraction. The structures of Sn(IV) and Sb(III) complexes show that both cationic and anionic fragments of the starting proton transfer compound have been involved in the complexation. Whereas the structure of Tl(I) complex demonstrates that only the anionic fragment of (phenH)2(pydc) is contributed to the complexation. The complexes 1‐3 show a variety of structural features including mononuclear, binuclear and polymeric structures. In compounds (1), (2) and (3) a large number of hydrogen bonds are observed. These interactions play an important role in the formation and stabilization of supramolecular systems in the crystal lattices. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

The 1:1 proton transfer compound LH 2, (creatH) ϩ (pydcH) Ϫ , has been prepared from the reaction of creatinine, creat, and dipicolinic acid, pydcH 2 , (2,6-pyridinedicarboxylic acid) and characterized using IR, 1 H and 13 C NMR spectroscopy. The first coordination complex (creatH)[Zn(pydc)(pydcH)]·4H 2 O, was prepared using LH 2 and zinc(II) nitrate, and characterized using IR, 1 H and 13 C NMR spectroscopy and single crystal X-ray crystallography. The crystal system is triclinic with space group P 1 with two molecules per unit cell. The unit cell dimensions are a ϭ 8.085(2) Å , b ϭ 10.802(4) Å , c ϭ 13.632(4) Å , α ϭ 104.98(2)°,β ϭ 90.31(2)°a nd γ ϭ 92.55(3)°. The structure has been refined to a final value for the crystallographic R factor of 0.0381 based on 3003 reflections. The zinc atom is six-coordinated with a distorted octahedral geometry. The (pydc) 2Ϫ and (pydcH) Ϫ units are almost perpendicular to each other. Extensive hydrogen bondings between carboxyl-

Key indicatorsSingle-crystal X-ray study T = 293 K Mean '(C±C) = 0.003 A Ê Disorder in main residue R factor = 0.048 wR factor = 0.162 Data-to-parameter ratio = 22.3 For details of how these key indicators were automatically derived from the article, see

Three new complexes of group thirteen metals, gallium(III), indium(III), and thallium(III) with proton transfer compounds, obtained from 2,6‐pyridinedicarboxylic acid (dipicolinic acid), were synthesized and characterized using elemental analysis, IR, 1H and 13C NMR spectroscopy and single crystal X‐ray diffraction. The gallium(III) and indium(III) complexes were prepared using (pydaH2)(pydc) (pyda = 2,6‐pyridinediamine, pydcH2 = dipicolinic acid) and thallium(III) complex was obtained from (creatH)(pydcH) (creat = creatinine). The chemical formulae and space groups of the complexes are (pydaH)[Ga(pydc)2] · 3.25H2O · CH3OH, $P{\bar 1}$ (1), [In(pydc)(pydcH)(H2O)2] · 5H2O, Pna21 (2) and [Tl2(pydcH)3(pydc)(H2O)2], $P{\bar 1}$ (3). Non‐covalent interactions such as ion‐pairing, hydrogen bonding and π‐π stacking are discussed. The complexation reactions of pyda, pydc, and pyda + pydc with In3+ and Ga3+ ions in aqueous solution were investigated by potentiometric pH titrations, and the equilibrium constants for all major complexes formed are described.

Key indicators: single-crystal X-ray study; T = 120 K; mean (C-C) = 0.003 Å; R factor = 0.041; wR factor = 0.108; data-to-parameter ratio = 16.8.The reaction of Zn(NO 3 ) 2 with pyridine-2,6-dicarboxylic acid (pydcH 2 ) and acridine (acr) in aqueous solution leads to the formation of the title compound, (C 13 + cation is present. In the crystal structure, extensive O-HÁ Á ÁO and N-HÁ Á ÁO hydrogen bonds involving acrH + , the complex anion and uncoordinated water molecules form a three-dimensional network. Related literature