Source of materialThe title compound was synthesized by the reaction of 0.5 g (4.23 mmol) succinic acid with an excess of fresh C0CO3 in 50 ml double destilled water, followed by filtrating the unreacted C0CO3 out. Rose-colored rhombohedral crystals grew at room temperature after slow evaporation for several days. DiscussionThe title compound is isostructural with Ni(C4H404)(H20)4 [1]. In the crystal structure, the Co atom is octahedrally coordinated by two О atoms of two bridging OOC-CH2-CH2-COO anions in

_C4H Source of material0.42 g (3.60 mmol) maleic acid was dissolved in 10 ml CH3OH/H2O (1:1 v/v) and then 1.0 ml (1 M) Na 2 C0 3 was added dropwise. The resulting solution (pH = 2.3) was allowed to stand at room temperature. Colorless needle-like crystals were grown by slow evaporation for several weeks. DiscussionNearly three decades ago, the crystal structure of sodium hydrogen maleate trihydrate was partially established by Gupta and coworkers using the photographic X-ray diffraction data collected at room temperature, but unfortunately hydrogen atoms were not located [ 1 ]. The structure was later refined at 120 Κ by Olovsson et al. [2]. In order to gain further insight into the nature of the possible intramolecular asymmetric hydrogen bonds, it was necessary to redetermine the crystal structure of Na(C4H304) · 3H2O by using accurate X-ray diffraction data at room temperature.In the crystal structure of the title compound, the hydrogen maleate (HOO(CH)2COO~) anions exhibit strong intramolecular asymmetric hydrogen bonds between two crystallographically distinct Ο atoms, namely 02 and 04, with J(02-04) = 2.442(2) Ä, Z02-H-04 = 173°. Such asymmetric hydrogen bonds are considerably shorter than those reported for symmetric hydrogen bonds, which are in general shorter than asymmetric ones [3,4]. In comparison with the respective ί/iso values of 0.0376(6) A 2 and 0.0369(3) A 2 for the associated 02 and 04 atoms, the reasonable Uho values of0.067(7) A 2 for the Η atom suggests that the present asymmetric hydrogen bonds are dynamically ordered. The short-* Correspondence author (e-mail: zhengcm@nbu.edu.cn) est CI-Ol bond (1.218(2) Ä) and longest CI-02 bond (1.300(2) A) indicate the double and single bond characters, respectively. The hydrogen atom is covalently bonded to the 02 atom (d(Ο-Η) = 1.00(2) A), which implies that the terminal containing CI atom belongs to the carboxylic group. For the carboxylate terminal, the C4-03 bond of 1.245(2) A is slightly shorter than that of 1.266(2) A to the 04 atom involved in the intramolecular hydrogen bond. The center C2-C3 bond of 1.329(2) A is significantly shorter than the remaining ones averaged at 1.494 A, indicating more double bond character. Owing to the fixation effect of the intramolecular hydrogen bonds, all atom s of the hydrogen maleate anion lie in a common plane. The Na + cations in the crystal structure are surrounded by six Ο atoms from five H2O molecules and one hydrogen maleate anion to form distorted NaOe octahedra with d(Na-O) = 2.380 A -2.476 A. Through two pairs of crystallographically equivalent bidentate bridging water Ο atoms, namely 05 and 07, the NaC>6 octahedra are edge shared resulting in one-dimensional (ID) J[Na(H20)^-H20)4/2(H00(CH) 2 C00)] chains along the [100] direction. Each Na atom has two close Na neighbors at 3.490( 1) A and 3.497(1) A, respectively. The formed ID chains are held into 2D layers parallel to (010) by linear interchain hydrogen bonds (

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Dichloromethane Solvate Nonahydrate : [ Cu( hen)^] C12. CH2C12 9H20 'Lbe crys&l and d [ a ( I Q * C&Q.gi&O @HEN= l,I&phenanthrdlne) have been de-by x-ray CrystsnOgraphY. complex crystallizes intridiniesystem, spacegrouppi, withlatticeparametersa 85.2970(1),p=66.8400(1), 7 = 83.09(1)", and z=2. 'Ibe =l.zaoOo(3), b = 1.37525(4), c = 1.42750(3)nm, a = coordhted catioas contain a six-coordtrated copper atom chplltprlbythreeF"ligands, andtheJahbTellereffectd tbea(II) ionresuitsinadistododahedralarrangement with the six ClrN distancep ranging h 0.2112(6) to 0.2265(7) 1 1 1 1 1 . In addition to the copper coordinsted cation, there are two chloride ioas, one dichloromethane dvate and nine water molecules in its asymmetric unit. In the solid slate, the titlecompouod forms three dimensid network structures through hydrogen bonds. The intermolecular hydrogen buds coaaect the [ C~(phen)~]'*, chloride ion, dichloromethane dvate and &O moieties altogether.

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