Half Water Molecules Research Articles

Synthesis and crystal structure of a cadmium(II) coordination polymer based on 4,4′-(1H-1,2,4-triazole-3,5-diyl)dibenzoate

The asymmetric unit of the title compound, catena-poly[[[aquabis(pyridine-κN)cadmium(II)]-μ2-4,4′-(1H-1,2,4-triazole-3,5-diyl)dibenzoato-κ4 O,O′:O′′,O′′′] 4.5-hydrate], {[Cd(C16H9N3O4)(C5H5N)2(H2O)]·4.5H2O} n or {[Cd(bct)(py)2(H2O)]·4.5H2O} n (I), consists of a Cd2+ cation coordinated to one bct2– carboxylate dianion, two molecules of pyridine and a water molecule as well as four and a half water molecules of crystallization. The metal ion in I possesses a pentagonal–bipyramidal environment with the four O atoms of the two bidentately coordinated carboxylate groups and the N atom of a pyridine molecule forming the O4N equatorial plane, while the N atom of another pyridine ligand and the O atom of the water molecule occupy the axial positions. The bct2– bridging ligand connects two metal ions via its carboxylic groups, resulting in the formation of a parallel linear polymeric chain running along the [1\overline{1}1] direction. The coordinated water molecule of one chain forms a strong O—H...O hydrogen bond with the carboxylate O atom of a neighboring chain, leading to the formation of double chains with a closest distance of 5.425 (7) Å between the cadmium ions belonging to different chains. Aromatic π–π stacking interactions between the benzene fragments of the anions as well as between the coordinated pyridine molecules belonging to different chains results in the formation of sheets oriented parallel to the (\overline{1}01) plane. As a result of hydrogen-bonding interactions involving the water molecules of crystallization, the sheets are joined together in a three-dimensional network.

Design, synthesis and physico-chemical studies of a Co(II)/Co(III) mixed-valence complex: An experimental and DFT approach

The bidentate amine, 2-picolylamine [2-(aminomethyl) pyridine: AMP], and concentrated hydrobromic acid have been used to synthesize a CoII/CoIII mixed-valence complex. Single crystals of the new compound were grown by the slow evaporation solution process at room temperature. The title compound crystallizes in the monoclinic system, space group P21/n, with a = 14.624 (5) Å, b = 10.302 (5) Å, c = 23.743(5) Å , β = 95.280(5)° and Z = 4. The crystal structure consists of three crystallographically independent bromide ions, one diprotonated AMP, one half water molecule and two crystallographically independent Cobalt(II) and Cobalt(III) ions: one has an octahedral geometry while the other is tetrahedrally coordinated. The crystal packing diagram reveals interesting non-covalent interactions involving NH···Br, OH···O and OH···Br hydrogen bonds, leading to the generation of 3D supramolecular architecture. The structural data, the BVS (Bond Valence Sum) calculations, the magnetic and the spectroscopic measurements are in agreement with a six-coordinate Cobalt(III) and four-coordinate Cobalt(II) mixed-valence complex. In this work, the experimental and theoretical study on molecular structure and vibrational spectral analysis of the new product has been reported. Theoretical calculations were performed by using density functional theory (DFT) at the B3LYP/LAN2DZ basis set levels. The electronic parameters such as frontier molecular orbitals, electrostatic potential and HOMO-LUMO energy were calculated. NLO and thermodynamic properties were studied. The theoretical values show good agreement with experimental values. Finally, thermal analysis and temperature dependent magnetic susceptibility measurements have been performed.

Quantifying intermolecular interactions in solid state indapamide and other popular diuretic drugs: Insights from Hirshfeld surface study

Hirshfeld surfaces (HS) and two-dimensional fingerprint plots are used to analyze the intermolecular interactions in indapamide and other popular thiazide diuretic derivatives. The crystal structure of indapamide (INDP) at 100 K determined by single-crystal X-ray analysis, is also reported. The title compound crystallizes in the centrosymmetric I2/a space group with one indapamide and half water molecule (lying on the glide plane) in the asymmetric unit. An interplay of N–H⋯O hydrogen bonds connects the indapamide molecules generating chains with the graph-set motifs: C (8) and C23 (16), and together with C–H⋯O and π⋯π stacking interactions create a 3D net. The Hirshfeld surface study facilitates comparison of diverse and numerous intercontacts, such as H⋯H, O⋯H, Cl⋯H, C⋯C (π⋯π), C⋯O (π⋯lone pair), O⋯O (lone pair⋯lone pair), Cl⋯O, Cl⋯Cl, N⋯N, C⋯H (C–H⋯π) with regard to building self-assembled framework of indapamide and related thiazide derivatives retrieved from the Cambridge Structural Database. The HS analysis highlights that H⋯H, O⋯H/H⋯O and C⋯H/H⋯C contacts play an influential role contributing to about 80% of the HS areas in this class of compounds. Nevertheless, in the case of INDP the H⋯H interactions, while in hydrochlorothiazide (HCTZ) O⋯H/H⋯O are dominant amongst all intercontacts towards the HS. Notably, indapamide has the highest proportion of C⋯C contacts.

N-Benzyl-N-[2-(N-benzyl-N′,N′,N′′,N′′-tetramethylguanidiniumyl)ethyl]-N′,N′,N′′,N′′-tetramethylguanidinium dibromide 1.5-hydrate

The asymmetric unit of the hydrated title compound, C26H42N62+·2Br−·1.5H2O, comprises one cation, two bromide anions and one and a half water molecules, as one water molecule is fully occupied and the other is only half occupied [0.500 (6)]. Both bromide ions are disordered over two sites with refined occupancies of 0.938 (3):0.062 (3) and 0.520 (9):0.480 (9). The C—N bond lengths in both central C3N units of the bisguanidinium ion range between 1.336 (3) and 1.349 (3) Å, indicating a degree of double-bond character. The central C atoms are bonded to the three N atoms in a nearly ideal trigonal–planar geometry and the positive charges are delocalized in both CN3planes. The crystal structure is stabilized by a three-dimensional network of O—H...O, O—H...Br and C—H...Br hydrogen bonds.

Crystal structures of Na2SeO4·1.5H2O and Na2SeO4·10H2O.

The crystal structures of Na2SeO4·1.5H2O (sodium selenate sesquihydrate) and Na2SeO4·10H2O (sodium selenate deca-hydrate) are isotypic with those of Na2CrO4·1.5H2O and Na2 XSeO4·10H2O (X = S, Cr), respectively. The asymmetric unit of the sesquihydrate contains two Na(+) cations, one SeO4 tetra-hedron and one and a half water mol-ecules, the other half being generated by twofold rotation symmetry. The coordination polyhedra of the cations are a distorted monocapped octa-hedron and a square pyramid; these [NaO x ] polyhedra are linked through common edges and corners into a three-dimensional framework structure, the voids of which are filled with the Se atoms of the SeO4 tetra-hedra. The structure is consolidated by O-H⋯O hydrogen bonds between coordinating water mol-ecules and framework O atoms. The asymmetric unit of the deca-hydrate consists of two Na(+) cations, one SeO4 tetra-hedron and ten water mol-ecules. Both Na(+) cations are octa-hedrally surrounded by water mol-ecules and by edge-sharing condensed into zigzag chains extending parallel to [001]. The SeO4 tetra-hedra and two uncoordinating water mol-ecules are situated between the chains and are connected to the chains through an intricate network of medium-strength O-H⋯O hydrogen bonds.

Acridine 0.75-hydrate

The title compound, C13H9N·0.75H2O was obtained during a study of the polymorphic system of acridine, by slow evaporation from an ethanol–water solution. There are two acridine mol­ecules (indicated by I and II, respectively) and one and a half water mol­ecules in the asymmetric unit. The half-mol­ecule of water is located on a crystallographic twofold axis. The crystal structure is built up from two threads of mol­ecule II sewn together with water mol­ecules through O—H⋯O and O—H⋯N hydrogen bonds from one side and with π–π inter­actions [centroid–centroid distance = 3.640 (3) and 3.7431 (3) Å] between overlapping mol­ecules II on the other side. Mol­ecule I is attached to this thread from both sides by C—H⋯O hydrogen bonds. The threads are connected to each other by π–π inter­actions [centroid–centroid distances = 3.582 (3) and 3.582 (3) Å] between the inner side of mol­ecule I and stabilized by a C—H⋯π inter­action on the other side of mol­ecule I. This thread with rows of mol­ecule I hanging on its sides is generated by translation perpendicular to the a axis.

Cis-Dichloridobis(5,5′-dimethyl-2,2′-bipyridine)manganese(II) 2.5-hydrate

The metal site in the title compound [MnCl2(C12H12N2)2]·2.5H2O has a distorted octa­hedral geometry, coordinated by four N atoms of two 5,5′-dimethyl-2,2′-dipyridine ligands and two Cl atoms. Two and a half water molecules of hydration per complex unit are observed in the crystal structure. The compounds extend along the c axis with O—H⋯Cl, O—H⋯O, C—H⋯Cl and C—H⋯O hydrogen bonds and π–π inter­actions [centroid-centroid distance = 3.70 (2) Å] contributing substanti­ally to the crystal packing. The Mn and one of the water O atoms, the latter being half-occupied, are located on special positions, in this case a rotation axis of order 2.

Ethane-1,2-diaminium dipicrate dihydrate

The title compound, C2H10N2 2+·2C6H2N3O7 −·2H2O, crystallizes with a complete picrate anion and half an ethyl­enediammonium dication on a mirror plane, and two half-water mol­ecules (both on a mirror plane) in the asymmetric unit. The N atoms from separate half ethyl­enediammonium dications are in near proximity to a phenolate O atom and two o-NO2 groups from the picrate anion, which, along with the water mol­ecule form N—H⋯O, O—H⋯O and weak intermolecular C—H⋯O hydrogen bonds that create cyclic patterns with graph-set descriptors R 2 4(8), R 4 4(12), and R 4 4(16). The crystal packing is strongly influenced by these inter­molecular inter­actions between symmetry-related water mol­ecules, the half ethyl­enediammonium dication and the picrate anion, forming a three-dimensional supermolecular structure.

Bis(2,3-diaminopyridinium) succinate trihydrate

In the title salt, 2C5H8N3 +·C4H4O4 2−·3H2O, the asymmetric unit contains a protonated 2,3-diamino­pyridinium cation, half of a succinate dianion (disposed about a centre of inversion), and one and a half water mol­ecules. One of the water mol­ecules is disordered over two sites with occupancies of 0.670 (17) and 0.330 (17). The other water mol­ecule has an occupancy of 0.5 (from refinement). The pyridine N atom of the 2,3-diamino­pyridine mol­ecule is protonated. The protonated N atom and one of the 2-amino H atoms are hydrogen bonded to the succinate anion through a pair of N—H⋯O hydrogen bonds, forming an R 2 2(8) ring motif. In the crystal, mol­ecules are consolidated into a three-dimensional network by N—H⋯O and O—H⋯O inter­actions.

Structural Characterization of Di- and Mono-Imidazolyl-Substituted 1,8-Naphthyridine Derivatives

Two imidazolyl derived 1,8-naphthyridine compounds (2,7-diimidazolyl-1,8-naphthyridine (a), and 2-benzimidazolyl-5,7-dimethyl-1,8-napthyridine (b)) were synthesized and structurally characterized by X-ray crystallography. The compound a co-crystallizes with one ethanol and two water molecules to give compound 1. Compound 1 crystallizes in the triclinic, space group P-1, with a = 6.943(2) A, b = 9.009(3) A, c = 13.760(3) A, α = 96.793(2)°, β = 97.431(3)°, γ = 107.080(2)°, V = 804.6(4) A3, Z = 2. Compound 1 forms a 3D interpenetrated network through hydrogen bonds. Compound b co-crystallizes with three and one half water molecules to form 2. Compound 2 crystallizes in the monoclinic, space group C2/c, with a = 24.926(8) A, b = 10.608(3) A, c = 16.751(5)A, β = 110.133(4)°, V = 4159(2) A3, Z = 8. The free water molecules form six-membered rings, these water rings connect the naphthyridine to form one dimensional chain when viewed from b axis. The naphthyridyl rings in a and b axis are connected through C–H···π, and π–π interactions, due to the weak interactions the compound shows 3D network structure. Due to the weak interactions, the naphthyridine derivatives showed 3D network structure.

One novel 1D coordination polymer with parallel dinuclear copper(II) macrocyclic platforms bridged by trans dimeric half-water molecules and two dinuclear copper(II) macrocyclic complexes with different coordination geometry obtained from different solvents

Three dinuclear copper(II) macrocyclic complexes, formulated as [Cu 2L(N 3) 2(0.5H 2O) 2] n ( 1), [Cu 2L(ClO 4) 2(CH 3CH 2OH)] ( 2) and [Cu 2L(CH 3OH) 2](ClO 4) 2 ( 3) (LH 2 = [2+2] Schiff base macrocyclic ligand condensed from 4-chloro-2,6-diformylphenol and 1,3-diaminopropane), have been prepared and determined by X-ray single-crystal diffraction. Complex 1 shows two six-coordinate Cu(II) centers in which two monodentate N 3 - anions and two half-water molecules are bonded at the apical positions in the trans configuration. Furthermore, the dimeric half-water molecules serve as a μ 2-bridge linking adjacent macrocyclic units together with the multiple O H…N hydrogen bonds with azide anions, forming a novel 1D chain-like coordination polymer. Complexes 2 and 3 are obtained from different solvents (ethanol and methanol) and they can be converted into each other. The molecular structures and packing mode of 2 and 3 are different where six-coordinate and five-coordinate copper(II) centers are present, respectively.

Diaqua(2,2′-bipyridine-5,5′-dicarboxylato-κ2N,N′)(ethylenediamine-κ2N,N′)copper(II) 2.5-hydrate

In the mol­ecule of the title compound, [Cu(C12H6N2O4)(C2H8N2)(H2O)2]·2.5H2O, the CuII atom is six-coordinated in a distorted octa­hedral configuration by two N atoms from a 2,2′-bipyridine-5,5′-dicarboxyl­ate anion, two N atoms from ethyl­enediamine and two O atoms from two water mol­ecules. There are also two and a half water mol­ecules in the asymmetric unit. The planar five-membered ring is nearly coplanar with the adjacent pyridine rings, while the other five-membered ring adopts a twisted conformation, probably due to hydrogen bonding. In the crystal structure, intra- and inter­molecular N—H⋯O and O—H⋯O hydrogen bonds link the mol­ecules.

Catena-Poly[[[μ-cyanido-1:2κ2 C:N-tricyanido-1κ3 C-bis(ethylenediamine)-2κ4 N,N′-copper(II)iron(II)]-μ-cyanido-κ2 C:N-[bis(ethylenediamine-κ2 N,N′)copper(II)]-μ-cyanido-κ2 N:C] 4.5-hydrate

The asymmetric unit of the title compound, {[Cu2Fe(CN)6(C2H8N2)4]·4.5H2O}n, consists of two [Cu(C2H8N2)2]2+ cations, one [Fe(CN)6]4− anion, four water mol­ecules and a half water mol­ecule that lies on a twofold rotation axis. The FeII atom is coordinated by six C atoms from three terminal and three doubly bridging CN− ligands. The bridging CN− ligands connect the anion to a five-coordinate [Cu(C2H8N2)2]2+ cation and to two symmetry-related six-coordinate [Cu(C2H8N2)2]2+ cations, forming a one-dimensional polymer in the ab plane. Inter­molecular hydrogen bonds connect the polymer units into a three-dimensional network.

Molecular structure of hydrated complex of 1,4-dimethylpiperazine di-betaine with l-tartaric acid

1,4-Dimethylpiperazine di-betaine (DBPZ) forms a crystalline complex with l-tartaric acid (TA) and two and a half water molecules. The crystals are monoclinic, space group P2 1. The piperazine has a chair conformation with the methyl groups in the equatorial positions and the axial CH 2COO substituents. One of the CH 2COO group is protonated and forms with the neighboring DBPZ molecule the COO H⋯OOC hydrogen bond of the length 2.476(3) Å, which links them into a chain. The semi-tartrate anions, form a chain through the symmetrical, short COO⋯H⋯OOC hydrogen bond of 2.464(3) Å. The crystals have a layer structure, where hydrogen-bonded sheets of TA and water molecules are separated by the chains of DBPZ; no H-bonds between water and DBPZ are present. In the optimized molecules in the B3LYP/6-31G(d,p) approach, the tartaric acid interacts with the tartrate di-anions through the COO H⋯OOC hydrogen bonds of 2.506 Å, while the DBPZ has the same conformation as in the crystals. The FTIR spectrum of the solid complex is consistent with the X-ray results.

Second-sphere coordination complexes via hydrogen bonding: Synthesis, characterization of [Co(NH 3) 6](XO 3) 3· nH 2O (X=Br, I) and single crystal X-ray structure determination of [Co(NH 3) 6](BrO 3) 3·0.5H 2O

Single crystals of [Co(NH 3) 6](BrO 3) 3·0.5H 2O and peach coloured precipitate of [Co(NH 3) 6](IO 3) 3·3H 2O were obtained by reacting hexaamminecobalt(III) chloride with appropriate silver halate in 1:3 molar ratio in hot aqueous medium. These hexaamminecobalt(III) complexes have been characterized by spectroscopic studies (e.g. UV–vis and IR). Single crystal X-ray structure determination of title complex salt revealed the presence of discrete ions, i.e. cation [Co(NH 3) 6] 3+, three anions, BrO 3 − and half water molecule in the solid state. Crystal lattice is stabilized by electrostatic forces of attractions and hydrogen bonding interactions (N–H⋯O −, O–H⋯O −). The formation of salts of definite composition with halate ions and solubility product data suggest that purely inorganic hexaamminecobalt(III) cation may be used as an anion receptor for these weakly coordinating inorganic oxo-anions.

Second sphere coordination in anion binding: Synthesis, characterization and X-ray structure of cis-diazidobis(ethylenediamine)cobalt(III) mesitylenesulphonate hemihydrate

cis-diazidobis(ethylenediamine)cobalt(III) mesitylenesulphonate hemihydrate, [ cis-Co(en) 2(N 3) 2]C 9H 11SO 3·0.5H 2O was crystallized from a solution of cis-diazidobis(ethylenediamine) cobalt(III) nitrate and sodium mesitylenesulphonate in aqueous medium in 1:1 molar ratio. Elemental analysis, spectroscopic studies (IR, UV/visible, 1H and 13C NMR) and conductance studies were undertaken for characterizing the complex salt. The compound crystallizes in the triclinic space group P−1 with a=7.15220(10), b=14.5218(3), c=20.6925(5), V=2058.48(7), Z=4. X-ray structure determination revealed an ionic structure consisting of [ cis-Co(en) 2(N 3) 2] + cation, mesitylenesulphonate anion and half water molecule. In the complex cation [ cis-Co(en) 2(N 3) 2] +, the cobalt(III) is bonded to six nitrogen atoms, originating from two ethylenediamines, and two azide groups showing an octahedral geometry around cobalt. The crystal lattice is stabilized by electrostatic forces of attraction and hydrogen bonding interactions predominantly N–H…O −, suggesting that [ cis-Co(en) 2(N 3) 2] + is a promising anion receptor for the mesitylenesulphonate ion. This is the first report of a sulphonate salt containing the present cationic cobaltammine.

Di-μ-oxo-bis[bis(bipyridine-N,N')manganese(III, IV)] Triperchlorate Bis(nitrobenzene) Hemihydrate

The title compound, [Mn2O2(C10H8N2)4](ClO4)3.2C6H5NO2.0.5H2O, retains a half water molecule and incorporates two nitrobenzene molecules in the structure when recrystallized from a mixture of nitrobenzene and nitromethane. The two manganese sites have differing geometries suggestive of oxidation states MnIII and MnIV. The supposed d4 configuration of MnIII implies a Jahn–Teller distortion, which is observed.

A COPPER(II) COMPLEX CONTAINING THE PROTONATED FORM OF A DIAMINOPENTACARBOXYLIC ACID WITH AN UNSYMMETRICAL SKELETON

Abstract Crystalline samples of CuH3L · 3.5H2O (L = anion of N,N,N′,N′-tetrakis(carboxymethyl)-2,4-diamino-butyric acid; H5TDB = H5L) have been characterized by X-ray diffraction and other methods. The compound crystallizes in the monoclinic system, space group P21/n (a = 6.260(2), b = 18.505(5) c = 15.659(3) Å, β = 91.78(3)° and Z = 4). Final R = 0.049 and Rw = 0.054 for 1400 independent observed reflections. The structure consists of one-dimensional chains of CuH3L complex units and non-coordinated water molecules linked together in a network of hydrogen bonds. Only two [H(062) and H(N2)] of the three “acid” hydrogen atoms of the ligand (H3L2−) have been located in the structure. Each H3L2− anion acts as a tetradentate chelating agent for a Cu(II) ion by means of the C-substituted hydrogen nitrilotriacetato (NTA) group (Cu-N(1) 2.026(9), Cu-O(11) 1.971(8), Cu-O(81) 2.003(8) and Cu-O(61) 2.186(6)Å. The O(11) and O(61) atoms are part of carboxylato and carboxylic groups, respectively. The distorted five coordination of each Cu(II) ion is achieved by a rather short Cu-O(121i) bond (1.893(8)Å) with a carboxylate oxygen atom of the zwitterionic N-carboxymethyl-glycinato group in the adjacent CuH3L unit. The C(10)-carboxy group of the ligand IDA group exhibits two different statistical configurations with an unequal ratio of C-O distances. In addition, two and half water molecules in the formula CuH3TDB · 3.5H2O were also disordered. The Cu(11) coordination polyhedron is best described as an intermediate state between a trigonal bipyramid (wtih N(1) and O(121i) apices) and a square-based pyramid (with O(61) apex) both correlated by the “Berry twist” mechanism.

The structure of uranyl chloride monohydrate by neutron diffraction and the disorder of the water molecule

UO2Cl2. H2O and UO2Cl2.D2O have the space-group symmetry P21/m with Z = 2, and lattice constants, respectively, a = 5.836 (3), b = 8.563 (3), c = 5.566 (2) A, β = 97.70° and a = 5.847 (9), b = 8.596 (13), c = 5.543 (9) A, β = 97.51 (8)°. Neutron-diffraction powder studies of the two compounds have shown that previously assigned parameters of the uranyl oxygen and water oxygen atoms require modification. There is a pentagonal bipyramidal configuration around the uranium atom and the pentagonal ring consists of four chlorine atoms and a water oxygen atom. The interatomic distances and angles in the bipyramid are normal and close to the values found by neutron diffraction in a similar ring system in anhydrous UO2Cl2. The water molecule was found to be disordered. Half-hydrogens (or D) were observed in hydrogen bonding with the uranyl oxygens O(1) and O(2) (half-water molecule in mirror plane) and half-hydrogens (or D) were observed in hydrogen bonding with chlorine atoms above and below the mirror plane (half-water molecule in plane perpendicular to mirror plane). The hydrogen bond distances correspond to weak hydrogen bonding.