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The biomolecule chelidonic acid (H2chel, 4-oxo-4H-pyran-2,6-dicarboxylic acid) has been used to build new coordination polymers with the bridging N,N′-ligands 4,4′-bipyridine (4,4-bipy) and 1,2-bis(4-pyridyl)ethane (bpe). Four compounds have been obtained as single crystals: 1D cationic coordination polymers [M(4,4-bipy)(OH2)4]2+ with chelidonate anions and water molecules in the second coordination sphere in 1∞[Zn(4,4-bipy)(H2O)4]chel·3H2O (2) and in the two pseudopolymorphic 1∞[Cu(4,4-bipy)(H2O)4]chel·nH2O (n = 3, 4a; n = 6, 4b), and the 2D neutral coordination polymers 2∞[Zn(chel)(4,4-bipy)(H2O)]·2H2O (1) and 2∞[Zn(chel)(bpe)(H2O)]·H2O (3) where the chelidonate anion acts as a bridging ligand. The effects of the hydrogen bonds on the crystal packing were analyzed. The role of the water molecules hosted within the crystals lattices was also studied.

The asymmetric unit of the title compound, [ReCl(C5H5NO)2(CO)3]·C5H5NO, contains one molecule of the complex fac-[ReCl(4-pyOH)2(CO)3] (where 4-pyOH represents 4-hydroxypyridine) and one molecule of pyridin-4(1H)-one (4-HpyO). In the molecule of the complex, the Re atom is coordinated to two N atoms of the two 4-pyOH ligands, three carbonyl C atoms, in a facial configuration, and the Cl atom. The resulting geometry is slightly distorted octahedral. In the crystal structure, both fragments are associated by hydrogen bonds; two 4-HpyO molecules bridge between two molecules of the complex using the O=C group as acceptor for two different HO– groups of coordinated 4-pyOH from two neighbouring metal complexes. The resulting square arrangements are extented into infinite chains by hydrogen bonds involving the N—H groups of the 4-HpyO molecule and the chloride ligands. The chains are further stabilized by π-stacking interactions.

The synthesis and crystal structure of a monoclinic (P21/c) polymorph of the title compound, C6H10S2N8, are reported. The molecule has pseudo-twofold rotational symmetry, with the tetrazole rings being inclined to one another by 5.50 (6)°. In the crystal, molecules are linked by C—H...N hydrogen bonds, forming chains propagating along [101] and enclosing R22(20) ring motifs. The chains are linked by offset π–π interactions involving the tetrazole rings [intercentroid distances vary from 3.3567 (7) to 3.4227 (7) Å], forming layers parallel to the ac plane. The crystal structure of the triclinic polymorph (P\overline{1}) has been described previously [Li et al. (2011). Acta Cryst. E67, o1669].

The asymmetric unit of the title compound, C9H9N3OS, contains two approximately planar molecules (r.m.s. deviations for 14 non-H atoms = 0.094 and 0.045 Å), with different conformations. In one of them, the C=O group is syn to the S atom and in the other it is anti. Each molecule features an intramolecular N—H...N hydrogen bond, which generates an S(5) ring. In the crystal, molecules are linked by N—H...O and N—H...S hydrogen bonds, generating discrete networks; the syn molecules form [010] chains and the anti molecules form (100) sheets.

The structure of the title compound, C10H11N3OS, comprises an approximately planar molecule, with the r.m.s. deviation for the 15 non-H atoms being 0.089 Å. The conformation about the imine bond is E and an intramolecular N—H...N hydrogen bond is evident. Molecules are linked into a supramolecular chain along the b axis by N—H...S hydrogen bonds.

Las enfermedades neuropsiquiátricas afectan a más de 10 % de la población cubana y alcanzan 25 % a nivel mundial. La mayoría de los fármacos empleados para el tratamiento de trastornos del sistema nervioso central son costosos y generan severas reacciones colaterales. Actualmente, se desarrollan esfuerzos para la aplicación de metabolitos secundarios como fuentes ecológicamente sostenibles para tratamiento de patologías del sistema nervioso -incluyendo isquemias y otras neuropatologías tipo Parkinson, Alzheimer y trastornos motores de Huntington-, que permitan una neuroprotección efectiva, así como una neurorregeneración en cortos periodos, con mínimas secuelas. El objetivo del trabajo fue evaluar la acción neurorregeneradora y neuroprotectora de la sal de sodio de ácidos resínicos aislados de colofonia de coníferas cubanas; los resultados del estudio sugieren que esta sal puede utilizarse en calidad de precursores estructurales de isoanálogos bioisostéricos con acción terapéutica específica tipo neuroprotectora y neurorregeneradora en el tratamiento de patologías isquémicas.

The ligand 4bpytm [4bpytm = bis(4-pyridylthio)methane] in strongly acidic media afforded H24bpytm(NO3)2. The reaction of CuCl2.2H2O with 4bpytm at low pH values afforded three supramolecular compounds: H24bpytm[CuCl4] (1) and the monomeric complexes [CuCl3(H4bpytm)(4bpytm)] (2) and [CuCl2(H4bpytm)2]·Cl2(3). Nevertheless, the same reaction using aprotic solvents under microwave irradiation afforded the 1D coordination polymers [CuCl2(4bpytm)]·2dmf (4.dmf) and [CuCl2(4bpytm)]·2dmso (4.dmso). The 3D supramolecular organization through weak interactions has been analyzed for all of the compounds, and their thermal behavior and structural dynamics after solvent release were also investigated for 4.dmf and 4.dmso. X-ray structural analysis of these complexes showed that the synthetic conditions used represent an effective method to obtain metal−organic square grid networks with cavities. [ABSTRACT FROM AUTHOR]

The compound [2bpytmH]2[I3]2[I2], which contains protonated 2bpytm, and four neutral monomeric complexes [CoCl2(2bpytm)]·H2O (1), [CoBr2(2bpytm)] (2), [CoI2(2bpytm)]·1/2H2O (3) and [NiBr2(2bpytm)]·H2O (4) have been obtained during a study into the reactivity of the bis(2-pyridylthio)methane (2bpytm) ligand towards cobalt(ii) and nickel(ii) halides. Furthermore, a cyclic dimer [CuBr2(2bpytm)]2(5) and a 1D polymer [CuBr2(2bpytm)]n·CH3CN (6) have been obtained from copper(ii)/(I) bromide salts. An unprecedented S–CH2–S activation and cleavage in 2bpytm has been observed on using copper(ii) salts with organic and voluminous inorganic anions. The cleavage of 2bpytm enabled the isolation of copper(ii) complexes containing the in situgenerated ligands 2-pyridinethiolate, 2-pyridinesulfenate or 2-pyridinesulfonate. [ABSTRACT FROM AUTHOR]

The compound [2bpytmH]2[I3]2[I2], which contains protonated 2bpytm, and four neutral monomeric complexes [CoCl2(2bpytm)]·H2O (1), [CoBr2(2bpytm)] (2), [CoI2(2bpytm)]·1/2H2O (3) and [NiBr2(2bpytm)]·H2O (4) have been obtained during a study into the reactivity of the bis(2-pyridylthio)methane (2bpytm) ligand towards cobalt(ii) and nickel(ii) halides. Furthermore, a cyclic dimer [CuBr2(2bpytm)]2(5) and a 1D polymer [CuBr2(2bpytm)]n·CH3CN (6) have been obtained from copper(ii)/(I) bromide salts. An unprecedented S–CH2–S activation and cleavage in 2bpytm has been observed on using copper(ii) salts with organic and voluminous inorganic anions. The cleavage of 2bpytm enabled the isolation of copper(ii) complexes containing the in situgenerated ligands 2-pyridinethiolate, 2-pyridinesulfenate or 2-pyridinesulfonate. [ABSTRACT FROM AUTHOR]

Five coordination polymers 1{[Cu4(HCO2)6(OH)2(4dpds)2]·2CH2Cl2}n, 2{[Cu4(CH3CO2)6(OH)2(4dpds)2]}n, 3{[Cu(4dpds)2(H2O)2](4pySO3)2·2H2O}n, 4{[Cu(4pySO3)2(4dpds)2]·2H2O}nand 5{[Cu(4pySO3)2(dmso)2]·2H2O}n(where 4dpds = 4,4′-dipyridyldisulfide, 4pySO3= 4-pyridylsulfonate) have been obtained during a study into the reactivity of basic copper(II) salts (formate and acetate) with 4,4′-dipyridyldisulfide (4dpds). The coordination polymers 1and 2consist of a repeated rhomboid structure in which analogous Cu4(RCO2)6(OH)2cores are joined by two 4,4′-dipyridyldisulfide bridging ligands to generate two different chain topologies: planar ribbon in 1and ruffled ribbon in 2. 4-Pyridylsulfonate ions appear as ligands or counterions in the coordination polymers 3, 4and 5due to oxidative cleavage of the 4,4′-dipyridyldisulfide under mild conditions. The coordination polymer 3has been isolated repeatedly in several direct reactions of the copper(II) carboxylates with 4,4′-dipyridyldisulfide. However, the coordination polymers 4and 5have been obtained from 1and 2, respectively, by recrystallization from DMF and DMSO. In compound 4, as in 3, the 4,4′-dipyridyldisulfide has only been partially oxidized to 4-pyridylsulfonate and a proportion of these units remain in the structure as disulfide. However, in 5the oxidation is complete. The structural analysis of these coordination polymers reveals that, in all cases, weak interactions such as classical and non-classical hydrogen bonds, as well as CHπ, Sπ and SO interactions, join the polymeric chains to generate three-dimensional networks. [ABSTRACT FROM AUTHOR]

Five new complexes, [Cu(L 1) 2(SS) 2] ( 1), [Cu(L 1) 2(SS) 2]·H 2O ( 1w 1), [Cu 2(L 1) 2(SCS)]·H 2O ( 2w 1), 1∞[Cu(L 2) 2(SS)]·4H 2O ( 3w 1D), and 2∞[Cu(L 2) 2(SCS)]·2H 2O ( 4w 1D) (where SS = 4,4′-dipyridyldisulfide, SCS = bis(4-pyridylthio)methane, L 1= 2-methyllactate, and L 2= glycolate), have been synthesized by the reaction of the SS and SCS ligands with the corresponding copper(II) α-hydroxycarboxylates (2-methyllactate and glycolate). The structures of the mononuclear compounds 1and 1w 1, which could be considered as pseudo-polymorphs, show that the solvent molecules are not innocent partners and play a key role in the supramolecular association. Compound 2w 1is a discrete dinuclear molecule in which the SCS ligand acts as bridge between the two copper(II) ions. In these three compounds it seems that the presence of the 2-methyllactate ligand prevents the formation of the expected coordination polymers through the twisted SS and SCS ligands. Compounds 3w 1Dand 4w 1D, which both contain the glycolate ligand, are one- and two-dimensional (1D and 2D) coordination polymers, respectively. In the crystal lattices of the two compounds, two 1D water morphologies are hosted: a treelike chain for 3w 1Dand a staircase T4(2) tape for 4w 1D. In both cases, the dehydration−rehydration processes are investigated. [ABSTRACT FROM AUTHOR]

The combination of the flexible bpetha ligand with different copper(II) carboxylates in a 1:1 molar ratio leads to the formation by self-assembly of three new one-dimensional (1D) polymeric compounds:  Cu(L1)2(bpetha)(H2O)·2H2On(1), Cu(L2)2(bpetha)·5H2On(2), and Cu(L3)2(bpetha)n(3), where bpetha 1,2-bis(4-pyridyl)ethane, L1acetato, L2lactato, and L32-methyllactato. These compounds were characterized by elemental analysis, infrared and electronic absorption spectroscopy, and single-crystal X-ray diffraction. X-ray structural analysis revealed that the polymeric compounds created by the bridging bpetha ligand present different 1D structural motifs:  linear chains for 1, zigzag chains for 2, and ladderlike chains for 3. Weak interactions such as hydrogen bonding, ··· stacking and/or C−H··· interactions join the polymeric chains to generate three-dimensional networks. Variable temperature magnetic susceptibility measurements reveal very weak antiferromagnetic coupling between the copper(II) centers in the three compounds. [ABSTRACT FROM AUTHOR]

We report herein a novel infinite two-dimensional water morphology, found in a metallo-organic host, made up of discrete cyclic water hexamers and which contains large circular holes defined by 18 molecules of water. [ABSTRACT FROM AUTHOR]