Supramolecular pseudopolymorphs: double helix and planar structures with channels

Zinc amidoisophthalate complexes and their catalytic application in the diastereoselective Henry reaction

5-Propionamidoisophthalic acid and 5-benzamidoisophthalic acid are used to synthesize new zinc(ii) complexes which act as heterogeneous catalysts for the diastereoselective nitroaldol (Henry) reaction.

Bis[4-(4-pyridyl)pyridinium] μ-4,4'-bipyridine-bis-[tetra-aqua-(4,4'-bipyridine)manganese(II)] bis-(5-sulfonatobenzene-1,3-dicarboxyl-ate) 4,4'-bipyridine solvate penta-deca-hydrate

The crystal structure of the title compound, (C₁₀H₉N₂)₂[Mn₂(C₁₀H₈N₂)₃(H₂O)₈](C₈H₃O₇S)₂·C₁₀H₈N₂·15H₂O, consists of dinuclear Mn^II complex cations, sulfonato­benzene­dicarboxyl­ate trianions, 4-(4-pyridyl)pyridinium cations, uncoordin­ated 4,4′-bipyridine and uncoordinated water mol­ecules. One 4,4′-bipyridine mol­ecule bridges two Mn atoms, forming a centrosymmetric dinuclear complex; the mid-point of the C—C bond linking the pyridine rings of the bridging ligand is located on an inversion center. Each Mn^II atom is coordinated by four water and two 4,4′-bipyridine mol­ecules in a distorted octa­hedral geometry. The Mn^II atom deviates by 0.591 (5) and 0.209 (2) Å from the mean planes of the coordinated pyridine rings. In the 4-(4-pyridyl)pyridinium cation, the two pyridine rings are twisted with respect to each other, making dihedral angle of 34.78 (17)°. The uncoordinated bipyridine mol­ecule is also centrosymmetric. One of uncoordinated water mol­ecules has site symmetry 2, and the other uncoordinated water mol­ecule is located close to an inversion center and its one H atom is disordered equally over two sites. Extensive π–π stacking between pyridine rings is observed and an extensive hydrogen-bonding network of the types N—H⋯N, O—H⋯N and O—H⋯O is present.

Hydrogen bond mediated open-frame networks in coordination polymers: supramolecular assemblies of Pr(iii) and 3,5-dinitro-4-methylbenzoic acid with aza-donor compounds

A coordination assembly of 3,5-dinitro-4-methylbenzoic acid and Pr(III), synthesized by hydrothermal methods forms a host structure, which is stable up to 300 [degree]C, through C-HO hydrogen bonds and accommodates different types of guest species varying from simple molecules like water to larger molecules like trans-1,2-bis(4-pyridyl)ethene.

Solvent-Dependent Coordination Polymers: Cobalt Complexes of 3,5-Dinitrobenzoic Acid and 3,5-Dinitro-4-methylbenzoic Acid with 4,4‘-Bipyrdine

The synthesis, structure elucidation, and analysis of the self-assembly of Co(II) complexes of 3,5-dinitrobenzoic acid and 3,5-dinitro-4-methylbenzoic acid with 4,4'-bipyridine have been reported. Formation of the complexes and the self-assembly in the three-dimensional structures have been found to be dependent on the solvents (such as acetone, dimethly sulfoxide, etc.) employed for the synthesis of the aggregates. 3,5-Dinitrobenzoic acid forms two coordination polymers, 1a and 1b, from methanol and a mixture of methanol and acetone solvents, respectively, with entirely different recognition patterns. Similarly, 3,5-dinitro-4-methylbenzoic acid also forms two coordination complexes, 2a and 2b, incorporating the solvent of the reaction medium into the crystal lattice. Complex 2a forms a solvated channel structure, whereas 2b gives a bilayered structure, with the layers being separated by solvent of crystallization (dimethyl sulfoxide) molecules. All the complexes have been characterized by single-crystal X-ray diffraction studies. Complexes 1b, 2a, and 2b crystallize in a monoclinic lattice, but 1a adopts a tetragonal lattice. The unit cell dimensions are, for 1a, a = 8.095(1) A, b = 8.095(1) A, c = 46.283 (6) A, alpha = 90 degrees, beta = 90 degrees, and gamma = 90 degrees (space group P4(3)2(1)2, Z = 4), for 1b, a = 22.774(2) A, b = 11.375 (1) A, c = 22.533(2) A, alpha = 90 degrees, beta = 104.15(1) degrees, and gamma = 90 degrees (space group P2(1)/c, Z = 4), for 2a, a = 17.657(6) A, b = 18.709(4) A, c = 21.044(6) A, alpha = 90 degrees, beta = 108.68(3) degrees, and gamma = 90 degrees (space group, C2/c, Z = 8), and, for 2b, a = 11.025(5) A, b = 15.139(4) A, c = 11.443(4) A, alpha = 90 degrees, beta = 97.48(3) degrees, and gamma = 90 degrees (space group P2/n, Z = 2). In all the complexes 1a, 1b, 2a, and 2b, the basic interaction between Co(II) and 4,4'-bipyridine remains the same with the formation of linear Co-N dative bonds, but the carboxylates display various modes of interaction with Co(II). The average Co-N and Co-O distances are 2.161 and 2.108 A, respectively.