Search

Metal−organic layers (MOLs), with well-defined, abundant active sites and good electron transport capabilities, are ideal platforms for studying the photoreduction of CO2 to value-added chemicals feedstocks in 2D/2D assembled materials.

Solvothermal reaction of Co(II)/Zn(II) salt with 1,2,4,5-benzene tetracarboxylic dianhydride (BTD) leads to the formation of two coordination polymers based on benzene-1,2,4,5-tetracarboxylic acid (H4BTC), [Co2(BTC)(DMA)(H2O)]n (1) (DMA = N,N′-dimethylacetamide) and [Zn4(BTC)2(H2O)6]n·3nH2O (2). Both 1 and 2 have been characterized by infrared spectra (IR), elemental analyses (EA), thermogravimetric analyses (TG) and single-crystal/powder X-ray diffraction (XRD). The results of the single-crystal X-ray diffraction analyses reveal that both compounds are 3D coordination polymers. In 1, 1D Co(II)-carboxylate chains are linked together by the organic moiety of BTC4− ligands, forming a 3D coordination polymer. In 2, 1D Zn-BTC4− ribbons are connected together by [Zn2(H2O)3] building units, generating a 3D porous framework with 1D rectangular channels. Gas sorption measurements reveal that the two compounds can not adsorb N2. Photoluminescent study indicates that 2 exhibits luminescent properties with an emission peak at 527 nm.

By a pH value controlled synthesis strategy, hydrothermal reactions of Cd(NO3)2·4H2O with mixed-ligands of 5-amino-tetrazole (Hatz) and 1,2,4,5-benzenetetracarboxylic acid (H4btec) yielded two 3D cadmium(II) coordination polymers (CPs) of {K[Cd2(atz)(btec)(H2O)2]}n (1) and [Cd3(OH)(atz)(btec)(H2O)2]n·nH2O (2). Their structures were determined by elemental analysis (EA), infrared spectra (IR), thermogravimetric analysis (TGA) and single-crystal/powder X-ray diffraction. The results reveal that both 1 and 2 are 3D architectures. In 1, the Cd(II) ions are connected together by μ2-atz and μ6-btec4−, generating a rare (4,6)-connected anion framework. The anti-cation K+ ions locate the micropores and weakly interact with the carboxyl oxygen of the μ6-btec4− ligands. In 2, six Cd(II) ions are linked together through two μ3-OH− and two μ3-atz− to form a [Cd6(μ3-OH)2(μ3-atz)2]8+ unit, which is further connected with other equivalent units by μ9-btec4− spacers, resulting in a rare (5,10)-connected porous framework. The photoluminescent investigation illustrates that 1 and 2 show strong emissions at 470 and 457 nm upon excitation at 350 and 370 nm, respectively.

Six cadmium(II) coordination compounds with 2-propyl-imidazole-4,5-dicarboxylate (H3PIDC), including two mononuclear complexes, [Cd(H2PIDC)2(H2O)2]·4H2O (1) and [Cd2(H2PIDC)4(H2O)4]·7H2O (2), two square tetranuclear complexes, [Cd4(HPIDC)4(H2O)8]·2H2O (3) and [Cd4(HPIDC)4(py)8]·10H2O (py = pyridine, 4), one one-dimensional chain polymer, [Cd2(H2PIDC)4(H2O)2]n·2nH2O (5), as well as one two-dimensional layer polymer, [Cd(H2PIDC)2]n (6), have been prepared using solvent evaporation method and hydrothermal method. The results of single-crystal X-ray diffraction analyses indicate that, besides the common supramolecular interactions such as hydrogen bond and π···π stacking, the hydrophobic interaction among the propyl groups in the H3PIDC ligands also contributes to the stabilities of 1–6. The study of substance transformation for 3 reveals that the coordinated H2O molecules in 3 can be well replaced by pyridine molecules, indirectly leading to the formation of 4. The results of photoluminescent measurements il...

Two cadmium(II) metal–organic frameworks based on two mixed ligands of HBTA and H2BDC, [Cd5(BTA)6(BDC)2(DMF)4(H2O)2]n·n(2DMF·H2O) (1) and [Cd7(BTA)2(BDC)6(DMF)8]n·2nDMF (2) (HBTA = 1,2,3-benzenetriazole; H2BDC = 1,4-benzenedicarboxylic acid), have been prepared through methods of liquid to liquid diffusion and solvothermal reaction, respectively. The results of single-crystal X-ray diffraction analyses indicate that both MOFs are constructed from cadmium clusters. In 1, six BTA– anions connect five Cd(II) ions to generate a tetrahedral Cd5 cluster, which further links with four equivalent Cd5 clusters through four BDC2– bridges, forming a (4,4)-connected two–dimensional (2D) layer structure. In 2, each BTA– anion connects three Cd(II) ions to generate a triangular Cd3 cluster, which further links with four Cd3 clusters and two 3-connected BDC2– anions, forming a (3,6)-connected three-dimensional (3D) framework. The results of photoluminescent measurements illustrate that in the solid state, both 1 and 2 c...

In the title compound, [Co(C(9)H(8)NO(3))(C(12)H(8)N(2))(2)(H(2)O)]NO(3)·H(2)O, the Co(II) atom is six-coordinated by a carboxylate O atom of the hippurate (Hc) anion, a water O atom and four N atoms from two 1,10-phenanthroline ligands in a distorted octa-hedral geometry. The uncoordinated O atom of the hippuric acid anion is involved in an intra-molecular hydrogen bond to the coordinated water mol-ecule. The crystal packing is stabilized by inter-molecular O-H⋯O hydrogen bonds involving the Hc anions, the coordinated water mol-ecule, the nitrate anion and the uncoordinated water mol-ecule.

In the title dinuclear Cd(II) complex, [Cd(2)(C(2)N(4)O(2))(2)(C(10)H(8)N(2))(2)(H(2)O)(2)], each Cd atom is in a slightly distorted octa-hedral coordination by two N atoms and one O atom of two 1H-tetra-zole-5-carboxyl-ate (TZC) ligands, two N atoms of a 2,2'-bipyridyl ligand and one water O atom. The TZC ligand acts in a tridentate N,O-chelating N-bridging mode to two symmetry-equivalent Cd(II) atoms. The complex reveals mol-ecular C(i) symmetry. Extensive O-H⋯O hydrogen bonding plays an important role in the crystal packing.

The title mononuclear copper(II) complex, [Cu(C7H6ClN4O2)2(H2O)2]·2H2O, based on 8-chlorotheophylline (HCt), has the Cu atom at a center of symmetry in a slightly distorted trans square-planar geometry coordinated by two N atoms of two deprotonated HCt ligands and two O atoms of water molecules. The crystal packing is stabilized by hydrogen bonds involving deprotonated HCt ligands, coordinated water molecules and uncoordinated solvent water molecules.

In the title compound, [Co(C7H5O2)2(C5H6N2)2], the CoII atom is hexa­coordinated by four O atoms from two benzoate anions, and two N atoms from two 2-amino­pyridine mol­ecules, resulting in a distorted octa­hedral geometry. Both benzoate anions act as bidentate ligands and both 2-amino­pyridine mol­ecules are coordinated to the metal through their pyridyl N atoms. The crystal packing is stabilized by inter­molecular N—H⋯O hydrogen bonds, C—H⋯π, and π–π stacking inter­actions involving benzoate anions and 2-amino­pyridine mol­ecules.

In the title compound, [Cd(C7H5O2)2(C5H6N2)2], the CdII atom is hexa­coordinated by four O atoms from two crystallographically independent benzoate anions, and two pyridine N atoms from two crystallographically independent 2-amino­pyridine mol­ecules in a distorted octa­hedral geometry. In the crystal structure, the metal complexes are connected by N—H⋯O hydrogen bonding between the carboxylate O atoms of the benzoate anions and the amino H atoms of the 2-amino­pyridine ligands. The benzoate and the amino­pyridine rings are stacked in the direction of the crystallographic a axis, indicating π–π stacking inter­actions are present [centroid-centroid distance = 3.6790 (15) A].

The Zn atom of the title complex, [Zn(NCS)2(C7H8N4O)2(H2O)2] or [Zn(SCN)2(H-Pysc)2(H2O)2] [H-Pysc = N-aminocarbonyl-N′-(3-pyridylmethylene)hydrazine], derived from the condensation of pyridine-3-carbaldehyde and semicarbazone, is located at a crystallographic centre of inversion and is octahedrally coordinated by two thiocyanate anions, two aqua molecules and two molecules of the neutral Schiff base ligand H-Pysc. The Schiff base molecules act as monodentate ligands coordinating the metal through the pyridyl N atom, whereas the amide O and imine N atoms remain uncoordinated. The crystal packing is stabilized by intermolecular hydrogen bonds involving H-Pysc ligands, thiocyanate anions and water molecules.

The Cd atom in the title complex, [Cd(C2H3O2)(NCS)(C7H8N4O)(H2O)]·H2O, is coordinated by one neutral Schiff base ligand, one acetate anion, one thio­cyanate anion and one water mol­ecule, forming a distorted penta­gonal–bipyramidal geometry. The thio­cyanate S atom and the coordinated water ligand occupy the apical positions of the coordination polyhedron. The acetate acts as a bidentate ligand through the carboxylate O atoms. The Schiff base, derived from the condensation of pyridine-2-carbaldehyde and semicarbazone, acts as a tridentate ligand, coordinating the metal through the amide, imine and pyridyl N atoms in a meridional fashion. The crystal packing is stabilized by π–π stacking inter­actions between the neighboring pyridine rings and hydrogen bonds involving the Schiff base, thio­cyanate, water mol­ecules and uncoordinated solvent water mol­ecules.

In the title compound, [Pb(C7H4O3)]n, the PbII atom is coordinated by five O atoms from four salicylic acid ligands with Pb—O distances of 2.318 (16)–2.605 (15) A. Each ligand acts in a penta­dentate mode that leads to the formation of a two-dimensional polymeric network.

A three-dimensional tetrazole-based Cd(II) metal–organic framework containing rare large Cd8 and Cd23 secondary building units has been hydrothermally prepared through in situ metal/ligand reaction, which shows an unprecedented (4,10)-connected topology net.

In the crystal structure of the title compound, [Mg(CHN(4))(2)(H(2)O)(4)], the Mg(II) atom is six-coordinated by two N atoms from two tetra-zolide anions and four O atoms from four coordinated water mol-ecules in a slightly distorted octa-hedral geometry. The Mg atom is located on centres of inversion whereas the tetra-zolide anion and the water mol-ecules occupy general positions. The crystal packing is stabilized by intermolecular O-H⋯N hydrogen bonding between the tetra-zolide anions and the coordinated water mol-ecules.

The title compound, [Ni(2)(C(7)H(5)O(2))(4)(C(7)H(6)O(2))(2)], is composed of two Ni(II) ions, four bridging benzoate anions and two η(1)-benzoic acid mol-ecules. The [Ni(2)(PhCOO)(4)] unit adopts a typical paddle-wheel conformation. The center between the two Ni(II) atoms represents a crystallographic center of inversion. In addition, each Ni(II) ion also coordinates to one O atom from a benzoic acid mol-ecule. The crystal packing is realised by inter-molecular hydrogen-bonding inter-actions and π-π stacking inter-actions, with a centroid-centroid distance of 3.921 (1) Å.

The title compound, C(14)H(6)O(7)·C(10)H(8)N(2), has been hydro-thermally synthesized. Structural ananlysis indicates that the crystals are produced by cocrystallization of naphthalene-1,4,5,8-tetra-carboxylic acid 1,8-anhydride and 4,4'-bipyridine (bpy) mol-ecules. The crystal packing is stabilized by inter-molecular O-H⋯N and C-H⋯O hydrogen bonds and π-π stacking inter-actions [centroid-centroid distances = 3.5846 (9) Å].

In the crystal structure of the title compound, C(14)H(10)F(2)O, the dihedral angles between the benzene rings in the two crystallographically independent mol-ecules are 46.9 (2) and 47.6 (2)°. The mol-ecules are linked into dimers by C-H⋯F inter-actions and these dimers are further stacked into columns along the b axis by π-π inter-actions between the benzene rings [centroid-centroid distance = 3.8221 Å; the dihedral angle between the planes of these rings is 4.87 (2)°]. In addition, C-F⋯π interactions also contribute to the crystal packing (C⋯centroid distance = 3.5919 Å).

In the title complex, [Mn(SCN)2(H-Pysc)2(H2O)2] {H-Pysc = 3-[2-(amino­carbon­yl)hydrazonometh­yl]pyridine, C7H8N4O}, MnII, located at an inversion centre, is coordinated by two thio­cyanate anions, two water mol­ecules and two mol­ecules of the neutral Schiff base ligand H-Pysc, forming an octa­hedral configuration. The Schiff base acts as a monodentate ligand, coordinating to the metal through the pyridyl N atom, whereas the amide O and imine N atoms remain uncoordinated. The complex mol­ecules are held together by inter­molecular hydrogen bonds into a three-dimensional supra­molecular network.