Diaquabis(pyridine-2-carboxylato-κ2N,O)zinc dimethylformamide hemisolvate

In the title compound, [Zn(C6H4NO2)2(H2O)2]·0.5C3H7NO, the ZnII ion is coordinated in a distorted octahedral N2O4 environment by two N,O-chelating pyridine-2-carboxylate ligands and two cis water molecules. The chelating pyridine-2-carboxylate ligands create two five-membered Zn/N/C/C/O rings, which form a dihedral angle of 86.4 (2)°. In the crystal, O—H...O hydrogen bonds link the complex molecules into a two-dimensional network parallel to (100). The dimethylformamide solvent molecule is disordered about a twofold rotation axis

From Pink To Blue And Back To Pink Again: Changing The Co(Ii) Ligation In A Two-Dimensional Coordination Network Upon Desolvation

Heating of a pink two-dimensional Co(ii) coordination network {[Co2(μ2-OH2)(bdc)2(S-nia)2(H2O)(dmf)]·2(dmf)·(H2O)}n (1) built from 1,4-benzenedicarboxylic acid (H2bdc) residues and thionicotinamide (S-nia) ligands initiates a single-crystal-to-single-crystal transition accompanied by removal of both coordinated and co-crystallized solvents. In the dry blue form, [Co(bdc)(S-nia)]n (dry-1), the Co(ii) centers changed from an octahedral to a square pyramidal configuration

Robust Packing Patterns And Luminescence Quenching In Mononuclear [Cu(Ii)(Phen)2] Sulfates

Three mixed-ligand Cu(II) complexes with compositions [Cu(phen)2(SO4)]·CH3OH (1), [Cu(phen)2(SO4)](H2O)2(dmf) (2), and [Cu(phen)2H2O](SO4)(H2O)4 (3), where phen = 1,10-phenanthroline and dmf = N,Nβ-dimethylformamide, were prepared and studied. These compounds belong to the landscape of the mononuclear Cu(phen)2 sulfates, and the solvated complexes undergo frequent anion/water exchange at the metal center in aqueous solutions. Complexes are similar by the metal trigonal bipyramidal coordination geometry but differ by the mode of enclathration and number of protic and aprotic solvent guest molecules being accommodated in the crystal lattice. Crystal packing in 1-3 is determined by the robust supramolecular patterns that consist of stacking interactions between the planar extended phen fragments. These are observed in all three solids regardless of the interplay of other noncovalent interactions, including rather strong hydrogen bonds. The dual luminescence is detected at 580 and 470 nm for both crystals of phen and 3. Detailed analysis of singlet and triplet excitations in phen and 3 is performed by time-dependent density functional methods. Fluorescence is predicted with a low quantum yield at 386 nm, and dual phosphorescence from n-∗ and -∗ triplet states is predicted at 523 and 496 nm. Emission quenching was demonstrated for 3 and explained by nonradiative decay involving supramolecular stacking and low-lying metal-centered states

From Discrete Molecules To One-Dimensional Coordination Polymers Containing Mn(Ii), Zn(Ii) Or Cd(Ii) Pyridine-2-Aldoxime Building Unit

The syntheses, spectroscopic characterization and crystal structures for eight coordination compounds [Cd(HCO2)2(pya)2] (1), {[M(bdc)(pya)].1.5DMF}n (M = Mn(II), Zn(II), Cd(II) (2-4), [Zn(SO4)(pya)(H2O)3] (H2O) (5), [(ZnSO4)2(pya)4] DMF.2H2O (6), [Zn(SO4)(pya)(H2O)2]n (7), and [Cd(SO4)(pya)(H2O)]n (8) [pya = pyridine-2-aldoxime, bdc = 1,4-benzenedicarboxylate, DMF = N,N′-dimethylformamide] are reported. Compounds 1-4 and 6 contain two, while 5, 7, and 8 contain one neutral pya ligand coordinated in a chelate mode to the metal center through the N pyridyl and Noxime atoms. The dicarboxylic bdc anions provide an access to 1D polymeric arrays in 2-4. The hybrid sulfates including discrete mononuclear (5), binuclear (6), and 1D polymeric (7, 8) coordination arrays were obtained due to different binding modes of coordinated sulfate anion. While solid state fluorescence of new polymeric compounds 2-4 is similar to that of the H2bdc ligand, a rare dual emission is observed for compounds 7 and 8. According to TD-DFT calculations, emission at 400 and 650 nm originates from nπ* and ππ* states of the pya ligand respectively. © 2013 Elsevier Ltd. All rights reserved

Polymeric Luminescent Zn(Ii) And Cd(Ii) Dicarboxylates Decorated By Oxime Ligands: Tuning The Dimensionality And Adsorption Capacity

Ten Zn(II) and Cd(II) metal-organic materials were synthesized and studied by the X-ray method. Among these 10 structures, two represent binuclear clusters, and two are one-dimensional (1D) coordination polymers, while five are laminar two-dimensional (2D) solids and one is the three-dimensional (3D) framework. The investigation has been aimed at rational design of coordination polymers decorated by oxime ligands to increase the accessible adsorption area in these newly synthesized solids. The ligands used include three aliphatic dicarboxylic acids, HOOC-(CH2)n-COOH [n = 1, 2, 4 corresponding to malonic (H2mal), succinic (H2suc), and adipic (H2adi) acids], and three neutral oxime ligands [pyridine-2-aldoxime (2-pyao), pyridine-4-aldoxime (4-pyao), and 1,2-cyclohexanedionedioxime (Niox)]. These novel hybrid solids with the compositions [Zn2(suc)2(2-pyao)4] ·2H2O 1, [Cd2(suc)(2-pyao)4(H 2O)2][BF4]2 2, [Cd(suc)(2-pyao) 2]n 3, [Zn(mal)(4-pyao)(H2O)]n 4, [Cd(mal)(4-pyao)(H2O)]n 5, [Zn(suc)(4-pyao)]n 6, [Zn(adi)(4-pyao)2]n 7, {[Cd(adi)(4-pyao) 2]·dmf}n 8, [Zn(adi)(Niox)]n 9, and [Cd(adi)(Niox)]n 10 [dmf - N,N\u272-dimethylformamide] demonstrate a variable class of coordination supramolecular architectures dictated by the distinctions in the metals\u27 and oxime ligands\u27 coordination capacities and preferences, and length and flexibility of the dicarboxylic linkers. The discrete aggregates 1 and 2 differ by the components\u27 ratio and conformation of the bridging succinate anion; compounds 3 and 7 are 1D arrays, and compounds 4, 5, 6, 8, and 9 represent 2D layers of different topologies. Compound 10 is a 3D grid afforded by the concerted contribution of the longest in this series adipate anion, and the bigger atomic radius Cd(II) vs. Zn(II). The adsorptive properties of 7 and 9 are reported. For the laminar solid 9, the quantum chemical simulations of the adsorption capacity are in line with the experimental results. All new materials reveal dual green-blue wavelength emission in the solid state. © 2014 American Chemical Society

Mechanism Of Nonlinear Optical Enhancement And Supramolecular Isomerism In 1D Polymeric Zn(Ii) And Cd(Ii) Sulfates With Pyridine-4-Aldoxime Ligands

Interaction of zinc(II) and cadmium(II) sulfates with pyridine-4-aldoxime (4-pyao) and pyridine-4-amidoxime (4-pyamo) ligands resulted in four 1D metal-organic materials (MOMs) with identical composition, [M(SO 4)A2(H2O)2]n, where M = Zn(II), A = 4-pyao for 1, M = Cd(II), A = 4-pyao for 2, M = Zn(II), A = 4-pyamo for 3, M = Cd(II), A = 4-pyamo for 4, and mononuclear [Zn(SO4)(4- pyamo)2(H2O)3] 5. New coordination polymers represent the mixed-ligand supramolecular isomers different by the twisting of two pyridine-4-oxime ligands in the metal coordination environments, and crystallizing in the different space groups. Conformational preferences and nonlinear optical properties of the 4-pyao and 4-pyamo complexes were investigated using density functional theory. Spectral properties of 1-3 have been also evaluated. The solid-state emission of 1D polymers 1-3 appears to be ligand-based, as the positions of the emission maxima remain practically unchanged from free ligand to complexes. The enhancement of luminescence and two-photon absorption in polymers in comparison with the pure ligands is attributed to the chelation of the ligand to the metal center. The detailed mechanism of this enhancement upon complex formation is analyzed and can be used in future design of metal-organic nonlinear optical materials. © 2014 American Chemical Society

From 1D to 2D Cd(II) and Zn(II) Coordination Networks by Replacing Monocarboxylate with Dicarboxylates in Partnership with Azine Ligands: Synthesis, Crystal Structures, Inclusion, and Emission Properties

Eight mixed-ligand coordination networks, [Cd(2-aba)(NO3)(4-bphz)3/2]n·n(dmf) (1), [Cd(2-aba)2(4-bphz)]n·0.75n(dmf) (2), [Cd(seb)(4-bphz)]n·n(H2O) (3), [Cd(seb)(4-bpmhz)]n·n(H2O) (4), [Cd(hpa)(3-bphz)]n (5), [Zn(1,3-bdc)(3-bpmhz)]n·n(MeOH) (6), [Cd(1,3-bdc)(3-bpmhz)]n ·0.5n(H2O)·0.5n(EtOH) (7), and [Cd(NO3)2(3-bphz)(bpe)]n·n(3-bphz) (8) were obtained by interplay of cadmium nitrate tetrahydrate or zinc nitrate hexahydrate with 2-aminobenzenecarboxylic acid (H(2-aba)), three dicarboxylic acids, sebacic (decanedioic acid, H2seb), homophthalic (2-(carboxymethyl)benzoic acid, H2hpa), isophthalic (1,3-benzenedicarboxylic acid, H2(1,3-bdc)) acids, bis(4-pyridyl)ethane (bpe) and with four azine ligands, 1,2-bis(pyridin-4-ylmethylene)hydrazine (4-bphz), 1,2-bis(1-(pyridin-4-yl)ethylidene) hydrazine (4-bpmhz), 1,2-bis(pyridin-3-ylmethylene)hydrazine (3-bphz), and 1,2-bis(1-(pyridin-3-yl) ethylidene)hydrazine (3-bpmhz). Compounds 1 and 2 are 1D coordination polymers, while compounds 3–8 are 2D coordination polymers. All compounds were characterized by spectroscopic and X-ray diffraction methods of analysis. The solvent uptakes and stabilities to the guest evacuation were studied and compared for 1D and 2D coordination networks. The de-solvated forms revealed a significant increase of emission in comparison with the as-synthesized crystals

Mechanism of Nonlinear Optical Enhancement and Supramolecular Isomerism in 1D Polymeric Zn(II) and Cd(II) Sulfates with Pyridine-4-aldoxime Ligands

Interaction of zinc­(II) and cadmium­(II) sulfates with pyridine-4-aldoxime (4-pyao) and pyridine-4-amidoxime (4-pyamo) ligands resulted in four 1D metal–organic materials (MOMs) with identical composition, [M­(SO₄)­A₂(H₂O)₂]_<i>n</i>, where M = Zn­(II), A = 4-pyao for <b>1</b>, M = Cd­(II), A = 4-pyao for <b>2</b>, M = Zn­(II), A = 4-pyamo for <b>3</b>, M = Cd­(II), A = 4-pyamo for <b>4</b>, and mononuclear [Zn­(SO₄)­(4-pyamo)₂(H₂O)₃] <b>5</b>. New coordination polymers represent the mixed-ligand supramolecular isomers different by the twisting of two pyridine-4-oxime ligands in the metal coordination environments, and crystallizing in the different space groups. Conformational preferences and nonlinear optical properties of the 4-pyao and 4-pyamo complexes were investigated using density functional theory. Spectral properties of <b>1</b>–<b>3</b> have been also evaluated. The solid-state emission of 1D polymers <b>1</b>–<b>3</b> appears to be ligand-based, as the positions of the emission maxima remain practically unchanged from free ligand to complexes. The enhancement of luminescence and two-photon absorption in polymers in comparison with the pure ligands is attributed to the chelation of the ligand to the metal center. The detailed mechanism of this enhancement upon complex formation is analyzed and can be used in future design of metal–organic nonlinear optical materials