From Simple Palladium(II) Monomers to 2D Heterometallic Sodium-Palladium(II) Coordination Networks with 2-Halonicotinates.

The 2D heterometallic sodium-palladium(II) coordination polymers with 2-halonicotinates [2-chloropyridine-3-carboxylate (2-chloronicotinate), 2-Clnic and 2-bromopyridine-3-carboxylate (2-bromonicotinate), 2-Brnic], {[Na(HO)(μ-HO)PdCl(μ-2-Clnic-')]} (), and {[Na(HO)(μ-HO)PdBr(μ-2-Brnic-')]·2HO} () were prepared in aqueous solutions under the presence of NaHCO, while palladium(II) monomers with the neutral 2-chloronicotinic and 2-bromonicotinic acid ligands, [PdCl(2-ClnicH-)]·2DMF () and [PdCl(2-BrnicH-)]·2DMF (), were prepared in DMF/water mixtures (DMF = ,'-dimethylformamide). The zigzag chains of water-bridged sodium ions are in turn bridged by [PdCl(2-Clnic)] moieties in or by [PdBr(2-Brnic)] moieties in , leading to the formation of the infinite 2D coordination networks of or . The DFT calculations showed the halosubstituents type (Cl Br) does not have an influence on the formation of either or isomers.

Anion-assisted supramolecular assemblies of zinc(II) complexes with isonicotinamide.

Five zinc(II) coordination compounds, [ZnCl(isn)] (), [ZnBr(isn)] (), [Zn(NO)(HO)(isn)] (), [Zn(CHCOO)(isn)] () and [Zn(isn)(HO)](ClO) () (isn = isonicotinamide), were prepared by the reactions of the isonicotinamide (pyridine-4-carboxamide, isn) and corresponding zinc(II) salts. Their crystal structures were determined by the single-crystal X-ray diffraction method. The coordination environment of zinc(II) is tetrahedral in the compounds containing small halide anions (chloride, bromide), and .

The Solvent Effect on Composition and Dimensionality of Mercury(II) Complexes with Picolinic Acid.

Three new mercury(II) coordination compounds, {[HgCl(pic)]} (), [HgCl(pic)(picH)] (), and [HgBr(pic)(picH)] () (picH = pyridine-2-carboxylic acid, picolinic acid) were prepared by reactions of the corresponding mercury(II) halides and picolinic acid in an aqueous () or alcohol-methanol or ethanol ( and ) solutions. Two different types of coordination compounds were obtained depending on the solvent used. The crystal structures were determined by the single-crystal X-ray structural analysis.

Synthesis and crystal structure of a 6-chloro-nicotinate salt of a one-dimensional cationic nickel(II) coordination polymer with 4,4'-bi-pyridine.

A 6-chloro-nicotinate (6-Clnic) salt of a one-dimensional cationic nickel(II) coordination polymer with 4,4'-bi-pyridine (4,4'-bpy), namely, -poly[[[tetra-aqua-nickel(II)]-μ-4,4'-bi-pyridine-κ :'] bis-(6-chloro-nicotinate) tetra-hydrate], {[Ni(CHN)(HO)](CHClNO)·4HO} or {[Ni(4,4'-bpy)(HO)](6-Clnic)·4HO} , (), was prepared by the reaction of nickel(II) sulfate hepta-hydrate, 6-chloro-nicotinic acid and 4,4'-bi-pyridine in a mixture of water and ethanol. The mol-ecular structure of comprises a one-dimensional polymeric {[Ni(4,4'-bpy)(HO)]} cation, two 6-chloro-nicotinate anions and four water mol-ecules of crystallization per repeating polymeric unit. The nickel(II) ion in the polymeric cation is octa-hedrally coordinated by four water mol-ecule O atoms and by two 4,4'-bi-pyridine N atoms in the position.

The first coordination compound of 6-fluoro-nicotinate: the crystal structure of a one-dimensional nickel(II) coordination polymer containing the mixed ligands 6-fluoro-nicotinate and 4,4'-bi-pyridine.

A one-dimensional nickel(II) coordination polymer with the mixed ligands 6-fluoro-nicotinate (6-Fnic) and 4,4'-bi-pyridine (4,4'-bpy), namely, -poly[[di-aqua-bis-(6-fluoro-pyridine-3-carboxyl-ato-κ)nickel(II)]-μ-4,4'-bi-pyri-dine-κ :'] trihydrate], {[Ni(6-Fnic)(4,4'-bpy)(HO)]·3HO} , (), was prepared by the reaction of nickel(II) sulfate hepta-hydrate, 6-fluoro-nicotinic acid (CHFNO) and 4,4'-bi-pyridine (CHN) in a mixture of water and ethanol. The nickel(II) ion in is octa-hedrally coordinated by the O atoms of two water mol-ecules, two O atoms from -monodentate 6-fluoro-nicotinate ligands and two N atoms from bridging 4,4'-bi-pyridine ligands, forming a isomer. The bridging 4,4'-bi-pyridine ligands connect symmetry-related nickel(II) ions into infinite one-dimensional polymeric chains running in the [10] direction.

The first coordination compound of deprotonated 2-bromo-nicotinic acid: crystal structure of a dinuclear paddle-wheel copper(II) complex.

A copper(II) dimer with the deprotonated anion of 2-bromo-nicotinic acid (2-BrnicH), namely, tetrakis(μ-2-bromonicotinato-κ :')bis[aquacopper(-II)](-), [Cu(HO)(CHBrNO)] or [Cu(HO)(2-Brnic)], (), was prepared by the reaction of copper(II) chloride dihydrate and 2-bromo-nicotinic acid in water. The copper(II) ion in has a distorted square-pyramidal coordination environment, achieved by four carboxyl-ate O atoms in the basal plane and the water mol-ecule in the apical position. The pair of symmetry-related copper(II) ions are connected into a centrosymmetric paddle-wheel dinuclear cluster [Cu⋯Cu = 2.

Mechanically Responsive Crystalline Coordination Polymers with Controllable Elasticity.

Crystalline coordination polymers tend to be brittle and inelastic, however, we now describe a family of such compounds that are capable of displaying mechanical elasticity in response to external pressure. The design approach successfully targets structural features that are critical for producing the desired mechanical output. The elastic crystals all comprise 1D cadmium(II) halide polymeric chains with adjacent metal centres bridged by two halide ions resulting in the required stacking interactions and short "4 Å" crystallographic axes.

Building inorganic supramolecular architectures using principles adopted from the organic solid state.

In order to develop transferable and practical avenues for the assembly of coordination complexes into architectures with specific dimensionality, a strategy utilizing ligands capable of simultaneous metal coordination and self-complementary hydrogen bonding is presented. The three ligands used, 2(1)-pyrazinone, 4(3)-pyrimidinone and 4(3)-quinazolinone, consistently deliver the required synthetic vectors in a series of Cd coordination polymers, allowing for reproducible supramolecular synthesis that is insensitive to the different steric and geometric demands from potentially disruptive counterions. In all nine crystallographically characterized compounds presented here, directional intermolecular N-H⋯O hydrogen bonds between ligands on adjacent complex building blocks drive the assembly and orientation of discrete building blocks into largely predictable topologies.

Vibrational spectroscopic and DFT calculation studies of cobalt(II) complexes with 3-hydroxypicolinic acid.

Two cobalt(II) complexes with 3-hydroxypicolinic acid (3-hydroxypyridine-2-carboxylic acid, 3-OHpicH), trans-[Co(3-OHpic)2(py)2] (2) and cis-[Co(3-OHpic)2(4-pic)2] (3) (py=pyridine; 4-pic=4-picoline or 4-methylpyridine), previously synthesized and characterized by X-ray diffraction, are here studied by Raman and mid-infrared spectroscopy with the help from the corresponding DFT vibrational calculations using B3LYP/6-311G(d,p) computational model. Intramolecular O-H⋯O hydrogen bond appears in both complexes 2 and 3, while weak C-H⋯O hydrogen bonds assemble molecules of 2 or 3 into 3D architecture. A complete presentation of all Raman, infrared and theoretical results is given for complex 3.

A new coordination mode of 6-methylnicotinic acid in trans-tetraaquabis(6-methylpyridine-3-carboxylato-kappaO)cobalt(II) tetrahydrate.

The title compound, [Co(C7H6NO2)2(H2O)4] x 4 H2O, contains a Co(II) ion lying on a crystallographic inversion centre. The Co(II) ion is octahedrally coordinated by two 6-methylpyridine-3-carboxylate ligands in axial positions [Co-O = 2.0621 (9) A] and by four water molecules in the equatorial plane [Co-O = 2.

A one-dimensional CdII coordination polymer: catena-poly[cadmium(II)-bis(mu-6-methylpicolinato)].

In the title compound, [Cd(C(7)H(6)NO(2))2]n, the Cd(II) ion has a distorted octahedral geometry. The 6-methylpyridine-2-carboxylate anions are perpendicular to one another and act as bidentate and bridging ligands. Two carboxylate O atoms bridge the Cd(II) ions, forming centrosymmetric dinuclear units.

trans-Bis(dimethyl sulfoxide-kappaO)bis(3-oxo-3,4-dihydroquinoxaline-2-carboxylato-kappa2N1,O2)copper(II).

The title compound, [Cu(C(9)H(5)N(2)O(3))(2)(C(2)H(6)OS)(2)], consists of octahedrally coordinated Cu(II) ions, with the 3-oxo-3,4-dihydroquinoxaline-2-carboxylate ligands acting in a bidentate manner [Cu-O = 1.9116 (14) A and Cu-N = 2.1191 (16) A] and a dimethyl sulfoxide (DMSO) molecule coordinated axially via the O atom [Cu-O = 2.