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.

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.