Spontaneous Resolution of a Mixed-Ligand Nickel(II) Coordination Polymer with Achiral Precursors

Metal-center-driven spontaneous resolution of a chiral coordination polymer, [Ni(SDB)(BIX)](n) (1), from achiral precursors has been probed by single-crystal X-ray diffraction and circular dichroism spectroscopy. Enantiomorphs 1P and 1M showed a parallel interpenetrated 2D → 3D chiral framework with (8(2).10) topology. Switching of the metal center under the same reaction parameters resulted in isostructural achiral and noninterpenetrating (4,4) grid-type sql networks [M(SDB)(BIX)](n), where M = Co(II), Zn(II), and Cd(II) for 2-4, respectively.     

Valence Interconversion of Octahedral Nickel(II/III/IV) Centers

Three oxidation states (+2, +3, +4) of an octahedral nickel center were stabilized in a newly prepared RhNiRh trinuclear complex, [Ni{Rh(apt)₃}₂]^{n +} (apt=3‐ aminopropanethiolate), in which the nickel center was bound by six thiolato donors sourced from two redox‐inert fac ‐[Rh^III(apt)₃] octahedral units. The three oxidation states of the octahedral nickel center were fully characterized by single‐crystal X‐ray crystallography, as well as spectroscopic, electrochemical, and magnetic measurements; all three were interconvertible, and the conversion was accompanied by changes in color, magnetism, and Jahn–Teller distortion.     

Nickel(II) aminoalkoxides

Summary Nickel alkoxides react with mono-, di- and tri-ethanolamines in different stoichiometric ratios and novel products have been isolated and characterized by elemental analyses, i.r. and electronic reflectance spectra. Insertions across the Ni-O bond in aminoalkoxides have been studied for the first time.     

Achiral banana-shaped mesogenic bidentate ligands and their Cu(II) and Pd(II) complexes

The first achiral bent-core banana-shaped bidentate ligands and their Cu(II) and Pd(II) metal complexes have been synthesized and investigated for mesomorphic behaviour. The bidentate ligands exhibit only one enantiotropic mesophase. The ligand having C 6 -alkoxy chains shows a mesophase that has been assigned as a two-dimensional B 1 phase while the C 8 and C 10 homologues stabilize the fluid B 2 mesophase showing antiferroelectric switching characteristics. In constrast, their corresponding Cu(II) and Pd(II) metal complexes are non-mesomorphic.     

Achiral banana-shaped mesogenic bidentate ligands and their Cu(II) and Pd(II) complexes

The first achiral bent-core banana-shaped bidentate ligands and their Cu(II) and Pd(II) metal complexes have been synthesized and investigated for mesomorphic behaviour. The bidentate ligands exhibit only one enantiotropic mesophase. The ligand having C6 -alkoxy chains shows a mesophase that has been assigned as a two-dimensional B1 phase while the C8 and C10 homologues stabilize the fluid B2 mesophase showing antiferroelectric switching characteristics. In constrast, their corresponding Cu(II) and Pd(II) metal complexes are non-mesomorphic.     

Nickel(II) and cobalt(II) complexes of rhodanine

Summary Nickel(II) and cobalt(II) complexes of rhodanine (Hrd) were prepared from the metal chloride or acetate and the ligand. With an excess of NH3, the octahedral [Ni(NH₃)₆](Rd)₂ and [Co(NH₃)₅Rd]Rd complexes are ob-tained; use of only two NH₃ equivalents per metal ion yields the Ni(Rd)₂ sd HRd · NH₃ and [Co(Rd)₂ ] · 1.5 H₂O complexes, the first with tetragonally distorted hexacoordination and the second with polymeric octahedral coordination. By using two equivalents of NaOH per metal ion, the binuclear [Ni(Rd)₂][Ni(Rd)₂ · (HRd)₂] · 2 H₂O complex is formed having one diamagnetic planar and one high spin octahedral chromophore. Rhodanine is coordinated through the thiocarbonylic sulphur in the neutral form and through the thiocarbonylic sulphur and the deprotanated nitrogen atoms in the rhodanidato anionic form.     

Solvent‐Mediated Transformation from Achiral to Chiral Nickel(II) Metal–Organic Frameworks and Reassembly in Solution

Reactions of 5‐nitroisophthalic acid (NO₂‐H₂ip), 1,4‐bis(imidazol‐1′‐yl)butane (bimb), and Ni(NO₃)₂ ? 6 H₂O gave rise to four metal–organic frameworks (MOFs), [Ni₂(NO₂‐ip)₂(bimb)_1.5]_n ( 1 ), [Ni₄(NO₂‐ip)₃(bimb)₂(OH)₂(H₂O)]_n ? (CH₃CH₂OH)_{0.5 n} ( 2 ), [Ni(NO₂‐ip)(bimb)_1.5(H₂O)]_n ? (H₂O)_n ? (CH₃CH₂OH)_{0.5 n} ( 3 ), and [Ni(NO₂‐ip) (bimb)(μ‐H₂O)]_n ? (H₂O)_n ( 4 ). The metal/ligand ratio, pH value, and solvent exerted a subtle but crucial influence on the formation of complexes 1 – 4 , which possess different visual color and crystal structures. Complex 1 exhibits a twofold interpenetrating 3D pillared bilayer framework composed of binuclear and mononuclear Ni^II units, whereas complex 2 is a 3D chiral network that consists of asymmetric tetranuclear Ni^II units. Complexes 3 and 4 are 3D layer‐pillared frameworks that consist of mononuclear Ni^II ions and a 3D six‐connected network of μ‐water‐bridged dinuclear Ni^II units, respectively. Interestingly, achiral 4 can be transformed into chiral 2 by using a solvent‐mediated single‐crystal‐to‐single‐crystal process without any chiral auxiliary. Magnetic analyses of 2 and 4 show the occurrence of antiferromagnetic interactions. Complex 3 is difficult to obtain directly as a single solid phase, but it can be homogeneously formed by solvent‐mediated transformations from 1 , 2 , and 4 .     

Nickel(II) and cobalt(II) coordination compounds of dichloroguanidinopyrimidines

Summary New coordination compounds of Ni^II and Co^II with dichloropyrimidinoguanidine (L) have been obtained and characterized by physico-chemical and spectroscopic methods. The complexes have the general formulae: [ML₃](ClO₄)₂, [ML₂(SO₄)], [ML₂(NCS)₂], (M = Ni or Co), [NiL₂(ClO₄)₂] and [CoL₂](ClO₄)₂. The ligands are bonded to the metal ion via one nitrogen atom from the pyrimidine heterocyclic ring and one from the guanidine group.     

Double Hydrated Cobalt(II) Copper(II) and Nickel(II) Copper(II) Ammine Diphosphates

Synthesis of amorphous and crystalline double hydrated cobalt copper and nickel copper ammine diphosphates with a coordination structure is described.__________Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 3, 2005, pp. 369–372.Original Russian Text Copyright © 2005 by Voitenko, Zhilyak, Kopilevich.     

Nickel(II) complexes of ethylenediphosphinetetra-acetic acid

Ethylenediphosphinetetraacetic acid (H₄L) coordinates nickel(II) preferentially as a chelating di(tertiary phosphine). The two complexes identified in non-aqueous solutions are cis-square planar NiBr₂(H₄L) and square-pyramidal [NiBr₂(H₄L)₂Br; both structures are retained in the solid state. The square planar anion NiL₂^6? is the predominant complex in a neutral aqueous solution. A number of its solid salts M₆NiL₂·aq (M = Na, $\text{1}\text{2}$ divalent metal) has the same square planar NiP₄ core. The compound Ni₂L·8H₂O also belongs to this series and should be formulated as Ni₃[NiL₂]·16H₂O: one nickel(II) is located in the NiP₄ core and the remaining three are coordinated by the carboxyl group oxygen atoms and water molecules in a roughly octahedral environment. The results are based on preparative, X-ray powder, magnetic susceptibility, conductometric, UV-VIS, NMR, IR (both normal and ⁶²Ni) and XPS spectral studies.     

Nickel(II) and Zinc(II) Complexes with Benzoylacetaldehyde Derivatives

Russian Journal of Coordination Chemistry - Ni(II) and Zn(II) complexes, [M(Ln)A] (n = 1–3, A = NH3, Py), were prepared from the products of condensation of benzoylacetaldehyde with aromatic...     

Nickel(II) and copper(II) complexes of 5-substituted-salicylaldehyde thiosemicarbazones

Binuclear nickel(II) and copper(II) complexes with four 5-methoxysalicylaldehyde N(3)-substituted thiosemicarbazones and nickel(II) complexes of four 5-nitro-salicylaldehyde N(3)-substituted thiosemicarbazones have been prepared and characterized. I.r., electronic, and e.s.r. spectra of the complexes, as well as i.r., electronic, and 1H- and 13C-n.m.r spectra of the thiosemicarbazones, have been obtained. None of these compounds show significant growth inhibitory activity against the fungi Aspergillus niger and Paecilomyces variotii.     

Nickel(II) and Copper(II) complexes of sulphamide and ethylenediamine

Summary The following ethylenediamine(sulphamide)nickel(II) and ethylenediamine(sulphamide)copper(II) complexes were prepared: Ni(en)₃(H₂Su)Cl₂, in which H₂Su is not coordinated; Ni(en)₂(H₂Su)Cl₂ , Ni(en)₂(HSu)Cl · EtOH, Ni(en)₂(HSu)₂,Ni(en)₂(HSu)₂(H₂Su)₂ · EtOH, Cu(en)₂(HSu)₂(H₂Su) · O.5EtOH, in which the sulphamide molecule, H₂Su, or the sulphamidato anion [HSu] are totally or partially coordinated. The comparison of the i.r. spectra of these complexes with those of H₂ Su and NaHSu and with those of the M(en)₂Cl₂ complexes permits the isolation of the sulphamide or sulphamidato (SO₂) and (SN₂) bands which show oxygen-coordination of these ligands to the metal. Some (MO) bands were identified in the far i.r. region.     

Alcoholate Complexes of Nickel(II) Chloride

Alcoholate complexes of nickel chloride with the general formula, NiCL₂ · ROH (R = CH₃, C₂H₅, i-C₃H₇, n-C₄H₉, t-C₄H₉, t-C₅H₁₁, n-C₆H₁₃ and n-C₈H₁₇), synthesized either by the reaction of anhydrous nickel chloride with alcohols or by the replacement of methanol from NiCL₂ · MeOH with higher alcohols, depict interesting differences when R is a secondary or tertiary alkyl group instead of a primary group. A study of the magnetic susceptibility, thermogravimetric measurement, electron spin resonance and electronic reflectance spectra has been carried out to throw light on the structure of these derivatives.     

Nickel(II) 1,10-Phenanthroline complexes: cis-[Aqua(Bromo) bis (1,10-Phenanthroline)Nickel(II)] Bromide Trihydrate and ( tris (1,10-Phenanthroline)Nickel(II)] Bromide Octahydrate

[Ni(phen)₂(H₂O)Br]Br·3H₂O where phen is 1,10-phenanthroline, is a light-blue material which crystallizes in the monoclinic space group P2₁/c with Z = 4, a = 10.4300(4), b = 25.310(2), c = 9.7790(9)?Å and β = 102.932(6)°. The structure was determined at ambient temperature from 5161 reflections with R = 0.0643 and R _w = 0.1306. The structure consists of a complex cation, a bromide anion and three waters of hydration. The Ni atom is pseudo-octahedral with a cis arrangement of Br and H₂O. This cis geometry persists in solution, as evidenced by ¹H NMR spectroscopy, although the Br may be replaced by another H₂O. [Ni(phen)₃]Br₂·8H₂O is a light-red material which crystallizes in the monoclinic space group C2/m with Z = 8, a = 23.6320(11), b = 21.4880(13), c = 15.5470(9)?Å and β = 107.927(3)°. The structure was determined at 120?K from 6820 reflections with R = 0.0733 and R _w = 0.1022. The structure consists of a complex cation, two bromide anions and eight waters of hydration. The anions and waters are extensively disordered. The Ni atom is pseudo-octahedral.