A. A. Sidorov

New polynuclear cobalt trimethylacetate complexes: synthesis and structure

Extraction of polymer (1), formed in the reaction of CoCl2 with KOOCBut, with boiling hexane gives crystals of hexamer Co6(μ3-OH)2(OOCBu1)10(HOOCBu1)4 (2). According to data of X-ray study, four Co11 atoms in the hexanuclear molecule2 have an octahedral ligand environment and two Co11 atoms have a tetrahedral one. Dissolution of polymer1 in EtOH results in its splitting into Co4(μ3-OH)2(OOCBu1)6(HOEt)6 tetramers (3). In molecule3, two asymmetric dimeric (η2-OOCBut)(EtOH)Co(μ-OOCBut)Co(HOEt)2 fragments are bound by two tridentate bridging OH groups.

TRIMETHYLACETATE NICKEL COMPLEXES

The present review is devoted to the chemistry of trimethylacetate NiII complexes with various nitrogen-containing ligands. Pathways of formation of complexes containing the Ni2(μ-OH2)(μ-OOCCMe3)2 and Ni2(μ-OOCCMe3)4 fragments are discussed. Pathways of degradation of the nine-nuclear complex Ni9(HOOCCMe3)4(μ4-OH)3(μ3-OH)3)3(μ4-OOCCMe3)12 under the action of primary amines (aniline or propargylamine) as well as the process of dehydration ofN-phenyl-o-phenylenediamine up to the bischelate mononuclear complex [1,2-(NH)(NPh)C6H4]2Ni are demonstrated.

Synthesis, structures, and magnetic properties of binuclear carboxylate complexes with NiII and NiIII atoms

The reaction of NiCl2·6H2O with Me3CCOOH and KOH taken in a molar ratio of 1:2:2 in water afforded the nonanuclear antiferromagnetic complex Py2Ni2(Me3CCOOH)2(OOCCMe3)2(μ-OOCCMe3)2(μ-OH2), which apparently contains NiII and NiIII atoms. The complex was isolated by extraction with CH2Cl2, benzene, or hexane. The reactions of this complex with pyridine bases (pyridine (Py), 3,4-lutidine (Lut), and nicorandil (Nic)) gave the adducts L4Ni2(OOCCMe3)2(μ-OOCCMe3)2(μ-OH) (L=Py, Lut, or Nic, respectively). According to magnetic measurements, intramolecular ferromagnetic exchange interactions in these adducts are complemented by intermolecular antiferromagnetic interactions. Pyrolysis of the pyridine adduct in air or under an inert atmosphere in xylene yielded the antiferromagnetic complex Py2Ni2(Me3CCOOH)2(OOCCMe3)2(μ-OOCCMe3)2(μ-OH2), which contains NiII atoms. The structures of all the complexes synthesized were established by X-ray diffraction analysis. The electronic absorption spectra of these compounds are considered.

Synthesis, structure, and properties of trinuclear pivalate {Zn2Eu} complexes with N-donor ligands

New luminescent heterometallic complexes of Eu3+ and Zn2+ were synthesized: Zn2Eu(NO3)(Piv)6(L)2 (Piv is pivalate anion, L = MeCN (1), 2,3-lutidine (2), 2,2′-bpy (3)) and [Zn2(Piv)3(2,2′-bpy)2][ZnEu(NO3)3(Piv)3(2,2′-bpy)] (4). In the case of 2,2′-bpy, the order of mixing of the reagents ([Zn(Piv)2]n, Eu(NO3)3·6H2O, and 2,2′-bpy) affects the composition of the final reaction product: the reaction of [Zn(Piv)2]n and Eu(NO3)3·6H2O (in the ratio Zn : Eu = 3 : 1) in MeCN affords complex 1 and the subsequent addition of 2,2′-bpy (Zn : L = 1 : 1) affords complex 3. Complex 4 is formed in the reaction of [Zn(Piv)2]n and 2,2′-bpy (Zn : L = 1 : 1) in MeCN followed by the addition of Eu(NO3)3·6H2O (Zn : Eu = 3 : 1). The luminescence spectra of compounds 1–4 (Zn : Eu = 3 : 1) exhibit metal-centered luminescence of Eu3+. The most efficient ligand-antenna is 2,2′-bpy, which is due to the optimum position of the triplet level of this ligand.

Synthesis, structure, and ESR spectra of the new heteronuclear complex {Li4(VO)2[(OOC)2C(H)Bu]4(H2O)8}·H2O

The reaction of an aqueous solution of vanadyl sulfate VOSO4·3H2O, butylmalonic acid (H2Bumal = C4H10(COOH)2), and lithium carbonate at pH ∼4–5 gave crystals of the complex Li4(VO)2(Bumal)4(H2O)8]·H2O (1). The structure of complex 1 was established by X-ray diffraction analysis. The molecule of complex 1 consists of two mononuclear bischelate dianionic units {VO(Bumal)2(H2O)} linked by four lithium ions to form the hexanuclear heterometallic {V2Li4} structure. The crystals and an ethanolic solution of compound 1 were studied by ESR spectroscopy.

Polymeric heterometallic CuII dimethylmalonate complexes with potassium and cadmium ions

A reaction of (HPiv)2Cu2(Piv)4 with dimethylmalonic acid dipotassium salt (K2Me2mal) leads to the formation of a cage coordination polymer {(μ-H2O)6K8[(μ-H2O)Cu-(μ3,κ2-Me2mal)(μ6,κ2-Me2mal)]2[Cu2(μ5,κ2-Me2mal)2(μ5,κ2-Me2mal)2]}n (1). It was found that when 1 reacted with CdSO4·8H2O in a mixture of EtOH-H2O (3: 1), the potassium ions in 1 were displaced with cadmium(ii) ions with the formation of a heterometallic 1D-polymer [(κ1-H2O)4CdCu(μ,κ2-Me2mal)2]n (2). Compounds 1 and 2 were characterized by X-ray crystallography and ESR spectroscopy.

Deprotonated N-phenyl-o-phenylenediimine as a bridging ligand

The interaction of N -Ph- o -phenylenediamine with the trinuclear palladium complex Pd 3 (μ-OOCCMe 3 ) 6 was investigated. The ionic complex obtained [K·H 2 O] + {Pd 3 (OOCCMe 3 ) 4 (μ-OH)[μ- N , N -η 2 - N , N ′-(N)(NPh)(C 6 H 4 )] 2 } − has been structurally characterized by an X-ray diffraction study. It was found that the reaction of bis( N -phenyl- o -semiquinonediimine)platinum(+2) with Re(CO) 5 Cl, which has been preliminarily treated with silver triflate, afforded the heterometallic complex (CO)Pt[μ- N , N - o -(N)(NPh)C 6 H 4 ] 2 ReCl[(NH)(NPh)C 6 H 4 ].

New dinuclear palladium complex with a Chinese-lantern structure

The new dinuclear palladium complex Pd2(μ-S,N-SC7H5N2)4 with a Chinese-lantern structure was synthesized by the reaction of K2PdCl4 with 2-mercaptobenzimidazole and structurally characterized by X-ray diffraction analysis.

Synthesis, structure, electrochemical and magnetic properties of 2,6-bis(5-trifluoromethylpyrazol-3-yl)pyridine and its NiII complexes

Abstract2,6-Bis(5-trifluoromethylpyrazol-3-yl)pyridine (H2L) and its mono-, tri-, and tetranuclear NiII complexes were synthesized for the first time. All the obtained compounds were characterized by single-crystal X-ray diffraction analysis. In the complexes, 2,6-bis(5-trifluoromethylpyrazol-3-yl)pyridine exists in the neutral and dianionic forms and exhibits different coordination modes (κ3-, μ2-κ3:κ1-, and μ3-κ3:κ1:κ1). The electrochemical and magnetic properties of all compounds were studied. The tetranuclear NiII complex with the L2− dianion is reduced in two sequential reversible one-electron steps.

Unusual structure of new dimethylmalonate coordination polymer with strontium atoms and VO2+ fragments

A reaction of vanadyl sulfate VOSO4·3H2O with dimethylmalonic acid strontium salt led to the coordination polymer {Sr(H2O)8[VO(Me2mal)2]}n (1, Me2mal is the dimethylmalonic acid dianion), in which the carboxylate dianions did not form chelate metallocycles with the vanadyl ions. The complex was studied by ESR spectroscopy. The compound 1 exhibited weak spin-spin exchange interactions of ferromagnetic type between the VIV atoms.