E. N. Zorina-Tikhonova

2D coordination polymers of AgI—MII (MII = Ni, Cu) with anions of substituted malonic acids

Heterometallic malonate complexes [Ag2Ni(H2O)2(R2mal)2]n (R2mal2– is the dimethylmalonate dianion (Me2mal2–) (1) or the cyclobutane-1,1-dicarboxylate dianion (Cbdc2–) (2)) and [Ag2Cu(H2O)(Me2mal)2]n (3) were synthesized. The bis-chelate fragment {M(R2mal)2} (M = Ni, Cu) composed of two dianions of an acid and a 3d metal atom is the structure-forming unit of these complexes. The mononuclear fragments are linked by silver(I) atoms, which are involved in argentophilic interactions, to form 2D coordination polymers.

Structural influence of the substituent in carboxylate anion on example of α- and β-naphthoate complexes of Co(II), Ni(II), Cu(II), and Zn(II)

The results on the synthesis and study of the crystal structures of molecular complexes of transition metals with anions of α- and β-naphthoic acids and monodentate N-donor ligands (MeCN, 2,3-lutidine) are presented. The compositions and structures of the isolated complexes are determined by the following factors: steric hindrances, intermolecular interactions of the aromatic fragments, and the electronic structure of the metal center.

36-Nuclear CoII and NiII dimethylmalonate complexes with the [K(18-crown-6)]+ cationic fragments: synthesis and structure

A reaction of potassium dimethylmalonate (K2Me2Mal) with cobalt(II) or nickel(II) trimethylacetate in the presence of 18-crown-6 leads to the formation of 36-nuclear complexes {[K(18-crown-6)]2[K(H2O)(18-crown-6)]2[K6Co36(H2O)20(OH)18(Me2Mal)30(18-crown6)2(O)2]•xH2O}n (2) and {[K(H2O)2(18-crown-6)]6[K5Ni36(H2O)20(OH)18(18-crown-6)2(Me2Mal)28(HMe2Mal)2]4[K5Ni36(H2O)20(OH)20(18-crown-6)2(Me2Mal)29(HMe2Mal)]• •80H2O}n (3) (Me2Mal2– is the dianion of dimethylmalonic acid), respectively. The single crystal X-ray diffraction studies showed that the spherical 36-nuclear polyanions [Co36(H2O)12(OH)18(Me2Mal)30(O)2]10– (in compound 2) and [Ni36(H2O)12(OH)20(Me2Mal)30–x(HMe2Mal)x]y– (in compound 3; x = 1, y = 7; x = 2, y = 6) have similar structures, with their metal cores being formed of two layers: an internal one comprising 24 metal atoms and an external containing 12 metal centers. The inner cavity of the {MII36} anions was found to include one K+ aqua cation bonded to the oxygen atoms of the carboxylate or oxo ligands.

Structures and magnetic properties of new trinuclear CoII, NiII, and CuII complexes with trimethylacetate and 1,1-cyclohexanediacetate

The reactions of transition metal trimethylacetates [Cu2(Piv)4(HPiv)2], [Ni9(OH)6(Piv)12(HPiv)4], [Co(Piv)2]n (Piv− = −O2CBut) with 1,1-cyclohexanediacetic acid (H2Chda) neutralized by tetrabutylammonium hydroxide in the presence of 2,2-bipyridine (2,2′-bpy) afford linear trinuclear homometallic complexes [(2,2′-bpy)2Cu3(Chda)2(Piv)2]··2EtOH (1) and [(2,2′-bpy)2M3(Chda)2(Piv)2(EtOH)2] (M = NiII (2) or CoII (3)). In molecules of these compounds, anions of both mono- and dicarboxylic acids act as bridges between the transition metal atoms. Compounds 1–3 were characterized by X-ray diffraction, and their magnetic properties were studied. Spin-spin ferromagnetic interactions dominate in complexes 1–3 with CuII (S = 1/2) (1) and CoII (S = 3/2) (3) ions.

36-Nuclear anionic cobalt(II) and nickel(II) complexes in solid-phase insertion reactions

The reactions of single crystals containing 36-nuclear anionic complexes of cobalt(II), (NBu4)8[Co36(H2O-κO)12(μ3-OH)20(μ4-Me2Mal-κ2O,O′)24(μ4-Me2Mal)6] · 2.5H2O ∙ CH3OH (I), and nickel(II), (NBu4)8[Ni36(H2O-κO)12(μ3-OH)20(μ4-Me2Mal-κ2O,O′)24(μ4-Me2Mal)6] · 6H2O ∙ 2C2H5OH (II) and (NHEt3)3[Ni36(NHEt3)(H2O-κO)12.25(μ3-OH)20(μ4-HMe2Mal-κ2O,O′)4(μ4-Me2Mal-κ2O,O′)20(μ4-Me2Mal)6] · 39H2O (III), with solutions of 1,4-dioxane and a 0.1 M solution of Dabco (Dabco is 1,4-diazabicyclo[2.2.2]octane) in EtOH are studied. An ethanol solution of Dabco dissolves the crystals of the complexes, whereas the insertion of the solvent molecules with single crystal retention (for the cobalt compound containing tetrabutylammonium cation, I), cracking (for the nickel analog, II), or dissolution (for the cobalt complex containing triethylammonium, III) occurs in 1,4-dioxane. The X-ray diffraction analyses show the substitution of the uncoordinated water and ethanol molecules in the starting compound by 1,4-dioxane molecules in the structure of compound I to form (NBu4)8[Co36(H2O-κO)12(μ3-OH)20(μ4-Me2Mal-κ2O,O′)24(μ4-Me2Mal)6] · 7C4H8O2 (IV), which is accompanied by a change in the conformation and the shift of tetrabutylammonium cations, indicating a possibility of the modification of the 36-nuclear d-metal complexes with the malonic acid derivatives in the solid-phase resolvation reactions (CIF files CCDC no. 1557499 (III) and 1557500 (IV)).

Effect of geometric parameters of substituted malonate anions on coordination environment of CuII atoms coordinated with 2,2′;6′,2″-terpyridine

Structural data for known and newly obtained copper(II) complexes with 2,2′;6′,2″-terpyridine and substituted malonic (dimethylmalonic, 1,1-cyclopropane- and 1,1-cyclobutanedicarboxylic) acid dianions R2mal2- were used to show that the coordination environment of the metallocenter depends on the (O2C)C—C—C(CO2) angle. A chelate coordination of the R2mal2- dianion is realized for 1,1-cyclopropanedicarboxylate anion (~122.9°), while the dimethylmalonate and 1,1-cyclobutanedicarboxylate anions (107.4–110.8°) are characterized by a monodentate coordination.