Том 43, № 7 (2017)

Recent results on the synthesis of polynuclear niobium and tantalum oxohydroxo complexes, investigation of their reactivity, and specific features of the characterization of these compounds are reviewed.

The coordination polymer, catena-((μ₂-4,4,10,10-tetramethyl-1,3,7,9-tetraazaspiro[5.5]undecane-2,8-dione-O,O′)dichloro-zinc) {[Zn(C₁₁H₂₀N₄O₂)Cl₂]}_n (I), is prepared for the first time from zinc chloride and bicyclic bis(urea), 4,4,10,10-tetramethyl-1,3,7,9-tetraazaspiro[5.5]undecane-2,8-dione, and investigated by X-ray diffraction (CIF file CCDC no. 877812). The crystals of I are monoclinic: space group P2₁, a = 6.2121(17), b = 11.276(3), c = 11.387(3) Å, β = 94.99(3)°, V = 794.6(3) ų, ρ(calcd.) = 1.574 g/cm³, Z = 2. The singe-phase nature of the powder sample of I is confirmed by Rietveld refinement of the powder X-ray diffraction pattern; at 293 K, a = 6.20369(11), b = 11.23336(18), c = 11.36013(16) Å, β = 95.3001(11)°, V = 788.28(2) ų. The content of the major phase I in the sample is 100 ± 1%, no impurity lines are found. The zinc coordination polyhedron in the coordination polymer chain is a tetrahedron with vertices being occupied by two chlorine atoms and carbonyl O(1) and O(2) atoms of two TTSU molecules related by the symmetry code (2 − x, 1/2 + y, 2–z). The zinc bond angles are 101.05(12)°–122.13(9)°. The Zn···Zn distance in the polymer is 9.480(2) Å. The chains in the coordination polymers are additionally combined by intermolecular hydrogen bonds, N(2)–H(2)···O(2)ⁱ (ⁱ 2–x, 1/2 + y, 2 − z) (H···O 2.17 Å, N−H···O 147°) and N(4)–H(4)···Cl(2)ⁱⁱ (ⁱⁱ 1–x, −1/2 + y, 2–z) (H···Cl 2.48 Å, N−H···Cl 159°). The chains are joined into layers along the (0 0 1) plane by intermolecular hydrogen bonds, N(1)−H(1)···Cl(1)ⁱⁱⁱ (ⁱⁱⁱ 1 − x, −1/2 + y, 2–z) (H···Cl 2.78 Å, N−H···Cl 148°).

The reaction of bis(tetraphenylantimony) succinate with iodine in benzene affords [(μ₄-succinato) hexadecaphenyltetraantimony] triiodide solvate with benzene [(Ph₄Sb)₂O₂CCH₂CH₂-CO₂(Ph₄Sb)₂][I₃]₂ · 4PhH (I). The symmetrically nonequivalent Sb(1) and Sb(2) atoms in the centrosymmetric cation of compound I have a distorted trigonal bipyramidal coordination mode with the oxygen atoms in the axial positions (Sb(1,2)−O 2.347(4) 2.525(4) Å; Sb(1,2)−C_equiv 2.109(7)−2.120(7) Å, 2.082(5)−2.106(7) Å; Sb(1,2)−C_axial 2.158(7), 2.121(9) Å; angles OSb(1,2)C 178.8(2)°, 174.5(3)°). The geometry of the [I₃]⁻ anions is close to linear (angle III 179.41(4)°, I−I distances 2.880(1) and 2.921(1) Å) (CIF file CCDC no. 1486690).

In this study, a mononuclear CuL complex was prepared by the use of bis-N,N′-(salicylidene)-1, 3-propanediamine (LH₂) and Cu²⁺ ion. NiCl₂ and NiBr₂ salt were treated with this complex in dioxanewater medium and two new complexes [(CuL)₂NiCl₂(H₂O)₂] and [(CuL)₂NiBr₂(H₂O)₂)] with Cu(II)–Ni(II)–Cu(II) nucleus structure were obtained. In addition to this bis-N,N′-(2-hydroxybenzyl)-1,3-diaminopropane (L^HH₂) was prepared by the reduction of LH₂ with NaBH₄ in MeOH medium. The treatment of this reduced complex with Cu²⁺ ion resulted a complex [(CuL^H)₂CuCl₂] with a structure of Cu(II)–Cu(II)–Cu(II). The complexes prepared were characterized by the use of elemental analysis, IR spectroscopy, thermogravimetric and X-ray diffraction methods. The crystal structures of [(CuL)₂NiBr₂(H₂O)₂] (СIF file CCDC 1448402) and [(CuL^H)₂CuCl₂] (СIF file CCDC 1448401) complexes were elucidated. It was found that halogen ions are coordinated to terminal Cu²⁺ ions which are in a distorted square pyramid coordination sphere. It was determined that the central Cu(II), which joins terminal square pyramidal Cu(II), was coordinated only by the phenolic oxygens of the ligand while the central Ni(II) was coordinated by two phenolic oxygens of the organic ligand and two water molecules. These complexes were investigated by XPS and it was found that the terminal and central Cu²⁺ ions were different in Cu(II)–Cu(II)–Cu(II) complex. Also, the thermal degradation of the CuLH complex unit was observed to exothermic in contrast to the expectations.

Two novel rare earth metal coordination compounds, (MnH)₄[Ho₂^III(Dtpa)₂] · 12H₂O (I) (Mn = methylamine, H₅Dtpa = diethylenetriamine-N,N,N′,N″,N″-pentaaceticacid) and {(MnH)[Ho^III(Egta)] · 3H₂O}_n (II) (H₄Egta = ethyleneglycol-bis(2-aminoethylether)-N,N,N′,N′-tetraacetic acid) have been successfully synthesized through direct heating reflux and characterized by FT-IR spectroscopy, thermal analysis, and single-crystal X-ray diffraction techniques (CIF files CCDC nos. 890878 (I) and 1457061 (II)). Complex I shapes a binuclear nine-coordinate structure with distorted tricapped trigonal prismatic conformation and crystallizes in the triclinic crystal system with space group P1̄. The central Ho³⁺ ion is coordinated by three nitrogens and six oxygens from two octadentate Dtpa ligands. The cell dimensions are as follows: a = 9.8420(10), b = 12.1319(13), c = 13.2931(15) Å, α = 89.223(2)°, β = 68.4280(10)°, γ = 72.1280(10)° and V = 1396.0(3) ų. Complex II adopts a polynuclear nine-coordinate structure with pseudo-monocapped square antiprismatic conformation and crystallizes in the monoclinic crystal system with space group C2/c. The central Ho³⁺ ion is coordinated by two nitrogens and seven oxygens from two octadentate Egta ligands. The crystal data are as follows: a = 38.4755(13), b =13.5569(5), c = 8.7343(3) Å, β = 100.135(3)° and V = 4484.8(3) ų.