S. I. Dorovskikh

Copper(II) complexes with Schiff bases: Structures and thermal behavior

Ligands with Schiff bases are obtained in the condensation of propylenediamine (pda) or 2,2-dimethylpropylenediamine (dmpda) with acetylacetone (Hacac) in the 1:2 molar ratio. The ligands are characterized by the elemental analysis methods, Tmelt = 90–92 °C for pda(Hacac)2 (pda(acac)2 is N,N′-propylene-bis(acetylacetoniminato) (2-)), Tmelt = 84–86 °C for dmpda(Hacac)2 (dmpda(acac)2 is N,N′-2,2-dimethylpropylene-bis(acetylacetoniminato) (2-)). The tautomerism of the ligands is established by the single crystal X-ray diffraction (XRD) analysis, IR spectroscopy, and 1H, 13C NMR spectrometry. The synthesized complexes [Cu(pda(acac)2)] (1), Tmelt = 121–122 °C and [Cu(dmpda(acac)2)] (2), Tmelt = 156–158 °C are studied by the XRD method. In both complexes, copper atoms have a planar square geometry, and the chelate bond lengths and angles are: Cu-O ≈ Cu-N 1.903(2)–1.942(3) Å, ∠O-Cu-N = 94.44(12)–94.99(12)° for 1 and Cu-O ≈ Cu-N 1.909(1)–1.943(2) Å, ∠O-Cu-N = 94.63(6)° for 2. By the thermogravimetric method it is found that both complexes can be passed practically quantitatively into the gas phase.

Structure of platinum coatings obtained by chemical vapor deposition

To the best of our knowledge, it is the first time that the method of chemical vapor deposition (MOCVD) with platinum(II) bis(acetylacetonate) (Pt(acac)2) is used to obtain platinum coatings on the cathodes and anodes of the electrodes for pacemakers. The deposition processes are carried out under reduced pressure in the presence of oxygen. The phase and elemental composition, structure, and morphology of the coatings are examined by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). Platinum coatings with a columnar structure are prepared in the temperature range 280-340°C. An increase in the deposition temperature leads to a change in the structure of the coatings and reduction in their thickness. Cyclic voltammetry (CV) is used to estimate the specific capacities of the platinum coatings on the cathodes and anodes, the maximum values of which are 426 mC/cm2 and 1160 mC/cm2, respectively.

Crystal and molecular structures of bis(2,2,6,6-tetramethyl-3-methylaminoheptan-5-onate) copper(II) and nickel(II)

Two bis-chelates M(tmih)2 (M = Cu(II), Ni(II), tmih = (CH3)3C(NCH3)CHCOC(CH3)3)− are synthesized and their crystal structures are determined using XRD (Bruker APEX-II diffractometer with a CCD detector, λMoKα, λCuKα, graphite monochromator, T = 240(2) K and 296(2) K): Cu(tmih)2 (I) (space group P21/c, a = 12.9670(8) Å, b = 18.4921(9) Å, c = 11.0422(6) Å, β = 93.408(4)°, V = 2643.1(3) Å3, Z = 4) and Ni(tmih)2 (II) (space group P21/c, a = 12.810(2) Å, b = 18.529(2) Å, c = 11.243(2) Å, β = 91.959(7)°, V = 2667.1(6) Å3, Z = 4). The complexes are isostructural; the coordination polyhedron of metal atoms is a flattened tetrahedron formed from two O atoms (Cu-O of 1.901(2) Å, 1.892(2) Å, Ni-O of 1.845(2) Å, 1.833(2) Å) and two N atoms (Cu-N of 1.976(3) Å, 1.972(3) Å, Ni-N of 1.911(2) Å, 1.920(2) Å) of the ligand; the chelate OMN angles (M = Cu(II), Ni(II)) are in the 87.4–93.1° range; the OMO and NMN angles are 162.2° and 167.2° in I, 171.1° and 173.2° in II. The complexes have the molecular structures formed from isolated molecules bonded by van der Waals interactions. Using a quantum chemical hybrid M06 method, the structures of copper(II) chelates with the H, CH3, CH2CH3, CH(CH3)2, and C(CH3)3 substituents at the nitrogen atom are calculated. Found that with a bulky substituent at the nitrogen atom, the formation of chelates is hindered due to the intraligand repulsion between the atoms of this substituent and the tert-butyl group.

Crystal structure of nickel(II) bis-(1,1,1,-trifluoro-5,5-dimethyl-2,4-hexanedionate)-1,3-diaminopropane

The structure of the complex of nickel(II) bis-(1,1,1-trifluoro-5,5-dimethyl-2,4-hexanedionate) with 1,3-diaminopropane is determined by single crystal X-ray diffraction at a temperature of 150 K. Crystallographic data for C20H34F6N2NiO5: a = 17.5446(8) Å, b = 18.1171(10) Å, c = 18.6654(7) Å, β = 115.4150(10)°, space group C2/c, V = 5358.8(4) Å3, Z = 8, dcalc = 1.376 g/cm3, R = 0.0435. The structure is molecular; the metal atom coordinates four oxygen atoms of two β-diketonate ligands and two nitrogen atoms of propylenediamine. In the crystal, the molecules are bonded only by van der Vaals interactions.

Structure of Cu(II) and Pd(II) complexes with 2-(2,2-dimethylhydrazone)pentanone-4

Palladium(II) and copper(II) complexes with 2-(2,2-dimethylhydrazone) pentanone-4 are synthesized for the first time. The compounds are characterized by IR and NMR spectroscopy, elemental and single crystal X-ray diffraction analyses. The palladium complex crystallizes in the space group I41/a; the copper complex crystallizes in the space group P1̅. Both compounds are molecular; the palladium chelate core has a distorted square geometry and that of copper has a distorted tetrahedral geometry. The average M–O and M–N bond lengths are respectively 1.9808(15) Å and 2.0427(17) Å for M = Pd, 1.915(8) Å and 1.97(1) Å for M = Cu. The chelate O–M–N angles are 88.32(7)-91.67(7)° for M = Pd, 93.37(4)-99.02(5)° for M = Cu.

Structure and thermal properties of trimethylplatinum(IV)-pivaloyltrifluoroacetonate pyridine

The structure of (CH3)3Pt(ptac)Py (ptac = (CH3)3C(O)CHC(O)CF3) is determined by single crystal X-ray diffraction (XRD) at a temperature of 150 K. The crystallographic data are as follows: space group P21/c, a = 8.5513(2) Å, b = 16.1089(3) Å, c = 14.0877(3) Å, β = 107.4060(10)°, V = 1851.75(7) Å3, Z = 4, R = 0.0365. The structure is molecular; the coordination polyhedron of platinum is a distorted octahedron. The average Pt–O and Pt–CMe distances are 2.149(1) Å and 2.029(5) Å, respectively; the Pt–N distance is 2.179(2) Å, the chelate angle O–Pt–O = 89.77(8)°. The thermal properties of (CH3)3Pt(ptac)Py in the condensed phase are examined by thermogravimetry.

Structure of bis-(1,1,1-trifluoro-2-(methylimino)pentanoato-4)copper(II). Thermal properties of N-methylsubstituted copper(II) β-iminoketonates

The single crystal X-ray diffraction (XRD) method was used to determine the structure of the [Cu(mi-tfac)2] (mi-tfac = MeC(O)CHC(NMe)CF3) complex at the temperature of 150 K. The crystallographic data are as follows: space group Pnna, a = 11.8798(16) Å, b = 12.0315(16) Å, c = 10.6259(14) Å, V = 1518.8(4) Å3, Z = 4, R = 0.0288. The structure is molecular, the coordination environment of copper in the molecule adopts a distorted tetrahedral geometry. The Cu–O and Cu–N distances are 1.9182(13) Å and 1.9610(16) Å respectively, the OCuN chelate angle is 94.18(5)°. The thermal properties of the compounds [Cu(mi-tfac)2] and [Cu(RC(O)CHC(NMe)R)2] (R = Me, tBu) in the condensed phase have been studied by the methods of thermogravimetry and differential scanning calorimetry. The thermodynamic characteristics of the melting processes have been determined.

New β-diketonate cobalt(II) complexes with 1,3-diaminopropane: Synthesis, structures, and thermal behavior

Structures of β-diketonate cobalt(II) chelates with 1,3-diaminopropane (pda) are determined by single crystal X-ray diffraction (XRD) at temperatures of 100 K and 293 K respectively: Co(pda)(hfac)2 and Co(pda)(tmhd)2 (hfac is 1,1,1,5,5,5-hexafluoro-pentane-2,4-dionato(−), tmhd is 2,2,6,6-tetramethyl-heptane-3,5-dionato(−)). Crystallographic data for Co(pda)(hfac)2 (C13F12H12O4N2Co) are: a = 8.427(3) Å, b = 10.625(3) Å, c = 11.369(3) Å, α = 111.751(7)°, β = 97.968(7)°, γ = 93.070(7)°, space group

Synthesis, crystal structures and thermal behavior of Ni(pda)(hfac)2 and Ni(pda)(thd)2 as potential MOCVD precursors (pda-1,3-diaminopropane, hfac-1,1,1,5,5,5-hexafluoro-2,4-pentanedionato(-), thd-2,2,6,6-tetrametyl-3,5-heptanedionato(-))

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