Synthesis of chromium(III) bis(benzamidinate) complexes via single electron oxidation

Single-electron oxidation of the known Cr(II) bis(amidinate) Cr[(Me₃SiN)₂CPh]₂ (1) provides synthetic access to neutral Cr(III) complexes. The complexes Cr[(Me₃SiN)₂CPh]₂X were prepared by reaction of 1 with AgO₂CPh (X = O₂CPh, 2), of 1 with iodine in THF (X = I/THF, 3), or of 1 with iodine in pentane, followed by addition of 2-adamantanone (X = I/2-adamantanone, 4). Treatment of 2 or 3 with C₃H₅MgCl resulted in the thermally stable allyl complex (X = η³-C₃H₅, 5). A preliminary kinetics study of the reaction of 1 with excess allyl benzoate and allyl acetate was performed. The molecular structures of 2, 3 and 5 were confirmed by single crystal X-ray diffraction.     

Synthesis and crystal structure of tris(ethylenediamine)cobalt(III) bis(tetrachloroaurate(III)) chloride

The binary complex salt [Co(N₂C₂H₈)₃][AuCl₄]₂Cl has been synthesized. Its crystal structure has been determined. Crystal data for C₆H₂₄N₆Cl₉AuCo: a = 20.8976(14) Å, b = 14.4773(9) Å, c = 7.9944(5) Å; β = 110.809(2)°; V = 2260.9(3) ų, space group C2/c, Z = 4, d _calc = 2.798 g/cm³. The plane square environment of the gold atom of the complex anion is completed to a tetragonal pyramid by the chlorine atom of the neighboring complex anion (Au…Cl 3.538 Å). The structure is layered. Layers of complex cations and complex anions alternate along the X axis.     

Synthesis and structural characterization of iron complexes with 2,2,2-tris(1-pyrazolyl)ethanol ligands: Application in the peroxidative oxidation of cyclohexane under mild conditions

The reactions of FeCl₂.2H₂O and 2,2,2-tris(1-pyrazolyl)ethanol HOCH₂C(pz)₃ (1) (pz = pyrazolyl) afford [Fe{HOCH₂C(pz)₃}₂][FeCl₄]Cl (2), [Fe{HOCH₂C(pz)₃}₂]₂[Fe₂OCl₆](Cl)₂·4H₂O (3·4H₂O), [Fe{HOCH₂C(pz)₃}₂][FeCl{HOCH₂C(pz)₃}(H₂O)₂]₂(Cl)₄ (4) or [Fe{HOCH₂C(pz)₃}₂]Cl₂ (5), depending on the experimental conditions. Compounds 1-5 were isolated as air-stable crystalline solids and fully characterized, including (1-4) by single-crystal X-ray diffraction analyses. The latter technique revealed strong intermolecular H-bonds involving the OH group of the scorpionate 2 and 3 giving rise to 1D chains which, in 3, are further expanded to a 2D network with intercalated infinite and almost plane chains of H-interacting water molecules. In 4, intermolecular π?π interactions involving the pyrazolyl rings are relevant.Complexes 2-5 display a high solubility in water (S_25 °Cca. 10-12 mg mL⁻¹), a favourable feature towards their application as catalysts (or catalyst precursors) for the peroxidative oxidation of cyclohexane to cyclohexanol and cyclohexanone, with aqueous H₂O₂/MeCN, at room temperature (TON values up to ca. 385).     

Synthesis and Structures of Amino(triphenylgermyl) Boranes and Trihydro(triphenylgermyl) Borates

The B‐(triphenylgermyl)borazines 4 a and 4 b , the 1,2‐bis(dimethylamino)‐1,2‐bis(triphenylgermyl)‐diborane(4), 5 , and the (2,2,6,6‐tetramethylpiperidino)(triphenylgermyl)‐boranes 6 and 7 were prepared by allowing LiGePh₃ to react with the corresponding B‐bromoborazines and aminochloroboranes, respectively. BH₃ dissolved in thf readily adds to LiGePh₃ generating Li(H₃BGePh₃), 8 a , in thf solution. Addition of N‐bases to the solution of 8 a produced (tmen · thf)Li(H₃BGePh₃), 8 b , and dimeric (py)₂Li(H₃BGePh₃), 8 c . The borazine ring in 4 b is distorted into a boat shape. In 5 the NBGe planes are twisted against each other by 85°. Comparison with analogous (triphenylstannyl)boranes points to a more pronounced steric effect of the Ph₃Ge group over the Ph₃Sn group due to the shorter B–Ge bond. A fairly short B–Ge bond is found for the (triphenylgermyl)trihydroborates. The molecular structure of (Et₂O)₃LiGePh₃ shows compressed C–Ge–C bond angles. Its molecular parameters fit well into the series L_nLiEPh₃ (E = Si, Sn, Pb).     

Synthesis of bis(glycosylamino)alkanes and bis(glycosylamino)arenes

The condensation of D-mannose and D-galactose with aliphatic and aromatic diamines afforded a series of bis(glycosylamino)alkanes and-arenes. A possible mechanism was proposed for the formation of 1,2-bis(β-D-glycosylamino)benzenes. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2793–2801, December, 2005.     

Synthesis, structural investigation and thermal stability of aqua magnesium(II) phthalocyanine bis(diethylamine) solvate

Aqua magnesium phthalocyanine bis(diethylamine) complex was obtained in the crystalline form and its crystal structure was determined by single-crystal X-ray diffraction. The Mg atom is 4 + 1 coordinated by four N isoindole atoms and one O atom. The MgPc moiety is non-planar, the Mg(II) is deviated by 0.492(2) Å from the N₄-isoindole plane towards the oxygen atom of water molecule. The arrangement of MgPc(H₂O) and diethylamine molecules is determined by O–HN hydrogen bonds and π–π interactions. The complex is stable up to 140 °C. At this temperature the complex loses diethylamine molecules and next at 200 °C loses the water molecule and finally converts into β-MgPc.     

The interaction of nickelocene with bis(triphenylgermyl)cadmium

The reaction of bis(triphenylgermyl)cadmium with nickelocene proceeds through the displacement of a cyclopentadienyl ring and the formation of an organopolymetallic compound containing nine metal atoms:

This is a new type of organometallic compound, containing NiCd bonds.     

Synthesis,Spectroscopic Properties and Crystal Structure of 3,3＇-（Anthracene-9,10-diyl）bis（1-phenylpropan-1-one）

The compound 3,3'-(anthracene-9,10-diyl)bis(1-phenylpropan-1-one)(C32H26O2,Mr=442.55) has been synthesized by the reaction of 2,2'-(anthracene-9,10-diylbis(methy-lene))bis(1,3-diphenylpropane-1,3-dione) with CsCO3,and its structure was characterized by 1H NMR and single-crystal X-ray diffraction.The crystal of the title compound belongs to monoclinic,space group P21/c with a=9.154(3),b=5.2777(16),c=24.897(7) nm,β=107.337(10)°,Z=2 and V=1.1482 nm3.X-ray analysis indicates that an intermolecular hydrogen bond C(8)-H(8A)…O(1),weak C-H···π between H(9A) and the centre of anthracene rings and weak π-π interactions between two anthracene ring planes are observed.     

1,1,1,3,3,3-Hexamethyltrisilanylene-bridged bis(cyclopentadienyl)tetracarbonyldiiron and its derivatives: Synthesis,properties and molecular structures

The title ring-bridged bis(cyclopentadienyl)diiron complexes [η⁵,η⁵-C₅H₄–Si(SiMe₃)₂–C₅H₄]Fe₂(CO)L(μ-CO)₂ [L = CO (1), P(OPh)₃ (2), P(OMe)₃ (3), PPh₃ (4), PMe₃ (5)] that contain exocyclic Si–Si bonds attached to the bridging silicon atom have been synthesized. The Si–Si bonds were found to be stable to the intramolecular iron centers under both thermal and photochemical conditions, in sharp contrast to the facile cleavage of the Si–Si bond in 1,1,2,2-tetramethyldisilanylene-bridged analogous complexes. The stability of the Si–Si bonds in the present cases may be attributed to the fact that these Si–Si bonds are spatially unapproachable by the intramolecular coordinatively unsaturated iron centers. Molecular structures of 1 and 2 have been determined by X-ray diffraction methods. An obvious conformational change due to substitution of CO for P(OPh)₃ was observed.     

The reaction of dihydridotetrakis(triphenylphosphane)ruthenium(II) with methyl acrylate. Crystal structure of bis(methylacrylate)bis(triphenylphosphane)(aqua)ruthenium(0)

The complex H₂Ru(PPh₃)₄ reacts with methyl acrylate to give bis(methylacrylate)bis(triphenylphosphane)ruthenium(0). Temperature-dependent NMR spectra show that the complex exists in two isomeric forms in solution. The major form (ca. 74%) has one methyl acrylate ligand η²-coordinated and the other η⁴ -coordinated as a 1-oxabutadiene ligand. This complex reacts with water to give the monoaqua adduct, the crystal structure of which is reported.     

Thermal decomposition of manganese(II)bis(oxalato)nickelate(II)tetrahydrate

Summary A mixed metal oxalate, manganese(II)bis(oxalato)nickelate(II)tetrahydrate, has been synthesized and characterized by elemental analysis, IR spectral and X-ray powder diffraction (XRD) studies. Thermal decomposition studies (TG, DTG and DTA) in air showed that the compound decomposed mainly to Mn₂O₃, MnO₂ and NiO at ca.1000°C, via. the formation of several intermediates. DSC study in nitrogen upto 500°C showed the endothermic decomposition. The tentative mechanism for the thermal decomposition in air is proposed.     

Green and chemoselective oxidation of alcohols with hydrogen peroxide: A comparative study on Co(II) and Co(III) activity toward oxidation of alcohols

Two new cobalt (II) and cobalt (III) complexes of a terpyridine based ligand, (4′-(2-thienyl)-2,2′;6′,2″-terpyridine (L)), were synthesized. Each complex has two units of the tridentate ligand. The complexes were fully characterized by spectroscopic methods as well as CHN analysis. Moreover, their solid state structures were determined by single crystal X-ray diffraction. The cobaltous complex has the formula [Co(L)₂](NO₃)₂·2CH₃OH·H₂O (1), whereas the cobaltic complex shows the formula [Co(L)₂](NO₃)₃·2CH₃OH (2). Both complexes were tested as homogenous catalysts for the oxidation of a variety of aliphatic and aromatic alcohols utilizing aqueous hydrogen peroxide in water media. The Co(II) complex showed more activity in comparison with its isostructural Co(III) species. The results show that the aromatic alcohols were oxidized with higher conversions and selectivity compared to the aliphatic substrates, possibly due to their conjugation systems which thermodynamically stabilized the carbonyl products.     

Synthesis, growth and characterization of bis (glycine) lithium molybdate—A semi-organic NLO material

Single crystals of bis (glycine) lithium molybdate [BGLM] with dimensions 20 mm × 10 mm × 5 mm were grown by slow evaporation technique. The grown crystals were subjected to powder X-ray diffraction studies. Functional groups of the crystallized molecules were confirmed by FTIR analyses. Transmission range of the crystal was determined by UV–vis–NIR spectra. Vickers microhardness test was performed on the prominent plane (0 1 1) of the grown crystal. The NLO property of the crystal was confirmed by Kurtz SHG test and compared with NLO efficiency of KDP crystal.     

Barium bis(5,5-dimethyl-1,1,1-trifluorohexane-2,4-dionate)(crown-ether) complexes: Synthesis,characterization and crystal structure

The preparation of the barium β-diketonate complexes with crown-ethers [Ba(pta)₂(18-crown-6)] (1), [Ba(pta)₂(18-crown-6)] (THF) (2), [Ba(pta)₂(18-dibenzocrown-6)](C₆H₅CH₃) (3), [Ba(pta)₂(18-dibenzocrown-6)] (4) (pta = 1,1,1-trifluoro-5,5-dimethylhexanedionato-2,4; 18-crown-6 = 1,4,7,10,13,16-hexaoxacyclooctadecane; 18-dibenzocrown-6 = 6,7,9,10,17,18,20,21-octahydrodibenzo[b,k][1,4,7,10,13,16]-hexaoxacyclooctadecane) is described. The complexes 1 and 2 have been synthesized from reaction of metallic barium with 2 molar equiv. of Hpta and 1 molar equiv. of 18-crown-6 in toluene; the complexes 3 and 4 from reaction of Ba(OH)₂·8H₂O with 1 molar equiv. 18-dibenzocrown-6 and 2 molar equiv. Hpta. The complexes were characterized by elemental analyses, IR-spectroscopy, ¹H NMR spectroscopy. The crystal structures of 2 and 3 were determined by means of single-crystal X-ray diffraction methods. A single-crystal X-ray study of 2 and 3 has shown it be monomeric. The coordination number of Barium cation in 2 and 3 is nine owing to nine oxygen atoms from two pta ligands and crown-ether molecule.     

Synthesis of zinc-containing poly(urethane-ether)s based on zinc salt of mono(hydroxypentyl)phthalate

Zinc salt of mono(hydroxypentyl)phthalate, Zn(HPP)₂, was synthesized by reacting 1,5-pentanediol, phthalic anhydride and zinc acetate. Zinc-containing poly(urethane-ether)s (PUEs) were synthesized by reacting hexamethylene diisocyanate (HMDI) or toluene 2,4-diisocyanate (TDI) with a mixture of Zn(HPP)₂ and poly(ethylene glycol) (PEG₃₀₀ or PEG₄₀₀) in dimethylsulfoxide (DMSO) at 95 °C under nitrogen atmosphere using di-n-butyltin dilaurate as a catalyst. Blank PUEs without Zn(HPP)₂ were also prepared by reacting PEG₃₀₀ or PEG₄₀₀ with HMDI or TDI under similar conditions. The structure of the polymers was confirmed by FT-IR, ¹H NMR, ¹³C NMR, and solid-state ¹³C-CP-MAS NMR spectra. The zinc-containing polymers were soluble in only highly polar solvents. The inherent viscosity of the zinc-containing PUEs was found to be very low. X-ray diffraction studies revealed that HMDI-based (PUEs) were partially crystalline while TDI based (PUEs) were amorphous. The T_g values of the zinc-containing PUEs were found to be low and range from 5.3 to 7.5 °C. The thermogravimetric analysis revealed the influence of zinc on the initial decomposition and the overall thermal stability of the polymers.     

Novel organotin(IV) compounds derived from bis(organostannyl)methanes: Synthesis and crystal structures of bis[diphenyl(pyridin-2-onato)stannyl]methane and bis[bromophenyl(pyrimidine-2-thionato)stannyl]methane · C7H8

Reaction between bis(chlorodiphenylstanyl)methane and the sodium salt of 2-hydroxypyridine (pyONa) in the molar ratio of 1:2 provides the organotin hydroxide derivative [Ph₂(pyO)SnCH₂Sn(OH)Ph₂]₂ (1) (where pyO = anion of 2-hydroxypyridine), while reaction of bis(dibromophenylstanyl)methane with the sodium salt of pyrimidine-2-thione (pmtNa) in molar ratio of 1:4 gives the corresponding organotin thiolate derivative, as its toluene solvate [BrPh(pmt)Sn]₂CH₂ · C₇H₈ (2) (where pmt = anion of pyrimidine-2-thione). Both compounds were characterized by single crystal X-ray diffraction analysis and contain five-coordinate tin atoms. Compound 1 is a centrosymmetric head-to-tail dimmer with almost symmetrical Sn(1)-O(H)-Sn(2A) bridges.     

Thermal reactivity of cis- and trans-bis(triphenylgermyl)bis(tertiary phosphine)platinum(II)

The complex cis-Pt(Ph₃Ge)₂(PMe₂Ph)₂ underwent smooth isomerization to give the trans-isomer at room temperature via an associative five-coordinated intermediate. Thermodynamic parameters and activation energy for the cis to trans isomerization were obtained, ΔH^# = 105 kJ mol⁻¹, ΔS^# = 12.5 J mol⁻¹ K⁻¹, and Ea = 107 kJ mol⁻¹, respectively. Heating of trans-Pt(Ph₃Ge)₂(PMe₂Ph)₂ at 50 °C for 36 days produced trans-PtPh(Ph₃Ge)(PMe₂Ph)₂ followed by the formation of trans-PtPh₂(PMe₂Ph)₂, Pt(PMe₂Ph)₄, and Ph₄Ge finally via elimination of the phenyl group from Ph₃Ge ligand with liberation of the Ph₂Ge unit and subsequent reductive elimination of the remaining Ph₃Ge ligand at 80 °C for 1 month.     

Synthesis of bis(pyrimidyl)furoxanes by the oxidation of bis(pyrimidyl)glyoximes

Conclusions This is the first report of the synthesis of a 3,4-bis(pyrimidyl)furoxane by the oxidation of bis (pyrimidyl)glyoxime. The substrate used was 1,2-bis(2,4-diethoxypyrimidin-6-yl) glyoxime.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 915–917, April, 1988.Deceased.