Synthesis and characterization of a new family of spin bearing TTF ligands

The syntheses and characterization of two new tetrathiafulvalene (TTF) derivatives bearing pyridine-based substituents and 1,5'-dimethyl-6-oxoverdazyl radicals are described. The TTF-pyridine and bipyridine aldehydes were prepared via a palladium-catalyzed cross-coupling reaction between mono(tributylstannyl)tetrathiafulvalene (3) and the appropriate formylpyridyl halides (4). The radical precursors, the corresponding 1,2,4,5-tetrazanes, were prepared by condensation of the bis(1-methylhydrazide) of carbonic acid with the TTF bearing pyridyl aldehyde. Oxidation of tetrazanes 8 and 9 with 1,4-benzoquinone afforded the donor radicals 1 and 2 as 1:1 complexes with hydroquinone. Both complexes are stable in the solid state and their electronic properties have been characterized by EPR, cyclic voltammetry, and UV/vis spectroscopy. The TTF core of both compounds was oxidized both chemically and electrochemically to afford the corresponding cation diradical species. The electronic properties of both donor radicals have been probed by cyclic voltammetry, UV-vis spectroscopy, and preliminary EPR measurements.     

A new family of octanuclear Cu4Ln4 (Ln = Gd, Tb and Dy) spin clusters

The reaction of Cu(OAc)2 and Ln(OAc)3 (Ln = Gd, Tb and Dy) with 2-amino-2-methyl-1,3-propanediol (ampdH2) under solvothermal conditions has afforded a new family of isostructural octanuclear Cu4Ln4 complexes with the formula [Cu4Ln4(OAc)12(ampdH)8(OH2)2] (Ln = Gd (1), Tb (2) and Dy(3)) in good yield. Variable temperature magnetic susceptibility measurements reveal weak intramolecular exchange interactions for 1 and 2. Ferromagnetic coupling is observed for 1 and attributed to Cu...Gd interactions. In contrast, the magnetic susceptibility behaviour of 2 arises from a combination of intramolecular exchange interactions and the crystal field splitting of the (7)F6 ground state of the Tb(III) ions.     

Synthesis,spectroscopic characterization and crystal structure of disulfamethoxazole diaquo Ni(II) monohydrate

The novel disulfamethoxazole diaquo Ni(II) monohydrate, [Ni(sulfamethoxazole)₂(H₂O)₂]· H₂O, was synthesized, characterized by infrared and electronic spectroscopies and the crystal structure determined. The compound crystallized in the monoclinic centrosymmetric space group P2₁/c, with four asymmetric units per unit cell. The nickel atoms are in slightly distorted regular octahedra, coordinated by four nitrogen atoms, two from N-arylamine and two from N-sulfonamide with the apical positions occupied by two oxygen atoms from the water molecules.     

Synthesis, spectroscopic characterization and vulcanization activity of a new compound containing the anion bis(4-methylphenylsulfonyldithiocarbimato)zincate(II)

A new compound of the formula: (Bu₄N)₂[Zn(4-CH₃C₆H₄SO₂NCS₂)₂] (Bu₄N = tetrabutylammonium cation) was obtained by the reaction of CH₃C₆H₄SO₂NCS₂K₂ · 2H₂O with zinc(II) acetate dihydrate and tetrabutylammonium bromide in dimethylformamide. The elemental analyses of C, H, N and Zn are consistent with the proposed formula. The IR data point to the formation of a zinc(II)-bis(dithiocarbimato) complex. The ¹H NMR and ¹³C NMR spectra showed the expected signals for the tetrabutylammonium cation and the dithiocarbimato moiety. This compound was evaluated as for the vulcanization activity and compared to the commercial accelerators CBS, MBTS and TMTD. These studies showed that the zinc(II)-ditiocarbimates are a new class of rubber vulcanization accelerators, worth of further investigation.     

Synthesis and electrochemical and spectroscopic characterization of biicosahedral Au25 clusters

The synthesis and electrochemical and spectroscopic characterization of biicosahedral Au(25) clusters with a composition of [Au(25)(PPh(3))(10)(thiolate)(5)Cl(2)](2+) are described. The biicosahedral Au(25) clusters protected with various types of thiol ligands including alkanethiols, 2-phenylethanethiol, 11-mercaptoundecanoic acid, and 11-mercapto-1-undecanol were synthesized in high yields using a one-step, one-phase procedure in which Au(PPh(3))Cl is reduced with tert-butylamine-borane in the presence of the thiol ligand in a 3:1 v/v chloroform/ethanol solution. All biicosahedral Au(25) clusters prepared exhibit characteristic optical absorption and photoluminescence properties. The emission energy is found to be substantially smaller than the optical absorption energy gap of 1.82 eV, indicating a subgap energy luminescence. The electrochemical HOMO-LUMO gap (~1.54 eV) of the clusters is also substantially smaller than the optical absorption energy gap but rather similar to the emission energy. These electrochemical and optical properties of the biicosahedral Au(25) clusters are distinctly different from those of the Au(25)(thiolate)(18) clusters.     

Synthesis and spectroscopic characterization of new metal(II) complexes with methionine sulfoxide

Methionine sulfoxide complexes of iron(II) and copper(II) were synthesized and characterized by chemical and spectroscopic techniques. Elemental and atomic absorption analyses fit the compositions K₂[Fe(metSO)₂]SO₄·H₂O and [Cu(metSO)₂]·H₂O. Electronic absorption spectra of the complexes are typical of octahedral geometries. Infrared spectroscopy suggests coordination of the ligand to the metal through the carboxylate and sulfoxide groups. An EPR spectrum of the Cu(II) complex indicates tetragonal distortion of its octahedral symmetry. ⁵⁷Fe Mössbauer parameters are also consistent with octahedral stereochemistry for the iron(II) complex. The complexes are very soluble in water.     

Synthesis and characterization of a new family of square-planar nickel(II) carbonyl derivatives

The reaction of [NBu(4)](2)[Ni(C(6)F(5))(4)] (1) with solutions of dry HCl(g) in Et(2)O results in the protonolysis of two Nibond;C(6)F(5) bonds giving [NBu(4)](2)[[Ni(C(6)F(5))(2)](2)(mu-Cl)(2)] (2 a) together with the stoichiometrically required amount of C(6)F(5)H. Compound 2 a reacts with AgClO(4) in THF to give cis-[Ni(C(6)F(5))(2)(thf)(2)] (3). Reacting 3 with phosphonium halides, [PPh(3)Me]X, gives dinuclear compounds [PPh(3)Me](2)[[Ni(C(6)F(5))(2)](2)(mu-X)(2)] (X=Br (2 b) or I (2 c)). Solutions of compounds 2 in CH(2)Cl(2) at 0 degrees C do not react with excess CNtBu, but do react with CO (1 atm) to split the bridges and form a series of terminal Ni(II) carbonyl derivatives with general formula Qcis-[Ni(C(6)F(5))(2)X(CO)] (4). The nu(CO) stretching frequencies of 4 in CH(2)Cl(2) solution decrease in the order Cl (2090 cm(-1))>Br (2084 cm(-1))>I (2073 cm(-1)). Compounds 4 revert to the parent dinuclear species 2 on increasing the temperature or under reduced CO pressure. [NBu(4)]cis-[Ni(C(6)F(5))(2)Cl(CO)] (4 a) reacts with AgC(6)F(5) to give [NBu(4)][Ni(C(6)F(5))(3)(CO)] (5, nu(CO)(CH(2)Cl(2))=2070 cm(-1)). Compound 5 is also quantitatively formed ((19)F NMR spectroscopy) by 1:1 reaction of 1 with HCl(Et(2)O) in CO atmosphere. Complex 3 reacts with CO at -78 degrees C to give cis-[Ni(C(6)F(5))(2)(CO)(2)] (6, nu(CO)(CH(2)Cl(2))=2156, 2130 cm(-1)), which easily decomposes by reductive elimination of C(6)F(5)bond;C(6)F(5). Compounds 3 and 6 both react with CNtBu to give trans-[Ni(C(6)F(5))(2)(CNtBu)(2)] (7). The solid-state structures of compounds 3, 4 b, 6, and 7 have been established by X-ray diffraction methods. Complexes 4-6 are rare examples of square-planar Ni(II) carbonyl derivatives.     

Synthesis, spectroscopic characterization and semi-empirical calculations for a low spin carbonyl, pyridine(alpha-iminooxime)iron(II) macrocyclic complex

Synthetic route and detailed characterization of the macrocyclic complex [Fe(II)(dohpn)(py)(CO)](ClO4) (dohpn = 2,3,9,10-tetramethyl-1,4,8,11-tetraazaundecane-1,3,8,10-tetraen-11-ol-1-olate and py = pyridine) based on analytical, spectrometric and spectroscopic methods are herein reported. The corresponding vibrational and electronic features are discussed and a consistent assignment is proposed on the basis of semi-empirical theoretical calculations.     

Synthesis, spectroscopic characterization and crystal structure of mixed ligand Ni(II) complex of N-4-diethylaminosalicylidine-N′-4-nitrobenzoyl hydrazone and 4-picoline

A novel mixed ligand nickel complex [NiLB] [H₂L-N-4-diethylaminosalicylidine-N′-4-nitrobenzoyl hydrazone and B-4-picoline] has been synthesized and characterized by elemental analysis, IR spectrum, UV-Vis spectrum and structure has been confirmed by single crystal X-ray structure analysis. The crystal structure reveals that the complex adopts distorted square planar structure with ONO donor atoms of primary ligand and N donor atom of the secondary ligand 4-picoline.     

Synthesis, spectroscopic characterization and biological analysis of a new palladium(II) complex with methionine sulfoxide

A new palladium(II) complex with methionine sulfoxide was synthesized and characterized by a set of chemical and spectroscopic techniques. Elemental and mass spectrometry analyses of the solid complex fit to the composition [Pd(C5H10NO3S)2].H2O. 13C NMR, [1H-15N] NMR and infrared spectra indicate coordination of the amino acid to Pd(II) through the carboxylate and amino groups in a square planar geometry. The complex is soluble in water. Biological activity was evaluated by cytotoxic analysis using HeLa cells. Determination of cell death was assessed using a tetrazolium salt colorimetric assay, which reflects the cells viability. After incubation for 48 h, 20% of cell death was achieved at a concentration of 200 micromol L-1 of the complex.     

Synthesis,characterization and bioactivity of a new Fe(III) 18-metallacrown-6 and a new trinuclear linear Ni(II) complexes

A new trinuclear linear Ni(II) compound [Ni₃(H₂O)₂(DMA)₂(acshz)₂] · 2DMF (DMA = dimethylamine) (1) and a new Fe(III) 18-metallacrown-6 [Fe₆(acbshz)₆(DMF)(H₂O)₅] · 5DMF (2), with two similar pentadentate ligands, N-acryloyl-salicylhydrazide (H₃acshz) and N-acryloyl-5-bromosalicylhydrazide (H₃acbshz) have been synthesized and characterized by X-ray crystallography. In compound 1, three nickel ions arrange in a strictly linear structure, adjacent molecules are linked by intermolecular H bonds to form a 2D infinite wave-like structure. In compound 2, the ring of the metallacrown is consisted of six interlink [Fe–N–N] repeated units through hydrazide N–N group bridging. It is the first metallacrown that the coordination environments of metal ions in the cycle ring are different, and these differences make the two faces of the disc-shaped hexanuclear ring do not have opposite chiralities. The studies in solution integrity and stability of the metallacrown 2 show it is soluble and stable in DMF. UV–Vis titrations demonstrate the metallacrown 2 is stable in DMF even in the presence of excess metal ions. Antibacterial screening data indicate the two compounds all have antimicrobial activities against the tested microorganisms. The activities of metallacrown 2 are stronger than trinuclear compound 1.     

新型钼-氧簇化合物Ni(en)3MoO4的水热合成及表征

采用水热方法合成一种新型钼-氧簇化合物Ni(en)3MoO4,并通过X射线单晶结构分析、红外光谱分析、元素分析、差热热重分析对该化合物进行了表征.结构分析数据表明该化合物属三方晶系,P-31c空间群,晶胞参数a＝0.922 6(13) nm,b＝0.922 6(13) nm,c=0.995 9(2) cm,α＝90°,β＝90°,γ＝120°,V＝0.734 2(2) nm3,Z＝2,Dc=1.805 mg/ m3,μ＝2.153 mm-1,F(000)=408,R=0.055 3,Rw=0.173 2;该化合物是分立结构,是由MoO4四面体簇和Ni(en)3八面体簇形成,其中MoO4四面体簇和Ni(en)3八面体簇交替排列,存在较强的氢键作用,结构中分立的手性配合物Ni(en)3的两种对映体构象以MoO4簇为中心对称排布.     

Synthesis, spectroscopic characterization and electronic structure of some new Cu(I) carbene complexes

Reaction of oligomeric Cu(I) complexes [Cu(Μ-S-C(=NR)(O-Ar-CH₃)]_n with Lewis acids gave Cu(I) carbene complexes, which were characterized by¹H and¹³C NMR spectroscopy. Cu(I) carbene complexes could be directly generated from RNCS, Cu(I)-OAr and Lewis acids; this method can be used to prepare Cu(I) carbene complexes with different substitutents on the carbene carbon. The complexes were unreactive towards olefins and do not undergo cyclopropanation. Electronic structure calculations (DFT) show that the charge on the carbene carbon plays an important role in controlling the reactivity of the carbene complex.     

Synthesis and spectroscopic characterization of cobalt(II) thiosemicarbazone complexes

Thiosemicarbazone derivatives are formed on reaction between acetophenone, salicylaldehyde, benzophenone and/or 2-hydroxy-4-methoxybenzophenone and thiosemicarbazide or its N⁴H substituents (ethyl-, phenyl-, and p-chlorophenyl-). The ligands were investigated by elemental analysis and spectral (IR, ¹H?NMR and MS) studies. The formulas of the prepared complexes have been suggested by elemental analyses and confirmed by mass spectra. The coordination sites of each ligand were elucidated using IR spectra revealing bidentate and tridentate coordination. Different geometries for the complexes were proposed on the basis of electronic spectra and magnetic measurements. The complexes have been analyzed thermally (TG and DTG) and the kinetic parameters for some of their degradation steps were calculated.     

Synthesis and spectroscopic characterization of copper(H)-dextran complexes

Synthesis of stable copper(II) complexes with reduced dextran derivatives can be realized with low molar polysaccharides of an average molar mass 5000 g mol⁻¹. A copper(II) content of 4–20% is achieved at pH 7–8 and at the boiling point. Copper(II) complex formation with dextran was analyzed by spectrophotometric VIS methods. The IR spectra of copper(II) complexes with dextran were analyzed to find the most stable conformation of the glucopyranose unit. The ESR parameters of the spectrum indicate a square-planar coordination of the Cu(II) ion with four oxygen ligand atoms in the same plane. Copper deficiency causes a number of pathological states [1]. In both human and veterinary medicine, commercial copper preparations based on dextran and its derivatives are used for such purposes [2]. According to the literature data, dextran has the ability of complex formation with various biometals (Zn, Fe, Co, Ca, and Mg) [3–6]. Iron complexes with different polysaccharides have special importance and they have been described in detail [7]. Synthetic procedures for the complex formation of Cu(II) with polysaccharides, including dextran, are described in scientific and patent literature [8]. However, literature data on the complex formation possibility of the Cu(II) ion with dextran derivatives are scarce. The text was submitted by the authors in English. An erratum to this article is available at .     

Synthesis and spectroscopic characterization of new mono- and binuclear complexes of some NH(1) thiosemicarbazides

4-Ethylthiosemicarbazide and its NH(1) derivatives have been prepared and confirmed by elemental analysis and ¹H?NMR spectra to produce diverse complexes with Co(II), Ni(II) and Cu(II) ions. The obtained complexes have been investigated based on elemental and thermal analyses, spectral (UV/VIS, ESR, mass) studies and magnetic measurements. The IR data reveal the presence of variable modes of chelation for the investigated ligands. The electronic spectra of the complexes as well as their magnetic moments provide information about geometries. The ESR spectra give evidence for the proposed structure and the bonding for some Cu(II) complexes. Thermal decomposition of some complexes ended with metal or metal oxide as a final product.     

Synthesis and spectroscopic properties of a new bipyridine-bipyrazoyl(pyridine)-thiocyanato-ruthenium(II) complex

The complex [Ru(II)(dcbpyH₂)(bdmpp)NCS](PF₆) (1) (where dcbpyH₂ is 2,2′-bipyridine-4,4′-dicarboxylic acid, bdmpp is 2,6-bis(3,5-dimethyl-N-pyrazoyl)pyridine,) is synthesized and characterized extensively by ¹H NMR and ¹³C NMR 1D and 2D, mass spectroscopy, cyclic voltammetry, electronic absorption spectroscopy and IR. The half-wave potential of the Ru(II)/Ru(III) redox couple was measured at E_1/2=+0.795 V versus Ag/AgCl in CH₃CN. The complex presents three intense metal-to-ligand charge transfer (MLCT) (d_M→π_L*) absorption bands centered at 383 (=21 300 M⁻¹ cm⁻¹), 432 (=22 400 M⁻¹ cm⁻¹) and 475 nm (=23 400 M⁻¹ cm⁻¹), respectively. The absorbance is extremely strong between 400 and 500 nm and even at 620 nm, the extinction coefficient is still high (=3768 M⁻¹ cm⁻¹). The strong π-acceptor property of the trans-isothiocyanate ligand compared with the Cl⁻ ligand is probably the cause of the blue-shift observed in complex 1. These properties make the complex potentially promising for the photosensitization process. The incorporation of TiO₂ photoelectrodes derivatized with this complex into a solar cell using a composite polymer/inorganic oxide solid-state electrolyte confirmed its sensitizing ability. Incident monochromatic photon-to-current conversion efficiency (IPCE) values of about 30% and overall energy conversion efficiency (η) of 1.7% were obtained.     

Synthesis,spectroscopic and structural characterization of new complex of ruthenium(II) with Hmtpo ligand

The [(PPh₃)₂RuHCl(CO)(Hmtpo)] complex has been prepared and studied by IR, NMR, UV–VIS spectroscopy and X-ray crystallography. The complex was prepared in reactions of [RuHCl(CO)(PPh₃)₃] with 7-hydroxy-5-methyl[1,2,4]triazolo[1,5-a]pyrimidine in methanol. The electronic structure and UV–Vis spectrum of the obtained compound have been calculated using the TD–DFT method.     

Synthesis and spectroscopic characterization of new organotin(IV) complexes with bis(3,5-dimethylpyrazol-1-yl)dithioacetate

New organotin(IV) derivatives containing the anionic ligand bis(3,5-dimethylpyrazolyl)dithioacetate [L₂CS₂]^? have been synthesized by reaction of SnR _n X_{4? n} (R?=?Me, Ph, ⁿ Bu or Cy; n?=?1–3) acceptors and Li[L₂CS₂]. Mononuclear complexes of the type [L₂CS₂]R _n SnCl_{4? n ?1}} have been obtained and fully characterized by elemental analyses and FT-IR in the solid state, and by NMR (¹H and ¹¹⁹Sn) spectroscopy, conductivity measurements and electrospray ionization mass spectrometry (ESI-MS) in solution. ESI-MS spectra of methanol solutions of diorganotin derivatives, recorded with fragmentor potentials of 0, 50, 100 and 150?V, show the occurrence at 150?V of peaks attributable to the loss of the CS₂ group from the ligands and the formation of stable tetraorganodistannoxane species.     

Incorporation of a tripodal ligand with a (N,O,O)-donor set into a new family of nickel and cobalt spin clusters

The reaction of Ni(OAc)₂, NiX₂ (X = Cl, Br) or CoCl₂ with the proligand 2-amino-2-methyl-1,3-propanediol (ampdH₂) affords a new family of tetranuclear complexes. The syntheses of [Ni₄(OAc)₄(ampdH)₄] (1) and [M₄X₄(ampdH)₄] (M = Ni, X = Cl, 2; M = Ni, X = Br, 3; M = Co, X = Cl, 4) are reported, together with the single crystal X-ray structures of 1, 2 and 4 and the magnetochemical characterization of 1, 3 and 4. Each member of this family of complexes displays a low symmetry structure that incorporates a {M₄O₄} core unit based on a distorted cubane. Magnetic measurements reveal ferromagnetic exchange interactions for 1, 3 and 4. These give rise to S = 4 ground state spins for the tetranuclear Ni complexes and an anisotropic effective S′ = 2 ground state for the Co complex.