Synthesis and characterization of the [Cu(Cin2bda)2]ClO4 and [Cu(Ncin2bda)2]ClO4 complexes: Crystal structure of [Cu(Ncin2bda)2]ClO4

Two copper(I) complexes [Cu(Cin₂bda)₂]ClO₄ (I) and [Cu(Ncin₂bda)₂]ClO₄ (II) have been prepared by the reaction of the ligands N²,N²′-bis(3-phenylallylidene)biphenyl-2,2′-diamine (L¹) and N²,N²′-bis[3-(2-nitrophenyl)allylidene]biphenyl-2,2′-diamine (L²) and copper(I) salt. These compounds were characterized by CHN analyses, ¹H NMR, IR, and UV-Vis spectroscopy. The C=N stretching frequency in the copper(I) complexes shows a shift to a lower frequency relative to the free ligand due to the coordination of the nitrogen atoms. The crystal and molecular structure of II was determined by X-ray single-crystal crystallography. The coordination polyhedron about the copper(I) center in the complex is best described as a distorted tetrahedron. A quasireversible redox behavior was observed for complexes I and II. The article is published in the original.     

2,6-Diacetyl- and 2,6-diformylpyridine bis(N4-substituted thiosemicarbazones) and their copper(II) and nickel(II) complexes

2,6-Diformylpyridine bis(N4-methylthiosemicarbazone) and bis(N4-dimethylthiosemicarbazone), H₂2,6Fo4M and H₂2,6Fo4DM, respectively, and 2,6-diacetylpyridine bis(N4-methylthiosemicarbazone) and bis(N4-dimethylthiosemicarbazone), H₂2,6Ac4M and H₂2,6Ac4DM, and their copper(II) and nickel(II) complexes have been synthesized. The ¹H-n.m.r. spectra of the free bis(thiosemicarbazones) show that, most often, one of the thiosemicarbazone moieties is hydrogen bonded to the pyridine nitrogen, and in [²H₆]-DMSO there is interaction with solvent oxygen. Golden yellow H₂2,6Ac4DM has a bifurcated hydrogen bonding interaction by one of the thiosemicarbazone moieties resulting in conjugation. Coordination to copper(II) and nickel(II) centers is via the pyridine nitrogen, amine nitrogen and thiolato sulfur and most of the complexes formed are polynuclear with thiosemicarbazone moieties from the same ligand coordinating to different metal centers.     

Nickel(II) complexes of N-(dialkylcarbamothioyl)-4-nitrobenzamide as single-source precursors for the deposition of nanostructured nickel sulfide thin films by chemical vapor deposition

Nickel(II) complexes of N-(di-alkyl-carbamothioyl)-4-nitrobenzamide (alkyl?=?ethyl or n-propyl) have been synthesized and characterized by infrared spectroscopy, elemental analysis, nuclear magnetic resonance spectroscopy, and mass spectrometry. The structures of bis[N-(diethylcarbamothioyl)-4-nitrobenzamide]nickel(II) (2a) and bis[N-(dipropylcarbamothioyl)-4-nitrobenzamide]nickel(II) (2b) have been determined by X-ray crystallography. FTIR and NMR of the nickel complexes showed the absence of the N–H proton resonance and the N–H stretch and shift of ν _C=O and ν _C=S as expected. Both complexes have been used as single-source precursors for the deposition of nickel sulfide nanostructured thin films by aerosol-assisted chemical vapor deposition. The nanostructured thin films were characterized by X-ray powder diffraction, scanning electron microscopy, energy dispersive X-ray analysis, and atomic force microscopy.     

Structural characterization of a novel self-assembly heterohexanuclear complex: [Ni2Ag4(μ-dppm)4(pymt)6](SbF6)2 · 2DMF · H2O

A novel heterohexanuclear complex [Ni₂Ag₄(μ-dppm)₄(pymt)₆](SbF ₆)₂ · 2DMF · H₂O (1), was synthesized by self-assembly with [Ag₂(μ-dppm)₂(MeCN)₂](SbF₆) ₂ and [Et₄N][Ni(pymt)₃] (dppm = bis(diphenylphosphino)methane, pymt = pyrimidine-2-thiolate) as components and characterized by IR spectra, elemental analysis, ¹H-NMR spectrum, ³¹P-NMR spectrum and Visible-Ultraviolet spectrum. Structure of the complex was determined by X-ray analysis.     

Copper(II) complexes of entwined 2,9-di(o-substituted phenyl)-1,10-phenanthroline type ligands and intramolecular quenching in copper(I) complexes

Cu¹¹ complexes of 1,10-phenanthroline, disubstituted at the 2 and 9 positions or monosubstituted at the 2 position by phenyl moieties possessingortho substituents, were prepared and investigated by spectroscopic and electrochemical methods. The electronic spectral d-d band position varies from 14 500 to 13 200 cm⁻¹. E.s.r. g_‖ values are between 2.256 to 2.283 and A_‖ between 164 to 117×10⁻⁴ cm⁻¹. Thebis[2,9-di(o-substituted phenyl)-1,10-phenanthroline]Cu¹¹ complexes undergo reversible one-electron electrochemical reduction (Cu¹¹/Cu¹) in the +0.536 to +0.825 V potential range versus s.c.e., whereas thebis[2-mono(o-substituted phenyl)-1,10-phenanthroline]Cu¹¹ complexes undergo reduction in the +0.360 to +0.405 V range; the redox couple is found to be quasireversible. Emission studies on copper(I) complexes show that onlybis[2,9-di(o-tolyl)-1,10-phen]Copper(I) complex exhibits emission properties. Emission behaviour of other structurally similar compounds is explored. TMC 2555     

Oxomolybdenum(V) complexes of bis-(2-benzimidazolyl) alkanes

Summary Oxomolybdenum(V) complexes of the type (LH₄) [MoOCl₅] (where LH₂ = dimethylene bis-2-benzimidazole or tetramethylene bis-2-benzimidazole), [MoOCl₃(LH₂)] (where LH₂ = tetramethylene bis-2-benzimidazole), [(Mo₂O₄Cl₂-(H₂O)₃)₂(LH₂)] (where LH₂ = dimethylene bis-2-benzimidazole, tetramethylene bis-2-benzimidazole or hexamethylene bis-2-benzimidazole) and [Mo₂O₃Cl₄(LH₂)₂] (where LH₂ = tetramethylene bis-5-nitro-2-benzimidazole) were prepared and characterised. The mononuclear complexes show u.v.-vis. absorptions characteristic of octahedral molybdenum(V). The dinuclear complexes do not absorb in the visible region, possibly due to the presence of an Mo₂O ₄ ^{2 +}} core, which is also indicated by their diamagnetic behaviour. The biological activities of the free ligands and their complexes have been studied.     

Oxidation of the thiosulfate ion by some iron(III) complexes with phenolate - amide-amine coordination: A comparative kinetic study

The redox reactions of thiosulfate with four iron(III) complexes having phenolate-amide-amine coordination, Fe^III(L){L = 1,2-bis(2-hydroxybenzamido)ethane, L¹; 1,3-bis(2-hydroxybenzamido)propane, L²; 1,5-bis(2-hydroxybenzamido)3-azapentane, L³; and 1,8-bis(2-hydroxybenzamido)3,6-diazaoctane, L⁴} have been investigated in 10% v/v MeOH + H₂O and I = 0.3 mol dm⁻³. At constant pH (~ 4.8) and under pseudo-first order conditions of [S₂O ₃ ²⁻ ] the reaction obeyed the rate law : − d[Fe^III(L)]/dt = k _obs [Fe^III(L)] + k _obs ^′ where k _obs ^′ denotes the observed rate constant of thiosulfate decomposition; k _obs = a[S₂O ₃ ²⁻ ] + b[S₂O ₃ ²⁻ ] _T ² is valid for all the complexes, particularly at pH < 6, while k _obs ^′ = [H⁺][S₂O ₃ ²⁻ ] _T ² is consistent with the rate law for thiosulfate decomposition proposed earlier. The rate data (k _obs) were analysed on the basis of the reactivities of various species of Fe^III(L) generated by the equilibrium protonation of the sec-NH of dien and trien spacer units resulting in the ring opening (for [Fe^III(L³/L⁴)]), and acid base equilibrium of the aqua ligand bound to the iron(III) centre ([Fe^III(L)(OH₂) _n ]). The redox activities, both for second and third order paths, show the ligand dependencies : L⁴<L³<L¹<L² conforming to the fact that the complexes tend to be less susceptible to electron transfer from S₂O ₃ ²⁻ with (i) the increase of the number of chelate rings, (ii) the decrease of overall charge, and (iii) the decrease of ring size offered by the amine moiety (from six membered to five membered one as for [Fe^III(L¹/L²)(OH₂)₂]⁺. There was no evidence for the formation of inner sphere thiosulfato complex, the possibility of the formation of the outer sphere ion-pairs, [Fe(L/HL)(OH₂)n ^+/2+, S₂O ₃ ²⁻ ] with low equilibrium constant value may not be excluded. In view of this, the outer sphere electron transfer (ET) mechanism is the most likely possibility.     

A new octahedral cobalt(III) complex of (1,8)- bis (2-hydroxybenzamido)-3,6-diazaoctane incorporating phenolate-amide-amine coordination: synthesis, X-ray crystal structure, ligand substitution and redox activity with sulfur(IV) and l -ascorbic acid

The octahedral complex, [Co^III(HL)]·9H₂O (H₄L = (1,8)-bis(2-hydroxybenzamido)-3,6-diazaoctane) incorporating bis carboxamido-N-, bis sec-NH, phenolate, and phenol coordination has been synthesized and characterized by analytical, NMR (¹H, ¹³C), e.s.i.-Mass, UV–vis, i.r., and Raman spectroscopy. The formation of the complex has also been confirmed by its single crystal X-ray structure. The cyclic voltammetry of the sample in DMF ([TEAP] = 0.1 mol dm⁻³, TEAP = tetraethylammonium perchlorate) displayed irreversible redox processes, [Co^III(HL)] → [Co^IV(HL)]⁺ and [Co^III(HL)] → [Co^II(HL)]⁻ at 0.41 and −1.09 V (versus SCE), respectively. A slow and H⁺ mediated isomerisation was observed for the protonated complex, [Co^III(H₂L)]⁺ (pK = 3.5, 25 °C, I = 0.5 mol dm⁻³). H₂Asc was an efficient reductant for the complex and the reaction involved outer sphere mechanism; the propensity of different species for intra molecular reduction followed the sequence: [{[Co^III(HL)],(H₂Asc)}–H]⁻ <<< {[Co^III(H₂L)],(H₂Asc)}⁺ < {[Co^III(HL)],(H₂Asc)}. A low value (ca. 3.7 × 10⁻¹⁰ dm³ mol⁻¹ s⁻¹, 25 °C, I = 0.5 mol dm⁻³) for the self exchange rate constant of the couple [Co^III(HL)]/[Co^II(HL)]⁻ indicated that the ligand HL³⁻ with amido (N-) donor offers substantial stability to the Co^III state. HSO₃⁻ and [Co^III(HL)] formed an outer sphere complex {[Co^III(HL)],(HSO₃⁻)}, which was slowly transformed to an inner sphere S-bonded sulfito complex, [Co^III(H₂L)(HSO₃)] and the latter was inert to reduction by external sulfite but underwent intramolecular S^IV → Co^III electron transfer very slowly. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Tautomerism of quinazolin-4-ones with 2,3-annulated hydrogenated 1,3-diazaheterocycles. Synchronous and asynchronous double proton transfer in cyclic hydrogen-bonded associates

It was shown by quantum chemical methods and ¹H NMR spectroscopy that in the series of prototropic tautomeric quinazolin-4-ones with hydrogenated 1,3-diazaheterocycles annulated at positions 2 and 3, namely, imidazole, pyrimidine, or [1,3]diazepine (compounds 1–3, respectively), the 1H-tautomeric form strongly predominates in the gas phase and in solutions regardless of the nature of these cycles. Tautomerization of tricycles 1–3 occurs via the intermolecular mechanism to form as intermediates hydrogen-bonded cyclodimers of these compounds or their cyclosolvates with proton-donor solvents. The key step of the reaction is the intraassociated concerted double proton transfer, which can proceed in nearly synchronous and asynchronous modes. In particular, double proton transfer in cyclodimers of quinazolinones 1–3 is asynchronous and proceeds with the formation of solvate-stabilized polar transition states, which are similar in structure to ionic intermediates of the nonconcerted double proton transfer.     

Crystal structure and strong antiferromagnetic interaction of a terephthalate-bridged binuclear copper(II) Complex, [{Cu(dipn)}2(μ-TPHA)](ClO4)2 (dipn = N-(3-aminopropyl)-1,3-propanediamine)

Three binuclear copper(II) complexes bridged by three different bridging ligands: μ-TPHA (terephthalato), μ-PHTA (phthalato) and μ-TCB (tetracarboxylatobenzene) have been synthesized. The crystal structure of [{Cu(dipn)}₂(μ-TPHA)](ClO₄)₂ where dipn = N-(3-aminopropyl)-1,3-propanediamine was solved at room temperature. The [{Cudipn}₂(μ-TPHA)](ClO₄)₂ complex consists of a μ-terephthalato bridging binuclear copper(II) cationic unit and two non-coordinated perchlorate anions. The TPHA ligand bridges in a bismonodentate fashion. The environment of the copper(II) ion is a distorted plane-square-planar coordination sphere. The magnetic properties of the three complexes have been investigated in the 75–300 K range, and show that the geometry of the Cu^II atom is the important factor for magnetic interactions in the terephthalato bridging binuclear copper(II) complexes. This revised version was published online in June 2006 with corrections to the Cover Date.     

Synthesis, crystal structure and magnetic property of the novel dinuclear nickel(II) complex with 4-(p-methoxyphenyl)-3,5-bis(pyridine-2-yl)-1,2,4-triazole

A novel dinuclear nickel(II) complex, [Ni₂(MOBPT)₂Cl₂(H₂O)₂]Cl₂ · 7H₂O (MOBPT = 4-(p-methoxyphenyl) −3,5-bis(pyridine-2-yl)-1,2,4-triazole), has been synthesized and characterized by elemental analysis, IR and single crystal X-ray diffraction methods. The crystal structure determination shows that the dinuclear Ni₂N₈ unit is almost planer in which each Ni^II ion is coordinated by four nitrogen atoms from MOBPT equatorially and a water molecule and a chloride ion axially in a distorted octahedral geometry. Magnetic measurements reveal a relatively weak antiferromagnetic exchange in the complex.     

Structural and aromatic aspects for tautomerism of (Z)-6-((4-bromophenylamino)methylene)-2,3-dihydroxycyclohexa-2,4-dienone

The molecular and crystal structure of (Z)-6-((4-bromophenylamino)methylene)-2,3-dihydroxycyclohexa-2,4-dienone were determined by single crystal X-ray diffraction and spectroscopic methods. Molecules of the compound can be regarded as a resonance hybrid of cis-keto tautomer and zwitterionic form. Pairs of molecules of the compound generate pseudocyclic centrosymmetric R₂² (10) R_{2}^{2} (10) supramolecular synthons with the aid of O–H···O type intermolecular H-bonds. Stacking of R₂² (10) R_{2}^{2} (10) synthons along b-axis is stabilized by π···π interactions. Changes in both covalent topology and molecular geometry of the compound accompanying proton transfer were monitored by a relaxed PES scan with respect to hydroxyl bond length used as redundant internal coordinate. Quantum chemical studies at 6-311 + G(d,p) level reveal that bond lengths which are indicative to tautomerization process cannot reach their expected values even if proton transfer occurs in gas phase and pseudo-aromatic chelate ring formation has primary effect on the stabilization of NH tautomer. Resonance-assisted intramolecular H-bond affects the electronic state of its neighboring aromatic fragments.     

Chelating, bridging, and chain structures within Ag(I) and Cu(I) complexes of bis(nicotinyloxy), bis(isonicotinyloxy), and bis(pyrimidine-5-carboxyloxy)-1,8-disubstituted anthraquinone ligands

Reaction of Ag(I) and Cu(I) [M(NCCH₃)₄]X (X = BF₄⁻ and PF₆⁻) salts with 1,8-bis(nicotinyloxy)anthracene-9,10-dione (1), 1,8-bis(isonicotinyloxy)anthracene-9,10-dione (2), and 1,8-bis(pyrimidine-5-carboxyloxy)anthracene-9,10-dione (3), yield new chelating and bridging complexes and two new coordination polymers. The bridging capabilities of ligands 1 and 2 have not been demonstrated before, and ligand 1, by itself, has the flexibility to produce either chelated or bridged structures and an unusual ladder coordination polymer. The tetradentate ligand 3 also produces a one-dimensional coordination polymer in the presence of one equivalent of Ag(I). All complexes have been characterized by X-ray crystallography.     

Femtosecond dynamics of intramolecular photoinduced proton transfer in <Emphasis Type="Italic">N</Emphasis>-substituted 2-(2-aminophenyl)-4H-3,1-benzoxazin-4-ones

Femtosecond dynamics of processes in the excited state of 2-(2-aminophenyl)-4H-3,1-benzoxazin-4-ones has been studied by femtosecond absorption spectroscopy. The rate constants of intramolecular photoinduced proton transfer (IPPT) have been determined for the N-substituted derivatives (0.7–11 ps⁻¹). The IPPT rate constant depends on the inductive constant of the substituent and the potential barrier height, which was calculated by a quantum-chemical method (TDDFT). The multiexponential character of the kinetics of photoinduced absorption by the compounds with a low inductive constant of the N-substituent in the spectral region of the S₁ → S_N absorption and the stimulated emission of the IPPT product is explained by the rapid (∼10 ps⁻¹) relaxation process preceding the IPPT.     

Synthesis and characterization of Cu(II) and Ni(II) complexes of some 4-bromo- N -(di(alkyl/aryl)carbamothioyl) benzamide derivatives

4-Bromo-N-(di-R-carbamothioyl)benzamide (R = methyl, ethyl, n-propyl, n-butyl and phenyl) ligands and their Ni(II) and Cu(II) complexes have been synthesized and characterized by elemental analyses, FT-IR and ¹H-NMR spectroscopy. The crystal and molecular structure of bis(4-bromo-N-(di-n-propylcarbamothioyl)benzamido)nickel(II) has been determined from single crystal X-ray diffraction data. It crystallizes in the triclinic, space group P 1, Z = 2 with a = 9.286(2) Å, b = 13.215(3) Å, c = 14.125(3) Å, α = 64.180(5)°, β = 85.483(6)°, γ = 83.067(5)°, V = 1548.3(7) ų and D _Calcd = 1.594 mg m^?3. Loss of the N–H proton resonance and the N–H stretching vibration and the shift of the ν _C=O and ν _C=S stretching vibrations confirm formation of the metal complexes. These studies have shown that the metal complexes are neutral cis-[ML₂].     

Tin(II) Phthalocyaninate and Tin(IV) bis-Phthaloc Yaninate: A Quantum Chemical Study

The structural parameters of tin(II) phthalocyaninate PcSn and tin(IV) bis-phthalocyaninate Pc₂Sn as well as of their cations are determined by B3LYP/SDD and PBE0/SDD quantum chemical methods. The PcSn molecule is characterized by C_4v symmetry, and SnN bond lengths are 2.307/2.299 ? (B3LYP/PBE0). The Sn nucleus is by 1.11 ? (B3LYP, PBE0, single crystal X-ray diffraction analysis) higher than the plane of four neighboring nitrogen nuclei. The “hindered” configuration (D _4d symmetry) with a high (27–30 kcal/mole) internal rotation barrier corresponds to the Pc₂Sn energy minimum. The calculated equilibrium lengths of eight equivalent SnN bonds of 2.366/2.347 (B3LYP/PBE0) are similar to the average SnN bond length of 2.347 ? (single crystal X-ray diffraction). Vertical and adiabatic ionization potentials are calculated: I^v 6.40/6.48 eV, I^A 6.38/6.45 eV for PcSn and I^v 5.63/5.66 eV, I^A 5.60/5.63 eV for Pc₂Sn.     

Crystal structure of [Pd(NH3)4][Rh(NH3)(NO2)5]

An XRD analysis is used to study the single crystal of [Pd(NH₃)₄][Rh(NH₃)(NO₂)₅] double complex salt at T = 150(2) K. Crystallographic characteristics are as follows: a = 7.6458(5) ?, b = 9.8813(6) ?, c = 9.5788(7) ?, β = 109.469(2)°, V = 682.30(8) ?³, P2₁/m space group, Z = 2, d _x = 2.553 g/cm³. The geometry of the complex [Rh(NH₃)(NO₂)₅]²⁻ anion is described for the first time: Rh-N(NO₂) distances are 2.020(4)–2.060(3) ?, Rh-N(NH₃) 2.074(4) ?, N(NO₂)-Rh-N(NH₃) trans-angle is 178.8(2)°.     

Mn2+掺杂准二维钙钛矿(PEA)2PbyMn1-yBr4的制备及其电致发光性能

制备了具有高荧光量子产率(photoluminescence quantum yield,PLQY)的Mn²⁺掺杂准二维钙钛矿(PEA)₂Pb_yMn_1-yBr₄(PEA为苯乙胺,y为Pb²⁺占Mn²⁺和Pb²⁺总含量的物质的量分数)薄膜。宽带隙的(PEA)₂PbBr₄作为给体,掺杂杂质Mn²⁺作为受体,构筑了双发射的激发态传递系统。通过调控Mn²⁺掺杂的不同比例对(PEA)₂Pb_yMn_1-yBr₄的发光性能和薄膜形貌的影响,发现当前驱体溶液中Mn²⁺与Pb²⁺的物质的量之比为1∶4时,薄膜有着最高的PLQY和最低的表面粗糙度。利用飞秒瞬态吸收(transient absorption,TA)光谱,追踪其动力学过程,发现主客体之间的激发态传递是通过电荷转移来实现的。为了研究材料的电致发光特性,我们将(PEA)₂Pb_yMn_1-yBr₄作为活性层,加工得到了发光二极管(light emitting diodes,LEDs)。在室温下,器件发出明亮的橙色,其最高的发光强度为0.21 cd·m^-2,外量子效率(external quantum efficiency,EQE)为0.002 5%。     

Microwave synthesis and photoluminescent properties of Sr2CeO4/Ln3+ (Ln = Er, Ho, Tm)

Sr₂CeO₄/Ln³⁺ (Ln = Er, Ho, Tm) phosphors were synthesized with the microwave radiation method for the first time. The luminescent properties of the samples were investigated and the up-conversion luminescence of Er³⁺, Ho³⁺ and Tm³⁺ doped Sr₂CeO₄ phosphors was observed. The spectra indicate that the energy transfer takes place from the triplet excited state of MLCT (metal-to-ligand charge transfer) state for Sr₂CeO₄ (sensitizer) to the rare earth ions (activator). __________ Translated from Journal of Hebei Normal University (Natural Science Edition), 2007, 31(2): 212–216 [译自: 河北师范大学学报 (自然科学版)]     

Synthesis, crystal structures and properties of the novel mononuclear copper(II) and tetranuclear cobalt(II) complexes with 3,6-bis-(3,5-dimethylpyrazolyl)-pyridazine

A novel monomer copper(II) complex [Cu(L)₂(SCN)] · ClO₄ (1) and a tetranuclear cobalt(II) complex [Co₄(L)₄(N₃)₄](OH)₄ · 2H₂O (2)(L = 3,6-bis-(3,5-dimethylpyrazolyl)-pyridazine) have been synthesized and structurally characterized. Single crystal X-ray analyses show that the Cu(II) atom is in a distorted trigonal bipyramidal coordinated environment consisting of four N atoms of L and one N atom of SCN⁻ in complex (1), and the monomer is extended to a 1D chain by the weak intermolecular π...π stacking interactions. In the complex (2), four Co(II) atoms are linked by four bridging azido groups in μ-1,1-N₃ (end-on) coordination mode to form a tetranuclear configuration. The fungicidal activity of the title compounds have been studied, and the results show that there are certain activities against several bacteria for the complexes and the ligand. Furthermore, two complexes exhibit blue emission fluoresce in the solid state at room temperature.