X-ray structure,spectroscopic characterisation and DFT calculations of the [Re(CO)3(2,2′-biquinoline)Cl] complex

The fac-[Re(CO)₃(2,2′-biquinoline)Cl] complex has been obtained in reaction of Re(CO)₅Cl with 2,2′-biquinoline. The compound has been studied by IR, UV–Vis spectroscopy and X-ray crystallography. The molecular orbital diagram of the tricarbonyl has been calculated with the density functional theory (DFT) method. The spin-allowed singlet–singlet electronic transitions of [Re(CO)₃(2,2′-biquinoline)Cl] have been calculated with the time-dependent DFT method, and the UV–Vis spectrum of the title compound has been discussed on this basis.     

Novel Re(I) tricarbonyl complexes of chelating ligands with aromatic N-heterocycle ring and aliphatic amine donor - Synthesis, spectroscopic characterization, X-ray structure and DFT calculations

Three novel tricarbonyl rhenium(I) complexes of chelating ligands with aromatic N-heterocycle ring and aliphatic amine donor (2-aminomethylpyridine (ampy), 2-(2-aminophenyl)-1H-benzimidazole (apbi) and 2-(2-aminophenyl)benzothiazole (apbt)) have been synthesized and characterized. The compounds [Re(CO)₃(ampy)Cl] (1), [Re(CO)₃(apbi)Cl] (2) and [Re(CO)₃(apbt)Cl] (3) have been identified by IR, UV-Vis spectroscopy and X-ray analysis. The experimental studies on the complexes 1, 2 and 3 have been accompanied computationally by the density functional theory (DFT) calculations.     

A novel tricarbonyl rhenium complex of 2-benzoylpyridine - Synthesis, spectroscopic characterization, X-ray structure and DFT calculations

The reaction of Re(CO)₅Cl with 2-benzoylpyridine (bopy) has been examined and a novel Re(CO)₃⁺ tricarbonyl - fac-[Re(CO)₃(bopy)Cl] - has been obtained. The compound has been studied by IR, UV-Vis spectroscopy and X-ray crystallography. The molecular orbital diagram of the tricarbonyl has been calculated with the density functional theory (DFT) method. The spin-allowed singlet-singlet electronic transitions of [Re(CO)₃(bopy)Cl] have been calculated with the time-dependent DFT method, and the UV-Vis spectrum of the title compound has been discussed on this basis.     

Tricarbonyl rhenium complexes of bis(pyrazol-1-yl)methane and bis(3,5-dimethylpyrazol-1-yl)methane – Synthesis,spectroscopic characterization,X-ray structure and DFT calculations

Two novel tricarbonyl rhenium complexes based on the bidentate heterocyclic N–N ligands [bis(pyrazol-1-yl)methane(bpzm) and bis(3,5-dimethylpyrazol-1-yl)methane(bdmpzm)] have been synthesized by heating at reflux [Re(CO)₅Cl] with the appropriate N–N ligand in toluene. The compounds have been characterized by IR and UV–Vis spectroscopy and X-ray analysis. Density functional theory (DFT) and time-dependent (TD) DFT calculations have been carried out for the [Re(CO)₃(bdmpzm)Cl] complex.     

Novel tricarbonyl rhenium complexes of 5,8-quinolinedione derivatives - Synthesis, spectroscopic characterisation, X-ray structure and DFT calculations

The molecular structure of 7-acetamido-2-methyl-quinoline-5,8-dione has been determined and the reactivity of 7-acetamido-2-methyl-quinoline-5,8-dione (1) and 6-acetamido-2-methyl-quinoline-5,8-dione (2) towards Re(CO)₅Cl has been examined. Two novel tricarbonyl rhenium complexes, fac-[Re(CO)₃(7-acetamido-2-methyl-quinoline-5,8-dione)Cl]·CHCl₃ (3·CHCl₃) and fac-[Re(CO)₃(6-acetamido-2-methyl-quinoline-5,8-dione)Cl]₂·CHCl₃ (4·CHCl₃), have been synthesized and characterized spectroscopically and structurally. The electronic spectrum of 3 was investigated at the TDDFT level employing B3LYP functional in combination with LANL2DZ.     

Synthesis, spectroscopic characterization, X-ray structure and DFT calculations of [ReOCl2(8-Sqn)(OPPh3)]

The reaction of [ReOCl₃(PPh₃)₂] with 8-quinolinethiol (8-HSqn) has been examined, and the [ReOCl₂(8-Sqn)(OPPh₃)] complex has been obtained. It was characterized by IR, UV–Vis spectroscopy and single crystal X-ray analysis. The nature of the frontier orbitals and the electronic transitions involved in the absorption spectrum have been studied by means of the density functional and time-dependent density functional methods.     

Coordination chemistry of di-2-pyridylketone. Synthesis, spectroscopic investigations, X-ray studies and DFT calculations of Re(III) and Re(V) complexes

The paper presents a combined experimental and computational study of Re(III) and Re(V) complexes containing di-2-pyridylketone and its gem-diol form – [ReCl₃(dpk-N,O)(PPh₃)] (1), [ReCl₃(dpk-N,N′)(OPPh₃)] (2) and [ReOBr₃(dpk-OH)]·2(dpkH⁺Br⁻) (3). All the complexes have been characterized spectroscopically and structurally (by single-crystal X-ray diffraction). The complex 2 has been additionally studied by magnetic measurement. The magnetic behavior of 2 is characteristic of mononuclear octahedral Re(III) complex with d⁴ low-spin (³T_1g ground state) and arise because of the large spin–orbit coupling (ζ = 2500 cm⁻¹), which gives diamagnetic ground state. DFT and time-dependent (TD)DFT calculations have been carried out for [ReCl₃(dpk-N,N′)(OPPh₃)] and [ReOBr₃(dpk-OH), and their UV–vis spectra have been discussed on this basis.     

Design,Synthesis and Biological Evaluation of [1,2,4]Triazolo[1,5-a]pyrimidine Indole Derivatives against Gastric Cancer Cells MGC-803 via the Suppression of ERK Signaling Pathway

[1,2,4]Triazolo[1,5-a]pyrimidine and indole skeletons are widely used to design anticancer agents. Therefore, in this work, a series of [1,2,4]triazolo[1,5-a]pyrimidine indole derivatives were designed and synthesized by the molecular hybridization strategy. The antiproliferative activities of the target compounds H1–H18 against three human cancer cell lines, MGC-803, HCT-116 and MCF-7, were tested. Among them, compound H12 exhibited the most active antiproliferative activities against MGC-803, HCT-116 and MCF-7 cells, with IC₅₀ values of 9.47, 9.58 and 13.1 μM, respectively, which were more potent than that of the positive drug 5-Fu. In addition, compound H12 could dose-dependently inhibit the growth and colony formation of MGC-803 cells. Compound H12 exhibited significant inhibitory effects on the ERK signaling pathway, resulting in the decreased phosphorylation levels of ERK1/2, c-Raf, MEK1/2 and AKT. Furthermore, compound 12 induced cell apoptosis and G2/M phase arrest, and regulated cell cycle-related and apoptosis-related proteins in MGC-803 cells. Taken together, we report here that [1,2,4]triazolo[1,5-a]pyrimidine indole derivatives, used as anticancer agents via the suppression of ERK signaling pathway and the most active compound, H12, might be a valuable hit compound for the development of anticancer agents.     

Synthesis, X-ray studies, spectroscopic characterization and DFT calculations of p-tolylimido rhenium(V) complexes bearing an imidazole-based ligand

Novel p-tolylimido rhenium(V) complexes [Re(p-NC₆H₄CH₃)X₂(hpb)(PPh₃)] and [Re(p-NC₆H₄CH₃)(hpb)₂(PPh₃)]X (X = Cl, Br) have been obtained in the reactions of [Re(p-NC₆H₄CH₃)X₃(PPh₃)₂] with 2-(2-hydroxyphenyl)-1H-benzimidazole (Hhpb). The compounds were identified by elemental analysis IR, UV-Vis spectroscopy and X-ray crystallography. The electronic structures of the complex [Re(p-NC₆H₄CH₃)Cl₂(hpb)(PPh₃)] and the cation [Re(p-NC₆H₄CH₃)(hpb)₂(PPh₃)]⁺ have been calculated with the density functional theory (DFT) method. Additional information about binding in the [Re(p-NC₆H₄CH₃)Cl₂(hpb)(PPh₃)] and [Re(p-NC₆H₄CH₃)(hpb)₂(PPh₃)]⁺ has been obtained by NBO analysis. The electronic spectra of [Re(p-NC₆H₄CH₃)Cl₂(hpb)(PPh₃)] and [Re(p-NC₆H₄CH₃)(hpb)₂(PPh₃)]Cl were investigated at the TDDFT level employing B3LYP functional in combination with LANL2DZ.     

Copper(I)-Catalyzed Tandem Cyclization/Condensation Reaction to Novel 4,5-Dihydropyrazolo[1,5-a]quinolines and Pyrazolo[1,5-a]indoles

A facile copper(I)-catalyzed tandem reaction for the synthesis of 4,5-dihydropyrazolo[1,5-a]quinolines and pyrazolo[1,5-a]indoles is reported here. High efficiency and good yields are displayed in this transformation under mild reaction conditions.      

Synthesis,spectroscopic investigation,structural characterization and DFT calculation of the complexes [ReX2(N2COPh)(4-PhPyr)(PPh3)2] (X = Cl, Br)

The reactions of [ReX₂(η²-N₂COPh-N′,O)(PPh₃)₂] with 4-phenylpyrimidine have been performed. As a result, the two complexes [ReX₂(N₂COPh)(4-PhPyr)(PPh₃)₂] (X = Cl, Br) (4-PhPyr = 4-phenylpyrimidine), isostructural in the solid state, have been obtained. The crystal and molecular structures of ([ReCl₂(N₂COPh)(4-PhPyr)(PPh₃)₂])₂·CHCl₃ (1) and ([ReBr₂(N₂COPh)(4-PhPyr)(PPh₃)₂])₂·CHCl₃ (2) have been determined. The electronic structure of [ReCl₂(N₂COPh)(4-PhPyr)(PPh₃)₂] has been examined using the density functional theory (DFT) method. The spin-allowed electronic transitions of 1 have been calculated with the time-dependent DFT method, and the UV–Vis spectrum of [ReCl₂(N₂COPh)(4-PhPyr)(PPh₃)₂] has been discussed on this basis.     

Synthesis,spectroscopic characterization,crystal and molecular structure of [ReOBr(hmquin-7-COOH)2] and [ReOCl(hmquin-7-COOH)2] · MeCN complexes. DFT and TD-DFT calculations for [ReOBr(hmquin-7-COOH)2]

Novel [ReOBr(hmquin-7-COOH)₂] (1) and [ReOCl(hmquin-7-COOH)₂] · MeCN (2 · MeCN) complexes have been prepared by treatment of [ReOX₃(AsPh₃)₂] with an excess of 8-hydroxy-2-methylquinoline-7-carboxylic acid in acetonitrile. The compounds were characterized structurally and spectroscopically. The electronic structure of 1 has been calculated with the density functional theory (DFT) method, and additional information about binding has been obtained by NBO analysis. The UV–Vis spectrum of 1 has been discussed on the basis of TDDFT calculations.     

Synthesis,spectroscopic characterisation,crystal and molecular structure of [ReOBr(quin-2-c)2] and [ReOCl(quin-2-c)2] complexes: DFT and TD-DFT calculations for [ReOBr(quin-2-c)2]

Novel [ReOX(quin-2-c)₂] complexes (X = Cl, Br; quin-2-c = quinoline-2-carboxylate ion) have been prepared by treatment of [ReOX₃(AsPh₃)₂] with an excess of quinoline-2-carboxylic acid in acetonitrile. The complexes were characterised structurally and spectroscopically. The electronic structure of [ReOBr(quin-2-c)₂] has been calculated with the density functional theory (DFT) method, and additional information about binding has been obtained by NBO analysis. The UV–Vis spectrum of [ReOBr(quin-2-c)₂] has been discussed on the basis of TD-DFT calculations.     

New oxorhenium complexes with the 8-quinolinolato ligand: X-ray structure and DFT calculations for [ReOBr(hqn)2]

The reactions of [ReO(OEt)X₂(PPh₃)₂] (X = Cl or Br) with 8-hydroxyquinoline (Hhqn) have been examined and the [ReOX(hqn)₂] complexes have been obtained. The crystal and molecular structures of [ReOBr(hqn)₂] have been determined. The electronic structure of [ReOBr(hqn)₂] has been calculated with the density functional theory (DFT) method, and additional information about binding in the ReO³⁺ unit has been obtained by NBO analysis. The spin-allowed electronic transitions of [ReOBr(hqn)₂] have been calculated with the time-dependent DFT method, and the UV–Vis spectra of the [ReOX(hqn)₂] compounds have been discussed on this basis.     

Molecular and crystal structure of 5,7-diphenyl-7-methyl-4,7-dihydro-1,2,4-triazolo[1,5-a]pyrimidine

The molecular and crystal structures of 5,7-diphenyl-7-methyi-4,7-dihydro-1,2,4-triazolo[1,5-a]pyrimidine have been studied by X-ray structural methods. The crystal is monoclinic,a=16.112(3),b=13.489(3),c=14.480(3)Å, =101.62(2)°,Z=8, space groupC2/c,R=0.071. The presence of short intermolecular contacts indicates considerable steric strain in the molecule. The dihydropyrimidine ring exists in an unevenly planar boat conformation. Increasing the steric strain of the dihydrocycle leads to a twisted conformation.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 1912–1914, November, 1993.     

Synthesis,spectroscopic characterization,X-ray structure and DFT calculations of rhenium(III) complex with 1-isoquinolinyl phenyl ketone

The [ReCl₃(MeCN)(PPh₃)] complex reacts with 1-isoquinolinyl phenyl ketone (N–O) to give [ReCl₃(N–O)(PPh₃)]. The compound has been studied by IR, UV–Vis spectroscopy, magnetic measurements and X-ray crystallography. The magnetic behavior is characteristic of mononuclear octahedral Re(III) complex with d⁴ low-spin (³T_1g ground state) and arises because of the large spin–orbit coupling, which gives diamagnetic ground state. The molecular orbital diagram of [ReCl₃(N–O)(PPh₃)] has been calculated with the density functional theory (DFT) method, and time-dependent DFT (TD-DFT) calculations have been employed in order to discussion of its spectroscopic properties in more detail.     

Coordination studies of 5,6-diphenyl-3-(2-pyridyl)-1,2,4-triazine towards Cu cation. X-ray studies,spectroscopic characterization and DFT calculations

The reactions of 5,6-diphenyl-3-(2-pyridyl)-1,2,4-triazine with CuCl₂ · 2H₂O, Cu(NO₃)₂ · 3H₂O and CuSO₄ · 5H₂O have been examined, and four [CuCl₂(dppt)] (1), [CuCl₂(dppt)₂] · 2MeOH (2), [Cu(dppt)₂(H₂O)₂](NO₃)₂ (3) and [Cu(SO₄)(dppt)(H₂O)]_n · nH₂O (4) complexes have been obtained. All the complexes have been structurally and spectroscopically characterized, and compound 4 has been additionally studied by magnetic measurements. The electronic structure of 1 has been calculated with the density functional theory (DFT) method, and the time-dependent DFT calculations have been employed to calculate the electronic spectrum of 1.     

Seven-coordinate rhenium(III) complexes of 1-(2-pyridylazo)-2-naphtholate: X-ray studies,spectroscopic characterization and DFT calculations

The reactions of [ReX₃(MeCN)(PPh₃)₂] (X = Cl or Br) with 1-(2-pyridylazo)-2-naphthol (HPAN) have been examined and the [ReBr(PAN)₂] · 2CHCl₃ (1) and [ReCl(PAN)₂] (2) complexes have been obtained. The both complexes have been structurally and spectroscopically characterized, and compound 1 has been additionally studied by magnetic measurements. The magnetic behavior is characteristic of mononuclear seven-coordinated Re(III) complex with d⁴ low-spin configuration, which gives diamagnetic ground state.     

Novel rhenium(III) complexes with the picolinate ligand: Synthesis,spectroscopic investigations,X-ray structures and DFT calculations for [ReX2(pic)(PPh3)2] complexes

The paper presents a combined experimental and computational study of novel rhenium(III) complexes with the picolinate ligand – [ReCl₂(pic)(PPh₃)₂] (1) and [ReBr₂(pic)(PPh₃)₂] (2). Both complexes 1 and 2 have been characterised spectroscopically and structurally (by single-crystal X-ray diffraction). Complex 1 has been additionally studied by magnetic measurement. The magnetic behavior is characteristic of a mononuclear d⁴ low-spin octahedral Re(III) complex (³T_1g ground state) and arises because of the large spin–orbit coupling (ζ = 2500 cm⁻¹), which gives a diamagnetic ground state. DFT and time-dependent (TD)DFT calculations have been carried out for complex 1, and UV–vis spectra of the [ReX₂(pic)(PPh₃)₂] compounds have been discussed on this basis.