Synthesis,spectroscopic characterization,crystal and molecular structure of [ReOX2(bopyH)(PPh3)] complexes: DFT calculations for [ReOCl2(bopyH)(PPh3)]

The reactions of [ReOX₃(PPh₃)₂] (X = Cl, Br) with benzoylpyridine (bopy) have been examined and novel [ReOX₂(bopyH)(PPh₃)] oxocompounds have been obtained. The complexes were structurally and spectroscopically characterised. In the both structures two-electron reduced form of benzoylpyridine is coordinated to the central ion. The electronic structure of [ReOCl₂(bopyH)(PPh₃)] 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 the [ReOCl₂(bopyH)(PPh₃)] has been discussed on the basis of TDDFT calculations.     

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.     

Oxorhenium complexes with the 8-quinolinolato ligand. X-ray structure and DFT calculations for [ReOX2(hqn)(AsPh3)] and [ReOX2(hqn)(PPh3)] complexes

The reactions of [ReOX₃(AsPh₃)₂] and [ReOX₃(PPh₃)₂] with 8-hydroxyquinoline (Hhqn) have been examined and the complexes [ReOX₂(hqn)(AsPh₃)] and [ReOX₂(hqn)(PPh₃)] (X = Cl, Br) have been obtained, respectively. The crystal and molecular structures of [ReOCl₂(hqn)(AsPh₃)] (1) and [ReOBr₂(hqn)(PPh₃)] (4) have been determined. The electronic structure of 1 has been calculated with 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 [ReOCl₂(hqn)(AsPh₃)] has been discussed on this basis.     

Oxorhenium(V) complexes with quinoline-2-carboxylate ligand. X-ray structure of [ReOCl2(quin-2-c)(PPh3)] and [ReOBr2(quin-2-c)(AsPh3)] complexes: DFT and TD-DFT calculations for [ReOCl2(quin-2-c)(PPh3)]

Novel [ReOX₂(quin-2-c)(EPh₃)] complexes (X = Cl, Br; E = As, P; quin-2-c = quinoline-2-carboxylate ion) have been prepared by treatment of [ReOX₃(EPh₃)₂] with quinoline-2-carboxylic acid in acetone at room temperature. All the complexes were characterised by IR, UV–Vis spectroscopy and elemental analysis. The crystal and molecular structures have been determined for [ReOCl₂(qiun-2c)(PPh₃)] (1) and [ReOBr₂(qiun-2c)(AsPh₃)] (4). The electronic structure of 1 has been calculated with the density functional theory (DFT) method. The spin-allowed electronic transitions of 1 have been calculated with the time-dependent DFT method.     

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.     

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.     

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.     

Reactivity of [ReOX3(PPh3)2] and [ReOX3(AsPh3)2] towards 2-(2-hydroxyphenyl)-1H-benzimidazole: Synthesis, X-ray studies, spectroscopic characterization and DFT calculations for [ReOX2(hpb)(EPh3)] and [ReO(OMe)(hpb)2]·MeCN

The paper presents a combined experimental and computational study of mono- and disubstituted Re(V) oxocomplexes obtained in the reactions of [ReOX₃(EPh₃)₂] (X = Cl, Br; E = P, As) with 2-(2-hydroxyphenyl)-1H-benzimidazole (Hhpb). From the reactions of [ReOX₃(PPh₃)₂] with Hhpb in molar ratio 1:1 cis and trans stereoisomers of [ReOX₂(hpb)(PPh₃)] were isolated, whereas the [ReOX₃(AsPh₃)₂] oxocompounds react with Hhpb to give only cis-halide isomers. The [ReOX₂(hpb)(EPh₃)] and [ReO(OMe)(hpb)₂]·MeCN complexes have been characterized spectroscopically and structurally (by single-crystal X-ray diffraction). The DFT and TDDFT calculations have been carried out for the trans-[ReOBr₂(hpb)(PPh₃)], cis-[ReOBr₂(hpb)(AsPh₃)] and [ReO(OMe)(hpb)₂], and their UV–Vis spectra have been discussed on this basis.     

Syntheses, structures and DFT study of [W(CO)5(Ph2SbX)] X = Cl, Br, I

The complexes [W(CO)₅(Ph₂SbX)], X = Cl (1), Br (2) and I (3) were prepared by reaction of [W(CO)₅(tetrahydrofuran)] with Ph₂SbX. The structures of 1-3 were studied by X-ray diffraction. In the crystals there are weak contacts between the oxygen atoms of the CO ligands and antimony atoms of neighbouring molecules. DFT calculations were carried out for 1 using gradient corrected functional B3LYP. The bonding between Ph₂SbCl and the W(CO)₅ fragment in 1 was analysed using charge decomposition analysis.     

New oxorhenium complexes with 2-(2′-hydroxyphenyl)-2-benzoxazolinato ligand. X-ray structure and DFT calculations for [ReOX2(hbo)(AsPh3)] and [ReOX2(hbo)(PPh3)] complexes

The reactions of [ReOX₃(AsPh₃)₂] and [ReOX₃(PPh₃)₂] with 2-(2′-hydroxyphenyl)-2-benzoxazoline (Hhbo) have been examined and [ReOX₂(hbo)(AsPh₃)] and [ReOX₂(hbo)(PPh₃)] (X = Cl, Br) complexes have been obtained. The crystal and molecular structures of [ReOCl₂(hbo)(AsPh₃)] (1) and [ReOBr₂(hbo)(PPh₃)] (4) have been determined. The electronic structures of 1 and 4 have been calculated with the density functional theory (DFT) method. The spin-allowed electronic transitions of 1 and 4 have been calculated with the time-dependent DFT method, and the UV–Vis spectra of these complexes have been discussed.     

Novel rhenium(III) complexes with 5,6-diphenyl-3-(2-pyridyl)-1,2,4-trazine: X-ray structures and DFT calculations for [ReCl3(OPPh3)(dppt)] and [ReCl3(PPh3)(dppt)] complexes

The reaction of [ReOCl₃(PPh₃)₂] with 5,6-diphenyl-3-(2-pyridyl)-1,2,4-trazine (dppt) has been examined and [ReCl₃(OPPh₃)(dppt)] has been obtained. The triphenylphosphine oxide can be easily replaced by PPh₃ in the reaction of [ReCl₃(OPPh₃)(dppt)] with an excess of triphenylphosphine. The [ReCl₃(OPPh₃)(dppt)] and [ReCl₃(PPh₃)(dppt)] complexes have been structurally and spectroscopically characterized. Their molecular orbital diagrams have been calculated with the density functional theory (DFT) method, and their electronic spectra have been discussed on the basis of time-dependent DFT calculations. The compound [ReCl₃(OPPh₃)(dppt)] has been studied additionally by magnetic measurement. The magnetic behavior is characteristic of mononuclear complexes with d⁴ low-spin octahedral Re(III) complexes (³T_1g ground state) and arise because of the large spin–orbit coupling (ζ = 2500 cm⁻¹), which gives diamagnetic ground state.     

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.     

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.     

Synthesis, spectroscopic characterization, X-ray structure and DFT calculations of [Re(CO)3L2Cl] (L = 1,2,4-triazolo-[1,5-a]pyrimidine)

The paper presents a combined experimental and computational study of novel tricarbonyl complex – fac-[Re(CO)₃(tp)₂Cl] (tp = 1,2,4-triazolo-[1,5-a]pyrimidine). The compound has been characterized spectroscopically and structurally (by single-crystal X-ray diffraction). The absorption and emission spectra of the complex have been discussed on the basis of DFT and time-dependent (TD)DFT calculations.     

Quantum chemical study of ethylene addition to group-7 oxo complexes MO2(CH3)(CH2) (M = Mn, Tc, Re)

Quantum chemical calculations using DFT at the B3LYP level have been carried out for the reaction of ethylene with the group-7 compounds ReO₂(CH₃)(CH₂) (Re1), TcO₂(CH₃)(CH₂) (Tc1) and MnO₂(CH₃)(CH₂) (Mn1). The calculations suggest rather complex scenarios with numerous pathways, where the initial compounds Re1-Mn1 may either engage in cycloaddition reactions or numerous addition reactions with concomitant hydrogen migration. There are also energetically low-lying rearrangements of the starting compounds to isomers which may react with ethylene yielding further products. The [2 + 2]_Re,C cycloaddition reaction of the starting molecule Re1 is kinetically and thermodynamically favored over the [3 + 2]_C,O and [3 + 2]_O,O cycloadditions. However, the reaction which leads to the most stable product takes place with initial rearrangement to the dioxohydridometallacyclopropane isomer Re1a that adds ethylene with concomitant hydrogen migration yielding Re1a-1. The latter reaction has a slightly higher barrier than the [2 + 2]_Re,C cycloaddition reaction. The direct [3 + 2]_C,O cycloaddition becomes more favorable than the [2 + 2]_M,C reaction for the starting compounds Tc1 and Mn1 of the lighter metals technetium and manganese but the calculations predict that other reactions are kinetically and thermodynamically more favorable than the cycloadditions. The reactions with the lowest activation barriers lead after rearrangement to the ethyl substituted dioxometallacyclopropanes Tc1a-1 and Mn1a-1. The manganese compound exhibits an even more complex reaction scenario than the technetium compounds. The thermodynamically most stable final product of ethylene addition to Mn1 is the ethoxy substituted metallacyclopropane Mn1a-2 which has, however, a high activation barrier.     

The reactions of 2-benzoylpyridine with [RuHCl(CO)(PPh3)3] and [(C6H6)RuCl2]2

The reactions of [RuHCl(CO)(PPh₃)₃] and [(C₆H₆)RuCl₂]₂ with 2-benzoylpyridine have been examined, and two novel ruthenium(II) complexes – [RuCl(CO)(PPh₃)₂(C₅H₄NCOO)] and [RuCl₂(C₁₂H₉NO)₂] – have been obtained. The compounds have been studied by IR and UV–Vis spectroscopy, and X-ray crystallography. The molecular orbital diagrams of the complexes have been calculated with the density functional theory (DFT) method. The spin-allowed singlet–singlet electronic transitions of the compounds have been calculated with the time-dependent DFT method, and the UV–Vis spectra of the compounds have been discussed on this basis.     

Synthesis, spectroscopic characterization, X-ray structure, and DFT calculations of [ReOBr2(hmquin-7-COOH)(AsPh3)]

The reaction of [ReOBr₃(AsPh₃)₂] with 8-hydroxy-2-methylquinoline-7-carboxylic acid (Hhmquin-7-COOH) has been examined and the [ReOBr₂(hmquin-7-COOH)(AsPh₃)] 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 density functional and time-dependent density functional calculations.     

Isomerism in tetrahedral rhenium cluster complexes [Re4Q4(PMe2Ph)4X8]·nCH2Cl2 (Q = Se, X = Br; Q = Te, X = Cl, Br)

Three new tetrahedral rhenium cluster compounds [Re₄Se₄(PMe₂Ph)₄Br₈]·1.5CH₂Cl₂ (1), [Re₄Te₄(PMe₂Ph)₄Br₈]·CH₂Cl₂ (2), and [Re₄Te₄(PMe₂Ph)₄Cl₈]·CH₂Cl₂ (3) have been synthesized by the reaction of the corresponding precursor chalcohalide complexes [Re₄Q₄(TeX₂)₄X₈] (X = Br, Q = Se (for 1), Te (for 2); X = Cl, Q = Te (for 3)) with dimethylphenylphosphine in CH₂Cl₂. All compounds have been characterized by X-ray single-crystal diffraction and elemental analyses, IR and ³¹P NMR spectroscopy. ³¹P NMR spectroscopy indicates the formation of isomers in solution, confirmed by single-crystal X-ray analysis.     

Energy decomposition analysis of the metal-oxime bond in [M{RC(NOH)C(NO)R}2] (M = Ni(II), Pd(II), Pt(II), R = CH3, H, F, Cl, Br, Ph, CF3)

Quantum chemical calculations using gradient-corrected DFT at the BP86/TZ2P+ level were carried out for the metal-dioxime complexes [M{RC(NOH)C(NO)R}₂]with M = Ni, Pd, Pt, R = CH₃, H, F, Cl, Br, Ph, CF₃. The nature of the metal-ligand bond was investigated with an energy decomposition analysis (EDA). The complexes with electron donating substituents R = H, CH₃ have the strongest metal-ligand interaction energies ΔE_int, as well as the largest bond dissociation energies. The analysis of the bonding situation revealed that the metal ← ligand σ donation is much stronger than the metal → ligand π backdonation. The breakdown of the orbital interactions into the contributions of orbitals with different symmetry indicates that the donation from the in-plane lone-pair donor-orbitals of nitrogen into the d_xy AO of the metal provides about one half of the stabilization which comes from ΔE_orb. Inspection of the EDA data indicates that the electrostatic term ΔE_elstat is more important for the trend of the metal-oxime interactions in [M{RC(NOH)C(NO)R}₂] than the orbital term ΔE_orb.