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The pathways to the formation of the series of [RuCl2(CO)2(ERR′)2] (E = S, Se, Te; R, R′ = Me, Ph) complexes from [RuCl2(CO)3]2 and ERR′ have been explored experimentally in THF and CH2Cl2, and computationally by PBE0-D3/def2-TZVP calculations. The end-products and some reaction intermediates have been isolated and identified by NMR spectroscopy, and their crystal structures have been determined by X-ray diffraction. The relative stabilities of the [RuCl2(CO)2(ERR′)2] isomers follow the order cct > ccc > tcc > ttt ≈ ctc (the terms c/t refer to cis/trans arrangement of the ligands in the order of Cl, CO, and ERR′). The yields were rather similar in both solvents, but the reactions were significantly faster in THF than in CH2Cl2. The highest yields were observed for the telluroether complexes, and the yields decreased with lighter chalcogenoethers. PBE0-D3/def2-TZVP calculations indicated that the reaction path is independent of the nature of the solvent. The substitution of one CO ligand of the intermediate [RuCl2(CO)3(ERR′)] by the second ERR′ shows the highest activation barrier and is the rate-determining step in all reactions. The observed faster reaction rate in THF than in CH2Cl2 upon reflux can therefore be explained by the higher boiling point of THF. At room temperature the reactions in both solvents proceed equally slowly. When the reaction is carried out in THF, the formation of [RuCl2(CO)3(THF)] is also observed, and the reaction may proceed with the substitution of THF by ERR′. The formation of the THF complex, however, is not necessary for the dissociation of the [RuCl2(CO)3]2. Thermal energy at room temperature is sufficient to cleave one of the bridging Ru–Cl bonds. The intermediate thus formed undergoes a facile reaction with ERR′. This mechanism is viable also in non-coordinating CH2Cl2. peerReviewed

The nature of C–I⋯⁻O–N⁺ interactions, first of its kind, between non-fluorinated tetraiodoethylene XB-donor and pyridine N-oxides (PyNO) are studied by single-crystal X-ray diffraction (SCXRD) and Density Functional Theory (DFT) calculations. Despite the non-fluorinated nature of the C2I4, the I⋯O halogen bond distances are similar to well-known perfluorohaloalkane/-arene donor-PyNO analogues. With C2I4, oxygens of the N-oxides adopt exclusively 2-XB-coordination in contrast to the versatile bonding modes observed with perfluorinated XB-donors. The C2I4 as the XB donor forms with PyNO’s one-dimensional chain polymer structures in which the C2I4⋯(μ-PyNO)2⋯C2I4 segments manifesting two bonding motifs, namely, side-by-side (vicinal di-iodo) and head-to-head (geminal di-iodo), due to the nearly symmetric square planar structure of the C2I4. While the attractive nature between I- and O-atoms is mainly electrostatic, the narrow range of C⋯O bond parameters demonstrate that the -bond between four iodine atoms also plays an important role in enhancing the -hole strength. DFT-based monodentate XB interaction energies, ΔEint, in thirteen 1:1 XB complexes vary between 31.9 – 46.5 kJ mol–1, the strongest remarkably exceeding the value reported for I–I⋯⁻O–N⁺ = 42.0 kJ mol–1. In case of C2I4･(pyridine N-oxide) [31.9 kJ mol–1], the monodentate XB energy is on a par with perfluorinated donor complexes, namely, CF3I･(pyridine N-oxide) [31.1 kJ mol–1] and C6F5I･(pyridine N-oxide) [32.3 kJ mol–1]. peerReviewed

The Te⋅⋅⋅Te secondary bonding interactions (SBIs) in solid cyclic telluroethers were explored by preparing and structurally characterizing a series of [Te(CH₂)ₘ]ₙ (n=1–4; m=3–7) species. The SBIs in 1,7‐Te₂(CH₂)₁₀, 1,8‐Te₂(CH₂)₁₂, 1,5,9‐Te₃(CH₂)₉, 1,8,15‐Te₃(CH₂)₁₈, 1,7,13,19‐Te₄(CH₂)₂₀, 1,8,15,22‐Te₄(CH₂)₂₄ and 1,9,17,25‐Te₄(CH₂)₂₈ lead to tubular packing of the molecules, as has been observed previously for related thio‐ and selenoether rings. The nature of the intermolecular interactions was explored by solid‐state PBE0‐D3/pob‐TZVP calculations involving periodic boundary conditions. The molecular packing in 1,7,13,19‐Te₄(CH₂)₂₀, 1,8,15,22‐Te₄(CH₂)₂₄ and 1,9,17,25‐Te₄(CH₂)₂₈ forms infinite shafts. The electron densities at bond critical points indicate a narrow range of Te⋅⋅⋅Te bond orders of 0.12–0.14. The formation of the shafts can be rationalized by frontier orbital overlap and charge transfer.

The molecular recognition of nine quaternary alkyl- and aryl-ammonium halides (Bn) by two different receptors, Calkyl-tetrasodiumsulfonatomethyleneresorcinarene (An), were studied in solution using 1H NMR spectroscopy. Substitution of methylenesulfonate groups at 2-positions of resorcinol units resulted in an increase of cavity depth by ∼2.80 Å and a narrow cavity aperture compared to Calkyl-2-H-resorcinarenes. The effect of alkyl chain lengths on the endo-complexation, that is the ability to incorporate other than N-methyl chains inside the cavities, were investigated using ammonium cations of the type ⁺NH2(R1)(R2), (R1 = Me, Et, Bu, R2 = Bu, Ph, Bz ). The C−H⋯ interactions between guests and hosts are the key driving forces for 14 out of 16 observed endo-complexes. In case of N-butyl-N-benzylammonium cation, the hydrogen bonding between -NH2 and sulfonate oxygens and the larger size hamper the N-butyl and N-benzyl groups from entering the host cavity. Association constants derived from isothermal calorimetry titrations confirm 1:1 host-guest complexes highlighting guest affinity, based on size and orientation. X-Ray crystallographic analysis revealed two types of complexes viz sodium-containing co-crystals, [(An)4⁻･m(Bn)⁺･qNa⁺], and sodium-free, [(An)4⁻･4(Bn)⁺]. Both types accommodate (Bn⁺) guests in their cavities. The N-methylated heterocycle guests and host form capsule-like structures in which the two-halves were joined by O−Na coordination bonds and self-assembles in to 2-D polymeric sheets. From the crystal structures, different conformations of methylenesulfonate groups with respect to cavity arising due to tetrahedral geometry of methylene linker were observed. Density Functional Theory (DFT) computations were used to analyze the effects of endo-guests on host conformations and to estimate the relative strengths of host-guest interactions. peerReviewed

The Te…Te secondary bonding interactions (SBI) in solid heterocyclic telluroethers were explored by preparing and structurally characterizing a series of [Te(CH2)m]n (n = 1‐4; m = 3‐7) species. The SBIs in 1,7‐Te2(CH2)10, 1,8‐Te2(CH2)12, 1,5,9‐Te3(CH2)9, 1,8,15‐Te3(CH2)18, 1,7,13,19‐Te4(CH2)20, 1,8,15,22‐Te4(CH2)24, and 1,9,17,25‐Te4(CH2)28 led to the tubular packing of the molecules, as has been observed previously for related thio‐ and selenoether rings. The nature of the intermolecular interactions was explored by solid‐state PBE0‐D3/pob‐TZVP calculations involving periodic boundary conditions. The packing of molecules in 1,7,13,19‐Te4(CH2)20, 1,8,15,22‐Te4(CH2)24, and 1,9,17,25‐Te4(CH2)28 form infinite shafts. The electron densities at bond critical points indicate a narrow range of Te…Te bond orders of 0.12‐0.14. The formation of the shafts can be rationalized by frontier orbital overlap and charge‐transfer. peerReviewed

2D-spectroscopy in astronomy is defined as a technique where a spatially resolved electromagnetic spectrum is obtained over a two-dimensional field. In this paper the very basic principles of spectroscopy are briefly covered starting from the single slit concept via the Huygens principle and the Fraunhofer diffraction. The basic concept of a grating-based spectrograph is described. The connection between observed spectra, the chemical footprints and the underlying physical properties of the systems are briefly covered. The main IFU techniques used in the field of integral field spectroscopy are introduced. The basic ideas on how the data from the observed targets are produced and the wanted physical properties from the data are recovered are discussed. The work demonstrates the usage of 2D-spectroscopic data and its usefulness. The decay in the velocity dispersion profiles in the near central regions of galaxies known as sigma-drop is briefly introduced and a sample of 13 galaxies hosting a possible sigma-drop is analyzed via elliptical apertures. The radial profiles of each galaxy are extracted from given 2D-data connected to the kinematics of the sample galaxies. The radial profiles are then graphically presented with kinematic maps corresponding to the rotation velocity, the velocity dispersion, h₄ and h₃ profiles of the galaxy. Here the h₄ and h₃ are the amplitudes of the Gauss-Hermite series corresponding to the symmetric and asymmetric deviation from a Gaussian. The sample consists of only barred galaxies which could indicate star formation caused sigma-drops due to the bar-driven inflow of the gas to the central regions of the galaxies. Well-defined dust lanes are seen in ~70% of the sample showing a possible relation between the dust and the sigma-drops. There is no direct connection observed between the sigma-drops and the sizes of the galaxies.

[TiCp2S5] (phase A), [TiCp2Se5] (phase F), and five solid solutions of mixed titanocene selenide sulfides [TiCp2SexS5−x] (Cp = C5H5−) with the initial Se:S ranging from 1:4 to 4:1 (phases B–E) were prepared by reduction of elemental sulfur or selenium or their mixtures by lithium triethylhydridoborate in thf followed by the treatment with titanocene dichloride [TiCp2Cl2]. Their 77Se and 13C NMR spectra were recorded from the CS2 solution. The definite assignment of the 77Se NMR spectra was based on the PBE0/def2-TZVPP calculations of the 77Se chemical shifts and is supported by 13C NMR spectra of the samples. The following complexes in varying ratios were identified in the CS2 solutions of the phases B–E: [TiCp2Se5] (51), [TiCp2Se4S] (41), [TiCp2Se3S2] (31), [TiCp2SSe3S] (36), [TiCp2SSe2S2] (25), [TiCp2SSeS3] (12), and [TiCp2S5] (01). The disorder scheme in the chalcogen atom positions of the phases B–E observed upon crystal structure determinations is consistent with the spectral assignment. The enthalpies of formation calculated for all twenty [TiCp2SexS5−x] (x = 0–5) at DLPNO-CCSD(T)/CBS level including corrections for core-valence correlation and scalar relativistic, as well as spin-orbit coupling contributions indicated that within a given chemical composition, the isomers of most favourable enthalpy of formation were those, which were observed by 77Se and 13C NMR spectroscopy.