The mol-ecule of the title compound, C(22)H(18)N(4)O(2)S(2), lies across a crystallographic inversion centre. The mol-ecule adopts a syn-anti configuration with respect to the positions of the carbonyl groups and terminal phenyl rings relative to the thione S atom across the C-N bond. There are two intra-molecular N-H⋯O and C-H⋯S hydrogen bonds within each molecule, resulting in the formation of four six-membered S(6) rings. The central and terminal rings make a dihedral angle of 13.55 (15)°. In the crystal, mol-ecules are linked by inter-molecular C-H⋯S hydrogen bonds, forming R(2) (2)(14) rings and resulting in zigzag chains.
Bis(dithiolene) tungsten carbonyl complex, W(S2C2Ph2)2(CO)2 was successfully synthesized and the structure, frontier molecular orbital and optical properties of the complex were investigated theoretically using density functional theory calculations. The investigation started with a molecular structure construction, followed by an optimization of the structural geometry using generalized-gradient approximation (GGA) in a double numeric plus polarization (DNP) basis set at three different functional calculation approaches. Vibrational frequency analysis was used to confirm the optimized geometry of two possible conformations of [W(S2C2Ph2)2(CO)2], which showed distorted octahedral geometry. Electronic structure and optical characterization were done on the ground states. Metal to ligand and ligand to metal charge transfer were dominant in this system.
In the title compound, C(16)H(16)N(2)OS, the conformation at the two partially double C-N bonds of the thio-urea unit is E. The amide group is twisted relative to the thio-urea fragment, forming a dihedral angle of 62.44 (16)°, and the two phenyl rings form a dihedral angle 75.93 (18)°. In the crystal, mol-ecules are linked by N-H⋯S hydrogen bonds, forming centrosymmetric dimers.
IN THE TITLE COMPOUND [SYSTEMATIC NAME: 1-(3-phenyl-prop-2-eno-yl)thio-urea], C(10)H(10)N(2)OS, the acetyl-thio-urea fragment and the phenyl ring adopt an E configuration. The roughly planar but-2-enoyl-thio-urea fragment [maximum deviation = 0.053 (3) Å] forms a dihedral of 10.54 (11)° with the phenyl ring. An intra-molecular N-H⋯O hydrogen bond generates an S(6) ring. In the crystal, mol-ecules are linked into sheets parallel to (100) by N-H⋯S hydrogen bonds.
In the title compound, C(14)H(16)N(2)O(3)S, the phenyl ring and the ethyl 2-(3-formyl-thio-ureido)acetate fragment adopt an E configuration with respect to the C=C bond. An intra-molecular N-H⋯O hydrogen bond generating an S(6) ring motif is observed. In the crystal, mol-ecules are linked by N-H⋯S, C-H⋯S and C-H⋯O hydrogen bonds, forming sheets lying parallel to the ab plane.
In the title compound, C(13)H(14)N(2)O(3)S, the methyl 2-(3-formyl-thio-ureido)acetate fragment and the phenyl ring adopt an E configuration. The mol-ecule exhibits an intra-molecular N-H⋯O hydrogen bond, which completes a six-membered ring. The crystal packing is stabilized by inter-molecular N-H⋯S contacts, generating a two-dimensional hydrogen-bonding network.
In the title compound, C(11)H(12)N(2)O(3)S, the methyl acetate and benzoyl groups adopt a cis-trans configuration with respect to the thiono S atom across the C-N bonds. An intra-molecular N-H⋯O hydrogen bond is observed. In the crystal packing, mol-ecules are linked by inter-molecular N-H⋯S and C-H⋯O hydrogen bonds to form a two-dimensional network lying parallel to (101).
In the title compound, C(14)H(18)N(2)O(3)S, the butyl acetate fragment and the benzoyl group adopt a cis-trans configuration, respectively, with respect to the thiono S atom across the C-N bonds. In the crystal packing, the mol-ecules are linked by inter-molecular N-H⋯O and C-H⋯O hydrogen bonds to form a one-dimensional chain along the c axis. The terminal butyl C atom is disordered with occupancies 0.82 (2)and 0.18 (2).
The title compound, C(13)H(16)N(2)O(3)S, is a thio-urea derivative with benzoyl and propoxycarbonyl-methyl groups attached to the two terminal N atoms. These groups adopt trans and cis configurations, respectively, with respect to the S atom across the thio-urea C-N bonds. The compound crystallizes in the P2(1)/c space group with Z = 8, resulting in two unique molecules in the asymmetric unit linked by C-H⋯S and C-H⋯O hydrogen bonds, forming a one-dimensional zigzag chain along the c axis.
The title compound, C(12)H(14)N(2)O(3)S, adopts a cis-trans geometry of the thio-urea group and is stabilized by intra-molecular hydrogen bonds between the carbonyl O atoms and the H atom of the thio-amide group and by a C-H⋯S interaction. Mol-ecules are linked by two inter-molecular hydrogen bonds (C-H⋯O and N-H⋯O), forming a one-dimensional chain parallel to the c axis.
The mol-ecule of the title compound, C(22)H(18)N(4)O(2)S(2), lies across a crystallographic inversion centre. The central benzene ring forms dihedral angles of 29.39 (9) and 79.11 (12)°, respectively, with the thio-urea unit and the terminal phenyl ring. Intra-molecular N-H⋯O hydrogen bonds generate two S(6) ring motifs. In the crystal, mol-ecules are linked into chains along [10] by inter-molecular N-H⋯S hydrogen bonds.
In the title compound, C(14)H(12)N(2)O(2)S, the amino-phenol and the benzoyl groups adopt a syn-anti configuration with respect to the thiono C=S group across the thio-urea C-N. The dihedral angle between the mean planes of the benzoyl and hy-droxy-phenyl rings is 36.77 (8)°. The mol-ecules are stabilized by intra-molecular N-H⋯O hydrogen bonds. In the crystal, weak inter-molecular C-H⋯O, O-H⋯S and N-H⋯O hydrogen bonds link the mol-ecules into a chain along the c axis.
In the title compound, C(13)H(16)N(2)OS, the piperidine ring exhibit a classical chair conformation. In the crystal, the mol-ecules are linked by N-H⋯O hydrogen bonds, forming zigzag chains running parallel to the c axis.
The crystal and molecular structures of two ReI tricarbonyl complexes, namely fac-tricarbonylchlorido[1-(4-fluorocinnamoyl)-3-(pyridin-2-yl-κN)pyrazole-κN2]rhenium(I), [ReCl(C17H12FN3O)(CO)3], (I), and fac-tricarbonylchlorido[1-(4-nitrocinnamoyl)-3-(pyridin-2-yl-κN)pyrazole-κN2]rhenium(I) acetone monosolvate, [ReCl(C17H12ClN4O3)(CO)3]·C3H6O, (II), are reported. The complexes form centrosymmetric dimers that are linked into one-dimensional columns by C-H...Cl and N-O...H interactions in (I) and (II), respectively. C-H...Cl interactions in (II) generate two R21(7) loops that merge into a single R21(10) loop. These interactions involve the alkene, pyrazole and benzene rings, hence restricting the ligand rotation and giving rise to a planar conformation. Unlike (II), complex (I) exhibits a twisted conformation of the ligand and a pair of molecules forms a centrosymmetric dimer with an R22(10) loop via C-H...O interactions. The unique supramolecular structures of (I) and (II) are determined by their planarity and weak interactions. The planar conformation of (II) provides a base for appreciable π-π stacking interactions compared to (I). In addition, an N-O...π interaction stabilizes the supramolecular structure of (II). We report herein the first n→π* interactions of ReI tricarbonyl complexes, which account for 0.33 kJ mol-1. Intermolecular C-H...Cl and C-H...O interactions are present in both complexes, with (II) showing a greater preference for these interactions compared to (I), with cumulative contributions of 48.7 and 41.5%, respectively. The influence of inductive (fluoro) and/or resonance (nitro) effects on the π-stacking ability was further supported by LOLIPOP (localized orbital locator-integrated π over plane) analysis. The benzene ring of (II) demonstrated a higher π-stacking ability compared to that of (I), which is supported by the intrinsic planar geometry. The HOMA (harmonic oscillator model of aromaticity) index of (I) revealed more aromaticity with respect to (II), suggesting that NO2 greatly perturbed the aromaticity. The Hirshfeld fingerprint (FP) plots revealed the preference of (II) over (I) for π-π contacts, with contributions of 6.8 and 4.4%, respectively.
This work presents an interpretation of the origin of changes in absorption spectra upon one-electron oxidation and reduction of two ruthenium polypyridyl complexes based on a combination of UV-Vis spectroelectrochemical experiments and theoretical calculations using the Gaussian 09 program. A bis-chelating ligand containing a p-bromobenzoylthiourea unit connected to 1,10-phenanthroline (phen-p-BrBT) has been prepared. Complexation of phen-p-BrBT to ruthenium bis-diimine centres, Ru(N-N)2 [N-N = 2,2'-bipyridine (bpy) or 1,10-phenanthroline (phen)], affords octahedral Ru(ii) tris-diimine complexes that are synthesised and structurally characterised. The two complexes exhibit similar MLCT bands and electronic energy levels owing to the similar electronic structures of the bpy and phen ligands. However, [Ru(phen)2(phen-p-BrBT)]2+ exhibits a slightly broader visible region MLCT (metal-to-ligand-charge transfer) band than [Ru(bpy)2(phen-p-BrBT)]2+ as expected from a slightly more delocalised π-electron system in the phen diimine ligands. In addition, the π → π* absorption in the UV is blue-shifted for [Ru(phen)2(phen-p-BrBT)]2+ relative to that for [Ru(bpy)2(phen-p-BrBT)]2+, because of greater stabilisation of the bpy HOMO relative to that of phen. The extra C-C bond in phen produces greater delocalisation of electron density leading to a blue-shift in the π → π* transition. The MLCT band is blue-shifted and diminished in intensity upon oxidation due to stabilisation of the Ru d-orbitals by removal of one electron. A new broad absorption band appears in the UV region upon reduction. The new transition is attributed to a blue-shift of the first MLCT transition for [Ru(bpy)2(phen-p-BrBT)]2+ and a red-shift of the second MLCT transition for [Ru(phen)2(phen-p-BrBT)]2+. The new transitions originate from destabilisation or stabilisation of the ligand LUMO orbitals relative to the Ru d-orbitals. A red-shift of the UV band in the initial complex also contributes to the new band produced upon reduction of [Ru(bpy)2(phen-p-BrBT)]2+. The new band does not involve an n(C[double bond, length as m-dash]S) → π* transition. Although both complexes show subtle differences in behaviour, their spectral changes are distinct, and the origin of changes in their absorption spectra upon oxidation and reduction is successfully interpreted.
An absorbance-based sensor employing ruthenium bipyridyl with a phenanthroline-fused benzoylthiourea moiety formulated as [Ru(ii)(bpy)2(phen-nBT)](PF6)2 {bpy = 2,2'-bipyridine, phen = 1,10-phenanthroline, nBT = n-benzoylthiourea} has been synthesized and characterized by elemental analyses, mass spectrometry, and infrared, ultraviolet-visible, luminescence and nuclear magnetic resonance spectroscopy. The changes in the intensity of absorption and emission of the complex induced by functionalization of the benzoylthiourea ligands with amino and carbonyl in their protonated and deprotonated forms were studied experimentally. The absorption and emission properties of the complex exhibit a strong dependence on the pH (1-11) of the aqueous medium. This work highlights the pH-sensitivity augmentation of the absorption band by elongating the conjugation length in the structure of the ruthenium bipyridine complex. The principle of this work was to design the title compound to be capable of enhancing the differences in the absorption sensitivity responses towards pH between the protonated and deprotonated complexes in the absorption measurement. Along with significant and noticeable changes in the absorption spectra, subsequent theoretical investigations specifically on the electronic and absorbance properties of the title compound were carried out in this study. Protonation of the molecule significantly stabilized the lowest-unoccupied molecular orbital (LUMO), whereas the highest-occupied molecular orbital (HOMO) is greatly destabilized upon deprotonation. A time-dependent density functional theory (TDDFT) calculation in the linear-response (-LR) regime was performed to clarify the origin of the experimentally observed linear dependence of absorption intensity upon pH (1-11). The MLCT band exhibits hyperchromic shift at low pH as indicated by the large transition dipole moment and a wider distribution of the response charge of the molecule, which is induced by the stabilization of the electrostatic potential at the carbonyl moiety by protonation. This study provides the possibility of employing theoretical information to gain insight into the origin of the optical absorption obtained experimentally. The ruthenium complex was designed with an elongated ligand conjugation length and exhibited a tremendously large change in the absorption intensity of the protonated and deprotonated forms, which therefore demonstrates its feasibility as an indicator molecule especially for absorbance measurements.
The title compound, C15H14N2O3, crystallizes with two independent mol-ecules (A and B) in the asymmetric unit that differ in the orientation of the 3-meth-oxy-phenyl group with respect to the methyl-idenebenzohydrazide unit. The dihedral angles between the two benzene rings are 24.02 (10) and 29.30 (9)° in mol-ecules A and B, respectively. In mol-ecule A, the meth-oxy group is twisted slightly relative to its bound benzene ring, with a Cmeth-yl-O-C-C torsion angle of 14.2 (3)°, whereas it is almost co-planar in mol-ecule B, where the corresponding angle is -2.4 (3)°. In the crystal, the mol-ecules are linked by N-H⋯O, O-H⋯N and O-H⋯O hydrogen bonds, as well as by weak C-H⋯O inter-actions, forming sheets parallel to the bc plane. The N-H⋯O hydrogen bond and weak C-H⋯O inter-action link different mol-ecules (A⋯B) whereas both O-H⋯N and O-H⋯O hydrogen bonds link like mol-ecules (A⋯A) and (B⋯B). Pairs of inversion-related B mol-ecules are stacked approximately along the a axis by π-π inter-actions in which the distance between the centroids of the 3-meth-oxy-phenyl rings is 3.5388 (12) Å. The B mol-ecules also participate in weak C-H⋯π inter-actions between the 4-hy-droxy-phenyl and the 3-meth-oxy-phenyl rings.
A new homoleptic dithiolene tungsten complex, tris-{1,2-bis(3,5-dimethoxyphenyl)-1,2-ethylenodithiolene-S,S'}tungsten, was successfully synthesized via a reaction of the thiophosphate ester and sodium tungstate. The thiophosphate ester was prepared from 3,5-dimethoxybenzaldehyde via benzoin condensation to produce the intermediate 1,2-bis-(3,5-dimethoxyphenyl)-2-hydroxy-ethanone compound, followed by a reaction of the intermediate with phosphorus pentasulfide. FTIR, UV-Vis spectroscopy, 1H NMR and 13C NMR and elemental analysis confirmed the product as tris{1,2-bis-(3,5-dimethoxyphenyl)-1,2-ethylenodithiolene-S,S'}tungsten with the molecular formula of C54H54O12S6W. Crystals of the product adopted a monoclinic system with space group of P2(1)/n, where a=12.756(2) Å, b=21.560(3) Å, c=24.980(4) Å and β=103.998(3)°. Three thioester ligands were attached to the tungsten as bidentate chelates to form a distorted octahedral geometry. Density functional theory calculations were performed to investigate the molecular properties in a generalized-gradient approximation framework system using Perdew-Burke-Ernzerhof functions and a double numeric plus polarization basis set. The HOMO was concentrated on the phenyl ligands, while the LUMO was found along the W(S2C2)3 rings. The theoretical optical properties showed a slight blue shift in several low dielectric solvents. The solvatochromism effect was insignificant for high polar solvents.
In the title compound, C13H16N2O2S, the pyrrolidine ring has a twisted conformation on the central -CH2-CH2- bond. Its mean plane is inclined to the 4-meth-oxy-benzoyl ring by 72.79 (15)°. In the crystal, mol-ecules are linked by N-H⋯O and C-H⋯O hydrogen bonds to the same O-atom acceptor, forming chains along [001]. The chains are linked via slipped parallel π-π inter-actions [inter-centroid distance = 3.7578 (13) Å], forming undulating slabs parallel to (100).
The presence of Ti3+ in the structure of TiO2 nanotube arrays (NTs) has been shown to enhance the photoelectrochemical (PEC) water-splitting performance of these NTs, leading to improved results compared to pristine anatase TiO2 NTs. To further improve the properties related to PEC performance, we successfully produced TiO2 NTs using a two-step electrochemical anodization technique, followed by annealing at a temperature of 450 °C. Subsequently, Mo2C was decorated onto the NTs by dip coating them with precursors at varying concentrations and times. The presence of anatase TiO2 and Ti3O5 phases within the TiO2 NTs was confirmed through X-ray diffraction (XRD) analysis. The TiO2 NTs that were decorated with Mo2C demonstrated a photocurrent density of approximately 1.4 mA cm-2, a value that is approximately five times greater than the photocurrent density exhibited by the bare TiO2 NTs, which was approximately 0.21 mA cm-2. The observed increase in photocurrent density can be ascribed to the incorporation of Mo2C as a cocatalyst, which significantly enhances the photocatalytic characteristics of the TiO2 NTs. The successful deposition of Mo2C onto the TiO2 NTs was further corroborated by the characterization techniques utilized. The utilization of field emission scanning electron microscopy (FESEM) allowed for the observation of Mo2C particles on the surface of TiO2 NTs. To validate the composition and optical characteristics of the decorated NTs, X-ray photoelectron spectroscopy (XPS) and UV absorbance analysis were performed. This study introduces a potentially effective method for developing efficient photoelectrodes based on TiO2 for environmentally sustainable hydrogen production through the use of photoelectrochemical water-splitting devices. The utilization of Mo2C as a cocatalyst on TiO2 NTs presents opportunities for the advancement of effective and environmentally friendly photoelectrochemical (PEC) systems.