DFT study on some polythiophenes containing benzo[d]thiazole and benzo[d]oxazole: structure and band gap.

The content of this paper focuses/shed light on the effects of X (X = S in P1 and X = O in P2) in C11H7NSX and R (R = H in P3, R = OCH3 in P4, and R = Cl in P5) in C18H9ON2S2-R on structural features and band gaps of the polythiophenes containing benzo[d]thiazole and benzo[d]oxazole by the Density Function Theory (DFT) method/calculation. The structural features including the electronic structure lattice constant (a), shape, total energy (Etot) per cell, and link length (r), are measured via band gap (Eg) prediction with the package of country density (PDOS) and total country density (DOS) of material studio software. The results obtained showed that the link angle and the link length between atoms were not changed significantly while the Etot was decreased from Etot = - 1904 eV (in P1) to Etot = - 2548 eV (in P2) when replacing O with S; and the Etot of P3 was decreased from Etot = - 3348 eV (in P3) when replacing OCH3, Cl on H of P3 corresponding to Etot = - 3575 eV (P4), - 4264 eV (P5). Similarly, when replacing O in P1 with - S to form P2, the Eg of P1 was dropped from Eg = 0.621 eV to Eg = 0.239 eV for P2. The Eg of P3, P4, and P5 is Eg = 0.006 eV, 0.064 eV, and 0.0645 eV, respectively. When a benzo[d]thiazole was added in P1 (changing into P3), the Eg was extremely strongly decreased, nearly 100 times (from Eg = 0.621 eV to Eg = 0.006 eV). The obtained results serve as a basis for future experimental work and used to fabricate smart electronic device.

Crystal structure of potassium hydrogen bis-((E)-2-{4-[3-(thio-phen-3-yl)acrylo-yl]phen-oxy}acetate).

The synthesis and spectroscopic data of (E)-2-{4-[3-(thio-phen-3-yl)acrylo-yl]phen-oxy}acetic acid are described. Crystallization from an ethanol-water mixture resulted in the title compound, C30H23KO8S2 or [K(C15H11O4S)(C15H12O4S)] n , containing one mol-ecule of the acid and one mol-ecule of the potassium salt in the asymmetric unit. Both mol-ecules share the H atom between their carboxyl groups and a potassium ion. The C=C bonds display an E configuration. The thio-phene and phenyl rings in the two mol-ecules are inclined by 43.3 (2) and 22.7 (2)°. The potassium ion is octa-hedrally coordinated by six O atoms. This distorted octa-hedron shares on opposite sides two oxygen atoms with inversion-related octa-hedra, resulting in chains of octa-hedra running in the [010] direction, which form ladder-like chains by C-H⋯π inter-actions. A Hirshfeld surface analysis indicates that the highest contributions to the surface contacts arise from inter-actions in which H atoms are involved, with the most important contribution being from H⋯H (31.6 and 31.9% for the two mol-ecules) inter-actions.

DFT Prediction of Factors Affecting the Structural Characteristics, the Transition Temperature and the Electronic Density of Some New Conjugated Polymers.

Conjugated polymers are promising materials for various cutting-edge technologies, especially for organic conducting materials and in the energy field. In this work, we have synthesized a new conjugated polymer and investigated the effect of distance between bond layers, side-chain functional groups (H, Br, OH, OCH3 and OC2H5) on structural characteristics, phase transition temperature (T), and electrical structure of C13H8OS using Density Functional Theory (DFT). The structural characteristics were determined by the shape, network constant (a, b and c), bond length (C-C, C-H, C-O, C-S, C-Br and O-H), phase transition temperatures, and the total energy (Etot) on a base cell. Our finding shows that the increase of layer thickness (h) of C13H8OS-H has a negligible effect on the transition temperature, while the energy bandgap (Eg) increases from 1.646 eV to 1.675 eV. The calculation of bond length with different side chain groups was carried out for which C13H8OS-H has C-H = 1.09 Å; C13H8OS-Br has C-Br = 1.93 Å; C13H8OS-OH has C-O = 1.36 Å, O-H = 0.78 Å; C13H8OS-OCH3 has C-O = 1.44 Å, O-H =1.10 Å; C13H8OS-OC2H5 has C-O = 1.45 Å, C-C = 1.51Å, C-H = 1.10 Å. The transition temperature (T) for C13H8OS-H was 500 K < T < 562 K; C13H8OS-Br was 442 K < T < 512 K; C13H8OS-OH was 487 K < T < 543 K; C13H8OS-OCH3 was 492 K < T < 558 K; and C13H8OS-OC2H5 was 492 K < T < 572 K. The energy bandgap (Eg) of Br is of Eg = 1.621 eV, the doping of side chain groups H, OH, OCH3, and OC2H5, leads to an increase of Eg from 1.621 eV to 1.646, 1.697, 1.920, and 2.04 eV, respectively.

Synthesis, crystal structure and Hirshfeld surface analysis of diethyl 2,6-dimethyl-4-(thio-phen-3-yl)-1,4-di-hydro-pyridine-3,5-di-carboxyl-ate.

In the title compound, C17H21NO4S, the 1,4-di-hydro-pyridine ring has an envelope conformation with the Csp 3 atom at the flap. The thio-phene ring is nearly perpendicular to the best plane through the 1,4-di-hydro-pyridine ring, the dihedral angle being 82.19 (13)°. In the crystal, chains running along the b-axis direction are formed through N-H⋯O inter-actions between the 1,4-di-hydro-pyridine N atom and one of the O atoms of the ester groups. Neighbouring chains are linked by C-H⋯O and C-H⋯π inter-actions. A Hirshfeld surface analysis shows that the most prominent contributuion to the surface contacts are H⋯H contacts (55.1%).

Some chalcones derived from thio-phene-3-carbaldehyde: synthesis and crystal structures.

The synthesis, spectroscopic data and crystal and mol-ecular structures of four 3-(3-phenyl-prop-1-ene-3-one-1-yl)thio-phene derivatives, namely 1-(4-hydroxy-phen-yl)-3-(thio-phen-3-yl)prop-1-en-3-one, C13H10O2S, (1), 1-(4-meth-oxy-phen-yl)-3-(thio-phen-3-yl)prop-1-en-3-one, C14H12O2S, (2), 1-(4-eth-oxy-phen-yl)-3-(thio-phen-3-yl)prop-1-en-3-one, C15H14O2S, (3), and 1-(4--bromophen-yl)-3-(thio-phen-3-yl)prop-1-en-3-one, C13H9BrOS, (4), are described. The four chalcones have been synthesized by reaction of thio-phene-3-carbaldehyde with an aceto-phenone derivative in an absolute ethanol solution containing potassium hydroxide, and differ in the substituent at the para position of the phenyl ring: -OH for 1, -OCH3 for 2, -OCH2CH3 for 3 and -Br for 4. The thio-phene ring in 4 was found to be disordered over two orientations with occupancies 0.702 (4) and 0.298 (4). The configuration about the C=C bond is E. The thio-phene and phenyl rings are inclined by 4.73 (12) for 1, 12.36 (11) for 2, 17.44 (11) for 3 and 46.1 (6) and 48.6 (6)° for 4, indicating that the -OH derivative is almost planar and the -Br derivative deviates the most from planarity. However, the substituent has no real influence on the bond distances in the α,ß-unsaturated carbonyl moiety. The mol-ecular packing of 1 features chain formation in the a-axis direction by O-H⋯O contacts. In the case of 2 and 3, the packing is characterized by dimer formation through C-H⋯O inter-actions. In addition, C-H⋯π(thio-phene) inter-actions in 2 and C-H⋯S(thio-phene) inter-actions in 3 contribute to the three-dimensional architecture. The presence of C-H⋯π(thio-phene) contacts in the crystal of 4 results in chain formation in the c-axis direction. The Hirshfeld surface analysis shows that for all four derivatives, the highest contribution to surface contacts arises from contacts in which H atoms are involved.

Crystal structure of two N'-(1-phenyl-benzyl-idene)-2-(thio-phen-3-yl)acetohydrazides.

The synthesis, spectroscopic data, crystal and mol-ecular structures of two N'-(1-phenyl-benzyl-idene)-2-(thio-phen-3-yl)acetohydrazides, namely N'-[1-(4-hy-droxy-phen-yl)benzyl-idene]-2-(thio-phen-3-yl)acetohydrazide, C13H10N2O2S, (3a), and N'-[1-(4-meth-oxy-phen-yl)benzyl-idene]-2-(thio-phen-3-yl)acetohydrazide, C14H14N2O2S, (3b), are described. Both compounds differ in the substituent at the para position of the phenyl ring: -OH for (3a) and -OCH3 for (3b). In (3a), the thio-phene ring is disordered over two orientations with occupancies of 0.762 (3) and 0.238 (3). The configuration about the C=N bond is E. The thio-phene and phenyl rings are inclined by 84.0 (3) and 87.0 (9)° for the major- and minor-occupancy disorder components in (3a), and by 85.89 (12)° in (3b). Although these dihedral angles are similar, the conformation of the linker between the two rings is different [the C-C-C-N torsion angle is -ac for (3a) and -sc for (3b), while the C6-C7-N9-N10 torsion angle is +ap for (3a) and -sp for (3b)]. A common feature in the crystal packing of (3a) and (3b) is the presence of N-H⋯O hydrogen bonds, resulting in the formation of chains of mol-ecules running along the b-axis direction in the case of (3a), or inversion dimers for (3b). The most prominent contributions to the surface contacts are those in which H atoms are involved, as confirmed by an analysis of the Hirshfeld surface.