Wide band-gap organic molecules containing benzodithiophene and difluoroquinoxaline derivatives for solar cell applications

Abstract

Two new semiconducting organic small molecules, namely BDTQ-BDT(EH) and BDTQ-BDT(OC), were prepared by attaching electron accepting 2,3-didodecyl-6,7-difluoro-5,8-di(thiophen-2-yl)quinoxaline (DTQ) unit on 2,6-position of electron donating 4,8-bis(2-ethylhexyloxy)benzo[1,2-b:4,5-b']dithiophene (BDT(EH)) and 4,8-bis(octyloxy)benzo[1,2-b:4,5-b']dithiophene (BDT(OC)) units. Molecule BDTQ-BDT(EH) showed higher thermal stability (5% weight loss temperature, T_d “349 ^оC), slightly lower band-gap (E_g “2.10?eV) and deeper highest occupied molecular orbital energy level (HOMO “–5.36?eV) level compared to those (T_d “336 ^оC, E_g “2.11?eV, and HOMO “–5.30?eV, respectively.) of the molecule BDTQ-BDT(OC). The organic solar cells (OSCs) made with the synthesized molecules as an electron donor and [6,6]-phenyl C₇₁ butyric acid methyl ester (PC₇₀BM) as an electron acceptor gave a maximum power conversion efficiency (PCE) of 1.20% and 0.83%, respectively, for BDTQ-BDT(EH) and BDTQ-BDT(OC). This study confirmed that the substituents attached on the 4,8-position of BDT unit greatly alter the properties of the resulting molecules.     

Synthesis of A-D-A type quinoxaline-based small molecules for organic photovoltaic cells

Abstract

We have synthesized two acceptor-donor-acceptor (A-D-A) type quinoxaline-based small molecules for organic photovoltaic cells (OPVs). To construct the A-D-A architecture, the electron-accepting quinoxaline derivative (Qx) was attached on both ends of the electron-donating benzodithiophene (BDT) unit via the Stille coupling reaction. After the confirmation of the structural features, the optical and electrochemical characteristics and the photovoltaic properties of the two small molecules were investigated. A typical inverted-type device with the configuration of ITO/ZnO/small molecules: PC₇₁BM/MoO₃/Ag was fabricated and examined. It has been observed that the performances of OPVs were improved by the incorporation of the additional thiophene linkage between the BDT and Qx moieties. Therefore, this study can provide insights into the design and structure–property correlation of quinoxaline-based organic small molecules for OPVs     

Structural,Raman, and photoluminescence properties of double‐shelled coaxial nanocables of In2O3 core with ZnO and AZO shells

We synthesized In₂O₃/ZnO/Al‐doped ZnO (AZO) core‐double shell nanowires, in which the inner shell (ZnO) and the outer shell (AZO) have been subsequently deposited on the core In₂O₃ nanowires. With their one‐dimensional morphology being preserved, the X‐ray diffraction (XRD), lattice‐resolved transmission electron microscopy (TEM) image, selected area electron diffraction, and Raman spectrum coincidentally revealed that the shell was comprised of hexagonal ZnO phase. In addition, TEM‐EDX investigation revealed the presence of Al elements in the shell region. The thermal annealing at 700 °C did not significantly change the nanowire morphology, however, the XRD spectrum indicated that the ZnO phase was crystallized by the annealing. PL spectrum of the 700 °C‐annealed In₂O₃/ZnO/AZO core‐double shell nanowires was comprised of three Gaussian bands at approximately 2.1 eV, 2.4 eV, and 3.0 eV, respectively. The integrated intensities of 2.1 eV‐, 2.4 eV‐, and 3.0 eV‐bands were decreased by the thermal annealing. This study will pave the road to the preparation and applicaition of double‐shelled nanowires. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Co-crystal structures of 2,4-diamino-6-phenyl-1,3,5-triazine – 4-chlorobenzoic acid/4-methoxybenzoic acid: Synthesis,structural and Hirshfeld surface analysis

The co-crystal structure of 2,4-diamino-6-phenyl-1,3,5-triazine with 4-chlorobenzoic acid/4-methoxybenzoic acid molecules are explain the link between the dimension and shape of their hydrogen-bonded assembly. The co-crystal structure of 2,4-diamino-6-phenyl-1,3,5-triazine with 4-chlorobenzoic acid/4-methoxybenzoic acid forming a cyclic R₂²(8) ring motif via N–H?O and O–H?N hydrogen bonding interactions, to form a supramolecular heterosynthon. In both the co-crystal structures, self-association of 2,4-diamino-6-phenyl-1,3,5-triazine moieties are connected via N-H^….N base pairs with cyclic R₂²(8) motif form a supramolecular homosynthon. In co-crystal II, the centrosymmetrically paired methoxy group of 4-methoxy benzoic acid form a supramolecular homosynthon via weak intermolecular C-H^….O hydrogen bonds, generating R₂²(6) ring motif. Both the co-crystal structures are stabilized by weak aromatic π-π and C—Cl???π stacking interactions. Hirshfeld surface and fingerprint plots were used to study the intermolecular interactions both of the crystal structures.     

Reactions of triosmium clusters with indole: X-ray structures of [Os3(CO)10(μ-OH)(μ-OMeCO)] and [Os3(μ-H)(CO)10(μ-1, 2-η2-NC8H6)]

Treatment of [Os₃(CO)₁₂] with indole in presence of a methanolic solution of Me₃NO⋅2H₂O at 60^∘C afforded the previously reported compounds [(μ-H)Os₃(CO)₁₀(μ-OMe)] 2, [(μ-H)Os₃(CO)₁₀(μ-OH)] 3 and [Os₃(CO)₁₀(μ-OH)(μ-OMeCO)] 4 in 10, 5 and 20% yields, respectively. The reaction of [Os₃(CO)₁₀(MeCN)₂] with indole at room temperature gave [(μ-H)Os₃(CO)₁₀(μ-1,2-η²-NC₈H₆)] 5 in 40% yield. Compounds 4 and 5 have been characterized by single crystal X-ray diffraction studies. Compound 4 crystallizes in the monoclinic space group P2(1)/c with a = 23.1239(3), b = 9.8087(4), c = 16.9017(6) ?, β = 92.6998(14)^∘, Z = 8 and V = 3829.3(2) ?³ and 5 crystallizes in the monoclinic space group P2(1)/c with a = 9.009(3), b = 9.764(4), c = 24.906(6) ?, β = 93.452(14)^∘, Z = 4 and V = 2186.9(13) ?³. Compound 4 consists of an open cluster of three osmium atoms with the hydroxy and methoxycarbonyl ligands bridging the open Os–Os edge. Compound 5 consists of an isosceles triangle of osmium atoms with one elongated Os–Os edge which is bridged by the hydride and the indolyl ligands.     

A density functional theory study on multiple exciton generation in lead chalcogenides

Abstract

Quantum confined structure-based solar cell is promising two folds increment of the maximum theoretical photovoltaic conversion efficiency i.e., > 60% in comparison with that of the bulk analogs e.g., silicon-based and dye sensitized solar cell (ca. 32% of maximum theoretical efficiency). The key to the significant increment is the ability of the fluorophore to exhibit multiple exciton generation upon absorption photon with sufficient energy. Small size of lead chalcogenides (PbS, PbSe, PbTe) crystals have been reported and proven experimentally could exhibit this unique property. We have investigated few clusters of narrow bandgap lead chalcogenides nanocrystals i.e., (PbS)n, (PbSe)n and (PbTe)n; which n?=?4 - 80. The cluster models were optimized using quantum chemical calculations to the lowest energy geometry at B3LYP/lanl2dz level of theory. The predicted realistic (PbS)₈₀, (PbSe)₅₀, and (PbTe)₇₄ clusters with the size, and bandgap of 4.58?nm (2.00?eV), 4.03?nm (1.51?eV), and 4.84?nm (1.55?eV) are smaller than that of their exciton Bohr radius i.e., 5.01, 13.1, and 24.8?nm respectively. Therefore, the occurrence of multi exciton generation in the clusters is hypothesized upon absorption of photon with E_photon = 2E_g.     

Properties of ZnO films grown on (0 0 0 1) sapphire substrate using H2O and N2O as O precursors by atmospheric pressure MOCVD

In this paper, we compare the properties of ZnO thin films (0 0 0 1) sapphire substrate using diethylzinc (DEZn) as the Zn precursor and deionized water (H₂O) and nitrous oxide (N₂O) as the O precursors, respectively in the main ZnO layer growth by atmospheric pressure metal–organic chemical vapor deposition (AP-MOCVD) technique. Surface morphology studied by atomic force microscopy (AFM) showed that the N₂O-grown ZnO film had a hexagonal columnar structure with about 8 μm grain diameter and the relatively rougher surface compared to that of H₂O-grown ZnO film. The full-widths at half-maximum (FWHMs) of the (0 0 0 2) and () ω-rocking curves of the N₂O-grown ZnO film by double-crystal X-ray diffractometry (DCXRD) measurement were 260 and 350 arcsec, respectively, indicating the smaller mosaicity and lower dislocation density of the film compared to H₂O-grown ZnO film. Compared to H₂O-grown ZnO film, the free exciton A (FX_A) and its three phonon replicas could be clearly observed, the donor-bound exciton A⁰X (I₁₀):3.353 eV dominated the 10 K photoluminescence (PL) spectrum of N₂O-grown ZnO film and the hydrogen-related donor-bound exciton D⁰X (I₄):3.363 eV was disappeared. The electron mobility (80 cm²/V s) of N₂O-grown ZnO film has been significantly improved by room temperature Hall measurement compared to that of H₂O-grown ZnO film.     

Synthesis of the Copolymer Based on Diketopyrrolopyrrole with Didecyl Chain for OPVs

A new accepter unit, diphenylpyrrolo[3,2-b]pyrrole-2,5-dione with didecyl chain, was prepared and utilized for the synthesis of the conjugated polymer containing electron donor-acceptor pair for OPVs. The iDPP, part of the structure of a natural dye found in lichens, is the regioisomer of the known DPP with switched position of the carbonyl group and nitrogen atom. At the 4-positions of the N-substituted phenyl groups of 1,4-bis(4-butylphenyl)-pyrrolo[3,2-b]-pyrrole-2,5-dione unit in P-butyl, the butyl group was substituted with decyl group to increase solubility. The absorption spectrum of polymer with diphenylpyrrolo[3,2-b]pyrrole-2,5-dione unit exhibit two maximum peaks at about 365 and 542 nm. The spectrum of the P1 as the solid thin film shows absorption band with maximum peaks at 370 and 536 nm, and the absorption onset at 703 nm, corresponding to band gap of 1.76 eV. The oxidation and reduction potential onset of the synthesized polymer were estimated to be 0.84 and ?1.22 V, which correspond to HOMO and LUMO energy levels of ?5.64 and ?3.58 eV, respectively. The devices comprising P1 with PC₆₁BM annealed at 100°C showed a V_OC of 0.79 V, a J_SC of 1.75 mA/cm², and a FF of 0.31, leading to the power conversion efficiency of 0.43% under white light illumination (AM 1.5 G, 100 mW/cm²).     

Network hydrogen bonding in two new cocrystals sustained by 731-1731-1731-1, a tetrahedral hydrogen bond donor

We report details of the synthesis and X-ray crystal structures of two new cocrystals that are sustained by the tetrahedral hydrogen bond donor [Mn(CO)₃(₃-OH)]₄. [Mn(CO)₃(₃-OH)]₄· 2(2,3,5,6-tetramethylpyrazine)·2H₂O·2MeCN,a=21.503(3),b=12.674(1),c=17.318(2), =102.15(2), C2/c,D _calc=1.46 mg/m³,Z=4,4188 observed reflns,R _f=0.047,R _w=0.040; 1.[Mn(CO)₃(₃-OH)]₄·4,4-dipyridyl·2MeCn,a=16.942(6),b=12.395(2),c=18.790(6), =114.88(3), C 2/c,D _calc=1.60 mg/m³,Z=4,2430 observed reflns,R _f=0.043,R _w=0.051;2. 1 crystallizes as a 2-D grid, whereas2 forms 1-D strands. The hydrogen bond patterns exhibited by1 and2 are analyzed in the context of our earlier studies involving [Mn(CO)₃(₃-OH)]₄ and other relevant literature.     

Gap Reduction of C60 and C70 at High Pressure

Abstract

The absorption spectra of the C₆₀ and C₇₀ are measured at pressures up to 19 GPa. The pressure dependence of the fundamental absorption edge position E(P) is determined for both materials. The initial value of dE/dP=?0.15 eV/GPa for the stronger-absorption region of C₆₀ decreases up to ?0.019 eV/GPa at 12 GPa. The weaker-absorption region located near the fundamental absorption edge shifts slower dE/dP=?0.05 eV/GPa. For the C₇₀ the initial value of dE/dP=?0.1 eV/GPa decreases up to ?0.029 eV/GPa at 10 GPa. All pressure induced changes are reversible in this pressure range.     

Enhancement of organic thin-film solar cells by incorporating hybrid Au nanospheres and Au nanorods on a metallic grating surface

Abstract

In this study, we demonstrate the fabrication of hybrid plasmonic solar cells using gold nanoparticles (AuNPs). Two types of AuNPs, gold nanospheres (AuNSs) and gold nanorods (AuNRs), were incorporated in a hole transport layer (HTL) (PEDOT:PSS) on a metallic grating electrode. The organic solar cells (OSCs) structure comprised an indium-tin-oxide (ITO)-coated glass substrate/PEDOT:PSS:AuNSs:AuNRs/P3HT:PCBM/Al grating electrode. Adding AuNPs induced localized surface plasmon resonance (LSPR), while grating structured Al at the interface with a photoactive layer excited the propagating surface plasmons. Compared with a flat reference device, the proposed OSCs exhibited improved photovoltaic properties by increasing both the short-circuit current density (J_SC) and the power conversion efficiency (PCE) with large enhancements of 16.23% and 14.06%, respectively. The efficiency improvement was attributed to increased broadband absorption and improved electrical properties inside the thin-film devices.     

Crystal Structure and Hirshfeld Surface Analysis of Bis(3-thienoyl) Disulfide

The spectroscopic characterization (¹H, ¹³C{¹H} NMR, UV–Vis) and single-crystal X-ray diffraction (scXRD) analysis accomplished by inspection of the Hirshfeld surface of bis(3-thienoyl) disulfide (1) is described. The title compound 1 crystallizes in the monoclinic space group P2₁/n. The unit cell parameters are a?=?7.9959(3) Å, b?=?6.4348(3) Å, c?=?22.4924(9) Å, β?=?100.108(4)°, V?=?1139.32(8) ų, Z?=?4, R_gt(F)?=?0.0278, wR_ref(F²)?=?0.0667. The packing of 1 is dominated by S?O and S?S interactions, giving a 2D layer structure parallel to (101). The X‐ray crystal structure analysis revealed the packing of 1 is dominated by S?O and S?S interactions, giving a 2D layer structure parallel to (101). The intermolecular interactions in 1 were analyzed using the Hirshfeld surface method including 2D fingerprint plots and enrichment ratios (E), which shows that the most favored intermolecular contacts are the O?H and C?S indicated by E values above 1.30. The interaction energies between molecular pairs revealed the importance of the weak O?H and C?S interactions in stabilizing the molecular structure of 1.

Graphic Abstract

Single crystal X-ray structure analysis, DFT calculations and Hirshfeld surface analysis to identify intermolecular interactions within the solid state structure of bis(3-thienoyl) disulfide (1).

     

Morphology,composition, structure and optical properties of thermally annealed Cu2O thin films prepared by reactive DC sputtering method

Abstract

Thin films copper oxides are perspective materials for many optoelectronic applications, including photovoltaics. The samples were deposited on glass and silicon substrates by magnetron sputtering method using Modular Platform PREVAC. After deposition the samples were thermally treated by annealing in oxygen atmosphere for 60?min at 450?°C. Morphology confirms that all the films have crystalline structure. Optical measurements show that the films have wide band gap within the range 2.20÷2.48?eV before and 2.03÷2.40?eV after annealing. The article presents the discussion about the influence of annealing on Cu₂O thin film parameters.     

Stereochemistry of 1,2-oxaphospholanes. Part X. Synthesis,X-ray structure and NMR spectroscopy of (2S*,3R*,5R*)-2-methoxy-3,5-dimethyl-2-oxo-1,2-oxaphospholan-3-ol

The title compound (4a) was synthesized from a phosphite compound obtained from 4-hydroxy-2-pentanone and dimethylphosphorochloridite, after addition of an equivalent of water. Thecis-configuration of the P=O and C3-OH groups was established based on³¹P NMR chemical shifts. In chloroform, as well as in benzene solution, the most favorable conformations of the title compound are ₄ ⁵ T,⁴ E, and ₄ ⁵ T. The crystal and molecular structure of4a has been determined by single-crystal X-ray diffraction data, and refined toR=0.056. The five-membered ring has an envelope⁴ E (C₅) conformation, with the asymmetry parameter C ₅(4)=3.5°. Both the C5-CH₃ and the C3-CH₃ groups are equatorial. In the solid state, the molecules form dimers with hydrogen bonding between the hydroxyl groups and the phosphoryl oxygen atom of an adjacent molecule. A quantitative comparison of the structure of 4a with the structure of the related 2-mcthoxy-3,5,5-trimethyl-2-oxo-1,2-oxaphosphospholan-3-ol is given.     

The molecular structures of three germacrolides related to parthenolide

The germacrolide-class sesquiterpene lactone, 1,10-epoxyparthenolide, C₁₅H₂₀O₄,1, crystallizes with two independent molecules in monoclinic space groupP2₁ witha=10.6845(5),b=9.0763(4),c=15.4326(7) ?, β=105.887(4)°,V=1439.4(3) ?³,Z=4.R=0.037 for 2425 observed data. Its 11βH, 13-dihydro-derivative 1,10-epoxydihydroparthenolide, C₁₅H₂₂O₄,2, crystallizes in orthorhombic space groupP2₁2₁2₁ witha=7.6414(10),b=12.559(2),c=14.6821(14) ?,V=1409.0(3) ?³ Z=4.R=0.031 for 1555 observed data. The corresponding unexposidized compound, 11βH,13-dihydrocostunolide, C₁₅H₂₂O₂,3, crystallizes with three independent molecules in orthorhombic space groupP2₁2₁2₁ witha=7.3576(5),b=23.505(3),c=24.185(2) ?,V=4182(1) ?³,Z=12.R=0.070 for 2767 observed data. In all, the 10-membered rings adopt approximate chair-chair conformations. In all, the double bonds or epoxidized double bonds are E, both methyl groups on the 10-ring are β, and the α-methylene-γ-lactone (or α-methyl-γ-lactone) istrans-fused at C6 and C7 with H6 β and H7 α. In the dihydro compounds, the H at C11 is β.     

X-ray diffraction study of p -(alkoxybenzylidene)- p ′-toluidines C2H5O-C6H4-CH=N-C6H4-CH3 and C4H9O-C6H4-CH=N-C6H4-CH3

The molecular and crystal structures of two p-alkoxybenzylidene)-p′-toluidines C₂H₅O-C₆H₄-CH=N-C₆H₄-CH₃ (1) and C₄H₉O-C₆H₄-CH=N-C₆H₄-CH₃ (2) are determined by X-ray diffraction. Crystals 1 and 2 contain four and two crystallographically independent molecules, respectively. In 1, the geometry of the independent molecules is almost identical. In 2, the independent molecules differ in the conformation of the alkyl chain, which is disordered in one of them. An analysis of the crystal packing of 2 reveals the alternation of spacious layers formed by loosely packed aliphatic fragments of molecules and layers of closely packed aromatic fragments, which ensures the formation of the mesogenic phase in the course of melting of crystals 2. In crystal 1, loose aliphatic layers are absent. Original Russian Text ? L.G. Kuz’mina, N.S. Kucherepa, M.N. Rodnikova, 2008, published in Kristallografiya, 2008, Vol. 53, No. 6, pp. 1072–1078.     

First-principles study on structural and electronic properties of Prussian blue cathode material for sodium-ion battery

Abstract

Prussian blue, Fe[Fe(CN)₆] currently attracts a huge attention as a promising material in the application of large-scale energy storage because of its cost-effective and environmental friendly material. Besides, open framework structure and stability are the main causes for PB performance. In this study, effects of sodium cation insertion/deinsertion toward the structural and electronic properties were analyzed. The use of Hubbard U method successfully delivered a good approximation on electronic properties of the transition-metal ions in PB. The calculated band gap of 1.84?eV was in good agreement with theoretical and experimental results. Upon the insertion of the sodium cation, volume of the cathode material expanded between 2% and 4% showing that this cathode material has good cycle retention. From partial density of states, Fe 3d dominated the conduction and valence band. Furthermore, the redox reaction mechanism of Prussian blue can also be depicted. The voltage obtained from energy calculation for the first and second insertion of cation was 3.32 and 3.42?V, respectively.     

Structural and optical properties of single-crystal ZnMgO thin films grown on sapphire and ZnO substrates by RF magnetron sputtering

High-quality ZnMgO films were grown by the radio frequency (RF) magnetron sputtering technique in pure oxygen ambient. Single-crystal films were obtained, when the Mg concentration was Zn_0.87Mg_0.13O or lower in the case of ZnMgO/Al₂O₃ and when it was Zn_0.65Mg_0.35O or lower in the case of ZnMgO/ZnO. Polycrystalline films were obtained when the growth temperature was lower than 500 °C, regardless of the Mg concentration. Position of the photoluminescence (PL) ultraviolet (UV) peak of the ZnMgO film shifted with the addition of Mg, from 3.33 eV (ZnO) to 3.51 eV (Zn_0.87Mg_0.13O) and 3.70 eV (Zn_0.65Mg_0.35O). It was also observed that growth of the ZnMgO films at higher temperature resulted in higher band-gap energy. It was proposed that this phenomenon is because concentration of the substitutional Mg atoms occupying Zn site is increased as the growth temperature increases.     

X-ray Crystallographic Structures of Two Lamotrigine Analogues: (I) 3,5-Diamino-6-(2-chlorophenyl)-1,2,4-triazine Water Solvate and (II) 3,5-Diamino-6-(3,6-dichlorophenyl)-1,2,4-triazine Methanol Solvate

Abstract The X-ray crystal structures of two lamotrigine derivatives (I) 3,5-diamino-6-(2-chlorophenyl)-1,2,4-triazine, C₉H₈ClN₅, (465BL) as a hydrate, and (II) 3,5-diamino-6-(3,6-dichlorophenyl)-1,2,4-triazine, C₉H₇Cl₂N₅, (469BR) as a methanol solvate, have been carried out at liquid nitrogen temperature and room temperature, respectively. A detailed comparison of the two structures is given. Both are centrosymmetric with (I) in the orthorhombic space group Pbca, a = 12.2507(3), b = 15.7160(6), c = 21.71496(9) ?, Z = 16, and (II) in the monoclinic space group C2/c, a = 38.553(3), b = 4.9586(2), c = 14.546(2) ?, β = 111.59(1)°, Z = 8. Final R indices [I > 2sigma(I)] for (I) are R1 = 0.0670, wR2 = 0.1515 and for (II) R1 = 0.0434, wR2 = 0.1185. Structure (I) has water of crystallization in the lattice and (II) includes a solvated CH₃OH. Structure (I) is characterized by having two crystallographically independent molecules, A and B, of 465BL, per asymmetric unit. Molecule B has a very unusual feature in that the 2-chlorophenyl ring is statistically disordered, occupying site (1) in 87.5% of the structure and site (2) in 12.5% of the structure. Sites (1) and (2) are related by an exact 180° pivot of the phenyl ring about the ring linkage bond. The presence of two independent molecules per asymmetric unit provides an ideal opportunity for the conformational flexibility of the molecule 465BL to be studied. Structure (I) also includes a further unusual feature in that the lattice contains one fully occupied water molecule and an additional solvated water which is only 33% occupied. Index Abstract Rex A. Palmer, Brian S. Potter, Michael J Leach and Babur Z. Chowdhry The crystal structures of two lamotrigine analogues: (I) 3, 5-diamino-6-(2-chlorophenyl)-1, 2, 4-triazine, water solvate and (II) 3, 5-diamino-6-(3,6-dichlorophenyl)-1, 2, 4-triazine methanol solvate are presented. Structure (I) includes two molecules per asymmetric unit labeled A and B where molecule B is unusually disordered having Cl in either position 2 (87.5% occupied) or position 6 of the phenyl ring (12.5% occupied), the two sites being related by 180deg rotation about the ring linkage bond. Molecule I(A) on the other hand shows no disorder. The relative orientations of the two rings in I(A and B) and in II is shown to be different. Lamotrigine and analogues have been investigated for some time for their effects on the central nervous system. For example both lamotrigine and 5-(2,3,5-trichlorophenyl)-2,4-diaminopyrimidine (code name BW 1003C87) are voltage-gated sodium channel blockers as well as blocking the release of the neurotransmitter glutamate. BW 1003C87 has also been shown to reduce the release of glutamate evoked by veratrine in brain tissue, providing a therapeutic approach in both cerebral ischemia and epilepsy [B. S. Meldrum, J. H. Swan, M. J. Leach, M. H. Millan, R. Gwinn, K. Kadota, S. H Graham, J. Chen, R. P. Simon , Brain Res., 1992, 593, 1.]. This is one of a series of papers on the structures of lamotrigine analogues.      

Copper(I) Derivative of Pyridine-3-carbaldehyde-N-ethylthiosemicarbazone and Triphenylphosphine—First Case of Crystal Structure Study

The synthesis and crystal structure of pyridine-3-carbaldehyde-N-ethylthiosemicarbazone (3-pytscH-NHEt) 1, and its Cu^I complex of stoichiometry, [CuCl(3-pytscH-NHEt)(PPh₃)₂] 2, studied using single crystal X-ray crystallography, are reported in this paper. Crystal data: 1, monoclinic, P2₁/n, a?=?6.6322(3), b?=?21.1200(8), c?=?7.2989(3) Å; β?=?91.883(4), T?=?173(2), R factor?=?0.0457; 2: triclinic, P-1, a?=?19.3600(5), b?=?20.6241(6), c?=?23.8015(6) Å,α?=?92.647(2), β?=?104.388(2), γ?=?114.377(3), R factor?=?0.0662. The thio-ligand, as a neutral entity, is coordinating to Cu through its S donor atom in complex 2. It has exhibited an unusual feature of forming four independent molecules (A, B, C, D) in the unit cell, with minor differences in the bond angles / distances / torsion angles. The geometry of each molecule of 2 is distorted tetrahedral. Crystal packing, as well as Infrared, electronic absorption and proton NMR spectroscopic studies, are also reported. Copper compound 2 represents the first example of a structurally studied copper coordination compound of 3-pyridyl based thiosemicarbazones.

Graphical Abstract

Copper(I) chloride with pyridine-3-carbaldehyde-N-ethylthiosemicarbazone and PPh₃ in CH₃CN yielded a copper compound, 2 (Green-Cl, blue-N; aqua-Cu, orange-S, magneta-P).