Dithiocarbamate Precursors Research Articles

Amplifying energy storage and production efficiency: Utilizing BaS3: Ni2S3: Sb2S3 synthesized from dithiocarbamate precursors for enhanced and sustainable energy solutions

During this period of increasing energy use, the scientific community and energy stakeholders have been closely monitoring electrochemical energy storage. In an attempt to enhance the functionality of charge storage devices, diethyldithiocarbamate ligand is employed as a chelating agent during the production of the novel BaS3: Ni2S3: Sb2S3. The semiconductor BaS3: Ni2S3: Sb2S3, which was made in an environmentally friendly manner, showed good photoactivity due to its 2.97 eV energy band gap and light absorption. The resultant chalcogenide had an average crystallite size of 19.69 nm and displayed outstanding crystallinity with mixed crystallographic phases. Furthermore, infrared spectroscopy was used to investigate metallic sulfide connections, and the findings indicated that they varied between 500 and 875 cm−1. This chalcogenide featured varied sites for electrochemical reactions due to its morphology. The electrochemical performance of BaS3: Ni2S3: Sb2S3 was assessed using a conventional three-electrode setup. With a specific capacitance of up to 1019.4 F g−1 and a power density of 11931.26 W kg−1, BaS3: Ni2S3: Sb2S3 has proven to be an excellent electrode material for energy storage. This remarkable electrochemical performance was further reinforced by the comparable series resistance (Rs) of 0.57 Ω. During electrocatalysis, the electrode produced an OER overpotential with a Tafel slope of 348 mV and 119 mV dec−1. In contrast, the overpotential and Tafel slope in terms of the HER activity and were 211 mV and 100 mV/dec, respectively.

Effect of Deposition Temperature on the Properties of Copper-Zinc Sulphide Thin Films using Mixed Copper and Zinc Dithiocarbamate Precursors

The influence of deposition temperatures on the structural, elemental, optical and electrical properties was investigated. The Rutherford backscattering (RBS) and scanning electron microscopy (SEM) were used to measure the elemental and morphological properties of the films. The RBS confirms that the stoichiometry was controlled by the deposition temperatures with a thickness that ranged between 51.00 to 63.00 nm. SEM data of the deposited films show different morphologies with several grains that increased with deposition temperature. Optical characterization shows that the films exhibited a direct transition with an energy gap that varies from 1.79 to 2.10 eV. For copper-zinc sulphides (CZS) film deposited at 470 ᴼC, the maximum electrical conductivity was 7.38 × 10-2 (Ω.cm)-1and minimum electrical resistivity was 1.35 × 101 (Ω.cm). The results confirm the possibility of using copper and zinc dithiocarbamate precursors in depositing high-quality CZS thin films with comparable properties.

Quantum Confined High-Entropy Lanthanide Oxysulfide Colloidal Nanocrystals.

We have synthesized the first reported example of quantum confined high-entropy (HE) nanoparticles, using the lanthanide oxysulfide, Ln2SO2, system as the host phase for an equimolar mixture of Pr, Nd, Gd, Dy, and Er. A uniform HE phase was achieved via the simultaneous thermolysis of a mixture of lanthanide dithiocarbamate precursors in solution. This was confirmed by powder X-ray diffraction and high-resolution scanning transmission electron microscopy, with energy dispersive X-ray spectroscopic mapping confirming the uniform distribution of the lanthanides throughout the particles. The nanoparticle dispersion displayed a significant blue shift in the absorption and photoluminescence spectra relative to our previously reported bulk sample with the same composition, with an absorption edge at 330 nm and a λmax at 410 nm compared to the absorption edge at 500 nm and a λmax at 450 nm in the bulk, which is indicative of quantum confinement. We support this postulate with experimental and theoretical analysis of the bandgap energy as a function of strain and surface effects (ligand binding) as well as calculation of the exciton Bohr radiii of the end member compounds.

Morphological studies and photocatalytic degradation of methylene blue by zinc sulfide nanoparticles

"We report the preparation, morphological and photocatalytic studies of zinc sulfide nanoparticles from zinc(II) dithiocarbamate precursors. Powder X-ray diffraction patterns were index to the wurtzite crystalline phase of zinc sulfide while transmission electron microscopy micrographs revealed spherically shaped particles with sizes in the range 2.8 to 5.2 nm. The ZnS nanoparticles were used as photocatalysts for the degradation of methylene blue with degradation efficiency of 71.41% for ZnS1 and 85.95% for ZnS2 nanoparticles at pH 9.43. The effect of catalyst concentration, pH, radical scavengers, and hole (h+ ) scavengers on the photodegradation of methylene blue dye were evaluated."

Preparation and morphological studies of tin sulfide nanoparticles and use as efficient photocatalysts for the degradation of rhodamine B and phenol

Abstract Tin sulfide nanoparticles were prepared from tin(ii) dithiocarbamate complexes: bis(benzylmethyl dithiocarbamate)tin(ii) (SnS1), bis(dibenzyl dithiocarbamato)tin(ii) (SnS2), and bis(imidazolyldithiocarbamato)tin(ii) (SnS3) single-source precursors. Powder X-ray diffraction patterns of the as-prepared tin sulfide nanoparticles confirmed orthorhombic crystalline phase irrespective of the tin(ii) dithiocarbamate precursors used to prepare the tin sulfide nanoparticles. Transmission electron microscopic images showed SnS nanoparticles with average particle size of 1.35 ± 0.04 nm for SnS1, 2.63 ± 0.65 nm for SnS2, and 1.55 ± 0.15 nm for SnS3. The energy bandgap of the SnS nanoparticles obtained from Tauc plots are in the range 3.80–4.37 eV. The as-prepared SnS nanoparticles were used as photocatalysts for the degradation of rhodamine B with efficiency of 90.97, 61.53, and 80.26% for SnS1, SnS2, and SnS3, respectively, while for phenol degradation efficiency was 96.45, 75.13, and 90.69% after 180 min. The results indicate that the as-prepared SnS nanoparticle are efficient photocatalyst for rhodamine B and phenol degradation. The photocatalytic degradation of rhodamine B and phenol follows pseudo-first-order reaction kinetics model from which the photodegradation rate could be obtained. Scavenger studies show that electrons (e−), hydroxy radicals (˙OH), and holes (h+) play significant role in the photodegradation of rhodamine B and phenol by the SnS nanoparticles. Recyclability studies show the SnS photocatalyst could be reused for four cycles without losing its photodegradation ability.

Synthesis and utilization of platinum(II) dialkyldithiocarbamate precursors in aerosol assisted chemical vapor deposition of platinum thin films as counter electrodes for dye-sensitized solar cells

A facile and cost effective AACVD procedure for the synthesis of platinum thin films has been reported using newly synthesized Pt-dialkyldithiocarbamate complexes, [Pt(S2CNR2)] (where R = isobutyl, iBu (1); benzyl, Bz (2)), as single source precursors. The structural characterization of the dithiocarbamate complexes has been performed by single crystal X-ray diffraction, 1H and 13C NMR, FT-IR and thermogravimetric analysis. The structure, composition, and morphology of the resulting Pt-films is established through XRD, XPS, EDX and FE-SEM analyses. The catalytic performance of the as-synthesized Pt-films is evaluated by using them as counter electrodes in dye sensitized solar cells as an example application. The efficiency of the AACVD produced electrodes is found to be better than conventionally used Pt-counter electrodes made from the doctor blade’s method. It is also demonstrated that films having a well-connected and defect free surface topography show better catalytic performance, which is due to their high conductivity and reflectivity. Thus a simple and low cost method employing dithiocarbamate precursors is manifested to be immensely efficient in generating Pt-films and electrodes of tremendous applicability.

Synthetic 2-D lead tin sulfide nanosheets with tuneable optoelectronic properties from a potentially scalable reaction pathway.

Solventless thermolysis of molecular precursors followed by liquid phase exfoliation allows access to two-dimensional IV-VI semiconductor nanomaterials hitherto unreachable by a scalable processing pathway. Firstly, the use of metal dithiocarbamate precursors to produce bulk alloys in the series Pb1-x Sn x S (0 ≤ x ≤ 1) by thermolysis is demonstrated. The bulk powders are characterised by powder X-ray diffraction (pXRD), Raman spectroscopy, scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) spectroscopy. It was found that there is a transition from cubic structures for the Pb-rich alloys including the end compound, PbS (0 ≤ x ≤ 0.4) to layered orthorhombic structures for Sn-rich alloys and the end compound SnS (0.5 ≤ x ≤ 1.0). A smooth elemental progression from lead-rich to tin-rich monochalcogenides across the series of materials is observed. Liquid phase exfoliation was applied to produce two dimensional (2D) nanosheets for a mixed Pb1-x Sn x S alloy (where x = 0.8) in 1-methyl-2-pyrrolidone (NMP) using the synthetic bulk powder as starting material. The nanosheet products were characterized by SEM, atomic force microscopy (AFM) and high angle annular dark field scanning transmission electron microscopy (HAADF STEM). First principle calculations of Pb1-x Sn x S alloys show that the Sn content x modifies the size of the band gap by several 100 meV and that x changes the gap type from indirect in SnS to direct in Pb0.2Sn0.8S. These results are supported by UV-Vis spectroscopy of exfoliated Pb0.2Sn0.8S. The method employed demonstrates a new, scalable, processing pathway which can potentially be used to synthesize a range of synthetic layered structures that can be exfoliated to as-yet unaccessed 2D materials with tunable electronic properties.

Near-IR Photoelectrochemical Response of Colloidally Synthesized (Cu,Ag)2ZnSnS4 solid Solution nanocrystals

Introduction Colloidally synthesized nanocrystals (NCs) of multinary semiconductors have attracted much attention due to their light-harvesting properties and tunable electronic energy structure depending on their size and composition. One of important application of colloidal semiconductor NCs is a precursor to prepare semiconductor films with homogeneous composition across whole films via spin-coating. So far, a lot of study have been reported for the fabrication of photovoltaic devices using these colloidal nanocrystals as a precursor ink. Cu2ZnSnS4 (CZTS), a multinary chalcogenide with p-type semiconductor property, has been intensely studied as a new type of photovoltaic materials owing to their optimal properties for solar energy conversion, such as high absorption coefficient, being composed of earth-abundant and non-toxic elements, and band gap energy of 1.4-1.5 eV. In our previous papers, we successfully synthesized CZTS nanocrystals via thermal decomposition of precursors in hot organic solution and investigated their photoelectrochemical properties depending on the particle size and composition.[1-3] Recently, Kudo and co-workers reported that the photocatalytic activities for hydrogen evolution can be greatly enhanced by formation of solid solution between CZTS and Ag2ZnSnS4 (AZTS) in bulk system.[4] The hydrogen evolution rate under visible-light irradiation of CZTS-AZTS photocatalyst particles was 150 times higher than that of pure CZTS particles due to increased ability for photocatalytic reduction and oxidation reaction with increased energy gap by making solid solution. Therefore the doping of Ag+ into CZTS nanocrystal to form solid solution is a promising strategy to enhance their photo-properties without changing nanocrystal size, but such attempt has not been carried out. In this study, we prepare the solid solution NCs of CZTS-AZTS uniformly dispersed in organic solution and report their photoelectrochemical properties. Experimental CZTS-AZTS solid solution ((Cu1-x Ag x )2ZnSnS4; CAZTS) NCs were prepared via thermal decomposition of metal diethyl dithiocarbamate precursors in hot oleylamine under N2 atmosphere. After removal of largely aggregated particles, the resulting NCs were dissolved in chloroform. Photoelectrochemical properties of CAZTS NCs immobilized on ITO electrodes were measured in an aqueous solution containing 0.2 mol dm-3 Eu(NO3)3 as an electron scavenger. The Ag/AgCl electrode and Pt wire were used as reference and counter electrodes, respectively. Results and discussions The X-ray diffraction patterns of thus-obtained NCs were assignable to kesterite crystal structure similar to that of CZTS and individual peaks were shifted to lower angle with increase in the Ag content in NCs, except for NCs with x = 1.0 in which sub-peaks assignable to orthorhombic AZTS were additionally observed. These indicated that the obtained NCs were not a mixture of pure CZTS and AZTS NCs but a solid solution between CZTS and AZTS. TEM measurement revealed that thus-obtained particles had polygonal shape with average diameter of ca. 10 nm, regardless of x value. The optical bandgap of CAZTS NCs in chloroform, estimated from absorption onset energy, was blue-shifted with an increase in Ag content from 1.1 eV (x = 0) to 2.0 eV (x = 1.0). We determined the composition-dependent electronic energy structure of CAZTS NCs with photoelectron yield spectroscopy. The energy level of valence band edge of CAZTS NCs became slightly higher from +0.8 to +0.2 V vs. Ag/AgCl with increasing Cu content in the products, while that of conduction band edge was nearly constant at ca. -1.0 ~ -1.1 V, irrespective of x value. CAZTS thin films were prepared onto ITO electrodes by spin-coating chloroform solutions containing corresponding NCs at 1000 rpm for 10 second, followed by heating the electrodes at 300°C. The irradiation (λ > 350 nm) to thus-obtained films under appropriate potential application produced cathodic photocurrents except for NCs of x = 1.0 (AZTS), the magnitude being increased with negative shift of the electrode potential. The observed behavior was similar to that of a p-type semiconductor photoelectrode. On the other hand, AZTS NCs-immobilized ITO electrodes exhibited anodic photocurrent like as an n-type semiconductor as reported in our previous paper.[5] Action spectra of the photocurrent were in good agreement with absorption spectra of CAZTS NPs used, indicating that CAZTS NPs effectively worked as photovoltaic materials driven by the irradiation of visible and near-IR lights. Reference [1] T. Kameyama, et al., J.Mater. Chem., 2010, 20, 5319. [2] H. Nishi, et al., Phys. Chem. Chem. Phys., 2013, 16, 672. [3] H. Nishi, et al., J. Phys. Chem. C, 2013, 117, 21055. [4] A. Kudo, et al., Chem. Mater., 2010, 22, 1402. [5] T. Sasamura, et al., Chem. Lett., 2012, 41, 1009.

Photoelectrochemical Properties of Colloidally Synthesized (Cu,Ag)2ZnSnS4 solid Solution nanocrystals

Introduction Multinary semiconductors of Cu2ZnSnS4 (CZTS) composed of earth-abundant and non-toxic elements have been intensively studied as a new type of potential photovoltaic materials for the application to thin film solar cells[1] and photocatalyst for hydrogen evolution[2] due to its promising optical properties for absorbing solar light, such as band gap energy of 1.4-1.5 eV and high absorption coefficient. Recently, Kudo and co-workers reported that the photocatalytic activities for hydrogen evolution can be greatly enhanced by formation of solid solution between CZTS and Ag2ZnSnS4 (AZTS).[2]The hydrogen evolution rate under visible-light irradiation of CZTS-AZTS photocatalyst particles was 150 times higher than that of pure CZTS particles due to an increase in conduction band edge energy by making solid solution. Nanometer-sized crystals of such photoactive semiconductors have also attracted much attention due to their light-harvesting properties and tunable electronic energy structure depending on their size. In addition, semiconductor nanocrystals (NCs) have opened up new ways to generate multiple charge carriers with a single photon. In our previous papers, we successfully synthesized CZTS NCs via thermal decomposition of precursors in hot organic solution and investigated their photoelectrochemical properties depending on the particle size and composition.[3-5] The incorporation of Ag+into CZTS nanocrystal solid solution is expected to enhance photo-properties of nanoparticles, but such attempt has not been carried out. In this study, we prepare CZTS-AZTS NCs uniformly dispersed in organic solution and report their photoelectrochemical properties. Experimental CZTS-AZTS solid solution ((Cu1-x Ag x )2ZnSnS4; CAZTS) NCs were prepared via thermal decomposition of metal diethyl dithiocarbamate precursors in hot oleylamine under N2 atmosphere. After removal of largely aggregated particles, the resulting NCs were dissolved in chloroform. Photoelectrochemical properties of CAZTS NCs immobilized on ITO electrodes were measured in an aqueous solution containing 0.2 mol dm-3 Eu(NO3)3 as an electron scavenger. The Ag/AgCl electrode and Pt wire were used as reference and counter electrodes respectively. Results and discussions TEM measurement revealed that thus-obtained particles were polygonal shape with average diameter of ca. 10 nm regardless of x value. Their chemical composition could be controlled between 0 < x < 1 by varying the Cu/Ag ratio in precursors. The X-ray diffraction patterns of NCs were assignable to kesterite-type crystal structure and each peak was shifted to lower angle with increase in the Ag content in NCs, indicating that the obtained NCs were not a mixture of CZTS and AZTS NCs but a solid solution between CZTS and AZTS. Figure 1 shows absorption spectra of CAZTS NCs in chloroform. The absorption onset of CAZTS NCs was blue-shifted with an increase in Ag content. The bandgap of the NCs was tunable from 1.1 eV (x = 0) to 2.0 eV (x = 1.0) only by changing value of x. To investigate the photoelectrochemical properties of CAZTS NCs, the NCs were immobilized onto ITO electrodes with spin-coating CAZTS NCs chloroform solution at 1000 rpm for 10 second, followed by heating the electrode at 300°C. Irradiation (λ > 350 nm) to thus-obtained films was carried out in an aqueous solution containing Eu(NO3)3 as an electron scavenger. Cathodic photocurrents were observed for CAZTS NC electrodes except for NCs of x = 1.0 (AZTS) under applied electrochemical bias, the magnitude being increased with negative shift of the electrode potential. The observed behavior was similar to that of a p-type semiconductor photoelectrode. On the other hand, AZTS NCs-immobilized ITO electrodes exhibited anodic photocurrent like as an n-type semiconductor as reported in our previous paper.[6]Action spectra of the photocurrent were in good agreement with absorption spectra of CAZTS NPs used, indicating that CAZTS NPs effectively worked as photovoltaic materials driven by irradiation of visible and near-IR light. Reference [1] D. Aldakov, et al., J. Mater. Chem. C, 2013, 1, 3756. [2] A. Kudo, et al., Chem. Mater., 2010, 22, 1402. [3] T. Kameyama, et al., J.Mater. Chem., 2010, 20, 5319. [4] H. Nishi, et al., Phys. Chem. Chem. Phys., 2013, 16, 672. [5] H. Nishi, et al., J. Phys. Chem. C, 2013, 117, 21055. [6] T. Sasamura, et al., Chem. Lett., 2012, 41, 1009. Figure 1

Excitation dependent multicolor emission and photoconductivity of Mn, Cu doped In2S3 monodisperse quantum dots

Indium sulphide (In2S3) quantum dots (QDs) of average size 6 ± 2 nm and hexagonal nanoplatelets of average size 37 ± 4 nm have been synthesized from indium myristate and indium diethyl dithiocarbamate precursors respectively. The absorbance and emission band was tuned with variation of nanocrytal size from very small in the strong confinement regime to very large in the weak confinement regime. The blue emission and its shifting with size has been explained with the donor–acceptor recombination process. The 3d element doping (Mn2+ and Cu2+) is found to be effective for formation of new emission bands at higher wavelengths. The characteristic peaks of Mn2+ and Cu2+ and the modification of In3+ peaks in the x-ray photoelectric spectrum (XPS) confirm the incorporation of Mn2+ and Cu2+ into the In2S3 matrix. The simulation of the electron paramagnetic resonance signal indicates the coexistence of isotropic and axial symmetry for In and S vacancies. Moreover, the majority of Mn2+ ions and sulphur vacancies (VS ) reside on the surface of nanocrystals. The quantum confinement effect leads to an enhancement of band gap up to 3.65 eV in QDs. The formation of Mn 3d levels between conduction band edge and shallow donor states is evidenced from a systematic variation of emission spectra with the excitation wavelength. In2S3 QDs have been established as efficient sensitizers to Mn and Cu emission centers. Fast and slow components of photoluminescence (PL) decay dynamics in Mn and Cu doped QDs are interpreted in terms of surface and bulk recombination processes. Fast and stable photodetctors with high photocurrent gain are fabricated with Mn and Cu doped QDs and are found to be faster than pure In2S3. The fastest response time in Cu doped QDs is an indication of the most suitable system for photodetector devices.

Phase control during the synthesis of nickel sulfide nanoparticles from dithiocarbamate precursors.

Square-planar nickel bis(dithiocarbamate) complexes, [Ni(S2CNR2)2], have been prepared and utilised as single source precursors to nanoparticulate nickel sulfides. While they are stable in the solid-state to around 300 °C, heating in oleylamine at 230 °C, 5 mM solutions afford pure α-NiS, where the outcome is independent of the substituents. DFT calculations show an electronic effect rather than steric hindrance influences the resulting particle size. Decomposition of the iso-butyl derivative, [Ni(S2CN(i)Bu2)2], has been studied in detail. There is a temperature-dependence of the phase of the nickel sulfide formed. At low temperatures (150 °C), pure α-NiS is formed. Upon raising the temperature, increasing amounts of β-NiS are produced and at 280 °C this is formed in pure form. A range of concentrations (from 5-50 mM) was also investigated at 180 °C and while in all cases pure α-NiS was formed, particle sizes varied significantly. Thus at low concentrations average particle sizes were ca. 100 nm, but at higher concentrations they increased to ca. 150 nm. The addition of two equivalents of tetra-iso-butyl thiuram disulfide, ((i)Bu2NCS2)2, to the decomposition mixture was found to influence the material formed. At 230 °C and above, α-NiS was generated, in contrast to the results found without added thiuram disulfide, suggesting that addition of ((i)Bu2NCS2)2 stabilises the metastable α-NiS phase. At low temperatures (150-180 °C) and concentrations (5 mM), mixtures of α-NiS and Ni3S4, result. A growing proportion of Ni3S4 is noted upon increasing precursor concentration to 10 mM. At 20 mM a metastable phase of nickel sulfide, NiS2 is formed and as the concentration is increased, α-NiS appears alongside NiS2. Reasons for these variations are discussed.

A Versatile Strategy for Shish-Kebab-like Multi-heterostructured Chalcogenides and Enhanced Photocatalytic Hydrogen Evolution.

A series of multi-heterostructured metal chalcogenides (CdS-Te, NiS/CdS-Te, and MoS2/CdS-Te) with a surprising shish-kebab-like structure have been synthesized via a one-step microwave-assisted pyrolysis of dithiocarbamate precursors in ethylene glycol. Subsequently, CdS-Te composites were exploited as a self-sacrificial template to craft various CdS-Te@(Pt, Pd) multi-heterostructures. Highly uniform dispersion and intimate interactions between CdS and multicomponent cocatalysts, together with improved separation of photogenerated carriers due to the presence of Te nanotubes (NTs) and trace CdTe, enable CdS-based heterostructured photocatalysts to exhibit greatly enhanced efficiency and stability in the photocatalytic production of H2. Thorough morphological characterizations revealed that the growth of metal sulfide/Te heterostructures originates from the growth of Te tubes, which is likely governed by diffusion-limited depletion of the Te precursor and the dissolution-crystallization process of Te seeds followed by the formation of metal sulfide kebabs.

Metal dithiocarbamate precursors for the preparation of a binary sulfide and a pyrochlore: Synthesis, structure, continuous shape measure and bond valence sum analysis of antimony(III) dithiocarbamates

The antimony(III) complexes [Sb(chmdtc)3] (1), [Sb(chedtc)3] (2) and [Sb(dchdtc)3] 0.5 C7H8 (3) (where chmdtc=cyclohexylmethyldithiocarbamate, chedtc=cyclohexylethyldithiocarbamate and dchdtc=dicyclohexyldithiocarbamate) have been prepared and characterized by electronic, IR and NMR (1H and 13C) spectra and single crystal X-ray diffraction. Electronic spectra of the complexes show charge transfer transitions. The characteristic thioureide bands occur at 1468, 1479 and 1445cm−1 for (1), (2) and (3) respectively. The single crystal X-ray structures of (1), (2) and (3) reveal anisobidentate binding of the dithiocarbamates. Short CH⋯S contacts are observed along the ‘a’ axis in (2) and (3). CShM calculations on the SbS6 chromophores support the distorted octahedral geometry in (1) and (2), and the distorted pentagonal pyramidal geometry in (3), clearly quantifying the extent of deviation from the ideal geometries. The nature of the substituents and the lone pair of electrons present in antimony are responsible for the shift of the metal atom position from the geometrical center of the six sulfur atoms. BVS of the compounds show the highly covalent nature of the SbS bonds. Nano Sb2S3 and (Tl+2/3−2δ)[Tl3+1−ySb3+y]Sb2O6O′1/3−δ, a pyrochlore, have been prepared from the precursors and have been characterized by PXRD, FESEM, EDX, HRTEM and SAED.

Morphological and structural characterization of Sm–O–S compounds prepared by thermolysis of dithiocarbamate precursors

Deposition and structural characterization of SmxSyOz-based thin films are reported. The chemical synthesis of the SmxSyOz compounds is performed by thermolysis of dithiocarbamate precursors, followed by the drop casting deposition of the synthesized material, and by the thermal treatment at different temperatures (250°C, 500°C and 900°C) and atmospheric conditions (nitrogen and air). Structural and morphological properties have been investigated by scanning electron microscopy, transmission electron microscopy and X-ray diffraction, and were found to depend closely on the treatment conditions. In particular, the treatment at temperatures as high as 900°C and in a nitrogen atmosphere enhances the crystalline nature of the films and increases the samarium content in comparison to the oxygen content. Therefore, the temperature of 900°C and the nitrogen atmosphere represent the optimal treatment conditions, among the process parameters, to obtain a single phase of Sm2SO2.

A generalized strategy for controlled synthesis of ternary metal sulfide nanocrystals

Ternary metal sulfide nanocrystals (TMS NCs) have drawn intense attention for their wide applications in photovoltaics and nanophotonics, etc. However, a facile and general method for controlled synthesis of TMS NCs with uniform size and pure crystal phase is yet to be realized. Here we report a simple and versatile one-pot method for preparing high quality TMS NCs with controlled morphologies, sizes, crystalline structures and compositions, including orthorhombic Cu3BiS3 nanosheets and nanoparticles, orthorhombic Cu4Bi4S9 nanowires and nanoribbons, wurtzite CuInS2 nanopencils, cubic AgBiS2 nanocubes, orthorhombic Ag8SnS6 nanoparticles, and orthorhombic Cu3SnS4 nanorods, based on the co-thermal decomposition of metal-diethyl dithiocarbamate (metal-DDTC) precursors. We expect that this methodology will be broadly applicable for synthesizing new metal sulfide NCs and play an important role in exploring their new properties for various applications.

Vysotskite structured photoactive palladium sulphide thin films from dithiocarbamate derivatives

Palladium dithiocarbamate precursors have been designed for the fabrication of palladium sulphide photoelectrode films using aerosol assisted chemical vapour deposition.

Nanothallium(III) sulfide from dithiocarbamate precursors: Synthesis, single crystal X-ray structures and characterization

Nanothallium sulfide was formed from Tl(chmdtc)3(1), Tl(chedtc)3(2) and Tl(dchdtc)3(3) (where chmdtc=cyclohexyl methyl dithiocarbamate, chedtc=cyclohexylethyl dithiocarbamate, dchdtc=dicyclohexyl dithiocarbamate). Single crystal structures of the complexes are reported. The ease of formation was the highest for (3) and is in line with the longest mean Tl–S and thioureide C–N bonds observed for (3). The nano metal sulfide formed is spherical in nature and has been characterized by PXRD, EDX, TEM. Tl4S3 was stable up to 300°C. Thioureide stretching bands are observed at 1471, 1468, 1448cm−1 for (1), (2) and (3) respectively. Thioureide stretching band of (3) is significantly lower than others due to steric effect of cyclohexyl substituents. Thallium(III) complexes exhibit fully allowed charge transfer transitions(CT) which appeared as intense absorptions. 1H NMR shows that the α-CH and α′-CH3 protons are affected to a maximum effect on complexation. 13C NMR spectra show thioureide carbon signal around 200ppm.

Copper zinc tin sulfide layers prepared from solution processable metal dithiocarbamate precursors

In this contribution we present a solution based route toward copper zinc tin sulfide – CZTS – layers using metal dithiocarbamate precursors. We focus on the synthesis of the precursor materials as well as on the fabrication of thin CZTS layers at low temperatures of 350 °C and their characterization. Powder X-ray diffraction measurements show that a precursor solution containing an excess of the zinc precursor, compared to the Cu and Sn precursors, has to be used to obtain CZTS films without secondary phases. Thus, the prepared films are Zn-rich, which is beneficial for solar cell applications. Raman as well as X-ray photoelectron spectroscopy studies confirm the formation of CTZS. No clear evidence for free ZnS has been found. Electron microscopy shows agglomerates of 10 nm-sized crystallites forming spherical particles with a diameter between 50 nm and 400 nm. The prepared films possess high optical absorption (>1.104 cm−1) and an optical band gap of approximately 1.6 eV.

Cyclic voltammetry studies of n-type polymers with non-alternant fluoranthene units

Poly( p-fluoranthenevinylenes) and their dithiocarbamate precursors have been deposited on indium–tin oxide electrodes and electrochemical properties of the obtained films have been investigated by means of cyclic voltammetry studies in acetonitrile solutions containing 0.1 M ( n-C 4H 9) 4NBF 4 as supporting electrolyte. It has been found that all investigated polymers display well pronounced n-doping processes. Electrochemical reduction of the dithiocarbamate precursors seems to be associated with C–S bond cleavage with elimination of –SC(S)N(C 2H 5) 2 group. In view of UV–vis spectroscopic data the obtained products, tentatively identified as polymers containing fluoranthene units connected by –CH 2–CH 2– bridges, are somewhat less conjugated than the corresponding poly( p-fluoranthenevinylenes). Reversible electrochemical reduction of poly( p-fluoranthenethanes) occurs at potentials only somewhat ( ca. 0.1 V) more negative as found for their poly( p-fluoranthenevinylenes) analogues suggesting relatively weak coupling between fluoranthene kernels in both kinds of investigated polymers.

Formal Synthesis of (−)‐Aphanorphine Using Sequential Photomediated Radical Reactions of Dithiocarbamates

Aphanorphine (1), an alkaloid isolated from the freshwater blue-green alga Aphanizomenon flos-aquae, has attracted considerable attention from the synthetic community owing to its structural similarity to natural and non-natural analgesics such as morphine, eptazocine, and pentazocine (Scheme 1). Approaches to aphanorphine developed to date have all relied on the formation of the B or C ring to complete theC-norbenzomorphan skeleton, typically exploiting the rigidity of the bridged tricyclic 3-benzazepine structure to set the second stereocenter from a preexisting quaternary benzylic stereocenter at C1, or from an abranched amine at C4. In this communication we present a complementary strategy for the synthesis of aphanorphine which is characterized by the late-stage incorporation of the aromatic A ring, and formation of the pyrrolidine C ring through a novel carbon–carbon bondforming reaction. We have recently reported a new method for the generation of carbamoyl (aminoacyl) radicals from dithiocarbamate precursors, and their subsequent intramolecular addition—dithiocarbamate group-transfer reactions with alkenes. Application of this methodology to the synthesis of the core 6-azabicyclo[3.2.1]octane ring system of aphanorphine was envisaged based upon a regioselective 5-exo-trig cyclization of carbamoyl radical 2 followed by dithiocarbamate group transfer to give the functionalized bicyclic lactam 3 (Scheme 1). It was further envisaged that the dithiocarbamate group in 3 would provide a handle for phenol annulation. Critical to the success of such an approach is the ability of carbamoyl radicals generated from dithiocarbamate precursors to undergo potentially difficult cyclizations onto unactivated alkenes. 4] Previous work by Quirante, Bonjoch, et al. had shown that a-amino radicals undergo analogous cyclizations onto alkenes carrying electron-withdrawing groups at C9a (aphanorphine numbering); however, unactivated alkenes did not undergo cyclization. The effect of a further alkene substituent at C1, which may also disfavor 5-exo-trig cyclization, was not evaluated. An asymmetric synthesis of the requisite secondary cyclohexenylamine is outlined in Scheme 2 and relies on Ellman6s sulfinamide auxiliary to set the amino-substituted stereocenter destined to be C4 of aphanorphine. 8] Condensation of enantiomerically pure (R)-tert-butanesulfinamide (5) with commercially available cis-4-heptenal gave the expected (E)-sulfinimine 6 (Scheme 2). Addition of 2methylallylmagnesium chloride gave rise to sulfinamide 7 in excellent yield as a 83:17 mixture of diastereoisomers. The configuration of the major stereoisomer 7 was predicted to be R on the basis of the Ellman model and was ultimately proven through a formal synthesis of ( )-aphanorphine. Separation of the two diastereomers could not be achieved at this stage, and so the mixture was carried through the following steps. Following N-methylation of 7, 1,7-diene 8 was subjected to ring-closing metathesis using the Grubbs second-generation catalyst, which furnished the trisubstituted alkene 9 in excellent yield. Finally removal of the sulfinyl auxiliary under acidic conditions gave the hydrochloride salt 10. At this stage, a single recrystallization of 10 gave enantiomerically pure material. Scheme 1. Analgesics structurally related to aphanorphine and a retrosynthesis of ( )-aphanorphine (1).