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Molecular engineering of dyes has become a popular and most successful approach towards improvement of photovoltaic power conversion efficiency of dye-sensitized solar cells (DSSCs). We report the geometrical, optical, and electronic properties for para-substituted triphenylamine (TPA)-based dyes with D-π-π-A architecture. Results were realized through density functional theory (DFT) and time-dependent density functional theory (TD-DFT) methods. We used B3LYP/6–31 + G(d,p) and CAM-B3LYP/6–31 + G(d,p) level of theory for DFT and TD-DFT, respectively. Six electron-donating (ED) and electron-withdrawing (EW) groups were symmetrically grafted to the para-direction of the phenyl rings. Two anchoring groups namely: cyanoacrylic acid (CA) and hydantoin (HY) were used. Excellent relationships between electronic energies and the Hammett constants (σp) have been reported. The results show that variation of both anchoring groups and substituents significantly affect the absorption of the dyes; maximum absorption for CA dyes was found ranging between 514–571 nm and 470–503 nm for ED and EW groups, respectively, while for HY dyes demonstrated maximum absorption between 502–537 nm and 480–496 nm for ED and EW, respectively. A linear correlation between σp and λmax with R2 > 0.97 was obtained. In addition, the mapping of the HOMO and LUMO energies suggests the intramolecular charge transfer and a strong electronic coupling between dye and semiconductor. Our theoretical calculations show that electron-donating substituents enhance the optoelectronic properties of the dyes. Analysis of chemical descriptors suggests that dyes containing alternative anchoring group HY substituted with –NH2 and –N(CH3)2 may demonstrate improved performance of DSSCs.

In this work, syntheses of Schiff-base ligand, N-2-(6-methylpyridyl)-2-hydroxy-1-naphthaldimine (1) and its hitherto unknown chelate with a Ni(II) salt, bis[N-2-(6-methylpyridyl)-2-oxo-1-naphthaldimnato-k 3N^N^O] nickel(II) (2) have been reported and characterized by spectral techniques (IR, 1H NMR, Mass). Solid state structures and non-covalent interactions persisting in 1 and 2 are studied by Density Functional Theory (DFT) optimizations and Hirshfeld Surface (HS) analysis. X-ray diffraction (XRD) study shows zwitter ionic keto-amine tautomer form of planar Schiff base 1 that exists as dimer formed by C13 ̶ H13A···O1 i [(i) -x+1, -y, -z+1] hydrogen bonds and distorted octahedral geometry around Ni +2 center in chelate 2, where overall crystal structure stability may be attributed to weak C ̶ H···π, π···π stacking, van der Waals interactions, and C ̶ H···O type intermolecular hydrogen bonds. The HS study and 2D Finger Print (FP) plots corroborate well with XRD data and show prominent O···H/H···O spikes (2.2 Å < d e+d i < 2.3 Å) and C···H/H···C (2.5 Å < d e+d i < 2.6 Å) spikes that arise from C ̶ H···O type H-bonds and C ̶ H···π interactions respectively, along with significant C···C interactions (d e+d i ∼ 3.3 Å) due to π···π stacking (2). The anticancer activity has been investigated by using cytotoxicity measure (MTT assay), apoptosis assay, quantitative polymerase chain reaction (qPCR), and colony formation assays. The Ni(II) metal complex demonstrates dose-dependent cytotoxicity in vitro, killing A549 lung cancer cells via an apoptotic pathway.

In the title compound, C15H12N2O3, pairs of molecules are linked into dimers by N-H center dot center dot center dot O hydrogen bonds, forming an R-2(2)(12) ring motif, with the dimers stacked along the a axis. These dimers are connected through pi-pi stacking interactions between the centroids of the benzene and furan rings of their 2,3-dihydro-1-benzofuran ring systems. Furthermore, there exists a C-H center dot center dot center dot pi interaction that consolidates the crystal packing. A Hirshfeld surface analysis indicates that the most important contacts are H center dot center dot center dot H (40.7%), O center dot center dot center dot H/H center dot center dot center dot O (24.7%), C center dot center dot center dot H/H center dot center dot center dot C (16.1%) and C center dot center dot center dot C (8.8%).

Cadmium dithiocarbamate and cadmium ethyl xanthate complexes were synthesized and characterized by microanalysis, Fourier transform infrared (FT-IR) spectroscopy and thermogravimetric analyses. The complexes were employed as molecular precursors for the fabrication of CdS nanoparticles in hexadecylamine (HDA) and oleylamine (OLA) at a temperature of 250 degrees C. Spherical and oval shaped particles with sizes ranging from 9.93 +/- 1.89 to 16.74 +/- 2.78 nm were obtained in OLA while spherical, oval and rod shaped particles with sizes ranging from 9.40 +/- 1.65 to 29.90 +/- 5.32 nm were obtained in HDA. Optical properties of the nanoparticles showed blue shifts as compared to the bulk CdS, with the OLA capped nanoparticles slightly more blue shifted than the corresponding HDA capped nanoparticles. Results of crystallinity patterns revealed hexagonal phase of CdS.

In the title compound, C15H15Br2NO2, two bridged tetrahydrofuran rings adopt envelope conformations with the O atom as the flap. The pyrrolidine ring also adopts an envelope conformation with the spiro C atom as the flap. In the crystal, the molecules are linked into dimers by pairs of C—H...O hydrogen bonds, thus generating R 2 2(18) rings. The crystal packing is dominated by H...H, Br...H, H...π and Br...π interactions. One of the Br atoms is disordered over two sites with occupation ratio of 0.833 (8):0.167 (8).

In the crystal, mol­ecules are linked by weak C—H⋯O hydrogen bonds, forming sheets lying parallel to the (002) plane. These sheets are connected only by weak van der Waals inter­actions., The title compound, C15H15Br2NO2, crystallizes with two mol­ecules in the asymmetric unit of the unit cell. In both mol­ecules, the tetra­hydro­furan rings adopt an envelope conformation with the O atom as the flap and the pyrrolidine rings adopt an envelope conformation. In the crystal, mol­ecules are linked by weak C—H⋯O hydrogen bonds, forming sheets lying parallel to the (002) plane. These sheets are connected only by weak van der Waals inter­actions. The most important contributions to the surface contacts are from H⋯H (44.6%), Br⋯H/H⋯Br (24.1%), O⋯H/H⋯O (13.5%) and C⋯H/H⋯C (11.2%) inter­actions, as concluded from a Hirshfeld surface analysis.

In the title compound, C

The stabilized conformation of the title compound, C13H9Cl2N3O2, is similar to that of the isomeric compound (E)-1-(2,6-dichlorophenyl)-2-(2-nitrobenzylidene)hydrazine. The 2,6-dichlorophenyl ring and the nitro-substituted benzene ring form a dihedral angle of 26.25 (16)°. In the crystal, face-to-face π-π stacking interactions along the a-axis direction occur between the centroids of the 2,6-dichlorophenyl ring and the nitro-substituted benzene ring. The molecules are further linked by C—H...O contacts and N—H...O and C—H...Cl hydrogen bonds, forming pairs of hydrogen-bonded molecular layers parallel to (100). The Hirshfeld surface analysis of the crystal structure indicates that the most important contributions to the crystal packing are from H...H (22.1%), Cl...H/H...Cl (20.5%), O...H/H...O (19.7%), C...C (11.1%) and C...H/H...C (8.3%) interactions.

In the crystal structure, mol­ecule pairs generate rings with (8) motifs by dimeric C—H⋯O hydrogen bonds. These pairs of mol­ecules form mol­ecular layers parallel to the (100) plane by C—H⋯π and C—Br⋯π inter­actions. Inter­layer van der Waals inter­actions stabilize the mol­ecular packing., The asymmetric unit of the title compound, C15H12Br2F3NO2, consists of two crystallographically independent mol­ecules. In both mol­ecules, the pyrrolidine and tetra­hydro­furan rings adopt an envelope conformation. In the crystal, mol­ecule pairs generate centrosymmetric rings with R 2 2(8) motifs linked by C—H⋯O hydrogen bonds. These pairs of mol­ecules form a tetra­meric supra­molecular motif, leading to mol­ecular layers parallel to the (100) plane by C—H⋯π and C—Br⋯π inter­actions. Inter­layer van der Waals and inter­halogen inter­actions stabilize mol­ecular packing. The F atoms of the CF3 groups of both mol­ecules are disordered over two sets of sites with refined site occupancies of 0.60 (3)/0.40 (3) and 0.640 (15)/0.360 (15). The most important contributions to the surface contacts of both mol­ecules are from H⋯H (23.8 and 22.4%), Br⋯H/H⋯Br (18.3 and 12.3%), O⋯H/H⋯O (14.3 and 9.7%) and F⋯H/H⋯F (10.4 and 19.1%) inter­actions, as concluded from a Hirshfeld surface analysis.

Cadmium sulfide (CdS) nanoparticles have been synthesized from CdX2 (X = Cl–, I–) complexes of 4-chlorobenzaldehyde and benzophenone thiosemicarbazone. The complexes have been studied by thermogravimetric analysis (TGA), elemental analysis, FT-IR, and NMR spectroscopy. The solvothermal decomposition of the complexes has afforded oleylamine-capped CdS nanoparticles with a wurtzite hexagonal phase. The transmission electron microscopy (TEM) studies show different morphologies which are influenced by reaction temperature and the nature of the ligands on the precursor complexes. Particles in the form of irregular cubes, elongated cubes and nanodendrites have been observed. The UV-Vis spectroscopy measurements show temperature and nature of complex-dependant optical properties. Blue-shifted band gap energies have been observed at lower reaction temperatures.

Copper sulfide thin films and nanoparticles have been prepared via aerosol assisted chemical vapour deposition and solvothermal hot injection routes, respectively. Both routes employed heterocyclic amine based benzoylthioureato-copper(II) complexes as single source precursors. Copper sulfide thin films of diverse morphologies ranging from cubic to snowy or irregular crystallites depending on the deposition temperature were observed. Powder X-ray diffraction studies of the as deposited thin films have indicated the formation of hexagonal and cubic phases of copper sulfide. In the case of the nanoparticles, Roxbyite (Cu1.75S) phase was obtained in dodecanethiol at temperatures of 150, 190 and 230 °C. However, a preferred growth of nanoparticles was observed in the presence of oleylamine whereas the roxbyite phase was obtained at temperatures of 150, 200 and 250 °C. Also transmission electron microscopy showed the formation of close to spherical, hexagonal nano-disk and rod shaped nanoparticles.

Exploitation of agricultural waste as green starting materials to produce various valuable products is attracting the attention of academic, industrial and other practitioners. Cashew nut shell (CNS) and its liquid extract (CNSL) in particular have been identified as agro-wastes rich in valuable and functional renewable products. The unique structural features of the CNSL constituents offer the possibility for different modifications to suit various applications. This review article provides recent developments in CNS and CNSL as green sources for use in the production of biorenewable chemicals, materials and energy. Extraction methods and applications of CNS, CNSL and isolates are discussed. Furthermore, a literature survey of the current status and efforts made on the utilization of these agricultural and food wastes for different applications is well outlined.

Two heterocyclic dithiocarbamate complexes, tris-(piperidinedithiocarbamato)bismuth(III) (1) and tris-(tetrahydroquinolinedithiocarbamato)bismuth(III) (2) were synthesized and characterized by elemental analysis and thermogravimetric analysis. The structure of complex (1) was confirmed by single-crystal X-ray analysis. Both complexes were used as single source precursors for the deposition of bismuth sulfide thin films by aerosol assisted chemical vapour deposition (AACVD) at 350, 400, 450 °C and spin coating followed by thermal treatment at 350 °C, 400 °C and 450 °C. Both deposition methods, gave sulfur deficient polycrystalline films of bismuthinite. Scanning electron microscopy (SEM) images of the films showed morphology was dependent on the solvent mixture, temperature, precursor type and method of deposition. AACVD gave films with hexagonal nanoplatelets, leaf-like platelet, ribbon-like fibre, needle-like fibre morphologies. Films in the form of rods and interwoven nanowires were obtained from spin coating.

The title mol­ecule comprises a fused tricyclic system containing two five-membered rings (cyclo­pentane and tetra­hydro­furan) and one six-membered ring (tetra­hydro­pyridinone). In the crystal, mol­ecules are linked by inter­molecular C—H⋯O hydrogen bonds and C—H⋯π, C—Br⋯π and C⋯O inter­actions into double layers., The mol­ecule of the title compound, C15H15Br2NO3, comprises a fused tricyclic system consisting of two five-membered rings (cyclo­pentane and tetra­hydro­furan) and one six-membered ring (tetra­hydro­pyridinone). Both five-membered rings of the tricyclic system have envelope conformations, and the conformation of the six-membered cycle is inter­mediate between chair and half-chair. In the crystal, the mol­ecules are linked by C—H⋯O hydrogen bonds and C—H⋯π, C—Br⋯π and C⋯O inter­actions into double layers. The layers are connected into a three-dimensional network by van der Waals inter­actions.

In the crystal, mol­ecules are linked into dimers by pairs of C—H⋯O hydrogen bonds, thus generating (18) rings. The crystal packing of the title compound is dominated by H⋯H, Br⋯H, H⋯π and Br⋯π inter­actions., In the title compound, C15H15Br2NO2, two bridged tetra­hydro­furan rings adopt envelope conformations with the O atom as the flap. The pyrrolidine ring also adopts an envelope conformation with the spiro C atom as the flap. In the crystal, the mol­ecules are linked into dimers by pairs of C—H⋯O hydrogen bonds, thus generating R 2 2(18) rings. The crystal packing is dominated by H⋯H, Br⋯H, H⋯π and Br⋯π inter­actions. One of the Br atoms is disordered over two sites with occupation ratio of 0.833 (8):0.167 (8).

C—H⋯N inter­actions, C—Cl⋯π inter­actions, and π-π stacking inter­actions link mol­ecules in the crystal, forming mol­ecular layers approximately parallel to the (002) plane. The three-dimensional packing is strengthened by additional weak van der Waals inter­actions between the layers., In the title compound, C17H14Cl2N4, the dihedral angle between the aromatic rings is 50.09 (9)°. The central –N=N– unit shows an E configuration. In the crystal, C—H⋯N inter­actions, C—Cl⋯π and π–π stacking inter­actions [centroid-to-centroid distance = 3.7719 (14) Å] link the mol­ecules, forming mol­ecular layers approximately parallel to the (002) plane. Additional weak van der Waals inter­actions between the layers consolidate the three-dimensional packing. Hirshfeld surface analysis indicates that the most important contributions for the crystal packing are from H⋯H (33.6%), N⋯H/ H⋯N (17.2%), Cl⋯H/H⋯Cl (14.1%) and C⋯H/H⋯C (14.1%) contacts.

The dihedral angle between the aromatic rings in the title compound is 31.84 (8)°; N—H⋯O and C—H⋯O hydrogen bonds and π–π stacking inter­actions connect mol­ecules in the crystal, producing a three-dimensional network., In the title compound, C16H12F5N3O, the dihedral angle between the aromatic rings is 31.84 (8)°. In the crystal, the mol­ecules are linked into dimers possessing crystallographic twofold symmetry by pairwise N—H⋯O hydrogen bonds and weak C—H⋯O hydrogen bonds and aromatic π–π stacking inter­actions link the dimers into a three-dimensional network. A Hirshfeld surface analysis indicates that the most important contributions to the crystal packing are from F⋯H/H⋯F (41.1%), H⋯H (21.8%), C⋯H/H⋯C (9.7%) C⋯C (7.1%) and O⋯H/H⋯O (7.1%) contacts. The contribution of some disordered solvent to the scattering was removed using the SQUEEZE routine [Spek (2015 ▸). Acta Cryst. C71, 9–18] in PLATON. The solvent contribution was not included in the reported mol­ecular weight and density.

In the title compound, the benzene rings make a dihedral angle of 62.73 (9)° with each other. In the crystal, mol­ecules are linked by a pair of C—Cl⋯π inter­actions, forming an inversion dimer. A short HL⋯·HL contact links the dimers, forming a ribbon propagating along the c-axis., In the tile compound, C17H17Cl2N3, the dihedral angle between the benzene rings is 62.73 (9)°. In the crystal, there are no classical hydrogen bonds. Mol­ecules are linked by a pair of C—Cl⋯π inter­actions, forming an inversion dimer. A short inter­molecular HL⋯HL contact [Cl⋯Cl = 3.2555 (9) Å] links the dimers, forming a ribbon along the c-axis direction. The Hirshfeld surface analysis and two-dimensional fingerprint plots reveal that the most important contributions for the crystal packing are from H⋯H (45.4%), Cl⋯H/H⋯Cl (21.0%) and C⋯H/H⋯C (19.0%) contacts.

Synthesizing nanoparticles with the less environmentally malignant approach using plant extract is of great interest; this is because most of the chemical approaches can be very costly, toxic, and time-consuming. Herein, we report the use of Acacia senegal leaf extracts to synthesize silver nanoparticles (AgNPs) using an environmentally greener approach. Silver ions were reduced using the bioactive components of the plant extracts with observable colour change from faint colourless to a brownish solution as indication of AgNP formation. The structural properties of the as-synthesized AgNPs were characterized using powder X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and UV-Vis absorption spectrum. Antimicrobial assessment of the as-synthesized AgNPs was explored on some strains of gram-positive and gram-negative bacteria. The obtained results indicate that the as-synthesized AgNPs are pure crystallite of cubic phase of AgNPs, fairly dispersed with a size range of 10–19 nm. The AgNPs were found to be small in size and exhibit significant antibacterial activities, suggesting that the as-synthesized AgNPs could be used in the pharmaceutical and food industries as bactericidal agents.

Two novel N ∧ " role="presentation"> ∧ ∧ \wedge O-type Schiff base ligands and the corresponding Co(II) complexes are reported. Thermogravimetric analysis indicated that the complexes are potential molecular precursors for the fabrication of cobalt and cobalt-containing nanomaterials. The significant difference in the thermal decomposition profiles is recognized as an influence of structural differences on the complexes. Thus, the complexes were thermally decomposed using the melt and hot injection methods to examine the properties of the obtained cobalt and cobalt sulfide nanoparticles, respectively. The reaction parameters employed during the fabrication processes, in addition to structural differences, influenced the morphological and crystallographic phases and magnetic properties of the synthesized nanoparticles. We have investigated the morphological properties and the crystallographic phase compositions of the nanoparticles by various electron microscopy and diffraction techniques, as well as energy-dispersive X-ray spectroscopy. The melt reactions produced phase-pure cobalt nanoparticles, which exhibit ferromagnetic behavior. The hot injection method utilized 1-dodecanethiol (DDT) as both sulfur source and capping agent. We indexed the DDT-capped cobalt sulfide nanoparticles to cubic Co 9 " role="presentation"> 9 9 _{9} S 8 " role="presentation"> 8 8 _{8} and Co 3 " role="presentation"> 3 3 _{3} S 4 " role="presentation"> 4 4 _{4} phases using powder X-ray diffraction, high-resolution transmission electron microscopy imaging, and selected area electron diffraction. The crystallite sizes for Co 9 " role="presentation"> 9 9 _{9} S 8 " role="presentation"> 8 8 _{8} and Co 3 " role="presentation"> 3 3 _{3} S 4 " role="presentation"> 4 4 _{4} nanoparticles, based on the Scherrer equation, were 12.4 nm and 14.1 nm, respectively. We find significant differences in the magnetic properties, attributed to nonmagnetic inclusions and vacancies due to the presence of S atoms.

Hexagonal cadmium sulfide (CdS) thin films were deposited on glass substrates by aerosol assisted chemical vapour deposition (AACVD) using cadmium(II) dithiocarbamate and xanthate complexes in tetrahydrofuran (THF) and mixed solvents (THF + chloroform) at 400 and 450 °C. The surface morphology and size of the CdS films determined using scanning electron microscopy, showed the formation of films of various morphologies depending on the precursor, the deposition temperature and solvent used. An increase in temperature resulted in an increase in particle size and a change in morphology with the formation of CdS films with distorted structures. The CdS films showed an overall blue shift in their absorption band edge (2.35–2.49 eV) compared to bulk CdS. In dithiocarbamates, a slight blue shift was observed with a shift to higher wavelengths with the reduction of the carbon chain of the dithiocarbamate and an increase in temperature. Films from xanthate complexes showed a strong blue shift at both deposition temperatures. The use of mixed THF + chloroform solvent at 450 °C showed the formation of films with irregular structures compared to those deposited using THF solvent alone, indicating the role of the solvent in shape direction of the films formation. The elemental composition determined by energy dispersive X-ray spectroscopy measurements revealed a 1:1 (Cd:S) ratio in all the samples confirming the stoichiometry of the CdS films.

The lead N’-benzoylthioureato complexes of N-morpholine (1) and N-pyrrolidine (2) were synthesized and characterized by elemental analysis, Fourier Transform Infra-Red (FT-IR) spectroscopy, proton nuclear magnetic resonance (1H nmr) and thermogravimetric analyses (TGA). The X-ray single crystal structure of complex (1) was determined. The compounds were both used as single source precursors to deposit PbS films on glass substrates at 350, 400 and 450 °C using aerosol assisted chemical vapour deposition (AACVD) The surface morphology of PbS films were determined by scanning electron microscopy (SEM), the crystalline phases established by powder X-ray diffraction (p-XRD) analyses and composition by energy dispersive X-ray spectroscopy (EDX). The particle sizes were found to range between 82 and 85 nm from complex (1) and 70–105 nm for (2) The PbS films were studied by Near Infra-red (NIR) UV–Vis spectroscopy, band gap ranging from 1.46 to 1.55 eV were observed.

Iron sulfide nanomaterials were prepared by the solvothermal decomposition of two single source precursors i.e. [FeCl2(cinnamtscz)2] (1) (cinnamtscz = cinnamaldehyde thiosemicarbazone) and [FeCl2(benztscz)2] (2) (benztscz = benzaldehyde thiosemicarbazone) at different temperatures of 230 and 300 °C in the presence of oleylamine. Powder X-ray diffractometry shows the formation of the pyrrhotite phase at both reaction temperatures. The solvothermal decomposition of [FeCl2(cinnamtscz)2] and [FeCl2(benztscz)2] at 230 °C produced iron sulfide nanoparticles in the form of spheres. When the temperature was increased to 300 °C, particles in the form of hexagons and nanorods were obtained. Furthermore, the photocatalytic activities of all the four iron sulfide nanomaterials were tested for the degradation of methylene blue under visible light irradiation. Amongst all the materials, nanospheres of iron sulfide obtained by the solvothermal decomposition of [FeCl2(benztscz)2] at 230 °C showed the highest photocatalytic efficiency (88.40%).

A bis(N′-ethyl-N-piperazinylcarbodithioato-S,S′)–nickel(II) complex was prepared and characterized using infrared spectroscopy, thermogravimetric and elemental analyses. The crystal X-ray structure for bis(N′-ethyl-N-piperazinylcarbodithioato-S,S′)–nickel(II) was determined. The complex was subsequently used as a single source precursor (SSP) for the synthesis of phase pure Ni3S2 and NiS nanoparticles and thin films via hot injection thermolysis and aerosol assisted chemical vapour deposition (AACVD) routes, respectively. For the hot injection thermolysis route, hexadecylamine (HDA) and oleylamine (OLA) were used as capping groups at varying temperatures. Chloroform was used as the solvent in the AACVD experiments. Powder X-ray revealed that the capping group does not change the phase of nanoparticles formed whereas the AACVD technique produced different phases. Variation of temperature did not affect the phase purity of the nanomaterials formed. The morphology of the thin films obtained via AACVD depended largely on the deposition temperature, whereas for the nanoparticles, temperature and the capping group had a significant impact.

We report a green route for the synthesis of PbS nanoparticles in an imidazolium based ionic liquid (IL) (1-ethyl-3-methylimidazolium methanesulfonate) using single source and dual source precursor methods. Lead ethyl xanthogenate complex was used as single source molecular precursor for the synthesis of PbS nanoparticles, whereas in dual source approach organic sulfur (1-dodecanethiol) and inorganic sulfur (sodium sulfide) sources were used to observe the suitability of different sulfur sources on formation of PbS nanoparticles. The results showed that the temperature has an effect on the as prepared nanoparticles for both routes. X-ray diffraction (XRD) studies confirmed formation of cubic phase of PbS from both routes. Electron microscopy techniques showed that the nanoparticle morphologies differed significantly depending on the synthetic factors such as temperature, nature of precursors and ranged from spherical to cubic shapes.

Different PbX2 (X = AcO, Cl, Br, I) metal salts were complexed to cinnamaldehyde thiosemicarbazone ligand. The resulting complexes were characterised using Fourier Transform Infrared spectroscopy, 1H and 13C {1H} Nuclear Magnetic Resonance spectroscopy, elemental analysis and thermogravimetric analysis techniques. They were then used as single source precursors for the preparation of lead sulfide (PbS) nanoparticles using the colloidal thermolysis route where oleylamine is used as the passivating agent. Each SSP is thermolysed at reaction temperatures of 190, 230 and 270 °C. Predominantly cubic-shaped PbS nanoparticles were obtained, with an exception of the truncated nanocubes obtained from thermolysis of the SSP prepared from lead bromide. Varying particle sizes are obtained when the halogen is varied, ranging from ca. 50 to 400 nm. The optical absorbance of the PbS nanoparticles in the UV-Vis-NIR range was found to be blue-shifted when compared to bulk PbS.

Iron sulfide nanoparticles Fe3S4 and Fe1-xS were synthesized via solvothermal decomposition of piperidine iron(III) dithiocarbamate complex in oleylamine. At a reaction temperature of 230 °C, the cubic Fe3S4 phase (greigite) was obtained whereas at 300 °C, monoclinic Fe1-xS (pyrrhotite) was obtained. In both cases, hexagonal sheet like structures with sizes ranging from 50 to 200 nm were obtained. Powder X-ray diffraction studies reveal that the temperature plays a significant role in determining the crystalline structure and chemical composition of the as-synthesized nanoparticles (NPs). Gas sensing applications further reveal activities which are phase-dependent. The greigite has a higher response to humidity but saturates faster than the pyrrhotite. The pyrrhotite phase however outwits the greigite on response to H2, NO2, NH3 and CH4. In these gases, the greigite displays early saturation as well as noisy and uncoordinated signals.

Bis( O -isobutyldithiocarbonato)copper(II) complex [Cu(SCSOCH 2 CH(CH 3 ) 2 ) 2 ] was used as a single source precursor to synthesize both copper sulfide thin films and nanoparticles. The copper sulfide thin films were deposited by the aerosol assisted chemical vapor deposition method, whereas the nanoparticles were synthesized by the hot injection route. The deposited copper sulfide thin films showed different morphologies based on spherical to flower or flakes-like crystallites depending on the temperature of deposition. Powder X-ray diffraction studies of the deposited films revealed formation of pure Covellite-hexagonal phase of copper sulfide, with high crystallinity at elevated temperature. The diffraction pattern of nanoparticles synthesized in dodecanthiol, and 1-octadecene at 150 °C, 190 °C and 230 °C showed the formation of monodispersed nanoparticles of Cu 1.78 S Roxbyite phase with an average size of ca . 12 ± 1 nm. Interestingly, when oleylamine was used as a capping solvent, the formation of Covellite and Digenite phases were obtained at temperatures of 110 °C and 190 °C respectively. Electron microscopic studies showed formation of rod shaped particles at 110 and 150 °C, whereas at higher temperatures formation of fairly spherical nanoparticles were observed.

We report the syntheses of Zn (II) thiosemicarbazone complexes, ZnCl2(benztsczH)2 (1), Zn(benztscz)2 (2) and Zn(4-Cl-benztscz)2 (3), where (benztscz = benzaldehyde thiosemicarbazone (L1) and 4-Cl-benztscz = 4-Chloro benzaldehyde thiosemicarbazone (L2)). The complexes were used as single source precursors for the fabrication of ZnS nanoparticles via thermal decomposition at 230 °C using oleylamine as coordinating solvent. The single crystal X-ray structure of complex (1) was also elucidated. The powder X-ray diffraction (p-XRD) analysis confirmed the cubic and crystalline nature of the as-synthesized ZnS nanoparticles. Transmission electron microscope (TEM) analysis showed formation of spherical nanoparticles with sizes between 5 and 10 nm for oleylamine capped ZnS nanoparticles. Optical absorption analysis showed ZnS displaying size quantum effect due to the small size of the as-synthesized particles. The value of absorption band gap determined varies in the range of 3.7–3.9 eV. Room temperature photoluminescence (PL) spectrum of ZnS nanoparticles exhibit a blue emission peak at ∼387 nm.

Two nickel(II) complexes, namely piperidine (1) and tetrahydroquinoline (2) dithiocarbamate complexes were synthesized and characterized by infra-red spectroscopy, elemental analysis and thermogravimetric analyses. The single crystal X-ray structure of complex (1) was also elucidated. The as-synthesized complexes have been utilized as single source precursors to afford nickel sulfide nanoparticles Ni3S4, Ni3S2 and mixed phases via solvothermal decomposition in oleylamine (OLA), dodecylamine (DDA) and hexadecylamine (HDA) at different temperatures. Powder X-ray diffraction studies reveal that the temperature and capping agents play a significant role in determining the crystalline structure and chemical composition of the as-synthesized nanoparticles (NPs). Electron microscopy images showed formation of nanoparticles of various shapes ranging from spherical, tetrahedral and irregular shaped morphologies. Magnetization measurements indicated that Ni3S4 nanoparticles prepared at 230 °C using DDA display ferromagnetic behaviour, while rhombohedral N3S2 also prepared at 230 °C but using HDA, displayed paramagnetic property.

We report the synthesis of castor oil capped hierarchical PbS nanostructures using piperidine dithiocarbamate of lead(II) complex as a single source precursor. The anisotropic structures of PbS were obtained at reaction temperatures of 190, 230, 270 and 300 °C. The optical properties of the PbS nanostructures show evidence of quantum confinement.

We report the synthesis of castor oil and ricinoleic acid capped CdS nanoparticles by the thermolysis of piperidine (1) and tetrahydroquinoline (2) dithiocarbamate complexes of cadmium(II) at temperatures varying from 190 °C to 300 °C. Reaction parameters such as time and temperature were varied to study their effect on the properties and morphology. The optical properties of CdS were typical of particles that displayed quantum confinement effects. X-ray diffraction studies revealed the existence of both cubic and hexagonal phases depending on the reaction conditions. Ricinoleic acid capped CdS gave cubic phase particles whereas castor oil capped CdS gave both cubic and hexagonal phases dependent on the reaction temperature and the type of complex used. The morphology of the particles varied from oval-short rods to spherical shaped particles with sizes ranging from 10 to 22 nm. Rhodamine B (RhB) dye photodegradation studies of a representative CdS nanoparticles’ sample have been carried out in the presence of halogen light and studied using UV–visible spectroscopy.

Castor oil and ricinoleic acid (an isolate of castor oil) are environmentally friendly bio-based organic surfactants that have been used as capping agents to prepare nearly spherical cadmium sulfide quantum dots (QDs) at 230, 250 and 280 °C. The prepared quantum dots were characterized by Ultra violet–visible (UV–vis), Photoluminescence (PL), Transmission Electron Microscopy (TEM), High Resolution Transmission Electron Microscopy (HRTEM) and X-ray diffraction (XRD) giving an overall CdS QDs average size of 5.14±0.39 nm. The broad XRD pattern and crystal lattice fringes in the HRTEM images showed a hexagonal phase composition of the CdS QDs. The calculated/estimated average size of the prepared castor oil capped CdS QDs for various techniques were 4.64 nm (TEM), 4.65 nm (EMA), 5.35 nm (UV–vis) and 6.46 nm (XRD). For ricinoleic acid capped CdS QDs, the average sizes were 5.56 nm (TEM), 4.78 nm (EMA), 5.52 nm (UV–vis) and 8.21 nm (XRD). Optical properties of CdS QDs showed a change of band gap energy from its bulk band gap of 2.42–2.82 eV due to quantum size confinement effect for temperature range of 230–280 °C. Similarly, a blue shift was observed in the photoluminescence spectra. Scanning electron microscope (SEM) observations show that the as-synthesized CdS QDs structures are spherical in shape. Fourier transform infra-red (FTIR) studies confirms the formation of castor oil and ricinoleic acid capped CdS QDs.

The crystal structure and phase transformations of iron sulfide nanomaterials have interesting properties that can be utilized in solar cells, biological and other applications. Iron (III) complexes piperidine (1) and tetrahydroquinoline (2) dithiocarbamate have been synthesized and subsequently utilized as single source precursors for the preparation of iron sulfide nanoparticles by solvothermal and pyrolysis methods. The powder X-ray diffraction (p-XRD) studies gave crystalline information of the iron sulfide nanoparticles which were dependent on the reaction conditions. Only the greigite phase (Fe3S4) was obtained when the solvothermal method was used during the synthesis. The pyrolysis method gave a mixture of pyrite (FeS2) and pyrrhotite phases when complex (1) was used while complex (2) gave pure pyrrhotite. Well interconnected microstructures and nanoflakes-like structures were obtained by scanning electron microscopy imaging. Furthermore, magnetic properties of the as-synthesized nanoparticles displayed ferromagnetic and antiferromagnetic behaviour, typical of greigite and pyrrhotite nanoparticles respectively. A direct band gap of 2.70 eV was obtained according to optical absorption studies.

Cadmium(II) thiosemicarbazone complexes were prepared and characterized by elemental analysis and IR and NMR spectroscopy. The complexes were then investigated as potential single-source precursors for the synthesis of oleylamine-capped cadmium sulfide nanoparticles by solvothermal decomposition. The resulting nanomaterials were characterized by powder XRD, TEM, HRTEM, energy-dispersive X-ray analysis, and UV/Vis spectroscopy. Peak broadening in the XRD patterns confirmed the presence of relatively small hexagonal CdS nanocrystals. The TEM studies evidenced that the chlorido precursors produced CdS nanostructures whose morphologies differed from those obtained from the iodido precursors. CdS nanoparticles in the form of cubes/spheres/rods and nanodendrite structures were obtained from CdCl2 and CdI2 thiosemicarbazone complexes, respectively. The UV/Vis spectra revealed that the as-synthesized CdS nanoparticles exhibited a quantum effect due to their sharp band edges, which are blueshifted relative to those of bulk CdS. The size, morphology and shape of the nanoparticles were also shown to depend on the temperature of formation.