Thiocyanate Compounds Research Articles

Synthesis and Anticancer Activity of New 2-methylquinoline with Pyridine, Thiazole and Pyrazole Derivatives

This work presents a novel class of 2-methylquinoline derivatives that combine pyridine, thiazole, pyrazole ring systems. The precursor 1-(2-methylquinolin-3-yl) ethanone (1) is combined with aldehydes, malononitrile and ethyl cyanoacetate in a one-pot synthesis to produce 2-amino-6-(2-methylquinolin-3-yl)-4-phenylpyridine hybrids 2 and 3. Synthetic approaches to the (E)-1-(1-(2-methylquinolin-3-yl) ethylidene) hybrids 5, 6, to treat 1 with thiosemicarbazide and 1-chloropropan-2-one and to get 7, 8, the compound 1 is treated with bromine and thiourea. Then by using 2-chloroacetyl chloride and ammonium thiocyanate compounds 9, 10 were prepared. Furthermore compound 11 is formed when dimethoxy-N,N-dimethylmethanamine and xylene are treated with compound 1. The 2-methyl-3-(1H-pyrazol-3-yl) quinoline motif 12 was prepared by reacting 1 with dimethylamine and then treating the mixture with hydrazine. When examined in vitro on A549 and MCF-7 cancer cell lines, the anti-cancer effects were comparable to those of doxorubicin.

Recent Advancement on the Indirect or Combined Alternative Thiocyanate Sources for the Construction of S-CN Bonds.

The process of thiocyanation is a notable chemical conversion owing to the extensive range of applications associated with thiocyanate compounds in the field of organic chemistry. In past centuries, the thiocyanation reaction incorporated metal thiocyanates or thiocyanate salts as sources of thiocyanate, which are environmentally detrimental and undesirable. In recent literature, there have been numerous instances where combined or indirect alternative sources of thiocyanate have been employed as agents for thiocyanation, showcasing their noteworthy applications. The present literature review focuses on elucidating the ramifications associated with the utilization of indirect or combined alternative sources of thiocyanate in various thiocyanation reactions.

Synthesis, structural characterization, antibacterial activity, DFT computational studies and thermal analysis of two new thiocyanate compounds based on 1-phenylpiperazine

Two hybrid materials, (HPhPip)2[Co(NCS)4] (I) and (HPhPip)(NCS)•PhPip (II), were grown using the slow evaporation method. The characterization of both compounds was accomplished by means of different analytical techniques such as IR, TGA–DTA, and single X-ray diffraction. XRD showed that compounds (I) and (II) crystallized into triclinic and noncentrosymmetric orthorhombic systems, respectively. In Compound (I), the Co(II) ion is surrounded by four NCS−anions and shows a distorted tetrahedral coordination geometry. Crystal packing analysis indicates that the [Co(NCS)4]2−anion and 1-phenylpiperazinium cation are linked together through N–H…S to form a graph set. Compound (II) presents an interesting 3-D network via N–H…N, C–H…S, and C–H•••π intermolecular interactions between HPhPip+, NCS−, and PhPip, consolidating the stacking of the crystal. FT-IR was used to explore the modes of vibration of the different functional groups present in two compounds. A theoretical investigation has also been performed via DFT on the molecular structure of compounds, allowing the determination of the Mulliken charge distribution, the Molecular Electrostatic Potential maps, and the HOMO–LUMO diagrams. The Hirshfeld surface, two-dimensional fingerprint plots and enrichment ratio were investigated to indicate the important role of intermolecular interactions. The robust thermal stability of the two crystals was ensured by thermogravimetric–differential thermal analysis. Finally, the bacterial potency of two compounds has been surveyed.

Synthesis, Crystal Structures and Properties of Ni(NCS)2‐3‐Cyanopyridine Coordination Compounds including a Ferromagnetic Layered Compound

AbstractReactions of Ni(NCS)2 and 3‐cyanopyridine in different solvents lead to the formation of Ni(NCS)2(3‐cyanopyridine)4 (1) already reported in the literature, Ni(NCS)2(3‐cyanopyridine)2(H2O)2 (2), Ni(NCS)2(3‐cyanopyridine)2(CH3OH)2 (3), Ni(NCS)2(3‐cyanopyridine)2(CH3CN)2 (4) and Ni(NCS)2(3‐cyanopyridine)2 (5). The crystal structures of 1–4 consist of discrete octahedral complexes, in which the thiocyanate anions, as well as the 3‐cyanopyridine coligands, are only terminally N‐bonded. In compound 5 the Ni cations are octahedrally coordinated and linked by pairs of thiocyanate anions into dinuclear units that are further connected into layers by single μ‐1,3‐bridging anionic ligands. TG‐DTA measurements of the discrete complex 1 reveal that in the first step half of the coligands are emitted leading to the formation of compound 5. In contrast, compounds 2 and 3 transform into a new crystalline phase of the same composition (6) upon heating that should also contain μ‐1,3‐bridging anionic ligands, but the outcome of this reaction strongly depends on the reaction conditions. The acetonitrile complex 4 is unstable at room temperature and decomposes into a mixture of different phases including the aqua complex 2. Magnetic measurements of compound 5 prove a ferromagnetic transition at Tc=6.0 K. This result is compared to those obtained for other thiocyanate compounds exhibiting a similar layer topology.

Pseudo‐Halide Perovskite Solar Cells

AbstractPerovskite solar cells (PSCs) have achieved certified power conversion efficiency (PCE) over 25%. Though their high PCE can be achieved by optimizing absorber layer and device interfaces, the intrinsic instability of perovskite materials is still a key issue to be resolved. Mixed‐halide perovskites using multiple halogen constituents have been proved to improve robustness; however, the anion at the X site in the ABX3 formula is not limited to halogens. Other negative monovalent ions with similar properties to halogens, such as pseudo‐halogens, have the opportunity to form perovskites with ABX3 stoichiometry. Recently, thiocyanates and formates have been utilized to synthesize stable perovskite materials. This review presents the evolution of pseudo‐halide perovskite solar cells in the past few years. The intrinsic properties, their effects on crystal structure, and bandgap engineering of the pseudo‐halide perovskites are summarized. Various thiocyanate compounds applied in the fabrication of perovskite solar cells are discussed. The fabrication process, film formation mechanism, and crystallinity of pseudo‐halide perovskites are elucidated to understand their effects on the photovoltaic performance and device stability. Other applications of pseudo‐halide perovskites are summarized in the final section. Lastly, this review concludes with suggestions and outlooks for further research directions.

Structures, bonding, and electronic properties of metal thiocyanates

Metal thiocyanates, such as copper(I) thiocyanate (CuSCN) and tin(II) thiocyanate [Sn(SCN)2], are emerging as novel semiconductors for electronic applications, and while other thiocyanate coordination polymers are known, their electronic structures and properties have not been investigated. In this work, we employed density functional theory (DFT) and crystal orbital Hamilton population (COHP) to analyze the electronic structures and bonding character of 18 structures of 15 metal thiocyanate compounds as well as a main group thiocyanate, selenium thiocyanate [Se(SCN)2]. Interestingly, the ionic thiocyanates (groups 1 and 2) display band dispersions despite their valence and conduction bands (VBs and CBs) being derived mostly from the thiocyanate ligand. Thiocyanates of group 11 show the strongest contributions from the metals with their d electrons strongly dominating the top of the VBs. In contrast, metals from group 12 contribute their s electrons to the bottom CBs. Metals of groups 13 and 14 have lone pair electrons in the s orbitals, which are featured at the top of their VBs, while the metal p states contribute to the CBs. The bonding character and orbital contributions can be explained based on the trend in the electron binding energies of the coordinated atoms. The versatility of adjusting the orbital contribution by changing the metals can be used for tuning the electronic properties of semiconductors based on thiocyanate compounds.

Mechanochemical Thiocyanation of Aryl Compounds via C-H Functionalization.

Aryl thiocyanate compounds are important building blocks for the synthesis of bioactive compounds and intermediates for several functional groups. Reported thiocyanation reactions via C–H functionalization have limited substrate scope and low RME. The ball-milling method reported here uses ammonium persulfate and ammonium thiocyanate as reagents and silica as a grinding auxiliary. It afforded aryl thiocyanates with moderate to excellent yields for a wide variety of aryl compounds (36 examples, 8–96% yield), such as anilines, phenols, anisoles, thioanisole, and indole, thus tolerating substrates with sensitive functional groups. New products such as benzo[d][1,3]oxathiol-2-ones were obtained with C-4 substituted phenols. Thus, to our knowledge, we report, for the first time, aryl thiocyanation reaction by ball-milling at room temperature and solvent-free conditions, with short reaction times and no workup. Analysis of several mass-based green metrics indicates that it is an efficient greener method.

Characterization of the simplest sulfenyl thiocyanate: isomers, spectroscopy and implications of astrophysical and biological relevance.

Sulfenyl thiocyanate compounds, RSSCN, are involved in the human immune system biochemical processes. They are also the routes for the synthesis of complex S-containing species such as polypeptides, or symmetrical (RSSR) and unsymmetrical disulfides (RSSR'). At present, we have characterized the stable forms of the simplest sulfenyl thiocyanate compound, HSSCN, at the coupled cluster level. We found twenty-three isomers, for which we determined a set of structural parameters, anharmonic frequencies and reaction energies for the formation of the corresponding diatomic + triatomic and atomic + tetratomic fragments. We also discussed the implications of the present findings for biological entities containing a disulfide bridge, where we identified three isomers that may serve as prototypes. Similarities and differences with other S/N hybrid bioactive molecules are also discussed. From an astrophysical point of view, we expect HSSCN isomers to be present in astrophysical media, since several of their molecular fragments have already been detected. In sum, the present set of data can be used for the identification of HSSCN compounds and understanding the physical chemistry of sulfur containing molecules in vivo, in the laboratory and in astrophysical media.

Electrosynthesis of ( E)-Vinyl Thiocyanates from Cinnamic Acids via Decarboxylative Coupling Reaction.

Thiocyanate compounds are key intermediates in the synthesis of pharmaceuticals and other sulfur-containing organic compounds. Herein, we first report an electrochemical protocol to synthesize vinyl thiocyanates from decarboxylative coupling of cinnamic acids with NH4SCN in aqueous solution. This method provides thiocyanation products with broad functional group tolerance under ambient conditions.

Structural Variability of 4f and 5f Thiocyanate Complexes and Dissociation of Uranium(III)-Thiocyanate Bonds with Increased Ionicity.

A series of complexes [Et4N][Ln(NCS)4(H2O)4] (Ln = Pr, Tb, Dy, Ho, Yb) have been structurally characterized, all showing the same structure, namely a distorted square antiprismatic coordination geometry, and the Ln-O and Ln-N bond lengths following the expected lanthanide contraction. When the counterion is Cs+, a different structural motif is observed and the eight-coordinate complex Cs5[Nd(NCS)8] isolated. The thorium compounds [Me4N]4[Th(NCS)7(NO3)] and [Me4N]4[Th(NCS)6(NO3)2] have been characterized, and high coordination numbers are also observed. Finally, attempts to synthesize a U(III) thiocyanate compound has been unsuccessful; from the reaction mixture, a heterocycle formed by condensation of five MeCN solvent molecules, possibly promoted by U(III), was isolated and structurally characterized. To rationalize the inability to isolate U(III) thiocyanate compounds, thin-layer cyclic voltammetry and IR spectroelectrochemistry have been utilized to explore the cathodic behavior of [Et4N]4[U(NCS)8] and [Et4N][U(NCS)5(bipy)2] along with a related uranyl compound [Et4N]3[UO2(NCS)5]. In all examples, the reduction triggers a rapid dissociation of [NCS]- ions and decomposition. Interestingly, the oxidation chemistry of [Et4N]3[UO2(NCS)5] in the presence of bipy gives the U(IV) compound [Et4N]4[U(NCS)8], an unusual example of a ligand-based oxidation triggering a metal-based reduction. The experimental results have been augmented by a computational investigation, concluding that the U(III)-NCS bond is more ionic than the U(IV)-NCS bond.

Coordination Chemistry of Homoleptic Actinide(IV)-Thiocyanate Complexes.

The synthesis, X-ray crystal structure, vibrational and optical spectroscopy for the eight-coordinate thiocyanate compounds, [Et4 N]4 [Pu(IV) (NCS)8 ], [Et4 N]4 [Th(IV) (NCS)8 ], and [Et4 N]4 [Ce(III) (NCS)7 (H2 O)] are reported. Thiocyanate was found to rapidly reduce plutonium to Pu(III) in acidic solutions (pH<1) in the presence of NCS(-) . The optical spectrum of [Et4 N][SCN] containing Pu(III) solution was indistinguishable from that of aquated Pu(III) suggesting that inner-sphere complexation with [Et4 N][SCN] does not occur in water. However, upon concentration, the homoleptic thiocyanate complex [Et4 N]4 [Pu(IV) (NCS)8 ] was crystallized when a large excess of [Et4 N][NCS] was present. This compound, along with its U(IV) analogue, maintains inner-sphere thiocyanate coordination in acetonitrile based on the observation of intense ligand-to-metal charge-transfer bands. Spectroscopic and crystallographic data do not support the interaction of the metal orbitals with the ligand π system, but support an enhanced An(IV) -NCS interaction, as the Lewis acidity of the metal ion increases from Th to Pu.

The effect of 1:2 Ag(I) thiocyanate complexes in MCF-7 breast cancer cells.

There is much interest currently in the design of metal compounds as drugs and various metal compounds are already in clinical use. These include gold(I) compounds such as auranofin and the anti-cancer platinum(II) complex, cisplatin. Bis-chelated gold(I) phosphine complexes have also shown great potential as anticancer agents, however, their efficacy has been limited by their high toxicity. In this study, silver(I) thiocyanate compounds linked to four specific ligands, were synthesized and characterized. These silver-phosphine adducts included [AgSCN{P(4-MeC6H4)3}2]2 (1); [AgSCN{P(4-ClC6H4)3}2]2 (2); [AgSCN{P(4-MeOC6H4)3}2]2 (3); [AgSCN(PPh3)2]2 (4). The compounds were found to be toxic to MCF-7 breast cancer cells while the ligands on their own were not toxic. Our findings further indicate that the silver(I) phosphine compounds induce apoptotic cell death in these breast cancer cells. In addition, the compounds were not toxic to nonmalignant fibroblast cells at the IC50 concentrations. This is an indication that the compounds show selectivity towards the cancer cells.

Studies on Molecular Interactions of Some Thiocyanate Salts in Coaqueous Solutions of 1,3-Dioxolane + Water by Volumetric, Viscometric, and Speed of Sound Measurements

The densities and viscosities of some thiocyanate compounds, viz., ammonium thiocyanate, sodium thiocyanate, and potassium thiocyanate, in 10 %, 20 %, and 30 % by mass of 1,3-dioxolane + water mixtures have been determined at T = (298.15, 308.15, and 318.15) K and p = 0.1 MPa. The speeds of sound of the thiocyanate compounds in 10 %, 20 %, and 30 % by mass of 1,3-dioxolane + water mixtures have also been determined at 298.15 K. Apparent molar volumes (Vϕ), viscosity B-coefficients, and adiabatic compressibility (β) of these electrolytes were obtained from their densities, viscosities, and speed of sound data. The limiting apparent molar volumes (Vϕo) and experimental slopes (Sv*) derived from the Masson equation and the obtained parameters have been interpreted in terms of ion−solvent and ion−ion interactions, respectively. The viscosity data were evaluated by using the Jones−Dole equation. The structure making/breaking capacities of the electrolytes have been inferred from the sign of (δ2ϕVo/δT2)p and dB/dT. The activation parameters of viscous flow for the ternary solutions studied were also calculated and explained by the application of transition state theory.

Thiocyanate compounds

Thiocyanate compounds

Some properties of a sequencing batch reactor for treatment of wastewater containing thiocyanate compounds

Thiocyanate (SCN) compounds in photo-processing wastewater (PPWW) could be treated by an SBR system without any release of thiocyanate to the atmosphere during the aeration step. An SCN loading greater than 84 g m −3 d −1 showed negative effects on the growth of bio-sludge and removal efficiencies of the system. The acclimatization period of the system was increased with an increase in SCN concentration or loading. The COD, BOD 5, TKN, and SCN removal efficiencies were 96.0±1.6%, 72±2%, 49±5%, and 82±3%, respectively, under an SCN loading of up to 84 g m −3 d −1. The removal efficiency of the system was repressed by SCN due to the repressed growth rate of nitrification bacteria. However, the removal efficiency could be increased with an increase in HRT or a decrease in SCN loading. Also, increases in HRT or decreases in SCN loading led to increased sludge age or solid retention time (SRT) and decreased the sludge volume index (SVI) value. The SRT and SVI of the system with synthetic wastewater containing 840 mg l −1 SCN under an HRT of 3 days (SCN loading of 280 g m −3 d −1) were 3.9±0.7 days and 65±4 ml g −1, respectively, while they were 11.2±0.8 days and 55±6 ml g −1, respectively under an HRT of 10 days (SCN loading of 84 g m −3 d −1).

Different oxidation states of copper(I, I/II, II) thiocyanate complexes containing 1,2,4-triazole as a bridging ligand: syntheses, crystal structures, and magnetic properties of 2-D polymer Cu I(admtrz)SCN, linear trinuclear [CuI2CuII(admtrz)6(SCN)2](ClO4)2, and triangular trinuclear [CuII3(admtrz)4(SCN)3(mu3-OH)(H2O)](ClO4)2.H2O (admtrz = 4-amino-3,5-dimethyl-1,2,4-triazole).

Copper thiocyanate compounds with three different oxidation states, Cu(I)(admtrz)SCN (1), [Cu(I)(2)Cu(II)(admtrz)(6)(SCN)(2)](ClO(4))(2) (2), and [Cu(II)(3)(admtrz)(4)(SCN)(3)(mu(3)-OH)(H(2)O)](ClO(4))(2).H(2)O (3), have been synthesized and characterized (admtrz = 4-amino-3,5-dimethyl-1,2,4-triazole). Compounds 1 and 3 crystallize in the space group Pbca of the orthorhombic system with eight formula units in cells of dimensions a = 8.0221(2) A, b = 32.3844(1) A, c = 13.5659(3) A, R1/wR2 = 0.0595/0.1674 for compound 1 and a = 21.501(3) A, b = 18.382(2) A, c = 21.526(2) A, R1/wR2 = 0.0638/0.1519 for compound 3. Compound 2 crystallizes in the space group C2/c of the monoclinic system with four formula units in cells of dimensions a = 18.772(4) A, b = 11.739(2) A, c = 22.838(5) A, beta = 91.11(3) degrees, R1/wR2 = 0.0482/0.1265. The layered-type structure of 1 can be regarded as constructed from the tetranuclear copper units double bridged by one of the two unique thiocyanate and admtrz ligands, which are bridged by the other unique thiocyanate ligands to form a two-dimensional layered structure along the a and b directions. The linear trinuclear copper cation in mixed-valence compound 2 consists of one two-valence copper and two one-valence copper atoms which are bridged by admtrz ligands, and the external copper(I) atoms are coordinated by terminal thiocyanate. The EPR spectra of 2 show the existence of localized mixed-valence copper ions. The triangle trinuclear copper cation in compound 3 has its Cu(3) triangle capped by one apical mu(3)-OH group, each edge bridged by a bridging admtrz ligand and each Cu atom coordinated by a N atom from the terminal thiocyanate, while one of the three edges is further bridged by another admtrz ligand and the opposite Cu1 atom is coordinated by a water molecule. The EPR and magnetic susceptibility of compound 3 were studied, showing antiferromagnetic behavior.

Comparative X-ray study of three nickel(II)-thiocyanate compounds.

Three cis nickel-dithiocyanate (SCN) complexes with different N,N'-bidentate bases have been prepared and their crystal structures determined: bis(2,2'-bipyridine-N,N')bis(-ato-N)nickel(II), [Ni(SCN)(2)(C(10)H(8)N(2))(2)], bis(1,10-phenanthroline-N,N')bis(thiocyanato-N)nickel(II), [Ni(SCN)(2)(C(12)H(8)N(2))(2)], and bis(2,9-dimethyl-1,10-phenanthroline-N,N')bis(thiocyanato-N)nickel(II) monohydrate, [Ni(SCN)(2)(C(12)H(8)N(2))(2)].H(2)O. Distortions due to ligand size are discussed.

Addition compounds of bis(trifluoromethyl)mercury with tetraphenylphosphonium and tetraphenylarsonium halides and thiocyanates

Addition compounds of Hg(CF 3) 2 with [Ph 4P]X and [Ph 4As]X in the 1:1 ratio for X = Cl, Br, I as well as in the 1:2 ratio for X = SCN, were isolated from aquaeous solution and identified by elemental analysis and infrared spectroscopy. Molar conductance of the thiocyanate compounds in nitrobenzene solution points to its complex-salt nature defined as [Ph 4P] 2[Hg(CF 3) 2(SCN) 2] and [Ph 4As] 2[Hg(CF 3) 2-(SCN) 2], but not for the halide compounds. However, in the monoclinic crystals of the chloride ccompound, as shown by X-ray diffractometry, pairs of [Hg(CF 3) 2 molecules are bridged over by two chlorides in a centro-symmetrical dimer with the CHgC bond angle of 160.5(8)° and the Hg…Cl bond length of 2.823(3) and 2.837(4) Å. The structure was refined to the R factor of 0.053. When X = CN no addition compounds were obtained, the reaction products were HCF 3 and the complex salts [Ph 4P] 2- [Hg(CN)] 4 and [Ph 4As] 2[Hg(CN)] 4, not described so far.

Synthese de fluoro-2 thiocyanates

2-Fluorinated thiocyanate compounds have been prepared by action of KSCN on an homologous series of 2-fluorotosylates in ethanol at about 100°C. The isomerization giving isothiocyanic derivatives does not take place under these conditions. The analysis of the NMR spectra on three members of the series has shown that the mechanism is of the SN 2 type.

Magnetic and Spectroscopic Properties of Metal(II) Thiocyanate Compounds with 3,4-Dialkyl Substituted 1,2,4-TriazoIes

Abstract Syntheses, spectroscopic and magnetic properties are described of a series of metal(II) thio-cyanate compounds with the asymmetric ligands 3-methyl-4-ethyl-l,2,4-triazole and 3-methyl-4-;-butyl-l,2,4-triazole. A dinuclear structure is proposed for the manganese, cobalt and nickel compounds based on the magnetic behaviour as well as on spectroscopic and analytical data. These compounds show antiferromagnetic interaction in the temperature range 4—80 K. The zinc compounds appear to be mononuclear, whereas a chain-like structure is proposed for the cad-mium compounds.