Single Crystal X-ray Crystallographic Techniques Research Articles

2-aminopyrimidine-oxalic acid liquid–liquid charge-transfer interactions: Synthesis, spectroscopic characterizations, and the effect of temperature

The intermolecular charge-transfer (CT) interaction of 2-aminopyrimidine (2AP) (as an electron donor) with oxalic acid (OA) (as a typical σ-electron acceptor) has been studied at multiple temperatures in methanol solvent. The stoichiometry of the generated CT complex (2AP-OA) was determined using the Benesi-Hildebrand method (BHM). The molecular interaction of 2AP donor with OA acceptor has been discussed as a function of temperature. The crystal structure and space group of the 1:1 adduct has been determined using the single-crystal X-ray crystallographic technique. The 1H NMR spectrum of 2AP-OA indicates the formation of N+H∙∙∙O− intermolecular hydrogen bonding. The FTIR spectrum of 2AP-OA also well resolved the complex absorption bands in the region where 2AP and OA bands have been observed. The thermal stability and composition of 2AP-OA were analyzed to compare with 2AP donor and OA acceptor using thermogravimetric (TGA) and differential thermal analysis (DTA). The Van’t Hoff equation was employed to calculate various important thermodynamic parameters (i.e., entropy; ΔS, enthalpy; ΔH, and Gibbs free energy; ΔG). The reaction between 2AP and OA was spontaneous and exothermic in nature, as indicated by the negative values of ΔG and ΔH.

Synthesis, Crystal structure, photoluminescence properties and quantum mechanics studies of two schiff bases of 2-amino-p-cresol

The compounds, (E)-2-((2,5-dimethoxybenzilidene) amino)-4-methylphenol (DMB–APC) and 2-((E)-((E)-3-(4-methoxyphenyl)allylidene)amino)-4-methylphenol (TPPC) were synthesized and characterized using FTIR, 1H and 13C NMR, MS and single crystal X-ray crystallographic techniques. The molecular geometry and vibrational frequencies of the compounds in the ground state were calculated using the density functional theory in conjunction with Becke 3-Lee–Yang Parr functional and 6–31 G (d,p) basis set. The electronic structure calculation (energy gap) and molecular electrostatic potential map of the compounds were performed at the B3LYP level of theory and the 6 -31 G (d,p) basis set.. The nonlinear optical properties [dipole moment(μ), average polarizability(α), anisotropy of polarizability (Δα) and first hyperpolarizability(β)] of the compounds were determined from fluorescence spectra and quantum mechanical calculation. The excitation spectra of the compounds showed bands in the UV region of 306, 345 nm for DMB–APC and 311, 410 nm for TPPC, while the emission spectra of the compounds showed bands in the visible region centred at 462, 486 nm for DMB–APC and 492, 533 nm for TPPC. The energy gap of the first electron excitation from HOMO to LUMO are 3.89 and 3.69 eV, while the first hyperpolarizability is 100.55 and 154.22 eV for DMB–APC and TPPC respectively. The calculated parameters of the compound are in good agreement with the experimental data. Based on the emission bands, low energy gap, and the high first hyperpolarizability values, DMB –APC and TPPC show promise for the development of non-linear optical materials.

Synthesis, structural characterization, in vitro comparative DNA/RNA binding, and computational studies of half-sandwich Ru (II)(ƞ6-p-cymene) aminoquinoline complex

We describe herein, synthesis of a half-sandwich Ru (II)(ƞ6-p-cymene) complex 1 containing aminoquinoline ligand. Complex 1 was characterized by various spectroscopic and single-crystal X-ray crystallographic techniques. The “piano-stool” complex crystallizes in a triclinic P1¯ space group with ruthenium (Ⅱ)(p-cymene) fragment tethered to a primary amine nitrogen atom of aminoquinoline. DFT calculations were performed to generate UV and IR spectra of complex 1 which further supported the experimental data. Comparative DNA/RNA binding studies of the complex were carried out by employing UV–vis, fluorescence, circular dichroism, and cyclic voltammetric techniques. The intrinsic binding constants of the complex 1 with ct-DNA and tRNA were calculated to be 3.9 × 105 (±0.09) M−1 and 2.45 × 104 (±0.10) M−1 which indicated a stronger binding affinity of the complex 1 towards ct-DNA. The pBR322 plasmid scissoring efficiency of the complex was explored by performing gel electrophoresis. The results suggested that the complex induced double-stranded DNA cleavage at 35 μM concentration which is mediated via an oxidative pathway. RNA gel fragmentation assay was also performed in both concentration and time-dependent manner and an appreciable reduction in the intensity of the bands was observed after 24 hr incubation which demonstrated complete cleavage of the tRNA. BSA and lysozyme binding studies of the complex were also carried out and the results revealed that complex 1 quenched the fluorescence intensity of the proteins. Cytotoxicity studies revealed low cytotoxicity against three human cancer cell lines. Furthermore, molecular modeling approach was applied to probe the binding-conformation of the complex with ct-DNA/tRNA and the results showed that complex 1 exhibited preferential binding propensity towards ct-DNA.

A photoswitchable “turn-on” fluorescent chemosensor: Quinoline-naphthalene duo for nanomolar detection of aluminum and bisulfite ions and its multifarious applications

A quinoline-naphthalene duo-based Schiff base probe (R) was synthesized and characterized by the usual spectroscopic and single-crystal X-ray crystallographic techniques. Probe R detects Al3+ and HSO3− ions via the fluorescent turn-on approach by dual pathways i.e., i) when probe R interacts with Al3+, the restriction of CN single bond rotation, blocking of both photoinduced electron transfer (PET) and CN isomerization were observed, and ii) when the sensor R interacts with HSO3−, imine (CH = N) bond was cleaved via hydrolysis and produced the respective aldehyde and amine behaving as a chemodosimeter. The binding stoichiometric ratio of R + Al3+ (1:1) was confirmed by Job’s plot, emission titration profile, NMR, and mass spectrometric analyses. This probe R is highly selective to both Al3+ -ions and HSO3− -ions, without any interference of other potentially competing cations and anions. Limit of detection (LOD) and quantification (LOQ) of R with Al3+ and HSO3− were downed to nanomolar concentrations, which is much lower than the recommended level of drinking water/food fixed by the World Health Organization (WHO). Furthermore, probe R was utilized in the detection of Al3+ and HSO3− ions in highly contaminated real samples, bioimaging in E. coli cells, multiple-targeting molecular logic gate, and in bovine serum albumin (BSA) binding.

The transition metal complexes of Fe(II), Ni(II) and Cu(II) derived from phthalazine based ligands: Synthesis, crystal structures and biological activities

Twelve metal complexes of Iron(II), Nickel(II) and Copper(II) have been synthesized in 1:1 and 1:2 molar ratio from new phthalazine based ligands (E)-2-(phthalazin-1-yl)-1-(1-(pyridin-2-yl)ethylidene)hydrazine (L1) and (E)-2-(phthalazin-1-yl)-1-((pyridin-2-yl)methylene)hydrazine (L2). The compounds have been characterized by UV-Visible, FT-IR, 1H-NMR, LC-MS/ESI-MS spectroscopic techniqueas well as conductivity measurements and finally structures of some of the compounds have been confirmed through single crystal X-ray crystallographic technique. Crystal data for [Cu(II)L1Cl](2) complex: C15H12ClCuN5, triclinic, Space group P-1, a = 10.5114(11) Å, b= 10.7962(11) Å, c = 13.7510(14) Å, α = 74.206(9)°, β = 71.981(9)°, γ = 84.122(8)° and Z = 1, final R1 was 0.0553(I > 2σ(I)) and wR2 was 0.1892(all data). Crystal data for [Ni(II)(L1)2](ClO4)2(7) complex: C30H26Cl2N10NiO8, monoclinic, Space group P21/n, a = 13.0740(7) Å, b = 19.1326(10) Å, c = 14.5808(9) Å, α = 90°, β = 104.511(6)°, γ = 90°, V = 3530.9(4) Å3, Z = 4, final R1 was 0.0778 (I > 2σ(I)) and wR2 was 0.2226 (all data). Crystal data for [(L2)2(μ-Cl)Cu2(II)]Cl(10) complex: C28H22Cl2Cu2N10, triclinic, Space group P-1, a = 7.7441(15) Å, b = 14.954(3) Å, c = 15.004(3) Å, α = 92.458(11)°, β = 96.234(11)°, γ = 96.291(12)° and Z = 2, final R1 was 0.0576(I > 2σ(I)) and wR2 was 0.1671(all data). Crystal data for [Ni(II)(L2)2](ClO4)2(14) complex: C28H22N10O8Cl2Ni, monoclinic, Space group P21/c, a = 13.1220(12) Å, b = 11.3216(10) Å, c = 23.982(2) Å, α = 90°, β = 104.621(4)°, γ = 90° and Z = 4, final R1was 0.0931(I > 2σ(I)) and wR2 was 0.3083 (all data). The compounds were investigated for their antimicrobial, antioxidant and DNA cleavage activities.

Synthesis, characterization and anticancer activity of Fe(II) and Fe(III) complexes containing N-(8-quinolyl)salicylaldimine Schiff base ligands.

A series of Fe(II) complexes (1-4) and Fe(III) complexes (5-8) from Fe(II)/(III) chloride and N-(8-quinolyl)-X-salicylaldimine Schiff base ligands (Hqsal-X2/X: X = Br, Cl) were successfully synthesized and characterized by spectroscopic (FT-IR, 1H-NMR), mass spectrometry, thermogravimetric analysis (TGA), and single crystal X-ray crystallographic techniques. The interaction of complexes 1-8 with calf thymus DNA (CT-DNA) was determined by UV-Vis and fluorescence spectroscopy. The complexes exhibited good DNA-binding activity via intercalation. The molecular docking between a selected complex and DNA was also investigated. The in vitro anticancer activity of the Schiff base ligands and their complexes were screened against the A549 human lung adenocarcinoma cell line. The complexes showed anticancer activity toward A549 cancer cells while the free ligands and iron chloride salts showed no inhibitory effects at 100µM. In this series, complex [Fe(qsal-Cl2)2]Cl 6 showed the highest anticancer activity aginst A549 cells (IC50 = 10µM). This is better than two well-known anticancer agents (Etoposide and Cisplatin). Furthermore, the possible mechanism for complexes 1-8 penetrating A549 cells through intracellular ROS generation was investigated. The complexes containing dihalogen substituents 1, 2, 5, and 6 can increase ROS in A549 cells, leading to DNA or macromolecular damage and cell-death induction.

Synthesis, crystal structures and antimicrobial activity of palladium metal complexes of sulfonyl hydrazone ligands

Palladium complexes of sulfonyl hydrazone based ligands have been prepared by refluxing with the corresponding ligands and Pd(II) salt in 2:1 ratio. The compounds have been characterized by FT-IR and UV-Vis spectroscopic methods. The crystal structure of the prepared palladium complexes has been determined by single-crystal X-ray crystallographic technique. Crystal data for C40H50N4O6PdS2 (PMHT-Pd(II) complex): triclinic, space group P-1 (no. 2), a = 7.1561(6) Å, b = 12.1300(11) Å, c = 12.6117(17) Å, α = 63.498(11)°, β = 86.694(9)°, γ = 81.451(7)° and Z = 1. The final R1 was 0.0699 (I > 2σ(I)) and wR2 was 0.1834 (all data). Crystal data for C36H42N4O6PdS2 (PTHC-Pd(II) complex): monoclinic, space group P21/n (no. 14), a = 8.6726(2) Å, b = 20.8824(4) Å, c = 10.3351(2) Å, β = 104.429(2)° and Z = 2. The final R1 was 0.0344 (I > 2σ(I)) and wR2 was 0.0840 (all data). Crystal data for C36H42N4O6PdS2 (PTHT-Pd(II) complex): monoclinic, space group P21/n (no. 14), a = 9.7658(2) Å, b = 10.0488(3) Å, c = 18.7714(4) Å, β = 99.602(2)° and Z = 2. The final R1 was 0.0334 (I > 2σ(I)) and wR2 was 0.0832 (all data). Crystal data for C40H50N4O6PdS2 (PMHC-Pd(II) complex): triclinic, space group P-1 (no. 2), a = 10.2070(9) Å, b = 12.1841(13) Å, c = 16.8879(19) Å, α = 109.005(6)°, β = 90.061(5)°, γ = 99.032(5)° and Z = 2. The final R1 was 0.0822 (I > 2σ(I)) and wR2 was 0.2293 (all data). The single-crystal structure data showed a good agreement with the experimental results. The synthesized complexes were screened for their in vitro antibacterial activity against one Gram-negative (Escherichia coli) and two Gram-positive (Bacillus subtilis and Staphylococcus aureus) bacterial strains and for in vitro antifungal activity against Aspergillus niger, Aspergillus flavus and Aspergillus fumigatus. The PTHC-Pd(II) complex possesses the nearby significant antifungal activity analogous to the standard drug fluconazole against selected fungal strains Aspergillus niger, Aspergillus Flavus and Aspergillus fumigatus as well as the same complex showed the antibacterial activity for Staphylococcus aureus as comparable to standard ofloxacin drug.

Experimental and computational investigation of polymorphism in methyl 3-hydroxy-4-(piperidin-1-ylmethyl)-2-naphthoate

A piperidine substituted methyl 3-hydroxy-2-naphthoate was synthesized for application as a supramolecular host, which yielded colorless and light yellowish orange crystals using different solvents for crystallization. The crystals of the substituted methyl 3-hydroxy-2-naphthoate were analysed using melting point, IR, Reflectance UV–Visible, fluorescence, SEM, 1H NMR, DSC, PXRD and single crystal X-ray crystallographic techniques to reveal polymorphism. The crystal data were also analysed computationally using Gaussian 09, CLP-PIXEL, Crystal Explorer software to reveal the differences in the intermolecular interactions and optical properties. The short intermolecular interactions such as C–H … π and π … π interactions differentiated the polymorphs of the molecule studied here.

New dinuclear Schiff base complexes of iron(II/III) and copper(II) ions: synthesis, crystal structure, and DNA-binding studies

Pyridine-2-carboxaldehyde-semicarbazone (PCS) complex [(H2PCS).Cl]+[Fe(II)(PCS)Cl3]–.[Fe(III)(PCS)Cl3] · (HPCS) · (Cl) (1) and 2,3-diacetylhydrazoneoxime (DAHO) complex [Cu2(μ-Cl)2(DAHO)2Cl2] (2) have been synthesized and characterized by different spectroscopic techniques. Structures were confirmed by single crystal X-ray crystallographic technique. Complex 1 crystallizes as Fe(II)/Fe(III) coordination complex in triclinic crystal system. EPR signals of 1 at g = 4.2 and g = 1.8 show transitions within mS = ±3/2 and mS = ±1/2 Kramers’ doublets of high spin (S = 5/2) distorted octahedral Fe(III) complex. Complex 2 crystallizes in triclinic system as square pyramidal chloro-bridged dinuclear copper(II) complex. The complexes were found to be groove binding to calf-thymus DNA.

Effect of H-bond and molecular geometry towards innocent and non-innocent behavior of 3,5-di-tert-butyl-2-aminophenol units attached to a piperazine backbone: Co(III) and Cu(II) complexes

A 2-aminophenol-based potential non-innocent ligand H4L have been synthesized by reacting 2,2′-(piperazine-1,4-diylbis(methylene))dianiline with 2.0 equivalent amounts of 3,5-di-tert-butyl-catechol. In the ligand, both 2-aminophenol units were connected by a piperazine unit. X-ray single crystal analysis of ligand H4L revealed that piperazine unit was present in the more stable chair conformation. The ligand provided six-coordinate, mononuclear, diamagnetic complex 1 {[CoIII(H2L)]Cl} upon reacting with CoCl2·6H2O. A binuclear biradical-containing complex 2 {[CuII2(L)Cl2]} was obtained by reacting ligand H4L with 2.0 equivalent amounts of CuCl2·2H2O. Both the complexes were characterized by using IR, mass, UV–Vis/NIR, and single crystal X-ray crystallographic techniques. X-ray crystallographic analysis revealed that in complex 1 the ligand unit retained its oxidation state, while one-electron oxidation of each 2-aminophenol unit to 2-iminosemiquinone unit was noticed in case of complex 2. Two strong intramolecular H-bond interactions were found to be responsible for the innocent character of the 2-aminophenol coordination units in complex 1. Herein, the boat conformation of the piperazine backbone and the octahedral geometry of the complex promoted the interactions. The ligand, upon reacted with an equivalent amount of Cu(ClO4)2·6H2O in the presence of Et3N under air in CH3CN, provided a green solid (complex 3). Spectroscopic characterization, and DFT–based computational study indicated that the green solid was a four-coordinate, mononuclear, paramagnetic Cu(II) complex {3; [CuII(L)]} with two coordinated iminosemiquinone radicals. The optimized structure revealed that the piperazine unit in the complex was in the boat conformation.

Synthesis, anticancer, structural, and computational docking studies of 3-benzylchroman-4-one derivatives

A series of 3-Benzylchroman-4-ones were synthesized and screened for anticancer activity by MTT assay. The compounds were evaluated against two cancerous cell lines BT549 (human breast carcinoma), HeLa (human cervical carcinoma), and one noncancerous cell line vero (normal kidney epithelial cells). 3b was found to be the most active molecule against BT549 cells (IC50 = 20.1 µM) and 3h against HeLa cells (IC50 = 20.45 µM). 3b also exhibited moderate activity against HeLa cells (IC50 = 42.8 µM). The molecular structures of 3h and 3i were solved by single crystal X-ray crystallographic technique. Additionally, the molecular docking studies between the tumour suppressor protein p53 with the lead compound 3h, which exhibited better anticancer activity against HeLa cells was examined.

A nickel(II) thiosemicarbazonato complex: synthesis, structure, electrochemistry, and application in catalytic coupling of terminal alkynes with arylboronic acids

A simple route for the synthesis of a new square-planar nickel(II) complex of 2-((3-methylthiophen-2-yl)methylene)hydrazinecarbothioamide is described. Elemental analysis, solution conductivity, and spectral measurements were used to authenticate the composition of the complex. In addition, the X-ray crystal structure of the complex was obtained. Each of the two ligands of the centrosymmetric structure is coordinated to the metal center via the azomethine N and the thioimidate S atoms, forming five-membered chelate rings. Infrared and NMR spectroscopic features of the complex are consistent with its molecular structure. The complex displays a quasi-reversible reduction with E 1/2 of −0.83 V (ΔE p 160 mV), indicating that the ligand system can stabilize the Ni(I) oxidation state. The complex acts as an active catalyst for the C–C coupling of aryl acetylenes with arylboronic acids containing a variety of substituents. The influence of solvent, base, reaction temperature, and catalyst loading on the C–C coupling reaction was evaluated. A new square-planar nickel(II) complex bearing 2-((3-methylthiophen-2-yl)methylene)-hydrazinecarbothioamide was synthesized and characterized by elemental analysis, FTIR, NMR, and single-crystal X-ray crystallographic technique. Cyclic voltammetric study indicates stabilization of Ni(I) oxidation state. The complex acts as an effective catalyst for the carbon–carbon cross-coupling reaction of substituted phenylacetylenes with various arylboronic acids under optimized conditions.

Synthesis, Characterization and Magnetic Studies of Dysprosium Complex, [Dy2(TEA)2(O2CPh)4·2H2O

A dysprosium complex, [Dy2 (TEA)2(O2CPh)4·2H2O] has been synthesized using TEA (tri-ethanolamine) and benzoic acid. The obtained complex is a dimer in which both of the TEA is linked with two dysprosium ions through the protonated oxygen atoms and the resultant molecule is Centro symmetric. The nature of bonding and structure of the synthesized dimer was explored from infrared, magnetic studies and single crystal X-ray crystallographic technique. The crystal structure of the complex has triclinic crystal system and P-1 space group. Unit cell parameters are: a = 10.0931(4) A, b = 10.8841(5) A, c = 10.9441(5) A, and α = 73.915(2)°, β = 74.833(2)°, γ = 67.764(2)°, V = 1052.54(8) A3, Dx = 1.801 Mg/m3 and Mr = 1141.84. The complex possesses small value of coercivity which indicates that it is a soft ferromagnetic material and can resist with external magnetic field without becoming demagnetized. A dysprosium complex was synthesized from tri-ethanolamine and benzoic acid and was characterized through various physical techniques such as infrared, magnetic studies and single crystal X-ray crystallography. Small value of coercivity indicates that it is a soft ferromagnetic material and can resist with external magnetic field without becoming demagnetized.

Dinuclear PdII/PtII complexes [M2(phosphine)n(thio-ligand)3]Cl incorporating N,S-bridged pyridine-2-thiolate and benzimidazoline-2-thiolate

Equimolar reaction of [PdCl2(dppm)] {dppm=bis(diphenylphosphino) methane} with pyridine-2-thione (pySH) in presence of NaOH base in aqueous ethanol formed dinuclear mixed-ligand complex, [PdII2(μ-κ2:N,S-pyS)3(μ-P,P-dppm)]Cl 1. Similarly, reaction of PdCl2(PPh3)2 with benzimidazoline-2-thione (bzimSH) in 1:2M ratio in the presence of Et3N base in acetonitrile has formed a dinuclear complex, [PdII2(μ-κ2:N,S-bzimS)2(κ1-S-bzimS)(PPh3)3]Cl·2H2O 2. Surprisingly, analogous thio-ligand, 1,3-imidazoline-2-thione (imzSH), merely formed a simple square planar complex, [Pd(κ1-S-imzSH)4]Cl2·2H2O 3. The reaction of H2PtCl6 with pySH and dppm (1:1:1M ratio) in the presence of Et3N base in toluene–ethanol (1:1:: v/v) mixture also formed a mixed-ligand dinuclear complex [PtII2(μ-κ2:N,S-pyS)3(μ-P,P-dppm)]Cl similar to 1. All these complexes have been characterized using analytical data, IR, NMR (1H, 31P), UV–vis, fluorescence, ESI-mass and single crystal X-ray crystallographic techniques. The anionic thio-ligands are N,S-bridged in complexes 1 and 4, both N,S-bridged and κ1-S bonded in 2 and as neutral κ1-S bonded in 3. There are short M⋯M contacts in 1 and 4 (1: 2.7249(5) Å; 4: 2.7350(8) Å). Complexes 1, 3 and 4 showed intense fluorescence. ESI mass spectral studies of 1, 3 and 4 revealed the formation of molecular ions and other species.

Design, Structural Characterization and Catalytic Activity of Incomplete Dicubane Clusters of N-Substituted Diethanolamines

A series of four new clusters with cationic unit [Co4(µ3-OH)(Rdea)2(L–L)4]4+ [R = –CH3 (1 and 2) or –CH2CH2CH2CH3 (3 and 4), L–L = 1,10-phenanthroline or 2,2′-bipyridine] is designed and characterized by elemental, spectroscopic (FTIR, ESI MS, UV–visible), thermal, electrochemical, magnetic, SEM, EDX, PXRD and single crystal X-ray crystallographic techniques. Spectral and single crystal X-ray studies reveal the complexes 1–4 are tetranuclear clusters where the primary aminoalcohol derivative ligand is present in dianionic form i.e., Medea2− or n Budea2−. It is confirmed from the magnetic and bond valence summation data that the four cobalt ions are present in mixed valent states (Co 2 2+ –Co 2 3+ ), which is further corroborated from the Co–O and Co–N bond lengths in X-ray structure. The bridging two hydroxide ions consolidate the tetranuclear clusters by bonding with three neighboring metal ions and a rare incomplete dicubane core is formed in all the complexes. A supramolecular framework is generated by H-bonding, π–π, CH···π, and H···H interactions. Presence of N-alkyl group and N-heterocyclic chelator facilitates the generation of these non covalent interactions thus stabilizing the framework. Of all the complexes reported here, 1 is found most efficient catalyst for the cobalt-catalyzed aerobic oxidation of neat ethylbenzene and p-xylene.

Square-planar Ni(II) thiosemicarbazonato complex as an easily accessible and convenient catalyst for Sonogashira cross-coupling reaction

A simple route for the synthesis of a new square-planar nickel(II) complex bearing 2-((3-methylthiophen-2-yl)methylene)-N-phenylhydrazinecarbothioamide ligand has been described. The composition of the complex has been established by elemental analysis, FT-IR, NMR, and single crystal X-ray crystallographic technique. The complex acts as an active homogeneous catalyst for the Sonogashira reaction of phenylacetylene with electron deficient (activating) and electron rich (deactivating) aryl halides (iodides and bromides) under optimized conditions.

Probing mechanism of α-formylketene dithioacetal towards the facile formation of functionalized pyrimidines: A structural approach

α-Formylketene dithioacetal is an active precursor for the synthesis of a variety of organic compounds including pyrimidines and its functionalized materials. The present study deals with the structural versatility of a solid representative compound from the family of α-formylketene dithioacetal to the formation of functionalized pyrimidines derivatives through experimental as well as theoretical methods. 2-(3,4-dimethoxybenzoyl)-3,3-bis(methylsulfanyl)prop-2-enal, the representative compound was synthesized with a reported protocol and characterized through spectral methods. The complete three dimensional solid state structural studies were carried out utilizing single crystal X-ray crystallographic technique along with theoretical methods like classical and accelerated molecular dynamics simulation. Various quantum chemical parameters were also discussed to reveals the complete molecular geometry and reactivity of designated compound.

Synthesis of tweezer type receptors for colorimetric detection of cyanide ions

Two tweezer type receptors based on the hydrazone functional group using o-phthalaldehyde moiety as spacer were synthesized and characterized via 1H, 13CNMR, MALDI-MS and single crystal X-ray crystallographic techniques. The anion sensing abilities of the synthesized receptors were investigated in DMSO using UV–Visible spectroscopy and naked eye detection. The crystal structure revealed the presence of a DMSO molecule in the cavity of the receptor. A receptor displayed the formation of dark red color visible to the naked eye in the presence of cyanide ions. The complex between the receptor and the cyanide ion proceeds through displacement of the DMSO molecule present in the cavity of the receptor. The stoichiometry of the complex between the receptor and the cyanide ion was determined by job’s plot. The proton NMR spectroscopy and the DFT calculations were used to study the mechanism of the complex formation.

Synthesis, structural elucidation and cytotoxicity of new thiosemicarbazone derivatives

Syntheses and characterization (1H &13C NMR and CHN) of four new thiosemicarbazone derivatives (1–4) are reported. The molecular structures of compounds 1–4 were determined using single crystal X-ray crystallographic technique. Cytotoxic effect of all the compounds was determined against three cancerous (PANC-1, HCT 116 and MCF-7) and one non-cancerous (NIH/3T3) cell lines. All the compounds remained safe against non-cancerous cells (IC50>500μM) but induced significant cytotoxicity in the cancerous cell lines. Importantly, compounds 2 and 4 showed excellent cytotoxicity (IC50=10.0 and 0.7μM against PANC-1; 14.9 and 9.4μM against HCT 116; 14.3 and 15.8μM against MCF-7 for 2 and 4 respectively). Based on the results it can be concluded that the thiosemicarbazone derivatives (2 and 4) can be further studied in detail for the purpose of chemotherapeutic drug development.

An efficient trifunctional benzhydrazone ligated Pd(II) complex for Heck reaction of aryl bromides

Synthesis of air and thermally stable trifunctional O, N, and O-terdentate benzhydrazone Pd(II) complex is reported and characterized by elemental analysis, spectral methods, and single crystal X-ray crystallographic technique. The new and reusable homogeneous catalyst has been effectively applied to the Mizoroki–Heck reaction of activated and deactivated aryl bromides with various olefins under mild reaction conditions in good to excellent yields up to 99%.