Structure–reactivity studies of chloro and isothiocyanato diorganotin (IV) complexes based on multidentate N‐donor ligands: Synthesis,spectral characterization and crystal structures

The reaction of [SnMe₂Cl₂] with the bidentate ligand 4,7‐phenanthroline (4,7‐phen) resulted in the formation of [SnMe₂Cl₂ (4,7‐phen)]_n ( 1a ) which is probably a polymeric chain in solution. On the other hand, the reaction of [SnEt₂Cl₂] with 4,7‐phen afforded the complex [Sn₂Et₄Cl₄ (κ¹‐N‐4,7‐phen)₂(μ‐κ²‐N,N‐4,7‐phen)] ( 1b ) which dissociates in dimethylsulfoxide solution. The reaction of [SnR₂Cl₂] (R = Me, Et) with 2,2′‐biquinoline (biq) yielded the complexes [SnMe₂Cl₂ (κ²‐N,N‐biq)] ( 2a ) and [SnEt₂Cl₂ (κ¹‐N‐biq)₂] ( 2b ) in the solid state. Moreover, the reaction of [SnR₂Cl₂] (R = Me, Et) with the tridentate ligand 4′‐(2‐furyl)‐2,2′:6′,2″‐terpyridine (ftpy) resulted in the formation of ionic penta‐ and hexa‐coordinated tin complexes [SnMe₂Cl (ftpy)][SnMe₂Cl₃] ( 3a ) and [SnEt₂Cl (ftpy)]Cl ( 3b ). The reaction of [SnMe₂ (NCS)₂] with ftpy afforded the hepta‐coordinated complex [SnMe₂ (NCS)₂(ftpy)] ( 4a ). The products were fully characterized using elemental analysis, and infrared, UV–visible, multinuclear (¹H, ¹³C, ¹¹⁹Sn) NMR, DEPT‐135°, HH‐COSY and HSQC NMR spectroscopies. The crystal structure of complex 3a reveals that it contains the simultaneous presence of penta‐ and hexa‐coordinated tin (IV) atoms. Notably, the crystal structure of complex 4a shows that tin (IV) is hepta‐coordinated in a pentagonal bipyramidal geometry SnC₂N₅ by three nitrogen atoms of ftpy, two nitrogen atoms of NCS^? and two Me groups with trans‐[SnMe₂] configuration. These data indicate the influence of halide or pseudo‐halide group on the coordination number and geometry of tin. Hirshfeld surface analysis and two‐dimensional fingerprint plots were calculated for 3a and 4a which show the π–π interaction between molecules in the solid is relatively weak.     

Two novel trinuclear cluster-based coordination polymers with 2,6-Di-imidazol-1-yl-pyridine: solvothermal syntheses,crystal structures,properties and Hirshfeld surface analysis

Two novel trinuclear cluster-based coordination polymers {[M₃(dip)(AcO)₆]·(X)}_n (1, M = Cu, X = CH₃OH; 2, M = Co, X = 2H₂O) (dip is 2,6-Di-imidazol-1-yl-pyridine), have been synthesised and structurally determined by single crystal X-ray diffraction, element analysis. Crystallographic unit of 1 consists of three Cu(II), six acetic ions, one dip ligand and one methanol molecule, which formed 1D chain through acetic bridges. The 1D chain further constructed 2-D network through dip ligand bridge which formed 3-D network through π···π interaction. Crystallographic unit of 2 consists of three Co(II), six acetic ions, one dip ligand and two water molecules. The trinuclear unit further formed a dimmer through dip ligand bridge which constructed 1-D through dip ligand bridge. The 1D chain further constructed 2-D network through π···π interaction. IR and UV–vis spectrum properties of 1 and 2 were studied. In addition, Hirshfeld surface analysis was also studied for 1.     

Mononuclear diorganotin(IV) complexes with arylhydroxamates: syntheses,structures and assessment of in vitro cytotoxicity

Two series of diorganotin(IV) complexes with dihalogenobenzohydroxamate ligands (substituents = 2,4‐Cl₂, 2,4‐F₂, 3,4‐F₂, 2,5‐F₂, 2,6‐F₂), formulated as [R₂Sn(HL)₂] ( a ), and the arylhydroxamato/arylcarboxylato mixed‐ligand complexes [R₂Sn(HL)(L′)] ( b ), were prepared and characterized by FT‐IR, ¹H, ¹³C and ¹¹⁹Sn NMR spectroscopies, elemental analyses and melting point measurements. X‐ray diffraction analysis was also carried out for the complex [Me₂Sn{3,4‐F₂C₆H₃C(O)NHO}₂], 1a . These compounds exhibit in vitro cytotoxic activities towards human leukemic promyelocites HL‐60, BGC‐823, BEL‐7402 and KB cell lines which, in some cases, are identical to, or even higher than, that of cisplatin. The type, position and number of the X substituents in the phenyl ring play a role in the cytotoxic activity, and complex 8a , with its 2,6‐difluorobenzohydroxamato ligand, is highly active against all tumor cells. A tentative structure–activity relationship is also described. Copyright © 2007 John Wiley & Sons, Ltd.     

Crystal structure analysis,Hirshfeld surface analysis,spectral investigations (FT-IR,FT-R), DFT calculations,ADMET studies and molecular docking of 3H-Methyl-1H-pyrazole-1-carboxamide (3MPC)

On 3H-Methyl-1H-pyrazole-1-carboxamide (3MPC), Single crystal XRD, Fourier Transform Infrared Spectroscopy, Fourier Transform Raman Spectroscopy, Molecular Electrostatic Potential, Density function theoretical analysis and Molecular docking analysis are conducted. The target protein docking experiments revealed that the small molecule (MET) is a good molecule that docks well with several Nav channel 1 targets. Molecular Electrostatic Potential (MEP) aids in the optimization of protein-ligand electrostatic interactions. The molecular surface and hydrogen bonding interactions in the 3MPC crystal structure were located and analyzed using a fingerprint plot and Hirshfeld Surfaces. DFT–B3LYP calculations with the 6-31G (d,p) basis set are used to establish the optimised structure of the MET molecule, and the measured vibrational frequencies are compared to experimental values. The parameters of absorption, distribution, metabolism, excretion (ADME) and toxic (Tox) were assessed using the online server preADMET.     

Hirshfeld surface analysis of two new phosphorothioic triamide structures

Hirshfeld surfaces and two‐dimensional fingerprint plots are used to analyse the intermolecular interactions in two new phosphorothioic triamide structures, namely N,N′,N′′‐tris(3,4‐dimethylphenyl)phosphorothioic triamide acetonitrile hemisolvate, P(S)[NHC₆H₃‐3,4‐(CH₃)₂]₃·0.5CH₃CN or C₂₄H₃₀N₃PS·0.5CH₃CN, (I), and N,N′,N′′‐tris(4‐methylphenyl)phosphorothioic triamide–3‐methylpiperidinium chloride (1/1), P(S)[NHC₆H₄(4‐CH₃)]₃·[3‐CH₃‐C₅H₉NH₂]⁺·Cl⁻ or C₂₁H₂₄N₃PS·C₆H₁₄N⁺·Cl⁻, (II). The asymmetric unit of (I) consists of two independent phosphorothioic triamide molecules and one acetonitrile solvent molecule, whereas for (II), the asymmetric unit is composed of three components (molecule, cation and anion). In the structure of (I), the different components are organized into a six‐molecule aggregate through N—H...S and N—H...N hydrogen bonds. The components of (II) are aggregated into a two‐dimensional array through N—H...S and N—H...Cl hydrogen bonds. Moreover, interesting features of packing arise in this structure due to the presence of a double hydrogen‐bond acceptor (the S atom of the phosphorothioic triamide molecule) and of a double hydrogen‐bond donor (the N—H unit of the cation). For both (I) and (II), the full fingerprint plot of each component is asymmetric as a consequence of the presence of three fragments. These analyses reveal that H...H interactions [67.7 and 64.3% for the two symmetry‐independent phosphorothioic triamide molecules of (I), 30.7% for the acetonitrile solvent of (I), 63.8% in the phosphorothioic triamide molecule of (II) and 62.9% in the 3‐methylpiperidinium cation of (II)] outnumber the other contacts for all the components in both structures, except for the chloride anion of (II), which only receives the Cl...H contact. The phosphorothioic triamide molecules of both structures include unsaturated C atoms, thus presenting C...H/H...C interactions: 17.6 and 21% for the two symmetry‐independent phosphorothioic triamide molecules in (I), and 22.7% for the phosphorothioic triamide molecule of (II). Furthermore, the N—H...S hydrogen bonds in both (I) and (II), and the N—H...Cl hydrogen bonds in (II), are the most prominent interactions, appearing as large red spots on the Hirshfeld surface maps. The N...H/H...N contacts in structure (I) are considerable, whereas for (II), they give a negligible contribution to the total interactions in the system.     

Crystal structure and solid state computational (DFT/Hirshfeld surface) study for probing a new efficient and recyclable oxidation reagent, 1,2-ethandiylbis(triphenylphosphonium) peroxodisulfate dihydrate

A new, efficient and recyclable reagent, 1,2-Ethandiylbis(triphenylphosphonium) peroxodisulfate dihydrate, for the oxidation of benzylic alcohols has been synthesized and characterized by IR, NMR spectroscopy, and single crystal X-ray crystallography. Using the title compound, the results indicate that the oxidation reactions are rapid, take place under mild reaction conditions, easily to work-up and high yielding. The Hirshfeld surface and associated finger print plots were derived from the X-ray structure to visualize the significant nonclassical C-H ??? O/π interactions in the crystal packing. The geometry, vibrational spectroscopy and electronic properties of the bis(triphenylphosphonium) dication have also been investigated by various DFT computational methods.     

Crystal structure and Hirshfeld surface analysis of the anhydrous form of the nucleoside analogue entecavir

The nucleoside analogue entecavir {systematic name: 2‐amino‐9‐[(1S,3R,4S)‐4‐hydroxy‐3‐hydroxymethyl‐2‐methylenecyclopentyl]‐1,9‐dihydro‐6H‐purin‐6‐one}, C₁₂H₁₅N₅O₃, is an antihepatitis B virus drug that has been approved in the US, EU and several countries worldwide. We report here the single‐crystal structure of the anhydrous form and compare it with that of the previously reported monohydrate form [Jiang & Liu (2009). Acta Cryst. E 65 , o2232]. Hirshfeld surface analysis has been employed to understand and visualize the subtle packing differences between the two crystalline forms. The results show that, compared to the previously reported hydrated form, the anhydrous crystal has significantly different intermolecular interactions and packing patterns.     

A one‐dimensional copper(II) coordination polymer incorporating succinate and N,N‐diethylethylenediamine ligands: crystallographic analysis,vibrational and surface features,and DFT analysis

Transition metal atoms can be bridged by aliphatic dicarboxylate ligands to produce chains, layers and frameworks. The reaction of copper sulfate with succinic acid (H₂succ) and N ,N‐ diethylethylenediamine (deed) in basic solution produces the complex catena‐poly[[[(N ,N‐diethylethylenediamine‐κ²N ,N ′)copper(II)]‐μ‐succinato‐κ²O ¹:O ⁴] tetrahydrate], {[Cu(C₄H₄O₄)(C₆H₁₆N₂)]·4H₂O}_n or {[Cu(succ)(deed)]·4H₂O}_n . Each carboxylate group of the succinate ligand coordinates to a Cu^II atom in a monodentate fashion, giving rise to a square‐planar coordination environment. The succinate ligands bridge the Cu^II centres to form one‐dimensional polymeric chains. Hydrogen bonds between the ligands and water molecules link these chains into sheets that lie in the ab plane. Density functional theory (DFT) calculations were used to support the experimental data. From these calculations, a good linear correlation was observed between the experimental and theoretically predicted structural and spectroscopic parameters (R ² ∼ 0.97).     

Crystal growth,structural, spectral,optical, DFT analysis and Z-scan analysis of pyridine-1-ium-2-carboxylatehydrogenbromide (PHBr) for optoelectronic and nonlinear optical applications

A single crystal of Pyridine-1-ium-2-carboxylatehydrogenbromide (PHBr) was grown using the Slow Evaporation Solution Technique. Using Single Crystal X-Ray Diffraction analysis, the crystal lattice characteristics and molecular structure of the grown crystal of PHBr were found and it corresponds to the Triclinic crystal system with space group Pī. Intra and intermolecular interactions were visualized using Hirshfeld surface analysis. The theoretical calculation conducted by Density Functional Theory (DFT) and it is well agreed with the experimental results. The Molecular optimized geometry, FT-IR and HOMO-LUMO energy gap were computed using the B3LYP level of theory with a 6-31 + G (d,p) basis set. The FT-IR spectrum studies are given here to look at the modes of vibration of numerous functional groups found in the PHBr crystal. The measurements of UV–visible NIR transmittance show that the crystal has a high transmittance over the whole visible spectrum. The Z-scan approach is used to perform third-order nonlinear optical (NLO) investigations on a PHBr crystal and optical properties such as linear and nonlinear refractive index are computed.     

Understanding metal–ligand interactions in coordination polymers using Hirshfeld surface analysis

Properties related to the size and shape of Hirshfeld surfaces provide insight into the nature and strength of interactions among the building blocks of molecular crystals. In this work, we demonstrate that functions derived from the curvatures of the surface at a point, namely, shape index (S) and curvedness (C), as well as the distances from the surface to the nearest external (d_e) and internal (d_i) nuclei, can be used to help understand metal–ligand interactions in coordination polymers. The crystal structure of catena‐poly[[[(1,10‐phenanthroline‐κ²N,N′)copper(II)]‐μ‐4‐nitrophthalato‐κ²O¹:O²] trihydrate], {[Cu(C₈H₃NO₆)(C₁₂H₈N₂)]·3H₂O}_n, described here for the first time, was used as a prototypical system for our analysis. Decomposition of the coordination polymer into its metal centre and ligand molecules followed by joint analysis of the Hirshfeld surfaces generated for each part unveil qualitative and semi‐quantitative information that cannot be easily obtained either from conventional crystal packing analysis or from Hirshfeld surface analysis of the entire polymeric units. The shape index function S is particularly sensitive to the coordination details and its mapping on the surface of the metallic centre is highly dependent on the nature of the ligand and the coordination bond distance. Correlations are established between the shape of the Hirshfeld surface of the metal and the geometry of the metal–ligand contacts in the crystals. This could be applied not only to estimate limiting coordination distances in metal–organic compounds, but also to help establish structure–property relationships potentially useful for the crystal engineering of such materials.     

Crystal structure and Hirshfeld surface analysis of a salt of antineoplastic kinase inhibitor vandetanib

A salt of vandetanib, namely, 4-({4-[(4-bromo-2-fluorophenyl)amino]-6-methoxyquinazolin-7-yl}methoxy)-1-methylpiperazin-1-ium 2-(butylamino)-4-phenoxy-6-sulfamoylbenzoate acetonitrile monosolvate, C₂₂H₂₅BrFN₄O₂⁺·C₁₇H₁₉N₂O₅S⁻·C₂H₃N, composed of kinase inhibitor vandetanib and sulfamyl diuretic bumetanide in a 1:1 molar ratio, is reported. There is proton transfer between the piperidine ring of vandetanib and the carboxyl group of bumetanide to form the salt. In the vandetanib cation, the arene and pyrimidine rings are not coplanar, their planes subtending a dihedral angle of 60.47 (14)°. The roles of the intermolecular interactions in the crystal packing were clarified using Hirshfeld surface analysis, and two-dimensional fingerprint plots indicate that the most important contributions to the crystal packing are from H…H (40.5%), O…H/H…C (20.7%), C…H/ H…C (18.8%) and N…C/C…N (9.0%) contacts.     

Synthesis,crystal structures,spectral FT‐IR,NMR and UV–Vis investigations and Hirshfeld surface analysis of two new 2‐hydroxyethyl‐substituted N‐heterocyclic carbene precursors

This study discusses the synthesis of two new 2‐hydroxyethyl substituted N‐heterocyclic carbene (NHC) precursors. The NHC precursors were prepared from 1‐(alkyl/aryl)benzimidazole and alkyl halides. They were characterized using ¹H NMR, ¹³C NMR, FT‐IR, UV–Vis spectroscopy, and elemental analysis techniques. Molecular and crystal structures of 1 and 2 were determined using the single‐crystal X‐ray diffraction method. Crystal structure of the compounds features NHC precursors and chloride anions. Additionally in 2 , the asymmetric unit has a water molecule, which forms a tetrameric chloride‐hydrate assembly with the chloride anion. The chloride anions play an important role in the stabilization of crystal structures to form a two‐dimensional supramolecular architecture. The 3D Hirshfeld surface and the associated 2D fingerprint plots were also drawn to gain insights into the behavior of the interactions in the compounds.     

Synthesis,structures and Hirshfeld surface analysis of Ni(II) and Co(III) complexes with N2O donor Schiff base ligand

Two octahedral complexes [NiL(HL)]ClO₄.0.5CH₃OH and [CoL₂]ClO₄ have been synthesized with N₂O donor Schiff base ligand {((2-(phenylamino)ethyl)imino)methyl}phenol (HL) and characterized by spectroscopic techniques and single crystal X-ray diffraction studies. The molar conductivities data of the two complexes show that the complexes are 1:1 electrolyte. Single crystal X-ray diffraction data shows both Ni(II) and Co(III) complexes have distorted octahedral geometry and two ligands are coordinated to the metal centers and one ClO₄⁻ ion outside the coordination sphere. The intermolecular interactions in the complexes are evaluated by Hirshfeld surface analysis and revealed a significant contribution of non- or weakly polar interactions to the packing forces for both molecules, with crystal structure of Co(III) complex featuring short H/H contacts.     

Crystal structures and Hirshfeld surface analysis of transition‐metal complexes of 1,3‐azolecarboxylic acids

The crystal structures of five new transition‐metal complexes synthesized using thiazole‐2‐carboxylic acid (2‐Htza), imidazole‐2‐carboxylic acid (2‐H₂ima) or 1,3‐oxazole‐4‐carboxylic acid (4‐Hoxa), namely diaquabis(thiazole‐2‐carboxylato‐κ²N,O)cobalt(II), [Co(C₄H₂NO₂S)₂(H₂O)₂], 1 , diaquabis(thiazole‐2‐carboxylato‐κ²N,O)nickel(II), [Ni(C₄H₂NO₂S)₂(H₂O)₂], 2 , diaquabis(thiazole‐2‐carboxylato‐κ²N,O)cadmium(II), [Cd(C₄H₂NO₂S)₂(H₂O)₂], 3 , diaquabis(1H‐imidazole‐2‐carboxylato‐κ²N³,O)cobalt(II), [Co(C₄H₂N₂O₂)₂(H₂O)₂], 4 , and diaquabis(1,3‐oxazole‐4‐carboxylato‐κ²N,O⁴)cobalt(II), [Co(C₄H₂NO₃)₂(H₂O)₂], 5 , are reported. The influence of the nature of the heteroatom and the position of the carboxyl group in relation to the heteroatom on the self‐assembly process are discussed based upon Hirshfeld surface analysis and used to explain the observed differences in the single‐crystal structures and the supramolecular frameworks and topologies of complexes 1 – 5 .     

A new supramolecular zinc(II) complex containing 4‐biphenylcarbaldehyde isonicotinoylhydrazone ligand: Nanostructure synthesis,catalytic activities and Hirshfeld surface analysis

A new potentially tridentate hydrazone ligand, 4‐biphenylcarbaldehyde isonicotinoylhydrazone (4‐bpinh), was prepared by the condensation of biphenyl‐4‐carboxaldehyde with isonicotinic acid hydrazide. Then, its nano‐sized and single crystal of zinc complex were synthesized using sonochemical and heat gradient methods, respectively. The structure of complex, [Zn(4‐bpinh)₂ Br₂] (1), was determined by single‐crystal X‐ray diffraction, FT‐IR, and elemental analysis, and the nano‐structure of complex was characterized by FT‐IR, XRD, and SEM. The single crystal X‐ray structure of complex showed that the metal center has a distorted tetrahedral geometry and the hydrazone ligand acts as monodentate trough the pyridyl N atom. Moreover, the analysis of crystal structures indicates the existence of intermolecular interactions such as N/C–H?Br/O, N/C–H?π, and π?π stacking in the stabilization of complex structure which finally led to the formation of the three‐dimensional supramolecular structure. Also, the impact of this interactions was more studied using Hirshfeld surface analysis and corresponding 2D fingerprint plots. Furthermore, the catalytic activity of 1 was studied in the selective oxidation of various sulfides to corresponding sulfoxides using hydrogen peroxide as the oxidative agent.     

Synthesis,spectroscopic characterization,crystal structure,and anti-bacterial activity of diorganotin(IV) complexes with 5-bromo-2-hydroxybenzaldehyde-N(4)-ethylthiosemicarbazone

Three new diorganotin(IV) complexes, [Me₂Sn(BDET] (2), [Bu₂Sn(BDET)] (3), and [Ph₂Sn(BDET)] (4), were synthesized by reacting R₂SnCl₂ (R = Me, Bu, and Ph) with 5-bromo-2-hydroxybenzaldehyde-N(4)-ethylthiosemicarbazone [H₂BDET, (1)] in the presence of KOH in absolute methanol. The newly synthesized complexes were characterized by elemental analysis, molar conductivity, UV–vis, FT-IR, ¹H, ¹³C, and ¹¹⁹Sn NMR spectroscopies. The molecular structure of 4 was confirmed by X-ray crystallography. X-ray crystallography revealed that the doubly deprotonated O,N,S-tridentate thiosemicarbazone coordinates to tin(IV), resulting in a distorted trigonal bipyramidal geometry. Their ¹H, ¹³C, and ¹¹⁹Sn NMR spectra support a five-coordinate tin(IV) in solution for all complexes, in accord with the solid-state X-ray structure determined for 4. Compounds 1–4 were evaluated for their antibacterial activities against Staphylococcus aureus, Enterobacter aerogenes, Escherichia coli, and Salmonella typhi. The results exhibited that 2–4 were active with comparable potency compared to the standard drug. Antibacterial studies also indicated that the complexes have potential for biological evaluation.