Intramolecular N→Sn coordination in tin(II) and tin(IV) compounds based on enantiopure ephedrine derivatives

The syntheses and molecular structures of the intramolecularly coordinated tin(II) compounds {CH(2)N(Me)CH(Me)CH(Ph)O}(2)SnL (2, L = lone pair; 4, L = W(CO)(5); 5, L = Cr(CO)(5)) and of the related hydroxido-substituted tin(IV) compound [{CH(2)N(Me)CH(Me)CH(Ph)O}(2)Sn(OH)](2)O, 6a, are reported. Also reported are the molecular structures of the enantiopure N,N'-ethylenebis-(1R,2S)-ephedrine, {CH(2)N(Me)CH(Me)CH(Ph)OH}(2) (1), and its hydrobromide {CH(2)N(Me)CH(Me)CH(Ph)OH}(2)·HBr (1a).     

Synthesis,characterization, and crystal structure determination of Cu(II) coordination compounds with 2,2′-dimethyl-4,4′-bithiazole

[{CuCl(dm4bt)}₂ μ-Cl)₂] (1) (dm4bt = 2,2′-dimethyl-4,4′-bithiazole) was prepared from the reaction of CuCl₂ · 2H₂O with 2,2′-dimethyl-4,4′-bithiazole in methanol; [Cu(dm4bt)₂NO₃](NO₃) (2) was prepared from the reaction of Cu(NO₃)₂ · 3H₂O with 2,2′-dimethyl-4,4′-bithiazole in methanol. Both complexes were characterized by IR, UV–Vis spectroscopy, and single-crystal structure. The structure of 1 consists of centrosymmetric dimeric [{CuCl(dm4bt)}(μ-Cl)], in which two chloro ligands bridge the coppers forming a four-membered ring; a terminal chloride and a bidentate chelating bithiazole complete five coordination at each Cu(II) in a highly distorted trigonal-bipyramidal geometry. The mononuclear structure 2 consists of a Cu(II), two 2,2′-dimethyl-4,4′-bithiazoles, one monodentate nitrate and one uncoordinated nitrate in a highly distorted square pyramid.     

Tin-119 Mössbauer spectral studies in organotin(IV) and tin(II) substituted oxinates

Organotin(IV) compounds of the type, R₂SnL₂ (R = CH₃, C₂H₅, C₄H₉, C₈H₁₇ or C₆H₅ and HL = 2-methyl-8-quinolinol), R₃SnL and R₂SnXL (R = C₆H₅ and X = Cl), SnL′₂ (HL′ = 2- or 5,7-substituted-8-quinolinol) and SnXL (X = Cl) have been synthesized and characterised. The ^119mSn Mössbauer spectra of these along with several other alkyl or aryl tin(IV) substituted oxinates have been recorded at 77°K and from the Mössbauer parameters the probable structures of these compounds are inferred. Bis(5,7-dinitro-8-quinolinolato)dialkyltin(IV) compounds (Q.S. = ∼4.3 mm/sec) are considered to have the two R-groups occupying trans-positions in the octahedral structure. The somewhat large and significantly varying quadrupole splittings observed in the three series of compounds, R₂SnL′₂ studied, may be associated with donor-acceptor interactions.     

Liquid-crystal ω-(2-pyridyl) acetophenones as representatives of mesogenic compounds with an intramolecular hydrogen bond

Representatives of a new class of mesogenic compounds have been synthesized, -(5-substituted-2-pyridyl)-4-alkylacetophenones, which have an intramolecular hydrogen bond. The mesogenic properties of these compounds have been investigated.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 486–488, April, 1993.     

Synthesis,characterization, and in vitro antibacterial and antifungal studies of tin(IV) thiohydrazide complexes

Reaction of tin dichloride and tin tetrachloride with cyclohexylamine-N-thiohydrazide (ChaThz) [L¹] and 1,3-propanediamine-N-thiohydrazide (PdaThz) [L²] results in [Sn(ChaThz)₂] (1), Sn(ChaThz)₂Cl₂] (2), [Sn(PdaThz)₂] (3), and [Sn(PdaThz)₂Cl₂] (4), in which the thiohydrazide coordinates to tin through imine nitrogen and thioamide sulfur. The ratio metal?:?ligand was 1?:?2 for all complexes. The tin(IV) thiohydrazide complexes were characterized by elemental analysis, IR, UV-Vis, ¹H-NMR, ¹¹⁹Sn NMR, and mass spectral studies. Using the disc diffusion method, the ligands and metal complexes were screened for in vitro antibacterial activities against four pathogenic bacteria, Escherichia coli, Staphylococcus aureus, P. aeruginosa, and Bacillus cereus and for antifungal activities against Aspergillus flavus, A. carbonarius, A. niger, and A. fumigatus. While the tin(IV) complexes exhibited moderate antifungal activities, their parent ligands showed much higher and long-lasting broad spectrum of bioactivity against fungal growth. This was particularly the case for L¹ whose fungal inhibitory activity by the end of the experimental period was comparable and, for the most part, more pronounced than that of AmB. This higher activity of L¹ was maintained specifically against S. Aureus but in general, bacteria were more susceptible to complexes than ligands.     

Synthesis, crystal structures and fluorescence properties of four mixed-ligands Zn(Ⅱ) and Cd(Ⅱ) coordination compounds

Four new coordination compounds, [Zn(dba)(bpy)]n (1), {[Zn(dba)(phen)]·2H2O}n (2), [Cd(dba)(bpy)(H2O)2] (3) and [Cd2(dba)2(phen)2]n (4) (H2dba = 2,5-dihydroxy-p-benzenediacetic acid, bpy = 2,2′-bipyridine, phen = 1,10-phenanthroline) have been prepared via solvothermal method and characterized by sin-gle-crystal X-ray diffraction, infrared spectroscopy, elemental analysis and powder X-ray diffraction. 1 and 2 possess 1D infinite chain structures. Complex 3 exhibits a mononuclear structure. Complex 4 owns bi...     

Ruthenium(II) complexes of 2-(2′-pyridyl)naphthoimidazole: synthesis,characterization and DNA-binding studies

The perchlorate salts of two new ruthenium(II) complexes incorporating 2-(2′-pyridyl)naphthoimidazole are synthesized in good yield. Complexes [Ru(phen)₂(PYNI)]²⁺ (phen = 1,10-phenanthroline) 1 and [Ru(dmp)₂(PYNI)]²⁺ (dmp = 2,9-dimethyl-1,10-phenanthroline, PYNI = 2-(2′-pyridyl)naphthoimidazole) 2 are fully characterized by elemental analysis, FAB-MS, ES-MS, ¹H NMR and cyclic voltammetric methods. The DNA-binding behavior of the complexes have been studied by spectroscopic titration, viscosity measurements and thermal denaturation. Absorption titration and thermal denaturation studies reveal that these complexes are moderately strong binders of calf-thymus DNA (CT-DNA), with their binding constants spanning the range (2.73–5.35) × 10⁴ M^?1. The experimental results show that 1 interacts with calf thymus DNA (CT-DNA) by intercalative mode, while 2 binds to CT-DNA by partial intercalation.     

Ruthenium(II)-CO complexes of N-[(2-pyridyl)methyliden]-α(or β)-aminonaphthalene: Synthesis, spectral studies, crystal structure, redox properties and DFT calculation

The characterization and properties of trans-(X)-[RuX₂(CO)₂(α/β-NaiPy)] (1, 2) (α-NaiPy (a), β-NaiPy (b); X = Cl (1), I (2)) are described in this work. The structures are confirmed by single crystal X-ray diffraction studies. Reaction of these compounds with Me₃NO in MeCN has isolated monocarbonyl trans-(X)-[RuX₂(CO)(MeCN)(α/β-NaiPy)] (3, 4). The complexes show intense emission properties. Quantum yields of 1 and 2 (? = 0.02-0.08) are higher than 3 and 4 (? = 0.006-0.015). Voltammogram shows higher Ru(III)/Ru(II) (1.3-1.5 V) potential of 1 and 2 than that of 3 and 4 (0.8-0.9 V) that may be due to coordination of two π-acidic CO groups in former. The electronic spectra and redox properties of the complexes are compared with the results obtained by density functional theory (DFT) and time-dependent density functional theory (TD-DFT) using polarizable continuum model (CPCM).     

Studies on the crystal structure and characterization of N-(4-acetylphenyl)-N’-(2-nitrobenzoyl)-thiourea

N-(4-acetylphenyl)-N′-(2-nitrobenzoyl)-thiourea has been synthesized in high yield under PEG-400 as the phase-transfer catalyst and its the compound structure was determined by single crystal X-ray diffraction. The compound is also a considerable plant-growth regulator. In addition, the compound L exhibited selective recognition for Hg²⁺ over other metals ions such as Ag⁺, Ca²⁺, Co²⁺, Ni²⁺, Cd²⁺, Pb²⁺, Zn²⁺, Cr³⁺, and Mg²⁺ in DMSO solutions.     

Synthesis and crystal structure of trans-dichloro(1,3-propylenediamine-n,n′-diacetato)platinum(IV) monohydrate

The trans-geometrical isomer of the first Pt(IV) complex with the tetradentate ligand 1,3-propylenediamine-N,N′-diacetate ion (pdda) was prepared by a direct synthesis from potassium hexachloroplatinate(IV) and pdda in the presence of lithium hydroxide. The crystal structure of trans-[Pt(pdda)Cl₂]·H₂O complex has been determined. The Pt(IV) ion has a distorted octahedral coordination due to intramolecular N–H···Cl interactions.     

Organotin(IV) complexes with 2-(2′-pyridyl)quinoxaline (L): The crystal structure of the [SnEt2Cl2L]·0.5 benzene

Complexes of 2-(2′-pyridyl)quinoxaline (L) with R₂SnCl₂ (R=Me, Et, Buⁿ) have been synthesized and characterized using IR, far-IR, ¹¹⁹Sn Mössbauer, ¹H and ¹³C spectroscopies. The X-ray crystal structure of Et₂SnCl₂L shows a bidentate chelating behaviour of L, which is observed in all the diorganotin compounds presented. Interaction of the ligand L with SnCl₄ resulted in the formation of a salt with the formula [(LH)₂]²⁺[SnCl₆]²⁻. Solution studies of the complexes R₂SnCl₂L (R=Me, Et, Buⁿ) revealed partial dissociation of the ligand in chloroform.     

Syntheses,crystal structures,and characterization of seven coordination compounds based on flexible 1,1′-(1,4-butanediyl)bis(3-carboxyl-2-oxidopyridinium)

Seven coordination compounds based on 1,1′-(1,4-butanediyl)bis(3-carboxyl-2-oxidopyridinium), [CoNa(L)_1.5(C₂H₅OH)₃] (1), [Zn(L)(OH)₂]?·?4H₂O (2), [Co(L)(OH)₂]?·?2H₂O (3), [Co(L)(H₂O)] (4), [Zn(L)(H₂O)] (5), [Ni(L)(H₂O)] (6), and [Mn(L)(H₂O)] (7), have been synthesized and crystal structures have been determined by single-crystal X-ray diffraction. Compound 1 exhibits a 0-D molecular structure. Compound 2 shows a 1-D “Z” chain structure. Neighboring chains are further linked by hydrogen-bonding interactions into a 2-D supramolecular layer. Compound 3 features a 1-D “Z” chain structure. The chains are further extended into a 2-D supramolecular structure by hydrogen-bonding interactions. Compounds 4–7 are isomorphous and display 2-D (4⁴)-SQL networks. These compounds are further characterized by infrared spectra, elemental analyses, and X-ray powder diffraction. The luminescent properties of the compounds were also investigated.     

Synthesis,spectral and RAHB studies on some arylhydrazones of β-diketones: crystal and molecular structures of 2-(2-(3-pyridyl)hydrazono)-5,5-dimethylcyclohexane-1,3-dione and 2-(2-(2-methoxyphenyl)hydrazono)-5,5-dimethylcyclohexane-1,3-dione

The present study describes the synthesis and spectral analysis of a series of arylhydrazones of β-diketones (1–6) along with the single crystal X-ray structural studies of 2-(2-(3-pyridyl)hydrazono)-5,5-dimethylcyclohexane-1,3-dione (3) and 2-(2-(2-methoxyphenyl)hydrazono)-5,5-dimethylcyclohexane-1,3-dione (6). Spectral and structural studies clearly exemplify the effective intramolecular hydrogen bonding and as a result the NH proton signals and carbonyl carbon signals are shifted to higher frequency region in NMR spectra. Structural implications imposed by the formation of pseudo six-membered ring after hydrogen bonding is well observed in XRD analysis. XRD analysis also evidences the envelop conformation of the dimedone ring in both the cases and resonance assisted hydrogen bonding (RAHB) studies were also performed.     

Synthesis and some transformations of 2-(2′-thienyl)benzothiazole

Condensation of ortho-aminothiophenol with 2-thenoyl chloride in 1-methyl-2-pyrrolidone was used to synthesize 2-(2′-thienyl)benzothiazole. Its reactions of electrophilic (nitration, bromination, oxymethylation, formylation, acylation) and radical (nitration, arylation) substitution were studied.     

Structures and NMR spectra of N-(ω-alkoxyethyl)N-(2-hydroxyethyl)-N,N-dimethylammonium chlorides

Russian Chemical Bulletin - Homoand heteronuclear NMR experiments (COSY, HSQC, and HMBC) were used for the attribution of the proton and carbon atom signals in the 1H and 13C NMR spectra of...     

Synthesis,crystal structure,fluorescence and electrochemical properties of two Ag(I) complexes based on 2-(4′-pyridyl)-benzoxazole/SPPh3 ligands

Abstract

To explore the luminescence properties of silver complexes in the solid state, two Ag(I) complexes, [Ag(4-PBO)₂(NO₃)] {di[2-(4′-pyridyl)-benzoxazole]silver(I) nitrate} (1) and [Ag₂(SPPh₃)₄](ClO₄)₂ {[tetra(triphenylphosphine sulfide)disilver(I)] diperchlorate} (2) (4-PBO =2-(4′-pyridyl)-benzoxazole, SPPh₃?=?triphenylphosphine sulfide), have been synthesized and characterized by elemental analysis, FT-IR and UV-Vis spectroscopy. Single-crystal X-ray diffraction revealed that 1 is three-coordinate by two nitrogen atoms from two 4-PBO ligands and an oxygen atom from the coordinated nitrate anion forming a triangular plane configuration. In 2, the SPPh₃ ligands adopt a monodentate coordinated and monoatomic bridging mode to connect two Ag(I) ions, resulting in a three-coordinate symmetrical binuclear structure. In the solid state, the luminescence properties of the ligands 4-PBO, SPPh₃ and their complexes were investigated. The results demonstrated that 1 results in the fluorescence quenching of aggregates due to the strong π–π stacking effect. The fluorescence enhancement of 2 may be attributed to the “aggregation-induced emission” (AIE) effect of restricted intramolecular rotations of the peripheral phenyl rings against the central core. In addition, cyclic voltammograms of 1 and 2 indicated an irreversible Ag⁺/Ag couple.     

Synthesis, crystal structure, magnetic property and thermal studies of [Ni(CH(3)COO)2·(NH2CH2Ph)4

[Ni(CH(3)COO)(2)·(NH(2)CH(2)Ph)(4)] complex was synthesized using benzylamine and nickel acetate. The molecular structure of this complex was obtained by single crystal X-ray diffraction and characterized by elemental analysis, IR spectrometry and thermal analysis. The complex crystallized in the monoclinic space group P2(1)/n with cell parameters a=11.234(4)?, b=6.459(2)?, c=22.647(8)?, α=90.00, β=91.149(4)°, γ=90.00, V=1642.8(10)?(3), Z=2. The structure has been solved by direct methods and refined to R(1)=0.0876 for 6377 observed reflections I>2σ(I). Magnetic studies for complex show the data over the whole temperature range 5-300 K are well fitted to the Curie-Weiss law with C=1.03 cm(3) K mol(-1) and θ=-1.38 K. This fitting indicates antiferromagnetic interaction between the Ni ions and the metal center exhibits distorted octahedral coordination geometries. The thermal analysis was carried out to understand the thermal stability of the title complex.     

Synthesis,crystal structures,and photophysical properties of dibromo-2-(2′-pyridyl)imidazole and its corresponding boron–fluorine complex

2-(2′-Pyridyl)imidazole L1 and its corresponding boron–fluorine complex, 1, were synthesized and their crystal structures correlated with their photophysical properties. L1 forms a rigid supramolecular network through hydrogen bonds and halogen bond in the single crystal, which induces amplified spontaneous emission in crystals; it emits rather poor fluorescence in solution and powder states. Its boron chelate 1 emits intense fluorescence in solution since boron chelate is an excellent chromophore, and it exhibits large Stokes shift (136?nm in acetonitrile), due to the charge-transfer transition from the electron-donating π system to the electron-accepting boron moiety. Interestingly, 1 is also highly fluorescent in amorphous powder and crystal states; C–C rotation between pyridyl and imidazole groups is inhibited by the formation of a five-member ring containing BF₂, and the formation of intermolecular non-covalent bonds is the key factor. Solid emission with large Stokes shift makes it a valuable chromophore for synthesis of functional materials.     

Synthesis and crystal structure of (E)-[(2-cyclohexenyl) vinyl]triaryltin

(E)-[(2-Cyclohexenyl)vinyl]triaryltin (aryl=phenyl, p-tolyl) were synthesized and characterized by elemental analysis, IR, 1H NMR spectroscopy. The crystal structure of (E)-[(2-cyclohexenyl)vinyl]triphenyltin was also determined by the X-ray diffraction. Experiments show that this compound has the conjugated system, which makes it have possible bioactivity and anti-tumor activity.