Chloro-diorganotin(IV) complexes of 4-methyl-1-piperidine carbodithioic acid: Synthesis, X-ray crystal structures, spectral properties and antimicrobial studies

Chloro-diorganotin(IV) complexes of 4-methyl-1-piperidine carbodithioic acid (4-MePCDTA) have been synthesized by the reaction with diorganotin dichloride in 1:1 molar ratio in anhydrous toluene. These newly synthesized complexes have been characterized by elemental, IR, multinuclear NMR (¹H and ¹³C) and mass spectrometric studies. The crystal structures of complex 1 [Me₂SnCl(4-MePCDT)] and 3 [Ph₂SnCl(4-MePCDT)] have been determined by X-ray single crystal analysis, which show trigonal bipyramid geometry. These complexes were tested for their antimicrobial activity against six different plant and human pathogens. The screening results show that the complexes exhibit higher antibacterial and antifungal activity than the free ligand.     

Synthesis and characterization of tin(IV)/organotin(IV) complexes with 2-benzoylpyridine-N(4)-cyclohexylthiosemicarbazone [HBPCT]: X-ray crystal structure of [SnCl3(BPCT)]

Four new tin(IV)/organotin(IV) complexes, [SnCl₃(BPCT)] (2), [MeSnCl₂(BPCT)] (3), [Me₂SnCl(BPCT)] (4), and [Ph₂SnCl(BPCT)] (5), have been synthesized by the direct reaction of 2-benzoylpyridine-N(4)-cyclohexylthiosemicarbazone [HBPCT, (1)] and stannic chloride/organotin(IV) chloride(s) in absolute methanol under purified nitrogen. HBPCT and its tin(IV)/organotin(IV) complexes (2–5) were characterized by CHN analyses, molar conductivity, UV-Vis, FT-IR, and ¹H NMR spectral studies. In all the complexes, tin(IV) was coordinated via pyridine-N, azomethine-N, and thiolato-S from 1. The molecular structure of 2 has been determined by X-ray single-crystal diffraction analysis. Complex 2 is a monomer and the central tin(IV) is six-coordinate in a distorted octahedral geometry. The crystal system of 2 is monoclinic with space group P121/n1 and the unit cell dimensions are a?=?8.3564(3)?Å, b?=?23.1321(8)?Å, c?=?11.9984(4)?Å.     

Synthesis, crystal structure and reactivity of uranium(IV) complexes with p-tert-butylcalix[4]arene ligands

Reactions of UCl4 with 25,27-dimethoxy-5,11,17,23-tetra-tert-butylcalix[4]arene (H2Me2calix) in THF or pyridine at 80 degrees C gave [UCl2(Me2calix)L2] [L = THF (1) or pyridine (2)]. Similar treatment of U(acac)(4) (acac = MeCOCHCOMe) with H2Me2calix in THF or pyridine afforded [U(acac)2(Me2calix)] (3). The bis-calixarene compound [U(Me2calix)(H2calix)] (4) was obtained by reaction of U(OTf)4 or U(OTf)3 with H2Me2calix in pyridine at 110 degrees C. Treatment of UCl4 with H2Me2calix in pyridine at 110 degrees C gave [Mepy][UCl2(Hcalix)(py)2] (5) resulting from demethylation and acid cleavage of the methoxy groups of the calixarene ligand of 2. Adventitious traces of air were responsible for the formation of [Hpy][Mepy]4[{UCl(calix)}3(mu3-O)][UCl6] (6) during the reaction of UCl4 and H2Me2calix, and of [{U(Me2calix)(mu3-O)LiCl(THF)}2] (7) during the reaction of 2 with tBuLi. The X-ray crystal structures of 1.2THF, 2.2py, 3.0.25L (L = THF and py), 4.2py, 5, 6.3py and 7.THF have been determined.     

Synthesis of molybdenocene(IV) and tungstenocene(IV) tropolonato complexes: Its derivative containing calix[4]arene moiety

The cationic di-μ-hydroxo dinuclear complexes of molybdenocene and tungstenocene [Cp₂M(μ-OH)₂MCp₂]⁺ (Cp = η-C₅H₅; M = Mo or W) react with tropolone to afford corresponding tropolonato complexes [Cp₂M(trop)]⁺ (trop = C₇H₅O₂). The products were investigated by IR, ¹H NMR, and ¹³C NMR spectroscopy as well as by X-ray crystallography (M = W). The structure shows that the central metal is surrounded by a distorted tetrahedral array of the two centers of cyclopentadienyl ligands and the two oxygen atoms of tropolonato ligand. The reaction has been extended to the synthesis of calix[4]arene receptor functionalized at the 1,3-positions of the upper rim with two tropolonato-molybdenocene centers.     

Crystal structure of isotactic poly(4-methyl-1-pentene)

The crystal structure of isotactic poly(4-methyl-1-pentene) was determined by x-ray analysis. The unit cell is tetragonal, P4 b2, with α = 18.70 Å and c (fiber axis) = 13.68 Å; it contains four molecular chains each consisting of seven monomeric units in the fiber period. The molecular conformation is essentially a (7/2) helix, but deviates slightly from the uniform (7/2) helix. The unusual low density is discussed from the structural point of view.     

Synthesis and characterization of tribenzyltin(IV) and dibenzyltin(IV) complexes of 2-{[(2Z)-3-hydroxy-1-methyl- 2-butenylidene]amino}acetic acid: Crystal structure of tribenzyl{2-{[(2Z)-3-hydroxy-1-methyl-2-butenylidene] amino}acetato}tin(IV)

Reactions of equimolar quantities of potassium 2-{[(2Z)-3-hydroxy-1-methyl-2-butenylidene]amino}acetate, with R _n SnX_4?n (R: benzyl– and n=2 or 3) in methanol yielded products of compositions LHSn(PhCH₂)₃ and LSn(PhCH₂)₂, respectively. The complexes were characterized by microanalysis, IR, NMR (¹H, ¹³C, ¹¹⁹Sn) and ^119mSn Mössbauer spectroscopy. A full characterization of the structure of the complex, tribenzyl{2-{[(2Z)-3-hydroxy-1-methyl-2-butenylidene]amino}acetato}tin(IV), was carried out by single crystal X-ray crystallography. The compound exists as centrosymmetric dimers in which two ligand molecules bridge the two tin centres. Each of the tin atoms in the dimeric unit is five coordinate in an approximately trigonal bipyramidal configuration, with carbon atoms in the equatorial positions and oxygen atoms arranged axially.     

Synthesis, characterization and luminescence study of dialkyl[1-arylmethyleneimino-2-naphthonato]gallium complexes: Crystal structure of dimethyl[1-(2-pridyl) methyleneimino-2-naphthonato]gallium

Eight dialkylgallium complexes of type R₂GaL [(M = Me, L = 1-(2-pyridyl)methyleneimino-2-naphthonato (1), M = Et, L = 1-(2-pyridyl)methyleneimino-2-naphthonato (2), M = Me, L = 1-phenylmethyleneimino-2-naphthonato (3), M = Et, L = 1-phenylmethyleneimino-2-naphthonato (4), M = Me, L = 1-(p-methoxylphenyl)methyleneimino-2-naphthonato (5), M = Me, L = 1-(3,4-dimethoxylphenyl)methyleneimino-2-naphthonato (6), M = Me, L = 1-naphthylmethyleneimino-2-naphthonato (7), M = Me, L = 1-naphthylmethyleneimino-2-naphthonato (8)) have been synthesized by reaction of trialkylgallium with appropriate 1-arylmethyleneimino-2-naphthols. The complexes have been characterized by elemental analysis, ¹H NMR, IR and mass spectrometry. Structure of dimethyl[1-(2-pyridyl)methyleneimino-2-naphthonato]gallium (1) has been determined by X-ray single crystal analysis. Ga atom is five coordinate in the structure. Photoluminescent properties have been measured. The maximum emission wavelengths are in the range of 358 and 412 nm with the intensity of 13-325 a.u. The electroluminescent properties of 3, 5, 7 and 8 have been measured. The maximum emission wavelengths are in the range of 450 and 480 nm.     

Coordination chemistry of 4-methyl-2,6,7-trioxa-1-phosphabicyclo[2,2,1]heptane: preparation and characterization of Ru(II) complexes

The complexes TpRu[P(OCH(2))(2)(OCCH(3)](PPh(3))Cl (2) [Tp = hydridotris(pyrazolyl)borate; P(OCH(2))(2)(OCCH(3)) (1) = (4-methyl-2,6,7-trioxa-1-phosphabicyclo[2,2,1]heptane] and TpRu(L)(PPh(3))Cl [L = P(OCH(2))(3)CEt (3), PMe(3) (4) or P(OMe)(3) (5)], (η(6)-C(6)H(6))Ru(L)Cl(2) [L = PPh(3) (6), P(OMe)(3) (7), PMe(3) (8), P(OCH(2))(3)CEt (9), CO (10) or P(OCH(2))(2)(OCCH(3)) (11)] and (η(6)-p-cymene)Ru(L)Cl(2) [L = P(OCH(2))(3)CEt (12), P(OCH(2))(2)(OCCH(3))P(OCH(2))(2)(OCCH(3)) (13), P(OMe)(3) (14) or PPh(3) (15)] have been synthesized, isolated, and characterized by NMR spectroscopy, cyclic voltammetry, mass spectrometry, and, for some complexes, single crystal X-ray diffraction. Data from cyclic voltammetry and solid-state structures have been used to compare the properties of (1) with other phosphorus-based ligands as well as carbon monoxide. Data from the solid-state structures of Ru(II) complexes show that P(OCH(2))(2)(OCCH(3)) has a cone angle of 104°. Cyclic voltammetry data reveal that the Ru(II) complexes bearing P(OCH(2))(2)(OCCH(3)) have more positive Ru(III/II) redox potentials than analogous complexes with the other phosphorus ligands; however, the Ru(III/II) potential for (η(6)-C(6)H(6))Ru[P(OCH(2))(2)(OCCH(3))]Cl(2) is more negative compared to the Ru(III/II) potential for the CO complex (η(6)-C(6)H(6))Ru(CO)Cl(2). For the Ru(II) complexes studied herein, these data are consistent with the overall donor ability of 1 being less than other common phosphines (e.g., PMe(3) or PPh(3)) or phosphites [e.g., P(OCH(2))(3)CEt or P(OMe)(3)] but greater than carbon monoxide.     

Homobimetallic complexes of ligand having O- and S-donor sites with same and different di- and trialkyl/aryltin(IV) moiety: their synthesis, spectral characterization and biological activities

Homobimetallic complexes with oxygen and sulphur donor ligand have been synthesized at room temperature under stirring conditions using R₂SnCl₂ (R?=?Me, n-Bu) and R₃SnCl (R?=?Me, n-Bu, Ph) in 1:1 molar ratio. The synthesized complexes have been characterized by elemental analysis, IR and multinuclear NMR (¹H, ¹³C) spectroscopy. These complexes have also been screened for their biological activities. IR data show that the ligand acts in a bidentate manner and exhibits trigonal bipyramidal geometry in solid state which is also confirmed by semi-empirical study. NMR data show that reported complexes exhibit tetrahedral geometry in solution. Results of antimicrobial screening activities indicated that complexes (6) and (7) are very effective antibacterial and antifungal agents, respectively, and they might indeed be a potential source of antimicrobial agents, while the complex (3) exhibits significant free radical scavenging ability with lower IC₅₀ value of 99.47?±?1.2???g/mL. Results of cytotoxicity/haemolytic activity showed the significant value of % haemolysis for complex (7) (18.101?±?2.3), while complex (4) was found to be least cytotoxic (5.733?±?1.0). Only a few colonies are observed in mutagenicity testing by Ames test.     

Synthesis,characterization and cytotoxic activity of diorganotin (IV) complexes with 4H-pyrido[1,2-a]pyrimidin-4-one derivatives

The coordination behaviour of the diorganotin (IV) compounds R₂SnCl₂ (where R = Me, Ph) with 4H-pyrido [1,2-a] pyrimidin-4-one derivatives (L) has been described. The complexes R₂SnCl₂ · L obtained have been characterized physicochemically and spectroscopically. The pyrimidin-4-one ligands were found to coordinate with R₂SnCl₂ species in a monodentate fashion, mainly via the oxygen atom of the 4-one group or possibly via the nitrogen atom of the (SINGLE BOND)C(DOUBLE BOND)N linkage (the less sterically hindered nitrogen of the pyrimidine derivative) to give pentacoordinate tin complexes. Of the complexes selected to be screened against five tumour cell lines, some exhibited significant in vitro activity.     

Organotin(IV) complexes of 4-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)benzoic acid: Synthesis, spectral characterization and biological applications

4-(2,5-Dioxo-2,5-dihydro-1H-pyrrol-1-yl)benzoic acid and its complexes with methyl-, n-butyl-, phenyl-, benzyl- and octyl-tin have been synthesized and characterized by elemental analysis and spectral studies. The geometry around the tin atom has been deduced from both solid and solution studies. These complexes were also tested against different bacteria and fungi to determine their toxicity. LD50 data was also calculated using the Brine Shrimp method.     

Synthesis and spectral characterization of alkaline earth metal complexes: Crystal structure of a Ca(II) hippuric acid complex

Alkaline earth metal (Mg, Ca, Sr and Ba) complexes of hippuric acid (hipH) have been synthesized and characterized by elemental analyses and IR spectroscopy. One of the complexes, [Ca(hip)₂(H₂O)₂]·H₂O, was characterized by single crystal X-ray diffraction studies. The polymeric structure is based on a dimeric unit and each calcium is coordinated to four hippurate anions and two coordinated water molecules. The hippurate anion functions as a bidentate ligand through the oxygen atoms of the carboxylate groups, one of which is bridging, forming a two dimensional coordination polymer. The water coordination is further confirmed by thermal analysis. The non-linear optical activity of the complexes was also measured.     

Organotin(IV) triazolates: Synthesis and their spectral characterization

Some organotin(IV) triazolates of general formula R_nSn(L)_4 − n (where R = Me, n-Bu and Ph for n = 2; R = Me, n-Pr and n-Bu for n = 3 and HL = 3-amino-5-mercapto-1,2,4-triazole) have been synthesized by the reaction of R₂SnCl₂/R₃SnCl with NaL in 1:2/1:1 molar ratio. Whereas, Oct₂SnL₂ has been synthesized azeotropically by the reaction of Oct₂SnO and HL in 1:2 molar ratio. As good single crystals were not obtained, a large number of experimental techniques, viz. UV/Vis, IR, far-IR, multinuclear (¹H, ¹³C and ¹¹⁹Sn) NMR and ¹¹⁹Sn Mössbauer spectroscopic studies, were used to accomplish a definitive characterization and determination of their most probable structures. In these compounds triazole acts as a monoanionic bidentate ligand, coordinating through S_exo and N(4). The IR and ¹¹⁹Sn Mössbauer spectroscopic studies allow us to deduce a highly distorted cis-trigonal-bipyramidal structure for R₃SnL and a distorted skew trapezoidal-bipyramidal structure for R₂SnL₂, in the solid state. However, ¹H, ¹³C and ¹¹⁹Sn NMR spectral studies revealed that weak bonding between tin and N(4) is further weakened in the solution leading to pseudo-tetrahedral/tetrahedral structure.     

Crystal structure of 1,1-dibutyl-1,1-bis[(4-methyl-1-piperidinyl)dithiocarbamato)] tin(IV)

The dibutyltin(IV) complex of 4-methyl-1-piperidinedithioic acid has been synthesized and characterized by X-ray diffraction. It was found that tin atom has distorted tetragonal geometry with the space group P-1.     

Crystal and molecular structure of [RuNO(NO2)4OHCuPy n ] heterometallic complexes

Heterometallic complexes [RuNO(NO₂)₄OHCuPy₂(H₂O)] (I) and [RuNO(NO₂)₄OHCuPy₃] (II) are described structurally for the first time. In complex I, the ruthenium anion is coordinated to the copper atom by the bridging OH group and two bridging nitro groups; in complex II, by the bridging OH group and one bridging nitro group. Dimers are formed in the crystal lattice of complex II due to the interaction of the copper atom and the nitro group of the ruthenium anion in trans position to the bridging NO₂ group.     

Synthesis and spectral analysis of (±)-cis-N-[1-(2-hydroxy-2-phenyl-ethyl)-3-methyl-4-piperidyl]-N-phenylpropanamide and (±)-cis-N-[1-(2-hydroxy-1-phenylethyl)-3-methyl-4-piperidyl]-N-phenylpropanamide

Treatment of (±)-cis-N-(3-methyl-4-piperidyl)-N-phenylpropanamide (2) with styrene oxide (1) yielded a mixture of (±)-cis-N-[1-(2-hydroxy-2-phenylethyl)-3-methyl-4-piperidyl]-N-phenylpropanamide (3) and (±)-cis-N-[1-(2-hydroxy-1-phenylethyl)-3-methyl-4-piperidyl]-N-phenylpropanamide (4) . The structure of compound 3 was confirmed by an unambiguous synthesis via (±)-cis-N-[1-(2-oxo-2-phenylethyl)-3-methyl-4-piperidyl]-N-phenylpropanamide (6) . The proton and carbon-13 resonances of compounds 3 and 4 were assigned with the aid of two-dimensional heteronuclear correlation experiments.     

Synthesis and characterization of diorganotin(IV) complexes of tridentate Schiff bases: crystal structure of [N-(3-hydroxypyridine-2-yl)-5-chlorosalicylideneiminato]dimethyltin(IV)

Some five-coordinated dimethyltin(IV) complexes of the type Me₂SnL (where L is the anion of a bifunctional tridentate Schiff base) were synthesized. These Schiff bases are N-(3-hydroxypyridine-2-yl)-3-methoxysalicylideneimine, HOC₆H₃OCH₃CH=NC₅H₃NOH (1), N-(3-hydroxypyridine-2-yl)-3-ethoxysalicylideneimine, HOC₆H₃OC₂H₅CH=NC₅H₃NOH (2), N-(3-hydroxypyridine-2-yl)-5-chlorosalicylideneimine, HOC₆H₃ClCH=NC₅H₃NOH (3), and N-(3-hydroxypyridine-2-yl)-3-methoxy-5-bromosalicylideneimine, HOC₆H₂OCH₃BrCH=NC₅H₃NOH (4). Dimethyltin(IV) complex of 3 (3a) was characterized by single crystal X-ray diffraction method and a coordination geometry that is nearly halfway between trigonal–bipyramidal and square pyramidal arrangement was found. Dimethyltin complexes of (1), (2), and (4) were also prepared and characterized by the comparison of their elemental analysis and ¹H-NMR-, IR-, UV- and mass spectral data with those of (3a). For example, in the ¹H-NMR spectra, the ²J(¹¹⁹Sn-¹H) in the Sn-CH₃ moiety have values between 80 Hz and 90 Hz, typical of five-coordinated tin species. By using these values in Lockart’s Equations, H₃C–Sn–CH₃ angles in the complexes were estimated to lie between 130° and 145°. X-ray diffraction value for 3a, confirms this estimate within 3.4% relative deviation (129.7° exp. Vs. 134.9° estimate).     

Crystal structure and properties of the [Cu(C11H10N4)Br2] compound. Stereochemistry of [Cu(planar tridentate ligand)(unidentate ligand)2] complexes

The crystal structure of the dibromo(pyridine-2-aldehyde 2′-pyridylhydrazone) copper(II) is reported. The compound crystallizes in space group P2₁/_n, with a = 12.86(2), b = 11.944(5), c = 8.770(7) Å, β = 97.17(6)°, U = 1336(3) ų, Z = 4, D_m = 2.06(1), D_x= 2.10 g cm⁻³, μ(Mo-K_α) = 78.92 mm⁻¹, F(000) = 812, T = 293 K. Final R is 0.047 (R_w = 0.049) for 854 observed reflections. The structure consists of discrete molecules in which the copper(II) ion is pentacoordinate with a distorted square pyramidal geometry. The spectroscopic data are in good agreement with the structural results. The stereochemistry of several pentacoordinate complexes of type [Cu(planar tridentate ligand) (unidentate ligand)₂] is examined and the distortions of the coordination polyhedra are calculated.     

Synthesis and Crystal Structure of N-[4-(4-Methyl-phenylsulfamoyl)-phenyl]-4-methyl-1,2,3-thiadiazole-5-carboxamide

The crystal structure of the title compound (C17H16N4O3S2, Mr = 388.46) has been determined by single-crystal X-ray diffraction. The crystal belongs to monoclinic, space group P21/c with a = 13.688(2), b = 16.704(3), c = 8.3308(12) , β = 99.474(6)o, V = 1878.8(5) 3, Mr = 388.46, Z = 4, Dc = 1.373 g/cm3, μ = 0.308 mm–1, F(000) = 808, R = 0.0389 and wR = 0.0917. X-ray analysis reveals that the crystal structure involves intermolecular N–H…O and N–H…N hydrogen bonds, which link the molecules into a layer parallel to the ac plane.