First example of antimoniated Schiff bases: Hypervalent Sb ← N(sp2) bonds

The first example of antimoniated Schiff bases viz. 1-[2-(bis-{2-[(1-R-p-tolylethylimino)methyl]phenyl}stibanyl)benz-E-ilidene]-(1-R-p-tolylethyl)amine (1) and tris[(R)-2-benzyliden-2-yl-amino)butan-1-ol]stibine (2) containing imino groups at the ortho position of aryl ring have been synthesized and characterized. The compounds were obtained by the reaction of tris(o-formylphenyl)stibine with R-4-dimethyl benzyl amine or (R)-2-aminobutan-1-ol, respectively. These chiral antimony based Schiff bases were characterized by IR, mass, ¹H, ¹³C, NMR spectroscopy. The X-ray crystal structures of these two Schiff bases show hypervalent interactions between antimony and sp² nitrogen atoms. Additionally compound 2 shows intramolecular Sb–O interaction also giving eight-coordination of antimony, both of these observations are uncommon in literature. These two compounds 1 and 2 show helicoidal chirality, which is a very new concept in antimony chemistry.     

Synthesis and Characterization of Some Triphenyltin(IV) Complexes from Sterically Crowded [((E)-1-{2-Hydroxy-5-[(E)-2-(aryl)-1-diazenyl]phenyl}methylidene)amino]acetate Ligands and Crystal Structure Analysis of a Tetrameric Triphenyltin(IV) Compound

Four new triphenyltin(IV) complexes containing [((E)-1-{2-hydroxy-5-[(E)-2-(aryl)-1-diazenyl]phenyl}methylidene)amino]acetate ligands (L) have been synthesized with formulations of Ph₃SnLH. They have been studied by multinuclear (¹H, ¹³C, ¹¹⁹Sn) NMR, ¹¹⁹Sn M?ssbauer and IR spectroscopy. A full characterization of one complex, Ph₃SnL¹H (1), was accomplished by single crystal X-ray crystallography, which revealed the compound to be a macrocyclic tetramer. In the tetramer, the five coordinate tin atoms have distorted trigonal bipyramidal geometries with the three phenyl groups occupying equatorial positions, while an oxygen atom of the carboxylate group of one L ligand and the oxide O-atom (formerly the hydroxy group) of a second L ligand in an apical positions. The carboxylate ligands bridge adjacent tin atoms and coordinate in the zwitterionic form with the phenolic proton moved to the nearby nitrogen atom. ¹¹⁹Sn NMR results indicate that the tetrameric structures of the complexes in the solid state, in which the tin atoms are five-coordinated, dissociate in solution to yield four coordinate monomeric species.     

Self-Assembly Syntheses and Crystal Structure of a New Organotin(IV) Schiff Base Complex Containing a Novel Sn<Subscript>5</Subscript>O<Subscript>5</Subscript> Hydrolysis Ladder

A new organotin(IV) Schiff base complex 4 containing a novel Sn₅O₅ hydrolysis ladder and a disulfide group has been synthesized through a self-assembly reaction. The complex 4 has been characterized by elemental analysis, IR, ¹H-, ¹³C-, and ¹¹⁹Sn-NMR spectra and X-ray crystallography diffraction analyses. The study of the supramolecular structure of complex 4 found that there exist two kinds of C–H···S and C–H···O intermolecular hydrogen bonds. The two kinds of intermolecular hydrogen bonds force the complex 4 into a 2-dimensional “wave” network. The geometry about each tin atom involved is distorted trigonal bipyramid.     

Nuclear γ-resonance spectra and local surrounding of 121Sb and 129I atoms in CuI-PbI2-As2Se3 and CuI-SbI3-PbI2-As2Se3 films

The local surrounding of copper, antimony, and iodine atoms in multicomponent chalcogenide films CuI-PbI₂-As₂Se₃ and CuI-SbI₃-PbI₂-As₂Se₃ deposited from solutions of chalcogenide glass in n-butylamine has been studied by the Mössbauer spectroscopy method on ¹²¹Sb and ¹²⁹I isotopes. It was established that antimony atoms are in the Sb (III) state, where each antimony atom is surrounded by three selenium atoms. Copper atoms are in the Cu (I) state and are surrounded by iodine atoms. The local surrounding of copper, antimony, and iodine atoms in chemically deposited chalcogenide films is analogous to the local surrounding of atoms in the initial chalcogenide glass.     

Spectral Studies and Bactericidal, Fungicidal, Insecticidal and Parasitological Activities of Organotin(IV) Complexes of Thio Schiff Bases Having no Donor Atoms

Twelve new organotin(IV) complexes of the type RnSnLm [where n = 3, m = 1, R = CH₃ or C₆H₅; n = 2, m = 2, R = C₆H₅ or C₄H₉ ; L = anion of Schiff bases derived from the condensation of 2-amino-5-(o-anisyl)-l,3,4-thiadiazole with salicylaldehyde (HL-1), 2- hydroxynaphthaldehyde (HL-2) and 2-hydroxyacetophenone (HL-3)] have been synthesized and characterized by elemental analysis, molar conductances, electronic, infrared, far-infrared, ¹H NMR and ¹¹⁹Sn Mössbauer spectral studies. Thermal studies of two complexes, viz., Ph₃Sn (L-1) and Ph₂Sn(L-2)₂ have been carried out in the temperature range 25-1000∘C using TG, DTG and DTA techniques. All these complexes decompose gradually with the formation of SnO₂ as an end product. In vitro antimicrobial activity of the Schiff bases and their complexes has also been determined against Streptococcus faecalis, Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus Penicillin resistance (2500 units), Candida albicans, Cryptococcus neoformans, Sporotrichum schenckii, Trichophyton mentagrophytes and Aspergillus fumigatus. The Schiff bases (HL-1), (HL-2) and the organotin(IV) compounds have also been tested against various important herbicidal, fungicidal, insecticidal species and also for parasitological activity against freeliving nematode.     

A Novel Twofold Interpenetrating 2D (3,5)-Connected Cd(II) Coordination Framework with (52.6)(55.64.7) Topology

The self-assembly of 4′-(4-carboxyphenyl)-4,2′:6′4″-terpyridine (HL) with Cd(II) cation afforded one novel twofold interpenetrating 2D coordination polymer, [Cd(L)₂(H₂O)_1.5] _n . In this compound, the Cd(II) atoms as 5-connected nodes are linked by the bridging ligands L acting as both linear connectors and 3-connected nodes to form a novel (3, 5)-connected 2D framework with the (5².6)(5⁵.6⁴.7) topology. Two equivalents of such 2D framework interpenetrate with each other to form a more complicated supramolecular network. Furthermore, fluorescent measurement on the powder sample shows that the complex strongly emits at 399 nm with the excitation of 331 nm.     

Synthesis, Characterization and Photoluminescence of Dimeric and Polymeric Metallaynes of Group 10–12 Metals Containing Conjugation-breaking Diphenylmethane Unit

A novel approach based on conjugation interruption was developed for a luminescent and thermally stable platinum(II) polyyne polymer trans-[–Pt(PBu₃)₂C≡C(C₆H₄)CH₂(C₆H₄)C≡C–] _n (1) containing the diphenylmethane chromophoric spacer. Particular attention was focused on the photophysical properties of this group 10 polymetallayne and comparison was made to its binuclear model complex trans-[Pt(Ph)(PEt₃)₂C≡C(C₆H₄)CH₂(C₆H₄)C≡CPt(Ph)(PEt₃)₂] (2) and their closest group 11 gold(I) and group 12 mercury(II) neighbors, [MC≡C(C₆H₄)CH₂(C₆H₄)C≡CM] (M = Au(PPh₃) (3), HgMe (4)). The regiochemical structures of these angular-shaped compounds were studied by various spectroscopic analyses. Upon photoexcitation, each of them emits an intense purple-blue fluorescence emission in the near UV region in dilute fluid solutions at room temperature. Harvesting of organic triplet emissions harnessed through the strong heavy-atom effects of group 10–12 transition metals was examined. These metal-containing phenyleneethynylenes spaced by the conjugation-breaking CH₂ unit were found to have high optical gaps and high-energy triplet states. The influence of metal and sp³-hybridized methylene conjugation-interrupters on the intersystem crossing rate and the spatial extent of the lowest singlet and triplet excitons was fully elucidated. Our investigations indicate that high-energy triplet states in these materials intrinsically give rise to very efficient phosphorescence with fast radiative decays. Dedicated to Professor Didier Astruc in recognition of his outstanding contribution to metallodendrimers and polymers.     

Hydrothermal Synthesis and Characterization of Trimethyltin(IV) Derivatives with 2-Carboxyethylphosphonic and Benzylphosphonic acid: X-ray Crystal Structures of 2D Network Polymers

Two organotin(IV) derivatives, {[(CH₃)₃Sn]₆·[O₃P(CH₂)₂CO₂]₂·3H₂O} _n 1 and {[(CH₃)₂Sn]₄·[O₃PCH₂Ph]₄} _n 2, were synthesized by the reaction of trimethyltin(IV) chloride, 2-carboxyethylphosphonic acid and benzylphosphonic acid, respectively. Characterization of complexes 1 and 2 were achieved using elemental analysis, IR, TGA, NMR (¹H, ¹³C, ³¹P and ¹¹⁹Sn) spectroscopy and X-ray crystallography diffraction analysis. X-ray characterization show that complexes 1 and 2 are 2D network structures.     

Solution Studies of Tris(2-aminoethyl)amine with Metal Ions of Biological Interest: The Electroanalytical Determination of the Phosphate Triester Hydrolysis

Complex formation of tris(2-aminoethyl)amine, Tren, with both Zn(II) and Cu(II) ions in aqueous solution was investigated spectroscopically by using ¹H NMR and UV-visible titrations as well as electrochemically by using cyclic voltammetry. Analysis of the titration data indicated that the aqua complexes [(Tren)Zn(OH₂)](ClO₄)₂ 1 and [(Tren)Cu(OH₂)](ClO₄)₂ 2 deprotonate at pH = 10.6 and 9.7, forming the dinuclear bridged hydroxo species {[(Tren)Zn]₂(μ-OH)}³⁺ 3 and {[(Tren)Cu]₂(μ-OH)}³⁺ 4, respectively. The catalytic hydrolysis of the activated phosphate ester tris(p-nitrophenyl)phosphate (TNPP) by using these model complexes was examined and the released phenolate anions were determined by using spectroscopic and electroanalytical techniques.     

A convenient method for the synthesis of [Pd{[(η5-C5H3)–CHN–(CH2)2–NMe2]Fe(η5-C5H5)}Cl] and the study of its reactivity with diphosphines

A one-pot method for the preparation of [Pd{[(η⁵-C₅H₃)–CHN–(CH₂)₂–NMe₂]Fe(η⁵-C₅H₅)}Cl] is described. Its X-ray crystal structure and its reactions with the diphosphines Ph₂P–(CH₂)_n–PPh₂ {with n=1 (ddpm) or 2 (dppe)} are also reported.     

Crystal and Supramolecular Structure of a Novel Organotin Sulphate: {[(Ph3Sn)2SO4]2 · (H2O)3} · 2EtOH

A novel sulphate of organotin was synthesized by the reaction of triphenyltin chloride with silver sulphate. The structure of {[(Ph₃Sn)₂SO₄]₂ · H₂O)₃} · 2EtOH has been determined by X-ray crystallography. The crystal data parameters are as follows: monoclinic, space group Cc, a = 14.146(6), b = 23.844(11), c = 23.777(11) Å, Z = 4. The title compound displays a dimeric tetra-tin nuclear structure. The geometry about tin is trigonal bipyramidal with a trans-O₂SnC₃ stereochemistry about the metal. Hydrogen bonding between the oxygen atoms of the anion and the solvate water produces a graphite-like 3D network lattice.     

An efficient method for synthesis of some heterocyclic compounds containing 3-iminoisatin and 1,2,4-triazole using Fe3O4 magnetic nanoparticles

1,2,4-triazole derivatives were prepared by reaction of thiocarbohydrazide and some esters in 60% ethanol. Condensation of 1,2,4-triazole derivatives with isatin gave Schiff bases of 3-iminoisatin derivatives. Reaction of malonic or succinic acid dihydrazide with isatin lead to formation of N,N'-bis-(3-imino-1,3-dihydro-indolyl-2-one)-malonamide 8a and N,N'-bis-(3-imino-1,3-dihydro-indolyl-2-one)succinamide 8b in good yields under mild reaction conditions. These reactions are catalyzed by Fe₃O₄ MNPs. The chemical structures were confirmed by Fourier transform-infrared, ¹H-NMR, ¹³C-NMR, gas chromatography-mass spectrometry spectroscopy, and elemental analysis.     

A New Tb(III) MOF for Selective Detection of Cu2+ Ion and Prevention Ability Against Staphylococcus aureus Biofilm Formation on Patients with Renal Failure

In the present study, a new fluorescent Tb(III)-based coordination polymer (CP) with the chemical formula of [Tb(TCPB)(DMF)₃]_n (1) has been presented via using a mixed-donor ligand 1,3,5-tris(1-(2-carboxyphenyl)-1H-pyrazol-3-yl)benzene (H₃TCPB) under the solvothermal reaction conditions. CP 1 becomes the predominated selection for luminescence probing experiments because of the highly developed stability in watery reagent and Lewis basic centers. Furthermore, the prevention ability of the synthetic compound against bacterial infection induced by Staphylococcus aureus during hemodialysis with renal failure was evaluated. With the help of molecular docking simulation, it can be seen from the molecular level that both carboxyl and pyrazole groups on the Tb complex are responsible for the binding interactions and therefore they are the origin of biological activities.

     

Synthesis and Polymerization of Novel Quinone Methide Ketals

Summary Novel quinone methide ketals, 8-[ 1'-cyano-1'-(ethoxycarbonyl)methylene]-l,4-dioxaspiro[4.5]deca-6,9-diene (1a) and 8-(1',l'-dicyanomethy1ene)-1,4-dioxaspiro[4.5]deca-6,9-diene (1b), were synthesized, and their polymerization behavior was investigated. Polymerizations of 1a and 1b initiated with BPO and BF₃·Et₂O gave corresponding novel ring-opening polymers, but no polymerization with BuLi. Copolymerization of 1a with St in the presence of AIBN at 60 °C gave the monomer reactivity ratios r₁(1a) = 0.50 ± 0.1 and r₂(St) = 0.1 ± 0.02, and Q and e values of 1a were 2.46 and +0.93, indicating that 1a is a highly conjugative, electron-accepting monomer. Homopolymers of 1a and 1b had better thermal stability than that of 7-cyano-7-(ethoxycarbonyl)- 1,4-benzoquinone methide. Received 23 January 2003/Revised version 28 February 2003/ Accepted 1 March 2003 Correspondence to Takahito Itoh     

In situ synthesis and dielectric properties of copper(II) and nickel(II) chiral Schiff base complexes

Two chiral Schiff base-containing complexes, [Cu(L¹)](ClO₄)₂·H₂O (1, L¹ = (S,S)-N1,N2-bis((1H-imidazol-4-yl)methylene)cyclohexane-1,2-diamine) and [Ni(L²)₂](ClO₄)₂ (2, L² = (S,S)-N1-((1H-imidazol-4-yl)methylene)cyclohexane-1,2-diamine) were synthesized from the reaction mixture of 1H-imidazole-4-carbaldehyde, (S,S)-1,2-diaminocyclohexane and Cu(ClO₄)₂·6H₂O or Ni(ClO₄)₂·6H₂O in methanol. Single-crystal X-ray diffraction analyses reveal that the in situ generated chiral Schiff base ligands L¹ and L² are bisubstituted and monosubstituted, respectively, corresponding to the different metal ions Cu^II and Ni^II. Variable-frequency and -temperature dielectric properties of 1 and 2 have been studied.     

Supramolecular Framework Based on Pyridiniodiketone Ligand via Non-classic Hydrogen Bonding

A novel ligand L, 4-(1-hydroxy-3-oxo-3-phenylpropenyl)-1-methylpyridinium was synthesized and identified by NMR spectra and X-ray single crystal structure analysis from L · CH₃SO₄ (1L). Through self-assembling reactions, two new Cu^II/La^III-organic complexes, [CuL₂(SCN)][SCN] · H₂O (2Cu) and [LaL₂(SO₄)Cl₂] · (toluene) (3La), have been synthesized and characterized by X-ray crystallography. Structural analysis of 1L revealed that L and HSO₄ ⁻ coexist in a unit cell. For 2Cu, Cu(II) ion show a five-coordinated structure with a highly compressed square pyramid configuration; For 3La, each La(III) ion has an eight-coordinated structure with a distorted capped pentagonal bipyramidal geometry. It should be mentioned that supramolecular framework was formed via a number of hydrogen bonding interactions. Here, intramolecular C–H···O hydrogen bonding interactions stabilized and restricted the distortion between different rings. On the contrary, intermolecular hydrogen bond, e.g. C–H···O dual hydrogen bond interactions (1L), O5-involving triple C–H···O/O–H···O(N) hydrogen bond (2Cu) and triple C–H···Cl hydrogen bonding(3La), greatly affect geometric distortion between rings from ligand. Finally, we believe that the cooperative effect plays more important roles in supramolecular self-assembly.     

NMR-spektroskopische Untersuchungen zum Komplexbildungsverhalten von Hydrazonen des Thiocarbazinsäure-O-methylesters mit Zink(II)-Ionen

Complexes of Zn(II) with Schiff Bases of Hydrazine-O-methylcarbothionates – NMR-Spectroscopic Investigations Schiff bases of hydrazine-O-methylcarbothionates react as bi- or tridentate ligands with Zn(II) ions forming neutral metal complexes ( 1a-1g ). ¹H-, ¹³C- and ¹⁵N-NMR-spectra of these complexes show the existence of configurational isomers of the CN-double bond. Furthermore, depending on the ligands 4 different coordination patterns with the donor atoms N₂S₂, N₄, N₂O₂ and NOS are demonstrated.     

Slow magnetic relaxation in a two-dimensional dysprosium(III) coordination polymer

A new two-dimensional (2D) dysprosium(III) coordination polymer, e.g. [Dy(HL)(NO₃)₂(H₂O)]_n (1, H₂L = 4-{[(2-hydroxy-3-methoxyphenyl)methylidene]amino}benzoic acid)), has been solvothermally synthesized and structurally characterized using single-crystal X-ray diffraction. The dysprosium ions in complex 1 display the capped trigonal prism geometry and are connected with each other through o-vanillin and carboxyl groups, generating an interesting 2D structure with a Shubnikov topological symbol of {3²4.3.4} (tts). Magnetic investigations indicate that the coordination polymer exhibits slow magnetic relaxation.     

From tetranuclear cluster with single-molecule-magnet behavior to 1D alternating spin-canting chain in a Fe(III)–Mn(III) bimetallic system

A tetranuclear cluster and an alternating zigzag chain were synthesized via rational assembly of the same cyanometalate building blocks with different Mn(III) Schiff bases possessing varying proportions of sterically hindered groups causing steric hindrances. The tetranuclear cluster [(Tp*)Fe(CN)₃]₂[Mn(salen)]₂·H₂O [1; [(Tp*)Fe(CN)₃]⁻ [Tp* = hydrotris(3,5-dimethylpyrazol-1-yl) borate], salen = N,N′-ethylenebis(salicylideneiminato) dianion] was formed with Schiff bases possessing smaller steric hindrances, whereas the one-dimensional alternating zigzag chain {[(Tp*)Fe(CN)₃Mn(salcyen)]·2CH₃OH·H₂O}_n [2; salcyen = N,N′-(1,2-cyclohexanediylethylene)bis(salicylideneiminato) dianion] was formed with Schiff bases possessing larger steric hindrances. Magnetic measurements revealed that 1 exhibits single-molecule-magnet behavior with dominant ferromagnetic interactions, whereas 2 exhibits spin-canting behavior with dominant antiferromagnetic interactions.     

Synthesis and gas permeability of poly(<Emphasis Type="Italic">p</Emphasis>-phenyleneethynylene)s having bulky alkoxy or alkyl groups

Dipropynylbenzene with branched alkoxy and alkyl groups [CH₃C≡CRC₆H₂RC≡CCH₃, R = 2-methylpropoxy (1a), 3-methylbutoxy (1b), 4-methylpentoxy (1c), cyclohexylmethoxy (1d), 2-ethylhexoxy (1e), 2-octoxy (1f), 2-ethylhexyl (1g), and 2-octyl (1h)] were polymerized with Mo(CO)₆ in the presence of 4-(trifluoromethyl)phenyl to afford poly(2,5-di(alkoxy or alkyl)-p-phenyleneethynylene)s (2a–h). Polymer 2a was insoluble in any solvents, but the other polymers (2b–h) were soluble in common organic solvents. The polymers with relatively long side chains (2e–h) had high molecular weight over 1.6 × 10⁴ and gave free-standing membranes by solution-casting method. The densities of membranes of 2e–h were 0.914–0.998, and their fractional-free volume values were relatively large (0.094–0.158). The oxygen permeability coefficients of membranes of 2e–h were 18.4, 12.7, 4.85, and 19.3 barrers, respectively. It was found that poly(p-phenyleneethynylene) with 2-octyl side groups, which have the branch at the nearest position from main chain, exhibited the highest gas permeability.