Synthesis,resolution and application of 2,2′-bis(di-2-furylphosphino)-1,1′-binaphthalene

A six step synthesis and resolution of (±)-2,2′-bis(di-2-furylphosphino)-1,1′-binaphthalene 4 (TetFuBINAP) is described along with its use in asymmetric inter- and intramolecular Heck reactions.     

Bidimensional chronoabsorptometric study of electropolymerisation of 4,4′-bis(2-methylbutylthio)-2,2′-bithiophene

Bidimensional chronoabsorptometry is a novel spectroelectrochemical technique that monitors simultaneously three different signals: current and absorbance both normal to the electrode plane and parallel to this plane during a time in which a fixed potential is imposed. This technique is applied in the visible range to the study of the electropolymerisation of 4,4^′-bis(2-methylbutylthio)- 2,2^′-bithiophene (MBTBT). Experiments are performed in a spectroelectrochemical cell under finite diffusion conditions (thin layer cell) with the aim of interpreting the processes taking place both at the electrode surface and in the adjacent solution during the potentiostatic electrogeneration and deposition of the polymer. Correlations are drawn out among the trends of the oligomers concentration in solution, the polymer electrodeposition and charging, and the current flow, on the time scales of the different steps of the process.     

Synthesis and structures of 4,5-dimethyl-1,3-bis(pyridin-2-ylmethyl)-1H-imidazolium chloride and 1,1′-bis(pyridin-2-ylmethyl)-2,2′-bis(4,5-dimethylimidazole)

4,5-Dimethyl-1,3-bis(pyridin-2-ylmethyl)-1H-imidazolium chloride (1) was synthesized and characterized by IR and NMR spectroscopy and X-ray diffraction. An attempt to prepare the free tridentate N-heterocyclic carbene pincer ligand by the reaction of 1 with KN(SiMe₃)₂ resulted in the formation of 1,1′-bis(pyridin-2-ylmethyl)-2,2′-bis(4,5-dimethylimidazole) as a product of dimerization of the target carbene followed by the rearrangement accompanied by the elimination of dipyridylethane.

     

Syntheses,structures, and properties of two metal-organic frameworks comprising bpdc (2,2′-biphenyldicarboxylate) and bipb (2,2′-bis(imidazol-1-ylmethyl)-biphenyl)

Two new coordination polymers, [Cd(bpdc)(bibp)(H₂O)₂] _n (1) and [Zn(bpdc)(bibp)] _n (2), have been hydrothermally synthesized from 2,2′-biphenyldicarboxylate (bpdc) and 2,2′-bis(imidazol-1-ylmethyl)-biphenyl (bipb). Polymer 1 features a 1-D tubelike porous chain along the a direction with coordinated water molecules occupying the pores. The double-chain of polymer 2 possesses alternating rectangular rings [(bpdc)₂Zn₂] and [(bibp)₂Zn₂] with Zn as nodes. The polymers exhibit strong fluorescent emissions in the solid state at room temperature and could be significant as photoactive materials.     

ZnII and HgII complexes of 2,2′-diamino-4,4′-bis(1,3-thiazole) (DABTZ), spectroscopic,thermal and structural studies

New zinc(II) and mercury(II) complexes of 2,2′-diamino-4,4′-bis(1,3-thiazole) (DABTZ), [M(DABTZ)(CH₃COO)₂], have been synthesized and characterized by elemental analysis, IR-, ¹H NMR-, ¹³C NMR spectroscopy and studied by thermal analysis and X-ray crystallography. The structural characterization of the [Zn(DABTZ)(CH₃COO)₂] complex shows the complex to be a monomer and the Zn coordinated by two nitrogen atoms of the “DABTZ” ligand and four oxygen atoms of the acetate anions.     

A novel bifunctional reagent: 2,2′-bis(methoxymethylene)- 2,2′-sulfonyldiacetonitrile

Preparation properties and reactions of the title reagent are reported. The reagent is potentially useful for cross-linking proteins and/or nucleic acids.     

The Syntheses of 4,4′-(1,n-Dioxaalkane)-bisbenzaldehydes and 4,4′-(1,n-Dioxaalkane)-bis(α-methoxy Phenylacetic Acids)

The syntheses of 4,4′-(1,n-dioxaalkane)-bis(α-methoxyphenylacetic acids) were conducted using a base-catalyzed reaction. The reactants were potassium hydroxide (or lithium hydroxide/lithium chloride), bromoform, methanol and 4,4′-(1,n-dioxaalkane)-bisbenzaldehydes. The aldehyde starting materials were prepared using the Williamson ether synthesis, by condensing p-hydroxybenzaldehyde and 1,n-dibromoalkanes with lithium hydride in ethanol. The effect of varying the hydrocarbon length in the dioxaalkane bridge unit is a significant consideration (the number of CH₂ units in the bridge varying from two to eight) in their acid salt formation.

     

Comparative analysis of physicochemical properties of dinuclear zinc(II) helicates with 2,2′-, 2,3′-, and 3,3′-bis(dipyrromethenes)

The effect of the attachment position of a methylene spacer in 2,2′-, 2,3′-, and 3,3′-bis(dipyrromethene) N₄-ligands (H₂L) on physicochemical properties of their dinuclear homoleptic helicates [Zn₂L₂], such as specific features of their molecular structure, luminescence spectral characteristics, lability in acid solutions, and thermal stability in an argon atmosphere, has been examined. It has been shown that the substitution of the biladiene-type helicand by its 2,3- and especially 3,3′-analogues leads to a considerable enhancement of the chromophoric properties, an increase (up to 30-fold) of the fluorescence quantum yield, and an increase in the stability of corresponding dinuclear helicates [Zn₂L₂].     

Synthesis and coordination chemistry of the tetradentate ligands 6,6′-bis(3-pyrazolyl)-2,2′-bipyridine and 6,6′-bis(2-hydroxyphenyl)-2,2′-bipyridine: intramolecular hydrogen-bonding in complexes of Cu(II), and a dinuclear double helicate with Ag(I)

Simple syntheses of the potentially tetradentate chelating ligands 6,6′-bis(3-pyrazolyl)-2,2′-bipyridine (H₂L¹), and 6,6′-bis(2-hydroxyphenyl)-2,2′-bipyridine (H₂L²) are described: H₂L¹ is a new ligand, whereas H₂L² is known, but investigation of its coordination chemistry has been hampered by the lack of a simple synthesis. Complexes of both have been structurally characterised and reveal many interesting features. [Cu(HL¹)(H₂O)][PF₆] is square pyramidal with an axial H₂O ligand, but, in the solid state, forms a hydrogen-bonded dimer in which the peripheral pyrazolyl groups of HL¹ (one protonated, one deprotonated) in one complex unit form a two-point ‘chelating’ hydrogen-bonding interaction with the axial water ligand of the second, and vice versa. In contrast, [Ag₂(L¹)₂][BF₄]₂ is a dinuclear double helicate because of the preference of Ag(I) ions for a pseudo-tetrahedral geometry. [Cu(L²)] has a typical near-planar geometry with a N₂O₂ donor set, and monomeric units are associated into centrosymmetric dimers in the crystal via weak axial Cu⋯O(phenolate) interactions to give an asymmetric [Cu₂(μ-phenolate)₂] core. In {[Cu(L²)]₂H}(PF₆), the two monomeric [Cu(L²)] units are also associated via axial phenolate interactions to give a dimer with a [Cu₂(μ-phenolate)₂] core, but, in addition, the extra proton per dimer unit is located at the centre of a short, strong O⋯H⋯O hydrogen-bond that links a phenolate group from each of the two monomer units. The geometry of dimer formation is changed in order to allow the phenolate groups to approach one another closely enough for this hydrogen-bond to form.     

Crystallographic and computational study of the structure of copper(II) 2,2′-bis(2-oxidobenzylideneamino)-4,4′-dimethyl-1,1′-biphenyl

The reaction of M(OAc)₂ with 2,2′-bis(2-hydroxybenzylideneamino)-4,4′-dimethyl-1,1′-biphenyl (H₂L1) allows the synthesis of 2,2′-bis(2-oxidobenzylideneamino)-4,4′-dimethyl-1,1′-biphenyl complexes of Cu(II) (CuL1), Co(II) (CoL1) and Ni(II) (NiL1) that were characterized by elemental analysis, FTIR spectroscopy and for CuL1 also by X-ray crystallography verifying a tetradentate binding mode of L1 via an (ONNO) motif of the two phenolic oxygen atoms and two azomethine nitrogen atoms. Recrystallization from a solvent mixture of dichloromethane and methanol promotes the formation of methanol adducts. Different binding modes of the methanol–complex were investigated using density functional theory calculations and binding energies, and thermodynamic data of the interaction are reported. The results show that the favored interaction occurs when the methanol molecule acts as a Lewis acid weakly binding via an O–H···O hydrogen bridge to a phenoxide moiety leading to an elongation of the respective M–O bond.

     

Structural and bonding investigation of an unbridged donor-acceptor complex 1-(2,2′-bipyrimidine)-1-(t-butyl)-2, 3-bis(trimethylsilyl) -2,3-dicarba-1-galla-closo-heptaborane(6)

The reaction between thecloso-gallacarborane, 1-(t-C₄H₉)-1-Ga-2,3-(SiMe₃)₂-2,3-C₂B₄H₄ (1), and 2,2-bipyrimidine in a molar ratio of 11 in dry benzene produced the unbridged donor-acceptor complex 1-(2,2-C₈H₆N₄)-1-(t-C₄H₉)-1-Ga-2,3-(SiMe₃)₂-2, 3-C₂B₄H₄ (2) as a pale-yellow crystalline solid in 81% yield. The spectroscopic data of2 are almost identical to those of the bridged species 1,1-(2,2-C₈ H₆N₄)-[1-(t-C₄H₉)-1-Ga-2,3-(SiMe₃)₂-2,3-C₂ B₄H₄]₂ (3). However, the single-crystal X-ray structure of2 reveals that the complex consists of only one distorted gallacarborane unit and a bipyrimidine molecule, that acts as a bidentate ligand. The apical gallium in2 is displaced further away from the centroidal position above the carborane than it is in 1. Despite the steric hindrance imposed by the bulky trimethylsilyl groups on the cage carbons, the Ga-C_(t-buty) bond is tilted toward the cage carbon atoms. Complex2 crystallizes in the monoclinic space groupP2₁ witha=11.279 (3),b=10.060 (3),c=11.911 (3) Å,=94.94 (2)°,V=1346.5 (6) ų,Z=2,D _x=1.24g cm^–3, (MoK) F(000)= 528, andT=220 K. Full-matrix least-squares refinement for2 converged at R=0.036 andRw= 0.045 for 3032 observed reflections. Molecular orbital calculations showed that antibonding interactions between the gallium and carborane cage carbons, induced by base complexation, are a contributing factor to the gallium's slip distortion that is found in2.     

Specific features of the reaction between tris(5-bromo-2-methoxyphenyl)antimony and 2-oxybenzaldoxime: Structure of bis(μ3-2-oxybenzaldoximato-O,O′,N)-(μ2-oxo)-bis(5-bromo-2-methoxyphenyl)antimony

Bis(μ₃-2-oxybenzaldoximato-O,O′,N)-(μ₂-oxo)-bis(5-bromo-2-methoxyphenyl)antimony, which crystallizes from toluene in the form of a solvate, has been synthesized by the reaction between tris(5-bromo-2-methoxyphenyl)antimony and 2-oxybenzaldoxime in the presence of hydrogen peroxide. According to X-ray diffraction data, the structurally equivalent antimony atoms in a binuclear complex molecule are linked via two tridentate bridging ligands and an oxygen atom and have a distorted octahedral coordination to the C₂O₃N surrounding The trans-angles of the octahedron are CSbO (168.7(1)°), CSbN (164.1(1)°), and OSbO (159.3(1)°), and the bond lengths are Sb-C (2.127(4), 2.159(3) Å) and Sb-N (2.238(3) Å). A molecule contains the three types of Sb-O distances with a bridging oxygen atom (1.950(1) Å), the oxygen atoms of oxy groups (2.002(2) Å), and the oxygen atoms of oxime groups (2.091(2) Å). Sb?OCH₃ intramolecular contacts (3.097, 3.290 Å) also exist.     

Übergangsmetall-carbin-komplexe: LXXXI. trans-Ph2As(CO)2(2,2′-bipy)WCNEt2 (2,2′-bipy = 2,2′-bipyridyl), der erste,neutrale diphenylarsano-carbinokomplex eines übergangsmetalls

trans-Br(CO)₂(2,2′-bipy)WCNEt₂ reacts with NaAsPh₂ undergoing substitution of the halogen ligand to yield trans-Ph₂As(CO)₂(2,2′-bipy)WCNEt₂, the first neutral transition metal carbyne complex which contains a heavier element of the Main Group V coordinated in the trans position relative to the carbyne ligand on the metal.Despite coordination the high reactivity of the AsPh₂ group is preserved in trans-Ph₂As(CO)₂(2,2′-bipy)WCNEt₂ because of the one free electron pair still left on arsenic. Thus at room temperature we observe a nucleophilic attack of trans-Ph₂As(CO)₂(2,2′-bipy)WCNEt₂ on CH₂Cl₂ which upon elimination of the AsPh₂ ligand yields trans-Cl(CO)₂(2,2′-bipy)WCNEt₂.     

Structural characterization,photophysical and BSA binding interaction studies of 4,4′-bis(benzimidazolyl)-2,2′-bipyridine

The title compound is synthesized from the precursors 1,2-diaminobenzene and 2,2′-bipyridine-4,4′-dicarboxylic acid (dcbpy) and characterized using ESI-Mass, ¹H NMR, FT-IR and single crystal X-ray analysis. We are the first to report the crystal structure of the 4,4′-bis(benzimidazolyl)-2,2′-bipyridine (bimbpy) ligand. The photophysical properties of the compound in dimethyl sulfoxide and in the aqueous medium are studied. The interaction studies of bimbpy with bovine serum albumin (BSA) were performed with the fluorescence technique and it strongly binds with BSA.     

Spectroscopic and structural properties of complexes of 3,3′-bis(2-benzimidazolyl)-2,2′-bipyridine with copper(I) and silver(I)

The pseudo-tetrahedral complexes [CuL₂]PF₆·7H₂O·CH₃OH (1) and [AgL₂]CF₃SO₃·H₂O (2) (L?=?3,3′-bis(2-benzimidazolyl)-2,2′-bipyridine) have been synthesized and characterized through crystal structure analyses, electrochemistry, and spectroscopic methods. X-ray structural analyses of 1 and 2 indicate that sterically constrained N₄ ligands L are cis and behave as bidentate chelates to a single metal ion in a pseudo-tetrahedral fashion through the benzimidazole. As two benzimidazolyl rings exhibit considerable steric hindrance, the bipyridine unit of L remains uncoordinated. The pseudo-tetrahedral cation [CuL₂]⁺ shows a quasi-reversible Cu^I/Cu^II oxidation–reduction wave in the CV in DMF (counter-ion PF₆^?). The fluorescence titration of L with copper(I), silver(I), and also with pH have been conducted to examine the selectivity. The ligand shows remarkably high selectivity and sensitivity for Ag(I).     

Synthesis,characterization and in vitro antitumor behavior of a vanadium(V) complex with 4′-(3-methoxyphenyl)-2,2′:6′2″-terpyridine

A dioxovanadium(V) complex, [VO₂(moptpy)](ClO₄) (1, moptpy = 4′-(3-methoxyphenyl)2,2′:6′2″-terpyridine), was synthesized and characterized by elemental analysis, ESI-MS, UV–vis, IR, and ¹H, ¹³C, and ⁵¹V NMR. The cytotoxicity in vitro of 1 was evaluated against cancer cell lines HepG-2 (hepatocellular carcinoma), SGC-7901 (gastric carcinoma), SiHa (cervical cancer), BEL-7402 (hepatocellular), and rat PC-12 (pheochromocytoma) by the MTT method. The results demonstrated that 1 exhibits superior anticancer activity in vitro with much lower values of 50% inhibitive concentration (IC₅₀) against the selected cell lines than cisplatin, and 1 shows the highest cytotoxic activity toward SGC-7901 cells (IC₅₀ = 1.3 ± 0.1 μM) among the selected cell lines. A series of cellular morphological and staining experiments were carried out, and the results indicated that 1 can effectively induce apoptosis of SGC-7901 cells through a ROS-mediated mitochondrial dysfunction pathway. In addition, cellular incorporation and cell cycle analysis were also performed, and it was concluded from the experimental observations that 1 can efficiently enter into the cell nuclei, and the complex inhibits cell growth in SGC-7901 cell at G0/G1 phase.     

Ring Closure of N,N′:N,N′-bis(decamethylene)-1, 4-diamino-2,5-bis(10-cyanodecyloxy)benzene (IV)

Recently, β-chloro-α,β-unsaturated carbonyl compounds have become increasingly useful as intermediates in organic synthesis. For example, reactions involving a number of different cyclic β-chloro-α,β-unsaturated ketones with a variety of reagents (a malonate anion², the anion of the dithiolane derivative of ethyl glyoxalate³, zinc-silver couple in methanol⁴, dimethylsulfoxonium methylide^5,6) have produced a series of structurally diverse and potentially fruitful synthetic intermediates. The second-mentioned reagent has also been successfully reacted with a β-chloro-α,β-unsaturated ester³.     

S- and N-alkylation of 2,2′-(alkane-α,ω-diyldisulfanediyl)-bis(1,3-benzothiazoles) with 1-iodopropan-2-one in the presence of iodine

Russian Journal of Organic Chemistry - The alkylation of 2,2′-(methylenedisulfanediyl)- and 2,2′-(ethane-1,2-diyldisulfanediyl)bis-(1,3-benzothiazoles) with 1-iodopropan-2-one involves...     

Role of the transition metal complexes of 2,2′-bis(diphenylphosphino)-1,1′-binaphthyl (BINAP) in asymmetric catalysis

Metal complexes of 2,2′-bis(diphenylphosphino)-1,1′-binaphthyl (BINAP) are being used as a chiral catalysts in many organic reactions. This review highlights recent developments on synthesis of metal BINAPs and its application in various organic synthesis. The studies done on the application of metal BINAPs show a unique reactivity, which enables its use in entirely different sets of chemical transformation.