Free Catalyzed Synthesis of 2,2′-Bipyridine via Ozonolysis Technique

The ozonation of a triple bond in organic compounds is rare in industry. The reaction is much more complicated to run, because ozone is an electrophilic agent and more likely to bind to the double bond compared to the triple bond in an organic compound. This may be a problem because some fine organic substances are very hard to synthesize and can only be solved by the ozonolysis technique of a triple-bond organic compound. In addition, oxidation by using ozone is also preferred because of the cleanliness and effectiveness of the reaction. A novel method for the synthesis of 2,2?-bipyridine was described, which involves ozonolysis of a 2-ethynylpyridine and is supported by a high-pressure reactor. The reaction proceeds via ozone attack on the acetylenic triple bond, cleavage, and free radical formation. The present study establishes the conditions for selective ozonolysis of 2-ethynylpyridine, leading to 2,2?-bipyridine. The 2,2?-bipyridine was characterized by gas chromatography flame ionization detector (GC-FID) and mass spectroscopy techniques. A novel suggested mechanism was used to explain the oxidation process. Analysis showed that the formation of oxidized product is shown when ozone is supplied in excess, which shows that the reaction between 2-ethynylpyridine and ozone is a first-order reaction, whe reby the result of the relationship only depends on the concentration of the starting material, which is 2-ethynylpyridine acts as the limiting reactant.     

Thermal and Fluorescence Properties of New Nanostructured Hg(ll) -2,2′-Bipyridine Derivative Complexes

Two new nano-structured Hg(II) supramolecular complexes, [Hg(5,5′-di-t-but-bpy)(μ-Br)Br]₂[Hg(5,5′-di-t-but-bpy)Br₂](1) and [Hg(5,5′-di-t-but-bpy)I₂] (2) were synthesized by the sonochemical method. The structures of 1 and 2 were characterized by elemental analysis, IR, ¹H-NMR, and ¹³C-NMR spectroscopy and single crystal X-ray diffraction. Their thermal stabilities were studied by thermogravimetric and differential thermal analyses. Solid-state luminescent spectra of 1 and 2 indicate a fluorescent broad emission band between 304 and 404 nm with excitation at 284 nm. These nanostructured coordination polymers were characterized by scanning electron microscopy, elemental analysis, and IR spectroscopy.     

Luminescent mononuclear Pt(II) chloride complexes with C-linked 2,2′-bipyridyl tetrazole terdentate chelating ligands

Two new luminescent mononuclear Pt(II) chloride complexes possessing C-linked 2,2′-bipyridyl tetrazole terdentate chelating ligands, namely, Pt(tbpy)Cl (1) and Pt(tmbpy)Cl (2) (tbpyH = 6-(1H-tetrazol-5-yl)-2,2′-bipyridine; tmbpyH = 6-(1H-tetrazol-5-yl)-4,4′-dimethyl-2,2′-bipyridine), have been synthesized and characterized. Complex 2 adopts a distorted square-planar geometry with a mono-anionic terdentate chelate tmbpy, and it presents a zigzag head-to-tail stacking array along the a axis with alternating Pt⋯Pt separations of 3.415 and 5.469 Å. For 2, a moderately intensive broad absorption band appears at 350–425 nm in dilute DMF solution, most likely assigned as the metal-to-ligand charge transfer ¹MLCT (Pt(5d) → tmbpy) transition, mixed with some halide-to-ligand charge transfer ¹XLCT (Cl → tmbpy) and intraligand (IL) ¹ππ* transitions inside tmbpy. It is demonstrated that the solubilities and luminescence properties of 1 and 2 are markedly influenced by the substituents in the 4 and 4′-positions of the 2,2′-bipyridyl ring. The solid-state emissions of 1 and 2 are perhaps best attributable to the ³MMLCT/³XLCT/³IL states, as supported by TD-DFT calculation of 2.     

New Diamides of 2,2′-dipyridyl-6,6′-dicarboxylic Acid for Actinide-Lanthanide Separation

The extraction of americium and lanthanides by diamides of 2,2′-dipyridyl-6,6′-dicarboxilic acid solutions in polar diluents was investigated. The dependence of extraction properties of the diamides on their structure was studied and the distribution ratios of americium and lanthanides from nitric acid solutions were determined. The highest extraction was found for the compounds with the ethyl-group and the alkyl-substituted aryl-group on the amidic nitrogen. The Am/Ln separation factors higher than 10 were achieved for extraction from high acidity media.     

Oxidation of Benzene Catalyzed by 2,2′-Bipyridine and 1,10-Phenantroline Cu(II) Complexes

The use of mononuclear Cu(II) 2,2′-bipyridine and 1,10-phenantroline complexes as catalysts in the oxidation of benzene, using hydrogen peroxide and tert-butyl hydroperoxide as oxidant in CH₃CN/H₂O solution is presented. The reactions were carried out at 25 and at 50 °C. The complexes [Cu(bipy)₃]Cl₂ · 6H₂O (1), [Cu(bipy)₂Cl]Cl · 5H₂O (2), [Cu(bipy)Cl₂] (3), [Cu(phen)₃]Cl₂ · 7H₂O (4), [Cu(phen)₂Cl]Cl · 5H₂O (5), [Cu(phen)Cl₂] (6) were able to oxidize benzene into phenol, hydroquinone and p-benzoquinone. Highest conversion (22%) was obtained using [Cu(Phen)Cl₂] (6) as catalyst.     

Two 2D metal–organic frameworks based on 2,2′-bibenzimidazole ligand with (6,3) net topology

Two 2D metal–organic frameworks (MOFs), {[Zn₄(Hbbim)₄(bbim)₂] 2H₂O}_n (1) and [Cd₂(Hbbim)₂(bbim)]_n (2) (H₂bbim = 2,2′-bibenzimidazole) were obtained by solvothermal reaction and characterized by single crystal X-ray diffraction analysis. Different metal ions, Cd(II)/Zn(II), adopt very different coordination geometries though two title compounds both have a 2D honeycomb network with (6,3) topology. The frameworks of compounds 1 and 2 are stable below 360 °C and 475 °C, respectively. Solid-state luminescent spectroscopy of compound 2 exhibits an emission peak at 407 nm.     

Synthesis, Structures and Luminescent Properties of Two New Cd(II) Coordination Polymers Based on V-Shaped 3,3′,4,4′-Oxidiphthalic Acid

Two new Cd(II) coordination polymers, namely [Cd₂(H₂OA)₂(μ₂-H₂O)(H₂O)₆] _n ·3nH₂O (1) and [Cd₂(H₂OA)(phen)₂] _n ·nH₂O (2) (H₄OA = 3,3′,4,4′-oxidiphthalic acid, phen = 1,10-phenanthroline) have been synthesized by combining H₄OA or H₄OA and phen with Cd(II) salts under hydrothermal conditions. Single-crystal X-ray diffraction analysis reveals that 1 features a hydrogen-bond directed two-dimensional (2D) layered structure constructed from alternating left- and right-handed double strand helical chains, 2 represents a one-dimensional (1D) chain structure with the phen molecules dangling on it, which is further extended into a three-dimensional (3D) supramolecular framework through strong face-to-face π···π interactions. In addition, luminescent properties of these two compounds were also investigated in the solid state at room temperature.     

Synthesis, Structure and Luminescence Property of Cadmium(II) Coordination Polymer with Mixed 5-(Oxidediphenylphosphino)isophthalic Acid and 4,4′-Bipyridine Ligands

A new metal–organic framework {[Cd(L)(4,4′-bpy)]₂·5H₂O} _n (1) had been synthesized by hydrothermal reaction of 5-(oxidediphenylphosphino)isophthalic acid, Cd(II) nitrate, NaOH and 4,4′-bipyridine (4,4′-bpy) as co-ligand. The novel compound was characterized by single crystal X-ray diffractometry as well as FTIR spectrum. Adjacent eight-member (C₂Cd₂O₄) rings are connected each other through pairs of L^2? ligands to result in a 1D double chain. Such ribbons are interconnected together by 4,4′-bpy to generate a 2D pillared layer, which are further held together by rich O–H···O hydrogen bonds to give a 3D supramolecular network. Solvent water molecules play an important role to bridge adjacent layers to form a 3D supramolecular architecture. The luminescence property and thermogravimetric analysis of title complex were investigated.     

New dinuclear lanthanide(III) complexes based on 6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedione and 2,2′-bipyrimidine

Reaction of mononuclear Ln(fod)₃ chelates (where fod is the anion of 6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedione and Ln = Nd, Eu, Tb and Lu) with potentially bridging ligand 2,2′-bipyrimidine (bpm) in 2:1 mole ratio in ethanol afforded new dinuclear lanthanide complexes of the form [Ln(fod)₃-(μ-bpm)-Ln(fod)₃]. Neodymium complex is one of the rare bipyrimidine-bridged dinuclear complexes. The absorption spectrum of the neodymium complex displays characteristic hypersensitive as well as non-hypersensitive transitions. The excitation of Eu–Eu and Tb–Tb complexes at 355 nm produces an intense red and green luminescence, respectively.     

A 3D Mesomeric Supramolecular Structure of a Cu(II) Coordination Polymer with 1,1′-Biphenyl-2,2′,3,3′-tetracarboxylic Acid and 5,5′-Dimethyl-2,2′-bipyridine Ligands

A novel metal–organic framework {[Cu(H₂bptc)(cbpy)(H₂O)]·(H₂O)} _n (1) has been hydrothermally synthesized through reaction of 1,1′-biphenyl-2,2′,3,3′-tetracarboxylic acid (H₄bptc) with Cu(II) salt in the presence of ancillary nitrogen ligand 5,5′-dimethyl-2,2′-bipyridine (cbpy), and its structure was determined by X-ray diffraction and characterized by elemental analysis, and IR spectrum. The title compound crystallizes in monoclinic space group P2₁/c. Both right- and left-handed helices are detected in the structure. In the ab-plane, adjacent chains are homochiral and parallel to each other, which are connected together by hydrogen bonds to form a 2D supramolecular structure. The supramolecular layers with opposite chirality are arranged alternatively along the c-axis to form a 3D mesomeric supramolecular structure through π···π interactions. The thermal stability of the complex 1 was studied by thermal gravimetric and differential thermal analysis.     

Sulfonated polyimide copolymers based on 4,4′-diaminostilbene-2,2′-disulfonic acid and 3,5,3′,5′-tetramethylbenzidine with enhanced solubility

A new series of six-membered ring sulfonated polyimides with different combinations of two comonomers in the nonsulfonated diamine was prepared by one-step high-temperature polycondensation in m-cresol to improve the solubility of the resulting sulfonated polyimides. They are based on 1,4,5,8-naphthalenetetracarboxylic dianhydride, 4,4′-diaminostilbene-2,2-disulfonic acid sulfonated diamine, and equimolar mixture of 3,5,3′,5′-tetramethylbenzidine (TMB) and 4,4′-oxydianiline, bis(4-aminophenyl)methane, or bis(4-(aminophenoxy)-4-phenyl)isopropylidene nonsulfonated diamines. The introduction of TMB comonomer in the nonsulfonated diamine resulted in a remarkable improvement in the solubility of the resulting polyimides in comparison with the corresponding single-monomer nonsulfonated diamine polyimides. Flexible, transparent, and tough membranes were prepared by solution casting method from the different polyimides. The membranes were characterized with FTIR and ¹H-NMR spectroscopy, differential scanning calorimetry, thermogravimetric analysis, water uptake, and ion-exchange capacity measurements. They exhibit high thermal stability and good correlation between the ion-exchange capacity and water uptake values.     

2,2′-联吡啶合成工艺研究

以Ni-Fe/硅藻土为催化剂,固定床为反应器,吡啶直接偶联合成2,2′-联吡啶.系统考查了Ni含量、Fe含量、催化剂用量、异丙醇用量、反应温度、反应压力的影响,筛选出合适的反应条件:采用M-3催化剂,空速2 h-1,异丙醇用量2％,反应温度450℃,反应压力2 MPa,此条件下吡啶转化率达到65.7％,2,2′-联吡啶收率达到65％.该工艺操作简单,安全性高,产品收率高,适合工业化生产.     

Synthesis of 2,2′-bithiophene-5,5′-tetrahydroisoquinoline as michellamine analogs

Atropisomers of 2,2′-bithiophene-5-tetrahydroisoquinoline, S -8, R -8, and 2,2′-bithiophene-5,5′-tetrahydroisoquinoline, (S,S)-11, (R,S)-11, (R,R)-11, analogs of michellamines have been synthesized in low yield under Stille coupling conditions (Pd⁰-mediated cross coupling reactions) of stannanes 1 or 2 with non-racemic bromotetrahydroisoquinoline 6. The use of non-racemic iodotetrahydroisoquinoline 7 instead of 6 significantly improves the efficiency of the coupling, affording the atropisomers in moderate yields.     

Simultaneous Growing of Two New Cd(II) Metal–Organic Frameworks with 2,6-Naphthalendicarboxylic Acid as New Precursors for Cadmium(II) Oxide Nanoparticles: Thermal, Topology and Structural Studies

Crystal structure and thermal stability of two new 3D Cd(II) metal–organic frameworks (MOF) containing 2,6-naphthalenedicarboxylate, [Cd(NDC)(DMF)], 1, and [Cd₃(NDC)₄], 2 (H₂NDC = 2,6-naphthalenedicarboxylic acid; DMF = N,N-dimethylformamide) have been studied. These two MOFs grow simultaneously within the same solution to give multiple crystals that are due to the general lability of Cd(II) complexes. Structure 1 shows a 3D neutral metal–organic framework with PtS topology and crystallizes in the triclinic system, space group P-1 (No. 2), whilst 2 crystallizes in the orthorhombic system, space group Fdd2 (No. 43) with body-centered cubic bcu-(4²⁴.6⁴) topology. The elongated nature of NDC results in large cavities in both compounds; however, the pores are filled by coordinated DMF molecules in 1. The thermal stability of 1 and 2 were studied by thermogravimetry and show stability to 400 °C for 1 and continuous weight loss for 2. CdO nanoparticles were prepared by direct calcination of 1 and 2 at 600 °C. The CdO nanoparticles were characterized by X-ray powder diffraction and its morphology were studied by scanning electron microscopy. The results show that the CdO is pure and has a uniform morphology.     

Syntheses and Characterization of Two New M(II)-5,5′-dimethyl-2,2′-bipyridine (M = Cd and Pb) Coordination Polymers and Study of Their Thermal and Electrochemical Properties

Two new cadmium(II) and lead(II)-thiocyanato coordination polymers with 5,5′-dimethyl-2,2′-bipyridine (5,5′-dm-2,2′-bpy) as chelating ligands were synthesized and characterized by elemental analysis, IR and ¹H NMR spectroscopy and by X-ray crystallography. Thermal and electrochemical properties were also studied as well. These complexes have formed formula [Cd(5,5′-dm-2,2′-bpy)(NCS)₂]_n (1) and [Pb(5,5′-dm-2,2′-bpy)(CH₃COO)(NCS)]_n (2). The coordination numbers of Cd^II in 1 and Pb^II in 2 are six (CdN₄S₂) and seven (PbN₃O₃S₂), respectively. In 2, “stereo-chemically active” electron lone pairs and the coordination spheres were hemidirected. Bridging properties of thiocyanato anions in 1 and 2 created one- and two-dimensional coordination polymers, respectively. The supramolecular features in these complexes were guided and controlled by weak directional intermolecular interactions.     

Synthesis and Structural Characterization of Triorganotin(IV) Derivatives with 2,2′-Thiodiglycolic Acid and 3,3′-Thiodipropionic Acid

The synthesis and structural characterization of four novel triorganotin(IV) complexes, {(R₃Sn)₂[C₂H₄S(COO)₂]} _n (R = Me: 1), {(R₃Sn)₄[C₂H₄S(COO)₂]₂} _n (R = nBu: 2), {(R₃Sn)₂[C₄H₈S(COO)₂]} _n (R = Me: 3; nBu: 4) were obtained by the reaction of 2,2′-thiodiglycolic acid, 3,3′-thiodipropionic acid and the corresponding R₃SnCl (R = Me, nBu) with potassium hydroxide in methanol. All the complexes were characterized by elemental analysis, Fourier transform infrared and nuclear magnetic resonance (¹H, ¹³C, ¹¹⁹Sn) spectroscopies, X-ray crystallography and thermogravimetric analyses. The crystal structures show that 1 has 2D network structure in which 2,2′-thiodiglycolic acid acts as a tetradentate ligand coordinating to the trimethyltin(IV) ions. Complexes 2, 3, and 4 are 3D metal-organic framework structures in which the deprotoned acids act as a tetradentate ligand afforded by four oxygen atoms.