Polymerization of 1,3-Butadiene Catalyzed by Cobalt(Ⅱ) and Nickel(Ⅱ) Complexes Bearing Pyridine-2-imidate Ligands

Cobalt and nickel complexes (1a-1d and 2a-2d, respectively) supported by 2-imidate-pyridine ligands were synthesized and used for 1,3-butadiene polymerization. The complexes were characterized by IR and element analysis, and complex 1a was further characterized by single-crystal X-ray diffraction. The solid state structure of complex 1a displayed a distorted tetrahedral geometry. Upon activation with ethylaluminum sesquichloride (EASC), all the complexes showed high activities toward 1,3-butadiene polymerization. The cobalt complexes produced polymers with high cis-1,4 contents and high molecular weights, while the nickel complexes displayed low cis-1,4 selectivity and the resulting polymers had low molecular weights. The catalytic activities of the complexes highly depended on the ligand structure. With the increment of polymerization temperature, the cis-1,4 content and the molecular weight of the resulting polymer decreased.     

Nickel(II) complexes prepared from NNN type ligands and pseudohalogens

Six nickel(II) complexes, using azide and thiocyanate ions, have been synthesized from bis-2,6(pyrazol-1-yl)pyridine (pp) and some methyl derivatives, 2-(3,5-dimethyl(pyrazol-1-yl)-6-(pyrazol-1-yl)pyridine (app) and bis-2,6(3,5-dimethyl(pyrazol-1-yl) pyridine (dmpp) in non-aqueous media. The complex structures were analyzed using elemental analysis, IR spectroscopy and thermogravimetry. Appropriate crystals of complex, containing azide [Nipp(N₃)₂]·MeOH (I) and thiocyanate [Nidmpp(SCN)₂·MeOH] (VI) were prepared and the molecular structures determined using X-ray diffraction. Complex I was seen to be dinuclear as stated in literature, space group P2₁/n, monoclinic, a=10.503, b=10.681, c=13.291 Å, β=106.56° and Z=2 whereas complex VI was found to be mononuclear, space group P2₁/n, monoclinic, a=8.646, b=12.614, c=20.697 Å, β=97.18° and Z=2. The Ni(II) coordination in both complexes were octahedral. Thermogravimetric studies showed azide containing structures to resemble the characteristics of explosive materials. Coordinative MeOH were seen to leave the structure in thiocyanate containing complexes, followed by irregular degradation above 300°C.     

4-acyloxy- and 4-acylaminophthalonitriles and phthalocyanines based thereon

Reactions of 4-hydroxy- and 4-aminophthalonitriles with substituted benzoyl chlorides gave the corresponding N- and O-benzoyl derivatives, and the latter were used to obtain copper and nickel phthalocyanine complexes. Effect of the substituents in the latter on their electronic absorption spectra was studied. The obtained complexes were found to undergo association in organic solvents.     

1,3-Dipolar Cycloaddition of Difluoro-Substituted Azomethine Ylides. Synthesis and Transformations of 2-Fluoro-4,5-dihydropyrroles

2-Fluoro-4,5-dihydropyrrole-3,4-dicarboxylic acid derivatives were obtained by reaction of difluorocarbene with N-substituted ketone imines in the presence of fumaronitrile, maleonitrile, or dimethyl maleate. The reaction involves intermediate formation of azomethine ylides and their subsequent cycloaddition at the double bond. 11H-Dibenz[b,e]azepine and 3,4-dihydroisoquinolines react with difluorocarbene in the presence of fumaronitrile to give fluoro-substituted dibenzo[c,f]pyrrolo[1,2-a]azepine and pyrrolo[2,1-a]-isoquinoline derivatives. Treatment of 2-fluoro-4,5-dihydropyrrole-3,4-dicarbonitrile with amines and alkoxides affords the corresponding 2-amino- and 2-alkoxy derivatives, while its reactions with hydrazine hydrate and benzimidamide lead to formation of substituted pyrrolo[2,3-c]pyrazole and pyrrolo[2,3-d]-pyrimidine derivatives.     

Condensation of fluorine-substituted benzaldehydes with amines and cyclic ketones

Condensation of fluorine-containing benzaldehydes with naphthalen-2-amine or quinolin-6-amine and cyclic ketones (cyclopentanone, cyclohexanone, and 4-methylcyclohexanone) gave new fluorine-containing derivatives of cyclopenta[c]benzo[f]quinoline, benzo[a]phenanthridine, and cyclopenta[a]- and benzo[a]-[4,7]phenanthroline. Intermediate products, 2-[(fluorophenyl)(2-naphthylamino or quinolin-6-ylamino)methylidene] cyclohexanones, dihydrobenzo[f]quinolines, and dihydro-4,7-phenanthrolines, were isolated.     

Synthesis,crystal structures,and antibacterial activities of Schiff base nickel(II) and cadmium(II) complexes with tridentate Schiff bases

Reaction of tridentate Schiff bases with nickel and cadmium salts in methanol afforded two new mononuclear complexes, [Ni(L¹)₂] (I) and [Cd(L²)₂] (II), where L¹ and L² are the anions of 2-bromo-4-chloro-6-[(3-dimethylaminopropylimino)methyl]phenol (HL¹) and 2-bromo-4-chloro-6-[(3-morpholin-4-ylpropylimino)methyl]phenol (HL²), respectively. The complexes were characterized by singlecrystal X-ray diffraction (CIF files CCDC nos. 1428653 (I) and 1428654 for (II)), FT-IR, and elemental analysis. Complex I crystallizes in the monoclinic space group P2 ₁/c, with a = 8.8216(8), b = 14.0424(8), c = 11.8687(12) Å, β = 111.238(2)°, V = 1370.4(2) ų, Z = 2. Complex II crystallizes in the monoclinic space group P2 ₁/n, with a = 9.6774(4), b = 15.8970(6), c = 20.3144(7) Å, β = 90.408(2)°, V = 3125.1(2) ų, Z = 4. The metal atoms in the complexes are coordinated by two tridentate Schiff base ligands, forming octahedral coordination. The free Schiff bases and the complexes were assayed for antibacterial activities. Both complexes are more active against the bacteria than the free Schiff bases. Complex II has the MIC value of 0.39 μg mL^–1 against Bacillus subtilis.     

Synthesis,X-ray crystal structures,and antibacterial activities of Schiff base nickel(II) complexes with similar tetradentate Schiff bases

Two new mononuclear complexes, [NiL¹] · CH₃OH (I) and [NiL²] (II), have been prepared from the tetradentate Schiff bases N,N'-bis(5-methylsalicylidene)ethylenediamine (H₂L¹) and N,N'-bis(5-methylsalicylidene)- o-phenylenediamine (H₂L₂), respectively. The complexes have been characterized by physico-chemical and spectroscopic methods, as well as single-crystal X-ray determination (CIF files nos. 1428969 (I), 1428968 (II)). Complex I crystallizes in the triclinic space group P1 with a = 6.7387(14), b = 10.7010(17), c = 12.681(2) Å, α = 87.059(2)°, β = 88.828(2)°, γ = 89.901(2)°, V = 913.0(3) ų, Z = 2. Complex II crystallizes in the monoclinic space group P2₁/n with a = 12.1437(11), b = 8.0537(8), c = 18.4545(18) Å, β = 105.088(2)°, V = 1742.7(3) ų, Z = 4. The nickel atoms in the complexes are coordinated by two phenolate O and two imine N atoms of the tetradentate Schiff base ligands, forming square planar coordination. The complexes and the Schiff base compounds were assayed for antibacterial activities against three Gram-positive bacterial strains (B. subtilis, S. aureus, and St. faecalis) and three Gram-negative bacterial strains (E. coli, P. aeruginosa, and E. cloacae) by MTT method. As a result, the complexes showed effective antimicrobial activity against the microorganisms tested.     

Structural studies of nickel(II) complexes with 1-<Emphasis Type="Italic">tert</Emphasis>-butylimidazole-2-thione and 3-phenyl-5-methyl-pyrazole ligands

The nickel(II) complexes dichlorobis(1-tert-butylimidazole-2-thione)nickel(II) [Ni(tm ^t-Bu)₂Cl₂] (1), dinitratobis(1-tert-butylimidazole-2-thione)nickel(II) [Ni(tm ^t-Bu)₂(NO₃)₂] (2), dichloro-bis(3-phenyl-5-methyl-pyrazole)(1-tert-butylimidazole-2-thione)nickel(II) [Ni(pz^Ph,MeH)₂(tm ^t-Bu)Cl₂] (3) and dinitratobis(3-phenyl-5-methyl-pyrazole)(1-tert-butylimidazole-2-thione)nickel(II) [Ni(pz^Ph,MeH)₂(tm ^t-Bu)(NO₃)₂] (4) have been synthesized and studied. The single crystal X-ray diffraction analysis was carried out for 1 and 4 {Bruker Kappa Apex-II CCD diffractometer, MoK _α radiation}. Crystal data for 1: monoclinic C2/c, a = 16.949(2) Å, b = 8.6647(10) Å, c = 15.461(3) Å, β = 117.662(4)°, V = 2011.1(5) ų, Z = 4, D _calc = 1.460 g/cm³. Crystal data for 4: triclinic P-1, a = 9.9775(7) Å, b = 11.2254(8) Å, c = 14.8068(10) Å, α = 75.401(4)°, β = 87.422(4)°, γ = 74.874(4)°, V = 1548.86(19) ų, Z = 2, D _calc = 1.405 g/cm³. Coordination core of complex 1 adopts distorted tetrahedral geometry whereas core 4 has distorted octahedral geometry. The bonded nitrates are of two types coordinating as monodentate and bidentate ligands.     

3-(4-fluorophenyl)-1<Emphasis Type="Italic">H</Emphasis>-pyrazole-4-carbaldehyde in the synthesis of aza-and diazaphenanthrene derivatives

Condensation of 3-(4-fluorophenyl)-1H-pyrazole-4-carbaldehyde with 2-naphthyl-or 6-quinolylamine and CH-acids (acetone, acetophenone, cyclic mono-and β-diketones) provided new derivatives of benzo[f]quinoline, benzo[a]phenanthridine, benzo[a]acridine, and 4,7-phenanthroline. The arising in the course of the reaction [3-(4-fluorophenyl)-1H-pyrazole-4-ylmethylene]-2-naphthyl-(or 6-quinolyl)amines, [3-(4-fluorophenyl)-1H-pyrazole-4-ylmethylene]-1,3-indandione, and octahydro-1,8-xanthenedione derivatives were isolated.     

Structure of Potassium and Cesium Barbiturates

The structures of catena-[K(μ₆-Hba?O,O,O,O′,O′,O″)] (I) and catena-[Cs(μ₆-Hba–O,O,O′,O′,O″,O″)] (II), where Н₂ba is barbituric acid C₄H₄N₂O₃, were characterized by powder X-ray diffraction. Crystallographic data: a = 14.1603 (4) Å, b = 3.68977 (9) Å, c = 10.9508 (3) Å, β = 82.226 (1)°, V = 566.90 (3) ų, space group P2₁/n, Z = 4 for I; a = 14.652 (1) Å, b = 11.7275 (7) Å, c = 3.8098 (3) Å, β = 79.140 (6)°, V = 642.90 (8) ų, space group C2/m, Z = 4 for II. The structural topologies of alkali metal complexes with barbituric acid and some its derivatives were compared. The thermal stability of complexes I and II in an air atmosphere was studied.     

Syntheses and crystal structures of copper(II) and nickel(II) complexes derived from 2-bromo-4-chloro-6-[(2-methylaminoethylimino)methyl]phenol

A new centrosymmetric mononuclear copper(II) complex [Cu(L)₂](ClO₄)₂ (I) and a new centrosymmetric mononuclear nickel(II) complex [Ni(L)₂(MeOH)₂](ClO₄)₂ (II), where L is the zwitterionic ligand 2-bromo-4-chloro-6-[(2-methylammonioethylimino)methyl]phenolate, have been prepared from the Schiff base 2-bromo-4-chloro-6-[(2-methylaminoethylimino)methyl]phenol with copper perchlorate and nickel perchlorate, respectively. The complexes were characterized by elemental analysis, infrared spectra, and single-cyrstal X-ray diffraction (CIF files CCDC nos. 1408054 (I) and 1407973 (II)). Complex I crystallizes in the monoclinic space group P2₁/c with unit cell dimensions a = 7.7736(4), b = 21.608(1), c = 8.5194(4) Å, β = 93.907(2)°, V = 1427.7(1) ų, Z = 2, R ₁ = 0.0546, and wR ₂ = 0.1531. Complex II crystallizes in the monoclinic space group P2₁/c with unit cell dimensions a = 21.324(3), b = 16.821(2), c = 9.425(1) Å, β = 90.114(2)°, V = 3380.5(7) ų, Z = 4, R ₁ = 0.0693, and wR ₂ = 0.1627. The Cu atom in I is in square planar coordination, and the Ni atom in II is in octahedral coordination.     

Synthesis and properties of cyanomethyl derivatives of imidazo[1,2-<Emphasis Type="Italic">a</Emphasis>]pyridine,imidazo[1,2-<Emphasis Type="Italic">a</Emphasis>]pyrimidine,and imidazo[2,1-<Emphasis Type="Italic">b</Emphasis>]thiazole

2-Cyanomethyl derivatives were obtained of imidazo[1,2-a]pyridine, imidazo[1,2-a]pyrimidine, and imidazo[2,1-b]thiazole, and their reactivity was investigated by an example of imidazo[1,2-a]pyridine: It was subjected to nitration, bromination, azo coupling and nitrosation. Acylation of the methylene group effected by amino acids esters with a subsequent addition of the amino group to the cyano group resulted in the formation of 5-amino-4-imidazo[1,2-a]-pyridin-2-yl-1-phenyl-1,2-dihydro-3H-pyrrol-3-one and 2-amino-1-ethyl-3-imidazol[1,2-a]pyridin-2-yl-4(1H)-quinolinone.     

Electrophilic heterocyclization of 6-alken(yn)ylsulfanyl-pyrazolo[3,4-<Emphasis Type="Italic">d</Emphasis>]pyrimidin-4(5<Emphasis Type="Italic">H</Emphasis>)-ones

6-Allylsulfanyl-1-arylpyrazolo[3,4-d]pyrimidin-4(5H)-ones react with iodine and sulfuric acid to give angular pyrazolothiazolopyrimidine derivatives. The reaction of 6-(prop-2-yn-1-ylsulfanyl)-1-(4-tolyl)-pyrazolo[3,4-d]pyrimidin-4(5H)-one with sulfuric acid gives angularly fused pyrazolo[4,3-e][1,3]thiazolo-[3,2-a]pyrimidin-4-one, whereas in the reaction with sodium methoxide linearly fused pyrazolo[3,4-d][1,3]-thiazolo[3,2-a]pyrimidin-4-one was formed. Linearly fused pyrazolo[3′,4′:4,5]pyrimido[2,1-b][1,3]thiazole derivatives were also obtained by reaction of 1-aryl-6-(3-phenylprop-2-en-1-ylsulfanyl)pyrazolo[3,4-d]pyrimidin-4(5H)-ones with sulfuric acid.     

Synthesis and crystal structures of the nickel(II) complex with nitronyl nitroxide

Two nickel(II) complexes [Ni(NIT-l′-MeBzlrn)₂(Dca)₂] (I, II) (NIT-l′-MeBzIm = 2-{2′-[(l′methyl)benzimidazolyl]}-4,4,5,5-tetramethylimidazoline-l-oxyl-3-oxide) have been prepared and structurally characterized by single-crystal X-ray diffraction. They are structural epimers. The complexe crystallizes in monoclinic, space group P2₁/n, Z = 4. Crystal data: C₃₄H₃₈N₁₄NiO₄, M _r = 765.49, a = 15.019(3), b = 18.803(4), c = 15.756(3) Å, β = 109.399(3)°, γ = 90° (I); a = 13.934(3), b = 11.046(2), c = 24.570(5) Å, β = 90.024(2)° (II). The X-ray analysis reveals that Ni²⁺ ion resides in a distorted octahedral center. The complex was linked by intermolecular hydrogen bonds, resulting in a ID chain structure for I and a 2D network configuration for II.     

Fused Imidazoles: I. Synthesis of 6,7-Dihydro-5<Emphasis Type="Italic">H</Emphasis>-pyrrolo[1,2-<Emphasis Type="Italic">a</Emphasis>]imidazole Derivatives

Dehydration of substituted 2-(2-oxopyrrolidin-1-yl)acetamides with phosphoryl chloride provides a convenient method of synthesis of 2-chloro-6,7-dihydro-5H-pyrrolo[1,2-a]imidazoles. The latter can be readily converted to various derivatives via introduction and modification of a substituent in the 3-position. The chlorine atom in the 2-position can be removed by hydrogenation over Raney nickel.     

Synthesis and crystal structures of cobalt(III) and zinc(II) complexes with Schiff bases

Two new cobalt(III) and zinc(II) complexes, [Co(L¹)₂ (H₂O)] · ClO₄ (I) and [Ni(L²)₂ (H₂O)₂] · 2ClO₄ (II), where L¹ is the deprotonated form of 5-methoxy-2-[(2-morpholin-4-ylethylimino)methyl]phenol, and L² is the zwitterionic form of 2-[(2-isopropylaminoethylimino)methyl]-5-methoxyphenol, were synthesized and structurally characterized by elemental analyses, IR spectra, and single-crystal X-ray diffraction. The crystal of I is monoclinic: space group P2₁/c, a = 11.1512(4), b = 28.2424(11), c = 10.9655(4) Å, β = 95.746(2)°, V = 3436.1(2) ų, Z = 4. The crystal of II is triclinic: space group P2₁/c, a = 8.1441(2), b = 10.4531(3), c = 10.8849(3) Å, α = 84.0240(10)°, β = 76.9800(10)°, γ = 74.2280(10)°, V = 867.92(4) ų, Z = 1. Complex I consists of a mononuclear cobalt(III) complex cation and a perchlorate anion. Complex II consists of a crystallographic centrosymmetric mononuclear nickel(II) complex cation and two perchlorate anions. Each metal atom in the complexes is in an octahedral coordination.     

Fluoro-containing Heterocycles: XIII. Fluoro-containing Derivatives of Thiazolo[3,2-<Emphasis Type="Italic">a</Emphasis>]-, Benzothiazolo[3,2-<Emphasis Type="Italic">a</Emphasis>]-, and Benzimidazo[3,2-<Emphasis Type="Italic">a</Emphasis>]quinazolinones

Reactions of 2-aminothiazole, derivatives of 2-aminobenzothiazole and 2-aminobenzoimidazole with polyfluorobenzoyl chlorides gave rise to acylation products that at heating in the diphenyl ether formed fluoro-containing derivatives of thiazolo[3,2-a]-, benzothiazolo[3,2-a]-, and benzimidazo[3,2-a]quinazolinone.     

Synthesis of Ni(II) complexes with chiral derivatives of cyclohexane-1,2-diamine,bycyclo[2.2.2]octane-2,3-diamine,and 1,2-diphenylethane-1,2-diamine

Chiral ligands—derivatives of (1R,2R)-cyclohexane-1,2-diamine, (1R,2R)-diphenylethane-1,2-diamine, and (2S,3S)-bicyclo[2.2.2]octane-2,3-diamine—and octahedral Ni(II) complexes on their basis have been synthesized.     

Induction of radiative forbidden transitions in an oxygen molecule in O<Subscript>2</Subscript>–H<Subscript>2</Subscript>O collision complexes

By the DFT/B3LYP method the equilibrium structures of oxygen complexes with water are calculated in various geometric conformations with symmetries C _2v and C _s . By the MRCI/CASSCF method potential energy surface cross-sections of the ^1.3[O₂–H₂O] complexation reaction are constructed. With taking into account the spin-orbit coupling, the forbidden transition moments a ¹Δ _g –X ³Σ _g ^?, b ¹Σ _g ⁺–a ¹Δ _g , c ¹Σ _u ^?–a ¹Δ _g , A ³Σ _u ⁺–X ³Σ _g ^? of the complexes are calculated and changes in their intensities at different geometric configurations of the complex are revealed.     

Syntheses and Crystal Structures of Quinidinum-Zinc(II)-Trichloride and Quinidinum Iron(III) Tetrachloride Hydrogen Chloride Hydrate

A mononuclear coordination complex, quinidinum-zinc(II)-trichloride (I), and a multi-component ionic complex, quinidinum iron(III) tetrachloride hydrogen chloride hydrate (II), have been synthesized and characterized by elemental analyses, IR spectra, and single crystal X-ray diffraction (CIF files nos. 1497628 (I) and 1497629 (II)). The weak hydrogen-bonding interactions exist in both complexes I and II. Both complexes crystallize in the chiral space groups with the absolute configuration. Complex I crystallizes in the orthorhombic space group P2₁2₁2₁ with a = 7.6651(6), b = 11.4923(9), c = 24.653(2) Å, and Z = 4. Complex II crystallizes in the monoclinic space group P2₁ with a = 6.6425(15), b = 18.660(4), c = 10.958(3) Å, β = 104.973(3), and Z = 2.