Reactions of azulenes with 1,2-diaryl-1,2-ethanediols in methanol in the presence of hydrochloric acid: comparative studies on products, crystal structures, and spectroscopic and electrochemical properties

Although reaction of guaiazulene (1a) with 1,2-diphenyl-1,2-ethanediol (2a) in methanol in the presence of hydrochloric acid at 60 °C for 3 h under aerobic conditions gives no product, reaction of 1a with 1,2-bis(4-methoxyphenyl)-1,2-ethanediol (2b) under the same reaction conditions as 2a gives a new ethylene derivative, 2-(3-guaiazulenyl)-1,1-bis(4-methoxyphenyl)ethylene (3), in 97% yield. Similarly, reaction of methyl azulene-1-carboxylate (1b) with 2b under the same reaction conditions as 1a gives no product; however, reactions of 1-chloroazulene (1c) and the parent azulene (1d) with 2b under the same reaction conditions as 1a give 2-[3-(1-chloroazulenyl)]-1,1-bis(4-methoxyphenyl)ethylene (4) (81% yield) and 2-azulenyl-1,1-bis(4-methoxyphenyl)ethylene (5) (15% yield), respectively. Along with the above reactions, reactions of 1a with 1,2-bis(4-hydroxyphenyl)-1,2-ethanediol (2c) and 1-[4-(dimethylamino)phenyl]-2-phenyl-1,2-ethanediol (2d) under the same reaction conditions as 2b give 2-(3-guaiazulenyl)-1,1-bis(4-hydroxyphenyl)ethylene (6) (73% yield) and (Z)-2-[4-(dimethylamino)phenyl]-1-(3-guaiazulenyl)-1-phenylethylene (7) (17% yield), respectively. Comparative studies of the above reaction products and their yields, crystal structures, spectroscopic and electrochemical properties are reported and, further, a plausible reaction pathway for the formation of the products 3-7 is described.     

A facile preparation, spectroscopic and chemical properties, crystal structures, and electrochemical behavior of monocarbenium ion compounds stabilized by 3-guaiazulenyl and dihydroxyphenyl (or hydroxymethoxyphenyl) groups

Reaction of guaiazulene (8) with 2,3-dihydroxybenzaldehyde (9) in methanol in the presence of hexafluorophosphoric acid (i.e., 65% aqueous solution) at 25 °C for 2 h gives (3-guaiazulenyl)(2,3-dihydroxyphenyl)methylium hexafluorophosphate (13) in 86% yield. Similarly, reaction of 8 with 2-hydroxy-3-methoxybenzaldehyde (10) [or 3,4-dihydroxybenzaldehyde (11) or 4-hydroxy-3-methoxybenzaldehyde (12)] under the same reaction conditions as for 9 affords the corresponding monocarbenium ion compound 14 (63% yield) [or 15 (43% yield) or 16 (77% yield)], respectively, each product of which is stabilized by 3-guaiazulenyl and dihydroxyphenyl (or hydroxymethoxyphenyl) groups. A facile preparation and crystal structures as well as spectroscopic, chemical, and electrochemical properties of 13-16, possessing two interesting resonance structures, respectively, i.e., a protonated o- (or p-) benzoquinonemethide form and a 3-guaiazulenylium ion form, in a solution of acetonitrile and further, in a single crystal, are reported.     

Reactions of guaiazulene with thiophene-2,5-dicarbaldehyde and furan-2,5-dicarbaldehyde in methanol in the presence of hexafluorophosphoric acid: a facile preparation and properties of delocalized dicarbenium-ion compounds stabilized by two 3-guaiazulenyl groups and a thiophene (or furan) ring

Reaction of guaiazulene (1) with thiophene-2,5-dicarbaldehyde (2) in methanol in the presence of hexafluorophosphoric acid at 25 °C for 3 h gives as high as 90% isolated yield of the delocalized dicarbenium-ion compound, 2,5-thienylenebis(3-guaiazulenylmethylium) bis(hexafluorophosphate) (3). Similarly, reaction of 1 with furan-2,5-dicarbaldehyde (4) under the same conditions as the above reaction affords the corresponding dicarbenium-ion compound, 2,5-furylenebis(3-guaiazulenylmethylium) bis(hexafluorophosphate) (5), in 84% isolated yield. Along with a facile preparation and the spectroscopic and electrochemical properties of 3 and 5, comparative studies on the ¹H and ¹³C NMR spectral and chemical properties of 3 and 5 with those of the delocalized mono- and dicarbenium-ion compounds [i.e., (3-guaiazulenyl)(2-thienyl)methylium hexafluorophosphate (7), (2-furyl)(3-guaiazulenyl)methylium hexafluorophosphate (9), α,α′-bis(3-guaiazulenylmethylium) bis(tetrafluoroborate) (10), 1,2-phenylenebis(3-guaiazulenylmethylium) bis(hexafluorophosphate) (11), and 1,4-phenylenebis(3-guaiazulenylmethylium) bis(tetrafluoroborate) (12)] are reported. Moreover, referring to the results of the X-ray crystallographic analyses of 7, 9, 11, and 12, the optimized 2,5-thienylenebis(3-guaiazulenylmethylium)- and 2,5-furylenebis(3-guaiazulenylmethylium)-ion structures for 3 and 5, calculated by a WinMOPAC (version 3.0) program using PM3 as a semiempirical Hamiltonian, are described.     

A facile preparation, the crystal structure, the chemical and electrochemical properties of [4-(dimethylamino)phenyl]-3-guaiazulenylmethylium tetrafluoroborate

Reaction of guaiazulene (1) with p-dimethylaminobenzaldehyde in methanol in the presence of tetrafluoroboric acid gives the title monocarbocation compound, [4-(dimethylamino)phenyl]-3-guaiazulenylmethylium tetrafluoroborate (2), in 90% yield. The title investigations of compound 2 compared with those of two other monocarbocations stabilized by a 3-guaiazulenyl group (i.e. phenyl-3-guaiazulenylmethyl and [4-(isopropyl)phenyl]-3-guaiazulenylmethyl cations) are reported.     

An efficient preparation, crystal structures, and properties of monocarbenium-ion compounds stabilized by 3-guaiazulenyl and anisyl groups

Reaction of guaiazulene (1) with 2-methoxybenzaldehyde (2) in methanol in the presence of hexafluorophosphoric acid at 25 °C for 2 h gives (3-guaiazulenyl)(2-methoxyphenyl)methylium hexafluorophosphate (5a) in 93% yield. Similarly, reaction of 1 with 3-methoxybenzaldehyde (3) or 4-methoxybenzaldehyde (4) under the same reaction conditions as for 2 affords (3-guaiazulenyl)(3-methoxyphenyl)methylium hexafluorophosphate (6) (91% yield) or (3-guaiazulenyl)(4-methoxyphenyl)methylium hexafluorophosphate (7) (97% yield). The crystal structures as well as the spectroscopic, electrochemical, and chemical properties of these monocarbenium-ion compounds, possessing interesting resonance forms, stabilized by the 3-guaiazulenyl and anisyl (i.e., 2-, 3-, or 4-methoxyphenyl) groups are reported.     

Reaction of guaiazulene with o-formylbenzoic acid in diethyl ether (or methanol) in the presence of hexafluorophosphoric acid: comparative studies on H and C NMR spectral properties of 3-guaiazulenylmethylium- and 3-guaiazulenium-ion structures

Reaction of guaiazulene (1) with o-formylbenzoic acid (2) in diethyl ether in the presence of hexafluorophosphoric acid at 25 °C for 90 min gives the corresponding monocarbenium-ion compound, [2-(carboxy)phenyl](3-guaiazulenyl)methylium hexafluorophosphate (3), quantitatively, which upon treatment with aq NaHCO₃ leads to 3-(3-guaiazulenyl)-2-benzofuran-1(3H)-one (5) in 96% isolated yield. Similarly, reaction of 1 with 2 in methanol under the same conditions as the above reaction affords two kinds of inseparable monocarbenium-ion compounds, 3 and (3-guaiazulenyl)[2-(methoxycarbonyl)phenyl]methylium hexafluorophosphate (4) with an equilibrium between them, which upon reaction with a solution of NaBH₄ in ethanol at 25 °C for 30 min leads to 5 in 46% isolated yield and (3-guaiazulenyl)[2-(methoxycarbonyl)phenyl]methane (6) in 37% isolated yield. Along with the ¹H and ¹³C NMR spectral properties of a solution of 5 in trifluoroacetic acid-d₁ at 25 °C, whose molecular structure is converted to a ca. 1:1 equilibrium mixture of 7 possessing a partial structure of the 3-guaiazulenylmethylium-ion and 8 possessing a partial structure of the 3-guaiazulenium-ion, comparative studies on the ¹H and ¹³C NMR spectral properties of 7 and 8 with those of the monocarbenium-ion compound, (3-guaiazulenyl)[4-(methoxycarbonyl)phenyl]methylium hexafluorophosphate (A), 5, and 6 are reported. From these NMR studies, it can be inferred that the positive charge of the 3-guaiazulenylmethylium-ion part of 7 apparently is transferred to the seven-membered ring, generating a resonance form of the 3-guaiazulenylium-ion structure η′, and the same result can be inferred for the previously documented monocarbenium-ion compounds A-I. Moreover, referring to a comparative study on the C-C bond lengths of A observed by the X-ray crystallographic analysis with those of the optimized (3-guaiazulenyl)[4-(methoxycarbonyl)phenyl]methylium-ion structure for A calculated by a WinMOPAC (Ver. 3.0) program using PM3, AM1, or MNDOD as a semiempirical Hamiltonian, the optimized [2-(carboxy)phenyl](3-guaiazulenyl)methylium-ion structure for 3 calculated using PM3 is described.     

Synthesis,spectroscopic, electrochemical and structural characterization of Cu(II) complexes with asymmetric NN′OS coordination spheres

A set of four Cu(II) complexes, [Cu(cdnapen)], [Cu(cdnappd)], [Cu(cdMenappd)] and [Cu(cdMeMeOsalpd)], derived from Schiff base ligands with an asymmetric NN′OS coordination sphere have been synthesized. The molecular and the crystal structures have been determined by X-ray diffractometry. The structural results confirm that the complexes are tetra coordinated. The copper (II) ion coordinates to two nitrogen atoms from the imine moiety of the ligand, a sulfur atom from the methyl dithiocarboxylate moiety and a phenolic oxygen atom. The complexes show an unusual tetrahedral distortion to the square-planar geometry around the metal centre in spite of the pseudomacrocyclic skeleton of the ligand. The complexes were further characterized by cyclic voltammetry and electron paramagnetic resonance spectroscopy. The degree of tetrahedral distortion of the complexes appears to be dependent on the number of carbon atoms of the aliphatic bridge and the nature of the coordinating atoms.     

Preparation, crystal structure, and spectroscopic, chemical, and electrochemical properties of (2E,4E)-4-[4-(dimethylamino)phenyl]-1-(3-guaiazulenyl)-1,3-butadiene compared with those of (E)-2-[4-(dimethylamino)phenyl]-1-(3-guaiazulenyl)ethylene

Wittig reaction of 3-[4-(dimethylamino)phenyl]propanal (5) with (3-guaiazulenylmethyl)triphenylphosphonium bromide (4) in ethanol containing NaOEt at 25 °C for 24 h under argon gives the title (2E,4E)-1,3-butadiene derivative 6E in 19% isolated yield. Spectroscopic properties, crystal structure, and electrochemical behavior of the obtained new extended π-electron system 6E, compared with those of the previously reported (E)-2-[4-(dimethylamino)phenyl]-1-(3-guaiazulenyl)ethylene (12), are documented. Furthermore, reaction of 6E with 1,1,2,2-tetracyanoethylene (TCNE) in benzene at 25 °C for 24 h under argon affords a new Diels-Alder adduct 8 in 59% isolated yield. Along with spectroscopic properties of the [π4+π2] cycloaddition product 8, the crystal structure, possessing a cis-3,6-substituted 1,1,2,2-tetracyano-4-cyclohexene unit, is shown. Moreover, reaction of 6E with (E)-1,2-dicyanoethylene (DCNE) under the same reaction conditions as the above gives no product; however, this reaction in p-xylene at reflux temperature (138 °C) for four days under argon affords a new Diels-Alder adduct 9 in 54% isolated yield. Although reaction of 6E with DCNE in toluene at reflux temperature (110 °C) for four days under argon provides 9 very slightly, reaction of 6E with dimethyl acetylenedicarboxylate (DMAD) in toluene at reflux temperature for two days under argon yields a new Diels-Alder adduct 10, in 58% isolated yield, which upon oxidation with MnO₂ in CH₂Cl₂ at 25 °C for 1 h gives 11, converting a (CH₃)₂N-4″ into CH₃NH-4″ group, in 37% isolated yield. The crystal structure of 11 supports the molecular structure 10 possessing a partial structure cis-3,6-substituted 1,2-dimethoxycarbonyl-1,4-cyclohexadiene. The title basic studies on the above are reported in detail.     

Reaction of azulene with 1,2-bis[4-(dimethylamino)phenyl]-1,2-ethanediol in a mixed solvent of methanol and acetonitrile in the presence of hydrochloric acid: a facile one-pot synthesis and properties of new triarylethylenes possessing an azulen-1-yl group

Reaction of azulene (1) with 1,2-bis[4-(dimethylamino)phenyl]-1,2-ethanediol (2) in a mixed solvent of methanol and acetonitrile in the presence of 36% hydrochloric acid at 60 °C for 3 h gives 2-(azulen-1-yl)-1,1-bis[4-(dimethylamino)phenyl]ethylene (3) (8% yield), 1-(azulen-1-yl)-(E)-1,2-bis[4-(dimethylamino)phenyl]ethylene (4) (28% yield), and 1,3-bis{2,2-bis[4-(dimethylamino)phenyl]ethenyl}azulene (5) (9% yield). Besides the above products, this reaction affords 1,1-di(azulen-1-yl)-2,2-bis[4-(dimethylamino)phenyl]ethane (6) (15% yield), a meso form (1R,2S)-1,2-di(azulen-1-yl)-1,2-bis[4-(dimethylamino)phenyl]ethane (7) (6% yield), and the two enantiomeric forms (1R,2R)- and (1S,2S)-1,2-di(azulen-1-yl)-1,2-bis[4-(dimethylamino)phenyl]ethanes (8) (6% yield). Furthermore, addition reaction of 3 with 1 under the same reaction conditions as the above provides 6, in 46% yield, which upon oxidation with DDQ (=2,3-dichloro-5,6-dicyano-1,4-benzoquinone) in dichloromethane at 25 °C for 24 h yields 1,1-di(azulen-1-yl)-2,2-bis[4-(dimethylamino)phenyl]ethylene (9) in 48% yield. Interestingly, reaction of 1,1-bis[4-(dimethylamino)phenyl]-2-(3-guaiazulenyl)ethylene (11) with 1 in a mixed solvent of methanol and acetonitrile in the presence of 36% hydrochloric acid at 60 °C for 3 h gives guaiazulene (10) and 3, owing to the replacement of a guaiazulen-3-yl group by an azulen-1-yl group, in 91 and 46% yields together with 5 (19% yield) and 6 (13% yield). Similarly, reactions of 2-(3-guaiazulenyl)-1,1-bis(4-methoxyphenyl)ethylene (12) and 1,1-bis{4-[2-(dimethylamino)ethoxy]phenyl}-2-(3-guaiazulenyl)ethylene (13) with 1 under the same reaction conditions as the above provide 10, 2-(azulen-1-yl)-1,1-bis(4-methoxyphenyl)ethylene (16), and 1,3-bis[2,2-bis(4-methoxyphenyl)ethenyl]azulene (17) (93, 34, and 19% yields) from 12 and 10 and 2-(azulen-1-yl)-1,1-bis{4-[2-(dimethylamino)ethoxy]phenyl}ethylene (18) (97 and 58% yields) from 13.     

Reactions of (E)-1,2-di(3-guaiazulenyl)ethylene and 2-(3-guaiazulenyl)-1,1-bis(4-methoxyphenyl)ethylene with tetracyanoethylene (TCNE) in benzene: comparative studies on the products and their spectroscopic properties

Reactions of the title ethylene derivatives, (E)-1,2-di(3-guaiazulenyl)ethylene (1) and 2-(3-guaiazulenyl)-1,1-bis(4-methoxyphenyl)ethylene (2), with a 2 M amount of TCNE in benzene at 25 °C for 24 h under argon give new cycloaddition compounds, 1,1,2,2,11,11,12,12-octacyano-3-(3-guaiazulenyl)-8-isopropyl-5,10-dimethyl-1,2,3,6,9,10a-hexahydro-6,9-ethanobenz[a]azulene (3) from 1 and 1,1,2,2,11,11,12,12-octacyano-8-isopropyl-3,3-bis(4-methoxyphenyl)-5,10-dimethyl-1,2,3,6,9,10a-hexahydro-6,9-ethanobenz[a]-azulene (4) from 2, respectively, in 66 and 87% isolated yields. Comparative studies on the above reactions as well as the spectroscopic properties of the unique products 3 and 4, possessing interesting molecular structures, are reported and, further, a plausible reaction pathway for the formation of these products is described.     

Reactions of (1R,2S)-1,2-di(2-furyl)-1,2-di(3-guaiazulenyl)ethane and (1R,2S)-1,2-di(3-guaiazulenyl)-1,2-di(2-thienyl)ethane with tetracyanoethylene (TCNE) in benzene: comparative studies on the products and their spectroscopic properties

Reactions of the title meso forms, (1R,2S)-1,2-di(2-furyl)-1,2-di(3-guaiazulenyl)ethane (1) and (1R,2S)-1,2-di(3-guaiazulenyl)-1,2-di(2-thienyl)ethane (2), with a two molar amount of TCNE in benzene at 25 °C for 5 h (for 1) and 48 h (for 2) under oxygen give new compounds, 2,2,3,3-tetracyano-4-(2-furyl)-8-isopropyl-6-methyl-1,4-dihydrocyclohepta[c,d]azulene (3) and 2,2,3,3-tetracyano-8-isopropyl-6-methyl-4-(2-thienyl)-1,4-dihydrocyclohepta[c,d]azulene (4), respectively, in 74 and 21% isolated yields. Comparative studies on the above reactions as well as the spectroscopic properties of the unique products 3 and 4, possessing interesting molecular structures, are reported and, further, a plausible reaction pathway for the formation of these products is described.     

Synthesis,crystal structures and spectral characterization of Cu(II) and Mn(II) complexes of 4-hydroxy-3-methoxybenzaldehyde: antioxidant properties and molecular docking studies

[Cu(L)₂(H₂O)₂] (1) and [Mn(L)₂(H₂O)₂] (2) (HL = 4-hydroxy-3-methoxybenzaldehyde) were synthesized and characterized using elemental, spectral (FTIR, ESI-MS, UV–visible, fluorescence and EPR), thermal, cyclic voltammetric, powder, and single crystal X-ray crystallographic studies. Spectral and X-ray data ascertained the structural features, binding modes of ligand and distorted octahedral geometry around the metal ions. Cyclic voltammetric studies confirmed the formation of a quasi reversible redox couple in solution. Crystal structure analysis of 1 and 2 reveal the presence of non-covalent interactions, resulting in a 1-D polymeric chain. Antioxidant properties (using DPPH and hydrogen peroxide assay) and molecular docking studies (using 1BNA) are also examined. The binding free energies (calculated from docked models), ?270 (1) and ?295 kJ mol^?1 (2), suggest that the complexes reasonably bind to DNA, and the DNA-binding affinity of 2 is stronger than that of 1.     

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 structural characterisation of redox-responsive N-ferrocenoyl amino acid esters; the X-ray crystal structure of N-ferrocenoyl alanine methyl ester; electrochemical anion recognition and H NMR complexation studies

The N-ferrocenoyl amino acid ester derivatives FcCOR {Fc=(η⁵-C₅H₅)Fe(η⁵-C₅H₄)} where R=Gly(OMe) 1, Gly(OEt) 2, Gly(OBn) 3, l-Ala(OMe) 4, l-Ala(OEt) 5, l-Leu(OMe) 6, l-Leu(OEt) 7, l-Leu(OBn) 8, l-Phe(OMe) 9 and l-Phe(OEt) 10, were prepared by coupling ferrocene carboxylic acid with the appropriate amino acid ester starting materials using the 1,3-dicyclohexylcarbodiimide (DCC), 1-hydroxybenzotriazole (HOBt) protocol and these have been characterised by spectroscopic techniques. The electrochemical anion sensing behaviour of compounds 1-10 with several anions using a platinum microdisk working electrode is described, together with ¹H NMR anion complexation studies. The X-ray single crystal structure of N-ferrocenoyl-l-alanine methyl ester 4 has been determined and contains two molecules which differ slightly in conformation in the asymmetric unit of space group P2₁ (No. 4); principal dimensions are amide N(H)CO 1.224(6) and 1.231(6) Å, ester CO 1.220(10) and 1.190(7) Å, with N-H?OC(amide) as the primary intermolecular hydrogen bond, N?O 2.992(6) and 2.971(6) Å and with graph set C(4).     

Crystal structures,theoretical calculations,spectroscopic and electrochemical properties of Cr(III) complexes with dipicolinic acid and 1,10-phenantroline

The crystal structures of compounds Na[Cr(dipic)₂] · 2H₂O (1) and [Cr(dipic)(phen)Cl] · 1/2H₂O (2), dipic = dipicolinate, phen = 1,10-phenantroline, were determined. In both complexes, Cr(III) is in a distorted octahedral environment. In complex (1), the metal is coordinated to two nearly perpendicular dipic anions acting as tridentate ligands through one oxygen of each carboxylate group and the pyridinic nitrogen atom. In complex (2), Cr(III) ion is similarly coordinated to a dipic anion, defining a ligand equatorial plane. The phen molecule bridges the remaining equatorial coordination site and one of the axial positions through its N-atoms. The other axial position is occupied by a chloride ion.     

Preparation,crystal structure,and spectroscopic,chemical, and electrochemical properties of (2E,4E)-1,4-di(3-guaiazulenyl)-1,3-butadiene compared with those of (E)-1,2-di(3-guaiazulenyl)ethylene

Wittig reaction of (E)-3-(3-guaiazulenyl)propenal (11) with (3-guaiazulenylmethyl)triphenylphosphonium bromide (9) in ethanol containing NaOEt at 25 °C for 24 h under argon gives the title new (2E,4E)-1,3-butadiene derivative 4, in 33% isolated yield, which upon treatment with hexafluorophosphoric acid (i.e., 65% HPF₆ aqueous solution) in tetrahydrofuran (=THF) at 25 °C for 1 h under aerobic conditions affords a new air (two-electron) oxidation product (E)-ethylene-1,2-bis(3-guaiazulenylmethylium) bis(hexafluorophosphate) (14), quantitatively, and further, zinc-reduction of 14 in trifluoroacetic acid (=CF₃COOH) at 0 °C for 1 h under argon reverts 4, quantitatively. Along with the above interesting results, our discovered another preparation method, spectroscopic properties, crystal structure, and electrochemical behavior of 4, which serves as a strong two-electron donor and acceptor, compared with those of the previously reported (E)-1,2-di(3-guaiazulenyl)ethylene (3) are documented in detail.     

4-hydroxy-2-quinolones. 96. Synthesis and properties of 4-methyl-2-oxo-1,2-dihydroquinoline-3-carboxylic acid

Alkaline hydrolysis of the ethyl ester of 4-(cyanoethoxycarbonylmethyl)-2-oxo-1,2-dihydroquinoline-3-carboxylic acid is accompanied by decarboxylation with loss of two molecules of CO₂ and leads to 4-methyl-2-oxo-1,2-dihydroquinoline-3-carboxylic acid. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 887–893, June, 2006.     

Synthesis, properties and molecular structure of a novel dicyanoheptafulvene derivative, 4′-dicyanomethylidenedispiro[cyclohexane-1, 1′-(1′,4′,7′-trihydrocyclopenta[f]azulene)-7′,1″-cyclohexane]

A novel dicyanoheptafulvene 9 annulated by two spiro[4,5]deca-1,3-dienes was synthesized by the reaction of dispirocyclopentaazulenium cation 8 with bromomalononitrile. Although 9 was found to have a nonplanar heptafulvene structure by its X-ray crystallographic analysis, it is still capable of π-conjugation and thus shows appreciable contribution of the dipolar resonance form 9B based on its spectroscopic data. The degree of the contribution was further evaluated for various dicyanoheptafulvenes in terms of the partial sum of atomic charges of the dicyanomethylene group in the calculated structures besides the interplanar angles of the heptafulvene part and the length of the exocyclic double bond in the crystal structures.     

Synthesis,spectral and quantum mechanical studies and molecular docking studies of Schiff base (E)2-hydroxy-5-(((4-(N-pyrimidin-2-yl)sulfamoyl)phenyl)imino)methyl benzoic acid from 5-formyl salicylic acid and sulfadiazine

A new Schiff base (E)2-hydroxy-5-(((4-(N-pyrimidin-2-yl)sulfamoyl)phenyl)imino)methyl benzoic acid (5FSADA) compound was synthesized by condensation of 5-formyl salicylic acid and sulfadiazine, and the product formed was characterized using FTIR and UV–Visible spectroscopy. The geometry was optimized using DFT. The FTIR were computed from DFT and is compared with experimental spectra, followed by detailed vibrational assignment, which shows that the experimental and simulated data is in close agreement. The UV–Vis spectrum calculated using TD-DFT, IEFPCM solvation model with DMSO as solvent. Wave function based properties like localized orbital locator, electron localization function and non-covalent interactions has been studied extensively. The physical properties (ADMET) of the compound 5FSADA indicated that the compound has excellent drug likeness and PASS studies showed that it has anti-infective properties, which is confirmed by a docking score of −9.0 ​kcal/mol.     

Antimony(V) catecholato complexes based on 4,5-dialkylsubstituted o-benzoquinone. The spectroscopic and electrochemical studies. Crystal structure of [Ph4Sb][Ph2Sb(4,5-Cat)2]

Triphenylantimony(III) and triethylantimony(III) readily react with 4,5-(1,1,4,4-tetramethyl-butane-1,4-diyl)-o-benzoquinone to form catecholato complexes R₃Sb(4,5-Cat) (R = Ph (1), Et (2); 4,5-Cat is dianionic 4,5-(1,1,4,4-tetramethyl-butane-1,4-diyl)-catecholate). In polar solvents (CHCl₃, acetone) complex 1 transforms easily to ionic complex compound [Ph₄Sb]⁺[Ph₂Sb(4,5-Cat)₂]⁻ (3) with diphenyl-bis-[4,5-(1,1,4,4-tetramethyl-butane-1,4-diyl)-catecholato]antimony(V) complex anion. Complexes were characterized by IR, ¹H, ¹³C NMR spectroscopy, cyclic voltammometry. Molecular structure of 3·CHCl₃ was confirmed by X-ray analysis. Cyclic voltammometry of 1 and 3 shows that both complexes undergo reversible one-electron oxidation to quite stable paramagnetic o-semiquinonato species [Ph₃Sb(4,5-SQ)]⁺ and [Ph₂Sb(4,5-SQ)(4,5-Cat)] (0.75 and 0.49 V in CH₂Cl₂ vs. Ag/AgCl/KCl, respectively).