Head-to-tail regioregular oligothiophene-functionalized 9,9'-spirobifluorene derivatives. 1. Synthesis

Two series of novel fully conjugated oligomers, oligothiophene-functionalized 9,9'-spirobifluorene derivatives, have been developed in this contribution. First, four 9,9'-spirobifluorene bromide derivatives (compounds 1a-d) are prepared through various synthetic routes. Oligothiophene derivatives with or without substituents are synthesized through the Grignard and Suzuki coupling reactions. The Negishi coupling reactions between oligothienylzinc chloride and various 9,9'-spirobifluorene bromides with Pd(PPh(3))(4) as catalyst successfully produce the desired compounds, unsubstituted oligothiophene-functionalized 9,9'-spirobifluorene derivatives, compounds 2 to 4a-d. Since the Negishi coupling reactions afford regioregularly head-to-tail (H-T) oligo(4-n-hexylthiophene)-functionalized 9,9'-spirobifluorene derivatives in poor yields, the Suzuki coupling reactions between sodium 4-n-hexylthienyl-2-boronate 8, and various 9,9'-spirobifluorene-based bromides 1a-d and 9-16 are employed to produce highly regioregular head-to-tail oligothiophene-functionalized 9,9'-spirobifluorene derivatives (compounds 5 to 7a-d) in very high yields. We also investigate the effect of solvents on the Suzuki coupling reactions. The structure and purity of all compounds are verified by FT-IR, (1)H and (13)C NMR, MS, and elemental analysis.     

结构规整有序的寡聚噻吩修饰9,9'-螺二芴衍生物的光物理性质及其电化学聚合

研究了结构规整有序的寡聚噻吩修饰的9,9'-螺二芴衍生物在溶液中和在固体膜状态下的光物理性质, 发现在四氢呋喃的稀溶液中, 随着有效共轭长度的增加这些化合物的最大吸收峰和发射峰发生了明显的红移. 实验结果表明, 9,9'-螺二芴骨架中的9位螺碳原子明显地阻断了二个共轭片段的共轭效应, 使它们成为了二个独立的共轭链节. 此外, 还进一步研究了这些化合物的电化学聚合性质.     

Furopyridines. XXII. Elaboration of the C-substituents alpha to the heteronitrogen atom of furo[2,3-b] -, -[3,2-b] -, -[2,3-c]- and -[3,2-c]pyridine

The Grignard reaction of fused ring cyanopyridine derivatives 1a-d with methyl- and phenylmagnesium bromide yielded the corresponding acylpyridine compounds 2a-d and 3a-d . Furopyridine N-oxides 4a-d were converted into the compounds having a phenyl group at the α-position to the ring nitrogen 5a-d . Reduction of 1a-d and the carboxylic esters 6a-d with diisobutylaluminium hydride yielded the corresponding amines 7a-d and aldehydes 9a-d . The aldehydes were converted to nitroethanol derivatives 10a-d by condensation with nitromethane and acrylic ester compounds 11a-d by the Wittig-Horner reaction with methyl diethyl phosphonoacetate.     

Molecular saddles. 4. Redox-active cyclophanes by bridging the 9,10-bis(1,3-dithiol-2-ylidene)-9,10-dihydroanthracene system: synthesis, electrochemistry, and X-ray crystal structures of neutral species and a dication salt.

We report the synthesis of a new series of cyclophanes 11a-d by ester-forming macrocyclization reactions of diol 9 with the dicarbonyl chloride derivatives of benzene, thiophene, ferrocene, and diphenyl ether, 10a-d, respectively. Compounds 11a-d display a two-electron, quasireversible oxidation wave in the cyclic voltammogram to yield the dication species at Eoxpa = 0.70-0.72 V (for 11a-c) and 0.47 V (for 11d) (vs Ag/AgCl in acetonitrile). The raised oxidation potentials for 11a-c reflect the reduced stability of the twisted dication structure within the steric constraints of the smaller cyclophanes. Consistent with this, the value of delta E (defined as Eoxpa - Eoxpc) decreases (i.e., reversibility of the oxidation process increases) in the sequence 11d > 11c > 11a > 11b as the bridging chain becomes shorter. X-ray crystal structures are reported for compounds 11a-d and the dication salt 11d2+(I3-)2.(CH2Cl2)2.25. For 11a-d the typical saddle-shaped conformation of the 9,10-bis(1,3-dithiol-2-ylidene)-9,10-dihydroanthracene moiety is observed, with the strain imposed by the cyclophane ring being accommodated in the structure of the bridging unit. In the dication 11d2+ both dithiolium rings are planar and the anthracene unit is essentially aromatic, with the conformation of the bridge basically the same as in neutral 11d.     

Synthesis, characterization and antimicrobial activity of new 1,2,3-selenadiazoles

The commercially available aromatic polyketones 1a-d were utilized for the synthesis of the multi-arm1,2,3-selenadiazole derivatives 3a-d. The preparation starts with the reaction between compounds 1a-d and p-toluenesulfonyl hydrazide to give the corresponding tosylhydrazones 2a-d. Subsequent reaction with selenium dioxide leads to regiospecific ring closure of the tosylhydrazones to give the target multi-arm 1,2,3-selenadiazole derivatives in high yield. A 1,2,3-selenadiazole derivative 3e containing an epoxide ring was also prepared. The structures of all the synthesized compounds were confirmed on the basis of spectral and analytical data. The compounds were screened in vitro for their antimicrobial activity against various pathogenic bacterial and Candida strains obtained from King Abdullah Hospital in Irbid -Jordan. Compounds 3a, 3c and 3e were found to be highly active against all the selected pathogens. Compound 3e showed an inhibition zone of 13 mm against the highly resistant P. aruginosa.     

Synthesis,stability and bonding situation of tris-, bis- and mono[9-(azuleno[1,2-b]thienyl)]methyl cations

Stable tris-, bis- and mono[9-(azuleno[1,2-b]thienyl)]methyl cations (7a, 8a and 9a) and their derivatives, with a 6-isopropyl substituent on each azuleno[1,2-b]thiophene ring (7b, 8b and 9b) were prepared by the hydride abstraction reaction of the corresponding methane derivatives. The bonding situation of these compounds including the methane derivatives was examined by analysis of the 3J(H,H) values for the seven-membered ring from the 1H NMR spectra. The methane derivatives exhibited a significant alternating pattern in the 3J(H,H) values, which indicated that the pi-system of the azulene core is perturbed by the fused thiophene ring, showing a tendency towards a localized heptafulvene substructure. The 3J(H,H) values of 7b and 8b in the seven-membered ring revealed that the alternating C-C bond lengths in the azulene core still existed. The cations 9a and 9b, which exhibited nearly equal 3J(H,H) values in the seven-membered ring, exhibit the development of a delocalized tropylium substructure in the azulene core. X-ray crystal analysis of 6-isopropylazuleno[1,2-b]thiophene revealed substantial bond-length alternation in the seven-membered ring. Significant bond-length equalization in the seven-membered ring was also confirmed by the X-ray crystal analysis of 9b. The stability of these carbocations was examined by measurement of the pKR+ values and the redox potentials, which revealed that the bond-length alternation in the azulene core does not significantly affect the stability of the carbocations.     

Synthesis and mesomorphic properties of four ring,rod-like fluorene derivatives – the influence of the lateral substitution on mesomorphic properties of 2,7-bis(4-alkylphenyl)-fluorenes

ABSTRACT

This work presents new rod-like compounds being fluorene derivatives linked with other parts of the core at 2 and 7 positions – its synthesis and properties. The fluorene moiety is located in the central position of the four rings molecular core. The chain system in most cases was symmetrical and limited to pentyl or hexyl chains. To study the influence of the lateral substituents on mesomorphic properties two types of substituents have been incorporated, centrally located various short alkyl groups at fluorene’s 9,9 positions and outer core fluorosubstitutions located at side phenyl rings. All synthesised compounds exhibit liquid crystalline properties, where for laterally non-substituted and fluorosubstituted derivatives the dominant phases are smectics, while the nematics phases (nematic and chiral nematic – observed mostly on cooling cycle) occurs for compounds having alkyl substituents at 9,9 positions of fluorene. The synthetic methodology and mesomorphic properties of title compounds will be presented in detail as well as photophysical properties such as UV-visible absorption spectra and fluorescence spectra.     

Molecular tectonics. Porous hydrogen-bonded networks built from derivatives of 9,9'-spirobifluorene

Molecules with multiple sites that induce strong directional association tend to form open networks with significant volumes available for the inclusion of guests. Such molecules can be conveniently synthesized by grafting diverse sticky sites onto geometrically suitable cores. The characteristic inability of 9,9'-spirobifluorene to form close-packed crystals suggests that it should serve as a particularly effective core for the elaboration of molecules designed to form highly porous networks. To test this hypothesis, various new tetrasubstituted 9,9'-spirobifluorenes with hydrogen-bonding sites at the 3,3',6,6'-positions or 2,2',7,7'-positions were synthesized by multistep routes. Four of these compounds were crystallized, and their structures were determined by X-ray crystallography. In all cases, the compounds form extensively hydrogen-bonded networks with high porosity. In particular, 43% of the volume of crystals of 3,3',6,6'-tetrahydroxy-9,9'-spirobifluorene (28) is available for the inclusion of guests, whereas the porosity is only 28% in crystals of tetrakis(4-hydroxyphenyl)methane, a close model that lacks the spirobifluorene core. Similarly, the porosities found in crystals of 2,2',7,7'-tetra(acetamido)-9,9'-spirobifluorene (33) and 2,2',7,7'-tetrasubstituted tetrakis(diaminotriazine) 39 are 33% and 60%, respectively. Moreover, the porosity of crystals of 2,2',7,7'-tetrasubstituted tetrakis(triaminotriazine) 40 is 75%, the highest value yet observed in crystals built from small molecules. These observations demonstrate that a particularly effective strategy for engineering molecules able to form highly porous networks is to graft multiple sticky sites onto spirobifluorenes or other cores intrinsically resistant to close packing.     

Photophysical Properties and Electropolymerization of Regioregular Head-to-Tail Oligothiophenes-Functionalized 9,9′-spirobifluorene Derivatives

The photophysical properties of oligothiophenes-functionalized 9,9′-spirobifluorene derivatives in solution and in solid state were investigated in detail. The enhanced red-shift was observed from the absorption and the photoluminescence (PL) spectra of these derivatives in dilute THF solution with the increase of thiophene unit at one branch of 9,9′-spirobifluorene identical with the increased p-electron delocalization and the more effective conjugation length of the whole molecular system. The investigation on the photophysical properties of these compounds further demonstrated that the sp3-hybrid carbon at the spiro-center completely obstructed the correlation between two branches of the 9,9′-spirobifluorene system and made every branch become an independent chromophore. The electrochemical polymerization of 6b as a representative was also investigated.     

New multi-1,2,3-selenadiazole aromatic derivatives

The aromatic polyketones 3a-d are versatile compounds for the synthesis of the multi-1,2,3-selenadiazole aromatic derivatives 1a-d. The preparation starts with the reaction between the multi-bromomethylene benzene derivatives 2a-d and 4-hydroxy- acetophenone to give compounds 3a-d which are transformed through the reaction with semicarbazide hydrochloride or ethyl hydrazine carboxylate into the corresponding semicarbazones derivatives 4a-d or hydrazones 5a-d. The reaction with selenium dioxide leads to regiospecific ring closure of semicarbazones or hydrazones to give the multi- 1,2,3-selenadiazole aromatic derivatives in high yield.     

寡聚噻吩取代的9,9'-螺二芴的合成和表征

以四种溴化的9,9'-螺二芴为原料,设计合成了一系列新型的寡聚噻吩取代的9,9'－螺二芴。其结构均经1^H,13^CNMR,MS,FT-IR或元素分析确证。通过核磁工振氢谱分析,我们对该类化合物芳环质了的化学位移进行了归属。热重差热分析表明,由于螺二芴的引入,该类化合物具有较高的玻璃化转变温度和明显改善的无定型性。初步的光学性能研究表明,该类化合物寡聚噻吩相比,其荧光效率明显增强,并且随着寡聚噻吩与螺二芴连接位置的不同,其光学性能也有明显差异。     

Density matrix analysis, simulation, and measurements of electronic absorption and fluorescence spectra of spirobifluorenes

The linear absorption and fluorescence spectra as well as the oscillator strengths of 2,2',7,7'-tetraphenyl-9,9'-spirobifluorene (A), 2,2',7,7'-tetrakis(biphenyl-4-yl)-9,9'-spirobifluorene (B), and 2,2',7,7'-tetrakis(9,9'-spirobifluoren-2-yl)-9,9'-spirobifluorene (C) are calculated on the basis of the collective electronic oscillator (CEO) approach of Mukamel et al. (see, e.g., Chem. Rev. 2002, 102, 3171). The graphical visualization and quantitative characterization of CEO modes allows one to extract the real-space distribution of electronic excitations of the molecules under study. Effects of the lengthening and branching of the oligophenylene segments have been analyzed. The influence of the lowest excited (S1) vs ground-state (S0) geometry changes on the CEO modes is investigated and related to the geometry changes of the molecular parts. The obtained theoretical results are in good agreement with experimental trends observed in absorption and fluorescence data.     

Efficient greenish blue electrochemiluminescence from fluorene and spirobifluorene derivatives

The spectroscopic and electrochemical behavior as well as electrogenerated chemiluminescence (ECL) of a series of donor-π-donor derivatives bearing triphenylamine groups as donor connected to a fluorene, 2,7-bis-(4-(N,N-diphenylamino)phen-1-yl)-9,9'-dimethylfluorene (1), or spirobifluorene core, 2,7-bis-(4-(N,N-diphenylamino)phen-1-yl)-9,9'-spirobifluorene (2) and 2,2',7,7'-tetrakis(4-(N,N-diphenylamino)phen-1-yl)-9,9'-spirobifluorene (3), were investigated. Besides a high photoluminescence (PL) quantum yield in solution (between 81 and 87%), an efficient radical ions annihilation process induces intense greenish blue ECL emission that could be seen with the naked eye. Only the tetrasubstituted spirobifluorene derivative (compound 3) shows weak ECL obtained by a direct annihilation mechanism. Because the energy of the annihilation reaction is higher than the energy required to form the singlet excited state, the S-route could be considered the pathway followed by the ECL process in these molecules. The ECL emissions recorded by direct ion-ion annihilation show two bands compared to the single structureless PL band. The ECL spectra obtained by a coreactant approach using benzoylperoxide as a coreagent show no differences relative to that produced by annihilation, except for an increasing of ECL intensity for all compounds.     

Thiophene 1-oxides. V. Comparison of the crystal structures and thiophene ring aromaticity of 2,5-diphenylthiophene,its sulfoxide and sulfone

The detailed preparation of 2,5-diphenylthiophene 1-oxide (2) is reported as well as the comparative study of the crystal structures of 2,5-diphenylthiophene, 1 , its sulfoxide 2 and sulfone 3 obtained by X-ray diffraction. This work represents the first experimental study of a complete heterocyclic series, including a thiophene derivative, and the corresponding sulfoxide and sulfone. On the basis of the geometrical parameters, the first unequivocal experimental parameters obtained for a thiophene 1-oxide derivative, we have also examined the evolution of the aromatic character of the thiophene ring when oxidizing the sulfur atom to the sulfoxide and the sulfone. Paolini's bond orders and Julg and Francois's aromaticity indices have also been calculated for the three compounds and compared to those previously calculated for related thiophene derivatives by semi-empirical or ab initio methods [6], [7]. All the data examined showed that, in spite of its non planarity, the thiophene ring of 2,5-diphenylthiophene 1-oxide 2 could still exhibit some de localization of its p electrons indicating a certain degree of aromaticity lower than in thiophene 1 but higher than in the sulfone 3 .     

Mass spectra of new groups of functionalized heterocycles

The influence of the position and nature of the substituent in the thiophene ring on the fragmentation of 3-alkyl- and 5-alkyl-2-thienylamines under electron impact was studied. The derivatives containing the ethyl group in position 3 decompose due to both the elimination of the fragments from the substituents and thiophene ring rupture. In the case of the compounds with thetert-butyl group in position 5, the last process is not observed. The fragmentation of the 3- and 5-methyl-substituted derivatives occurs mainly from the isomeric thiopyran form of the molecular ion. For Part 2, see Ref. 1. Deceased. Published inIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1560–1563, September, 2000.     

Structural chemistry of polycyclic heteroaromatic compounds. Part 13. Photoelectron spectra and electronic structures of tricyclic hetarenes of the anthracene type.

The ultraviolet photoelectron spectra of two tricyclic heteroaromatic compounds (2,3) that are pi-isoelectronic with anthracene (1) have been recorded and analysed making use of semi-empirical AM1 and PM3, as well as density functional theory (DFT) B3LYP calculations. In compounds 2 and 3, one peripheral benzene ring of compound 1 is substituted by a thiophene ring that is either [b]- or [c]-annellated. In compounds 2 and 3, only small shifts are found for most of the ionization potentials of pi electrons. Since the ionization energies of all occupied pi molecular orbitals of compounds 1-3 could be assigned, a direct comparison of their pi electron energy is possible. Compared with compound 1, the pi-electron system of naphtho[2,3-b]thiophene (2) is stabilized by 0.6 eV, while that of naphtho[2,3-c]thiophene (3) is destabilized by 0.2 eV. [b]-Annellation of the thiophene ring is thus favourable while [c]-annellation is unfavourable.     

Synthesis of cavity extended cyclotriveratrylenes

Aromatic nucleophilic substitution reaction of cyclotriguaiacylene 1 with fluorobenzene derivatives bearing electron-withdrawing groups X (CHO, COCH(3), CN, NO(2)) in the para position gives a series of cyclotriveratrylene derivatives (3a-d), where the X substituents can be transformed to hydrogen-bond donor groups to afford new CTV-based heteroditopic receptors. The substituents of compounds 3a-d favor the facile demethylation reaction of the CTV derivatives. Attempts to perform alkylation reactions on derivatives (8c,d) evidenced the formation of a stereoisomeric mixture of symmetrical and unsymmetrical compounds.     

Ter(9,9-diarylfluorene)s: highly efficient blue emitter with promising electrochemical and thermal stability

Novel ter(9,9-diarylfluorene)s were synthesized by a Suzuki-coupling reaction of 2-bromofluorene (1) and 2,7-fluorenediboronic ester derivatives (3) with high isolated yields (63-86%). The X-ray structure analysis of ter(9,9'-spirobifluorene) (4aa) revealed that the conjugated chromophore adopts a helical conformation. This conformation effectively releases the steric interaction between the fluorene moieties and prevents inter-chromophore interactions. The introduction of aryl groups at the C9 position of fluorene was highly beneficial to the thermal and morphological stability of these oligomers. These terfluorenes exhibit intense blue fluorescence with excellent quantum yields both in solution ( approximately 100%) and in solid state (66-90%), and possess interesting reversible redox properties. Highly efficient blue light-emitting OLED devices were fabricated using 4aa and 4cc as emitters as well as hole transporters. The devices exhibit low turn-on voltage ( approximately 3 V) and high EL external quantum efficiency (2.5-3%).     

1, 4-Benzodiazepines and their cyclic homologs and analogs

The physicochemical and pharmacological properties of compounds of eight series of derivatives of 1,2-dihydro-3H-1,4-benzodiazepine have been considered. A marked relationship between the half-neutralization potentials, half-wave potentials of polarographic reduction, and the dipole moments of the compounds with Hammett's constants of the substituents in position 7 has been found. In all the series studied, a tendency is observed to an increase in the physiological activity of the compounds with an increase in the electron-accepting nature of the substituents in position 7.For Communication XI, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1558–1565, November, 1973.     

Uses of ethyl benzoyl acetate for the synthesis of thiophene,pyran, and pyridine derivatives with antitumor activities

The N-(arly)propanamide derivatives 3a,b were used for a series of heterocyclization reactions to give thiophene, pyran, and pyridine derivatives. Thus, these compounds underwent the Gewald's thiophene synthesis through their reactions with either malononitrile or ethyl cyanoacetate and elemental sulfur to afford compounds 6a-f , respectively. In addition, they were subjected through a series of multicomponent reactions (MCRs) to give pyran and fused derivatives. The reactions of 3a,b with either malononitrile or ethyl cyanoacetate gave pyridine derivatives 14a-d , respectively. The latter compounds afforded arylhydrazone derivatives 15a-m through their reactions with any of the aromatic diazonium salts 15a-c . The antitumor of the synthesized compounds against A549 (nonsmall cell lung cancer), H460 (human lung cancer), HT-29 (human colon cancer), and MKN-45 (human gastric cancer cancer) cancer cell lines together with foretinib as the positive control by a MTT assay was measured, and the results obtained showed that many compounds exhibited high potency against the six cancer cell lines.