Syntheses and bioactivities of substituted 9,10-dihydro-9,10-[1,2]benzenoanthracene-1,4,5,8-tetrones. Unusual reactivities with amines

A number of substituted 9,10-dihydro-9,10-[1,2]benzenoanthracene-1,4,5,8-tetrones have been synthesized and their anticancer and antimalarial activities evaluated. A one-pot synthesis of 2,5,8-trimethoxy-9,10-dihydro-9,10-[1,2]benzenoanthracene-1,4-dione (4) was achieved by heating a mixture of 1,4-dimethoxyanthracene, methoxyhydroquinone, silver oxide, and zinc iodide in toluene. Regioselective bromination of 4 and 2-methoxy-9,10-dihydro-9,10-[1,2]benzenoanthracene-1,4,5,8-tetrone (7) with N-bromosuccinimide provided 2-bromo-3,5,8-trimethoxy-9,10-dihydro-9,10-[1,2]benzenoanthracene-1,4-dione and 2-bromo-3-methoxy-9,10-dihydro-9,10-[1,2]benzenoanthracene-1,4,5,8-tetrone (1), respectively. The reactions of 1 with aliphatic primary amines and secondary amines, respectively, produced different products, a result most likely attributed to the different basicities (or nucleophilicities) and steric effects of the two kinds of amines. The structure of the displacement product, 2-bromo-3-[2-(tert-butoxycarbonyl)ethylamino]-9,10-dihydro-9,10-[1,2]benzenoanthracene-1,4,5,8-tetrone, from the reaction of 1 with tert-butyl 3-aminopropanoate was unequivocally determined by a single-crystal X-ray analysis. IC(50) values of triptycene bisquinones for the inhibition of L1210 leukemia cell viability are in the 0.11-0.27 microM range and for the inhibition of Plasmodium falciparum 3D7 are in the 4.7-8.0 microM range.     

Novel Macrocycles. Part 6. Synthesis, Structures and Cation Binding from Optical Spectroscopy of 9,10-Anthraquinone-crown Ethers

The 9,10-anthraquinone-[12]crown-4, [15]crown-5 and [18]crown-6 derivatives were synthesized from 1,2-dihydroxy-9,10-anthraquinone and 1,8-dihydroxy-9,10-anthraquinone which were condensed with dihalides or ditosylates of polyethylene glycols in alkali carbonate/DMSO. The 9,10-anthraquinone derived polyoxacyclo-alkanes were characterized with IR, mass spectrometry, ¹H, ¹³C spectroscopy and elemental analysis. The cation binding properties were studied with UV-vis spectroscopy. The association constants found in acetonitrile were selectively dependent on the cation radius and macrocycle size as well as the molecular structures. The observed results from UV-vis studies, however, showed the stronger complexing role of 1,2-derived macrocycles compared to those of 1,8-derivatives. The theoretical conformational analysis and the energy optimisations of the 9,10-anthraquinone-macrocycles carried out with MM+ method explained the binding results.     

Five new peltogynoids from underground parts of Iris bungei: a Mongolian medicinal plant

Five new peltogynoids, irisoids A-E (1-5), have been isolated from the underground parts of Iris bungei. The structures of the new compounds were established on the basis of spectroscopic methods and were found to be 1,8,10-trihydroxy-9-methoxy-[1]benzopyrano-[3,2-c][2]-benzopyran-7(5H)-one (1), 1,8-dihydroxy-9,10-dimethoxy-[1]benzopyrano-[3,2-c][2]-benzopyran-7(5H)-one (2), 1,10-dihydroxy-8,9-dimethoxy-[1]benzopyrano-13,2-c][2]-benzopyran-7(5H)-one (3), 1,8-dihydroxy-9,10-methylenedioxy-[1]benzopyrano-[3,2-c][2]-benzopyran-7(5H)-one (4), and 1,8,11-trihydroxy-9,10-methylenedioxy-[1]benzopyrano-[3,2-c][2]-benzopyran-7(5H)-one (5). The structure of irisoid B (2) was established unambiguously by X-ray diffraction study.     

Efficient preparation of monoadducts of [60] fullerene and anthracenes by solution chemistry and their thermolytic decomposition in the solid state

The efficient preparation of monoadducts of [60]fullerene and seven anthracenes (anthracene, 1-methylanthracene, 2-methylanthracene, 9-methylanthracene, 9,10-dimethylanthracene, 2,3,6,7-tetramethylanthracene, and 2,6-di-tert-butylanthracene) by cycloaddition in solution is described. The seven mono-adducts of [60]fullerene and the anthracenes were characterized spectroscopically and were obtained in good yields as crystalline solids. The monoadducts of [60]fullerene and anthracene, 1-methylanthracene, 2-methylanthracene and 9,10-dimethylanthracene crystallized directly from the reaction mixture. The thermolytic decomposition at 180 degrees C of the crystalline monoadducts of [60]fullerene and anthracene, 1-methylanthracene, 9-methylanthracene and 9,10-dimethylanthracene all gave rise to the specific formation of a roughly 1:1 mixture of [60]fullerene and the corresponding antipodal bisadducts ("trans-1"-bisadducts) of [60]fullerene and the anthracenes. In contrast, the crystalline monoadducts of [60]fullerene and the anthracene derivatives 2-methylanthracene, 2,3,6,7-tetramethylanthracene and 2,6-di-tert-butylanthracene all decomposed to [60]fullerene and anthracenes (without detectable formation of bisadducts) upon heating in the solid state to temperatures of 180 to 240 degrees C. The formation of the antipodal bisadducts from thermolytic decomposition of crystalline samples of the monoadducts was rationalized by topochemical control.     

Orbital Unsymmetrization Affects Facial Selectivities of Diels-Alder Dienophiles

We investigated the Diels-Alder reactions of maleic anhydrides embedded in a dibenzobicyclo[2.2.2]octatriene motif as a nonsterically biased dienophile. Substituents on a benzene ring in these dienophiles are far from the reaction center, providing a sterically equivalent pi-face. Instead substituents can unsymmetrize the dienophilic pi face through pi (anhydride)-pi (aromatic) orbital interactions. Electron-withdrawing substituents affect the facial bias and relative rates of these cycloadditions. The preference of the cycloadditions is opposite in direction to those observed in nucleophilic additions of 2-substituted-9,10-dihydro-9,10-ethanoanthracen-11-ones (dibenzobicyclo[2.2.2]octadienones) and in electrophilic additions of 2-substituted 9,10-dihydro-9,10-ethenoanthracenes (dibenzobicyclo[2.2.2]octatrienes), though all of them have related dibenzobicyclic systems.     

Thermal and electron-impact transformations of cis-1,2-dibbnzoylalkenes

Several cis-1,2-dibenzoylalkene derivatives have been prepared in yields ranging between 60–80%, through the Diels-Alder addition of the appropriate dienes to dibenzoylacetylene. These include, 2,3-dibenzoyl-bicyclo [2.2.1]hepta-2,5-diene (10), 2,3-dibenzoylbicyclo[2.2.2]octa-2,5-diene (11), 7-oxa-2,3-dibenzoyl-bicyclo [2.2.1]hepta-2,5-diene (12), 1,4-diphenyl-2,3-dibenzoyl-1,4-epoxynaphthalene (13) and 9,10-dihydro-11,12-dibenzoy1-9, 10-ethenoanthracene (15), formed from cyclopentadiene, cyclohexa-1,3-diene, furan, 1,3-diphenylisobenzofuran and anthracene, respectively.

Thermolysis of 2,3-dibenzoylbicyclo[2.2.1]hepta-2,5-diene gave chiefly cyclopentadiene, arising through a retro-Diels-Alder mode of fragmentation. Similar retro-Diels-Alder fragmentations have been observed in the cases of 7-oxa-2,3-dibenzoylbicyclo[2.2.1]hepta-2,5-diene and 9,10-dihydro-11,12-dibenzoyl-9,10-ethenoanthracene. The thermoylsis of 1,4-diphenyl-2,3-dibenzoyl-1,4-epoxynaphthalene, however, gave a mixture of 1,3-diphenylisobenzofuran and 1,2-dibenzoylbenzene. The formation of 1,2-dibenzoylbenzene in this case has been shown to be through the air-oxidation of 1,3-diphenylisobenzofuran. Thermolysis of 2,3-dibenzoylbicyclo[2.2.2]octa-2,5-diene, on the other hand, gave a nearly quantitative yield of 1,2-dibenzoylbenzene, which did not undergo further transformation even on heating around 260° for several hours. In none of these cases, the expected pericyclic transformation, analogous to the conversion of cis-1,2-dibenzoylstilbene (6) to the isomeric 2,2,3,4-tetraphenylbut-3-enolide (9), has been observed under thermal conditions. Treatment of 9,10-dihydro-11,12-dibenzoyl-9,10-ethenoanthracene (15) with phosphorous pentasulphide resulted in the formation of a mixture of 12,14-diphenyl-9, 10(3', 4')furanoanthracene (28) and 12,14-diphenyl-9,10(3',4')thiophenoanthracene (31), arising through the postulated intermediates, 9,10-dihydro-11-benzoyl-12-thiobenzoyl-9,10-ethenoanthracene (26) and 9,10-dihydro-11,12-dithiobenzoyl-9, 10-ethenoanthracene (29), respectively.

The electron-impact induced transformations of the cis-1,2-dibenzoylalkenes, 6, 10, 11, 12, 13 and 15 on the other hand, can be rationalized in terms of both retro-Diels-Alder type fragmentations and pericyclic transformations of the dibenzoylalkene components.     

Polyfunctional macroheterocycles

The reaction of 1-[1,2-bis(carbomethoxy)ethyl]aziridine with ethane-1,2-dithiol leads to 1.8-bis[1,2-bis(carbomethoxy)ethylamino]-3,6-dithiaoctane. Condensation with phthalic and terephthalic acid dichloride gives 9,10-benzo-8, 11-dioxo-7,12-bis[1,2-bis(carbomethoxy)ethyl]-1,4-dithia-7,12-diazacyclotetradec-9-ene and 9,12-benzo-8,13-dioxo-7,14-bis[1,2-bis(carbomethoxy)ethyl]-1,4-dithia-7,14-diazacyclohexadeca-9,12-diene, respectively, while condensation with formaldehyde gives 7,9,18,20-tetrakis[1,2-bis(carbomethoxy)ethyl]-1,4,12,15-tetrathia-7,9,18.29-tetraazacyclodocosane. The corresponding disulfone is formed in the oxidation of 9,10-benzo-8,11-dioxo-7,12-bis[1,2-bis(carbomethoxy) ethyl]-1,4-dithia-7,12-diazacyclotetradec-9-ene with 30% hydrogen peroxide.See [1] for Communication 1.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1563–1565, November, 1988.     

Thiophenoanthracene-based conjugated polymers via direct arylation polycondensation

3,4-Appended thiophene monomers furnish unique optoelectronic properties due to electronic and steric effects on the donor unit. Here, we have demonstrated a new polymer synthesis by direct arylation polycondensation of 9,10-dihydro-9,10-[3,4]thiophenoanthracene, a thiophene-based monomer. Chloride-promoted direct arylation polycondensation of 9,10-dihydro-9,10-[3,4]thiophenoanthracene with dibromo monomers with acetate in N,N-dimethylacetamide gave conjugated alternating copolymers. The obtained polymer had a molecular weight of 38,000 and exhibited high film-forming ability. The optical and electrochemical properties of the polymers were also discussed.     

Thermal decomposition of O-benzyl ketoximes; role of reverse radical disproportionation

Thermolyses of seven dialkyl, two alkyl-aryl and two diaryl O-benzyl ketoxime ethers, R(1)R(2)C[double bond, length as m-dash]NOCH(2)Ph, have been examined in three hydrogen donor solvents: tetralin, 9,10-dihydrophenanthrene, and 9,10-dihydroanthracene. All the oxime ethers gave the products expected from homolytic scission of both the O-C bond (viz., R(1)R(2)C[double bond, length as m-dash]NOH and PhCH(3)) and N-O bond (viz., R(1)R(2)C[double bond, length as m-dash]NH and PhCH(2)OH). The yields of these products depended on which solvent was used and the rates of decomposition of the O-benzyl oxime ethers were greater in 9,10-dihydrophenanthrene and 9,10-dihydroanthracene than in tetralin. These results indicated that a reverse radical disproportionation reaction in which a hydrogen atom was transferred from the solvent to the oxime ether, followed by [small beta]-scission of the resultant aminoalkyl radical, must be important in the latter two solvents. Benzaldehyde was found to be an additional product from thermolyses conducted in tetralin. This, and other evidence, indicated that another induced decomposition mode involving abstraction of a benzylic hydrogen atom, followed by [small beta]-scission of the resulting benzyl radical, became important for some substrates. Participation by minor amounts of enamine tautomers of the oxime ethers was shown to be negligible by comparison of thermolysis data for the O-benzyloxime of bicyclo[3.3.1]nonan-9-one, which cannot give an enamine tautomer, with that of the O-benzyloxime of cyclohexanone.     

K-region oxides and imines of benzo[b]phenanthro[2,3-d]thiophene and benzo[b]phenanthro[3,2-d]thiophene

The syntheses of the K-oxides and K-imine derivatives of benzo[b]phenanthro[2,3-d]thiophene and benzo-[b]phenanthro[3,2-d]thiophene are described. The parent hydrocarbons 1 and 2 were oxidized with osmium tetroxide and sodium metaperiodate, and the dialdehydes 12 and 18 so formed, cyclized to the corresponding epoxides 1a,12b-dihydrobenz[b]oxireno[9,10]phenanthro[2,3-d]thiophene ( 7 ) and 1a,12b-dihydrobenz-[b]oxireno[9,10]phenanthro[3,2-d]thiophene ( 13 ). Reaction of the oxiranes with sodium azide gave mixtures of azido-alcohols that, in turn, were transformed to the thiaarene imines 1a,12b-dihydro-1H-benz[b]azirino-[9,10]phenanthro[2,3-d]thiophene ( 8 ) and 1a,12b-dihydro-1H-benz[b]azirino[9,10]phenanthro[3,2-d]thiophene ( 14 ), respectively, with the aid of tri-n-butylphosphine.     

Intramolecular behaviors of anthryldicarbenic systems: dibenzo[b,f]pentalene and 1H,5H-dicyclobuta[de,kl]anthracene

9,10-Bis[methoxy(trimethylsilyl)methyl]anthracenes (24), synthesized from 9,10-dilithioanthracene (26) and bromomethoxytrimethylsilylmethane (27, 2 equiv), decompose (550-650 degrees C/10(-3) mmHg) carbenically to dibenzo[b,f]pentalene (28, > 48%). 9,10-Anthryldicarbenes 39 or their equivalents convert to pentalene 28 rather than di-peri-cyclobutanthracenes 30 and 31, benzobiphenylene 32, or extended rearrangement products 33-38. Formation of 28 from 24 raises questions with respect to the behavior of 1,3,4,6-cycloheptatetraenyl-1-carbenes 49, 2,4,5,7-cyclooctatetraenylidene 51, 2,5,7-cyclooctatriene-1,4-diylidene 52, 1,2,4,5,7-cyclooctapentaene 53, and bicyclo[4.1.0]heptatrienyl-1-carbenes 54 and to carbon-skeleton and hydrogen rearrangements of anthryldicarbenes 39 and/or their equivalents at various temperatures. 1,5-Bis[methoxy(trimethylsilyl)methyl]anthracenes (25), prepared from 1,5-diiodoanthracene (63) and methoxytrimethylsilylmethylzinc bromide (57, 2 equiv) as catalyzed by PdCl(2)(PPh(3))(2), yield the di-peri-carbenic reaction product 1H,5H-dicyclobuta[de,kl]anthracene (30, > 40%) on pyrolysis at 550-650 degrees C/10(-3) mmHg. Proof of structure and various aspects of the mechanisms of formation of 30 are discussed.     

Derivatives of benzo[4,5]cyclohepta[1,2-b]thiophene. 4. Synthesis of 1-(9,10-dihydro-4H-benzo[4,5]cyclohepta[1,2-b]thiophen-4-yl)-3-alkylaminoazetidines

Thirteen 1-(9,10-dihydro-4H-benzo[4,5]cyclohepta[1,2-b]thiophen-4-yl)-3-alkylaminoazetidines 11 have been synthesized in three steps from 4-amino-9,10-dihydro-4H-benzo[4,5]cyclohepta[1,2-b]thiophene ( 6 ), which was obtained from the reduction of either 4-azido 4 or 4-hydroxyimino 5 derivatives. All the compounds have been evaluated as potential antidepressive agents.     

Some novel heterocyclic systems derived from 7-amino-2,3-dihydro-8-nitro-1H-pyrrolo[1,2-α]benzimidazole and the corresponding diamine

The preparation of 7-amino-2,3-dihydro-8-nitro-1H-pyrrolo[1,2-a]benzimidazole from 1,4-diacetamido-2,3-dinitrobenzene is described. Reaction of this compound with 2,5-dimethoxytetrahydrofuran produces 2,3-dihydro-8-nitro-7-N-pyrrolo-1H-pyrrolo[1,2-a]benzimidazole, which can be cyclised to produce two new heterocyclic ring systems, 9,10-dihydro-8H-pyrrolo[1,2-a]pyrrolo(1′,2′:1,2]imidazo[5,4-f]quinoxaline and 9,10-dihydro-8H-pyrrolo[2,1-c]pyrrolo[1′,2′:1,2]imidazo[4,5-h][1,2,4]benzotriazine. The corresponding diamine, 7,8-diamino-2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazole undergoes a variety of condensation reactions to produce several new heterocyclic systems, for example, with formic acid, 1,7,8,9-tetrahydroimidazo-[4,5-e]pyrrolo[2,1-6]benzimidazole is formed and with diacetyl, 9,10-dihydro-2,3-dimethyl-8H-pyrrolo-[1′,2′:1,2]imidazo[5,4-y]quinoxaline is obtained.     

The chemistry of polycyclic arene imines. VII. Reactions of phenanthrene 9,10-imine with aromatic carboxaldehydes,carboxylic acids and acetylenic esters

The reactions of phenanthrene 9,10-imine ( 1 ) with aromatic aldehydes, benzoic acids and acetylenedi-carboxylic esters were investigated. The aldehydes were shown to give 1-[N-(arylmethylidene)-9-phenanthreneamine-10-yl]-1a,9b-dihydrophenanthro[9,10-b]azirine 2. The ‘dimeric’ structure of these products was established by X-ray diffraction analysis. The carboxylic acids proved to form in the presence of dicyclohexylcarbodiimide, N-aroylphenanthrene 9,10-imines 7 , that readily undergo rearrangement to N-aroyl-9-phenanthrenamines 8. Esters of acetylenedicarboxylic acid gave the corresponding esters of (Z)-2-(1a,9b-dihydrophenanthro[9,10-b]azirine-1-yl)-2-butendioic acid 10 .     

meta-Photoaddition reactions of 2-chloro-, 2,5-dichloro-, and 2-halo-5-isopropyl-tropones with 9,10-dicyanoanthracene

Photoreactions of 2-halotropones with the excited 9,10-dicyanoanthracene gave a meta-adduct and substitution products occurred at the C-2 position of troponoids. The mechanism of the meta-adduct was proved by the product analysis of the reaction of 3,7-dideuterio-2-bromo-5-isopropyltropone and 9,10-dicyanoanthracene. In the photoreaction of 2-chloro-5-isopropyltropone and 9,10-dicyanoanthracene in a mixed solvent of benzene and methanol, a benzaldehyde with a dibenzo-2-oxabicyclo[3.2.2]nonane system was obtained to support occurrence of an [8+4] cycloaddition reaction between them.     

Transition metal induced derivatisations resulting in novel coordination behaviour of bis(oxamato) ligands

Two mononuclear bis(oxamato) complexes with the formula [nBu4N]2[M(2,3-acbo)] (M=Ni (), Cu (), with acbo=anthra-9,10-chinone-2,3-bis(oxamato) have been synthesized starting from symmetric diethyl N,N'-anthra-9,10-chinone-2,3-bis(oxamate) (, 2,3-acboH2Et2). The crystal structures of and have been determined, verifying that the transition metal ions are eta4(kappa2N,kappa2O) coordinated by the [2,3-acbo]4- ligands. Using the asymmetric diethyl N,N'-anthra-9,10-chinone-1,2-bis(oxamate) (, 1,2-acboH2Et2) leads, under otherwise identical reaction conditions, to the novel bis(oxamato) complex [(n)Bu4N]2[Ni(1,2-acbo)] () whereby in the case of Cu(II) the derivate [nBu4N]2[Cu(aibo)2] () (aibo=anthra[1,2-d]-(imidazole-2-carboxylato)-6,11-dione) has been obtained. The crystal structures of and have been determined, displaying that the Ni(II) ion of is eta4(kappa2N,kappa2O) coordinated by the [1,2-acbo]4- ligand. The Cu(II) ion of is coordinated by two [aibo]2- ligands, giving rise to an approximately square-planar trans-bis(aibo-N,O) arrangement. Using the symmetric diethyl N,N'-4,5-dinitro-o-phenylene-bis(oxamate) (, niboH2Et2), possessing strongly electron withdrawing NO2-groups, leads under otherwise identical reaction conditions to the bis(oxamato) complex [nBu4N]2[Ni(nibo)] (), whereby in the case of Cu(II) the derivate [nBu4N]2[Cu(niqo)2] () (niqo=7,8-dinitro-2,3-quinoxalinedionato) has been obtained. The crystal structures of and have been determined, ensuring that the Ni(II) ion of is eta(4)(kappa2N,kappa2O) coordinated by the [nibo]4- ligand. The Cu(II) ion of is coordinated by four oxygen atoms of two [niqo]2- ligands, giving rise to an approximately square-planar coordination geometry.     

Specificity of the cyclization of 1-alkyl(aryl)sulfonylamino-9,10-anthraquinones into naphtho[1,2,3-cd]indol-6(2H)-ones

Cyclization of N-(9,10-dioxo-9,10-dihydroanthracen-1-yl)methanesulfonamides to 2,6-dihydronaphtho[1,2,3-cd]indol-6-ones in DMSO-KOH involves intermediate formation of 2,3-dihydroanthra[1,9-cd]-[1λ⁶,2]thiazin-7-one 2,2-dioxides, whereas heterocyclization of N-(9,10-dioxo-9,10-dihydroanthracen-1-yl)-ethane- and -arenesulfonamides under analogous conditions occurs with participation of methylsulfonylmethanide.     

An efficient de novo synthesis of partially reduced phenanthrenes through C-C insertion

An efficient and novel approach to the synthesis of highly congested 3-alkyl-, 4-alkyl-, 3-aryl-, 3,4-dialkyl-, 4-alkyl-3-aryl-, and 3,4-diaryl-9,10-dihydro-1-sec-aminophenanthrene-2-carbonitriles has been delineated through the base-catalyzed ring transformation of 5,6-dihydro-2-oxo-4-sec-amino-2H-benzo[h]chromene-3-carbonitrile by carbanion derived in situ from various ketones in moderate to good yields. 9,10-Dihydrophenanthrenes with and without substituent in the bay region are efficiently and regioselectively synthesized by using propanal and acetyltrimethylsilane as a source of carbanion. Even the synthesis of bisphenanthrenes has been achieved by the ring transformation of 5,6-dihydro-2-oxo-4-sec-amino-2H-benzo[h]chromene-3-carbonitrile by 2-acetylphenanthrene in moderate yield. Highly substituted 3-amino-1-sec-amino-5,6-dihydrophenanthrene-2,4-dicarbonitriles have also been prepared from the reaction of 2-oxobenzo[h]chromene and malononitrile.     

A (pi-extended tetrathiafulvalene)-fluorene conjugate. Unusual electrochemistry and charge transfer properties: the first observation of a covalent D(2+)-sigma-A(.-) redox state(1)

The synthesis of novel electrochemically amphoteric TTFAQ-sigma-A compounds (TTFAQ = 9,10-bis(1,3-dithiol-2-ylidene)-9,10-dihydroanthracene, sigma = saturated spacer, A = polynitrofluorene acceptor) is reported. Their solution redox behavior is characterized by three single-electron reduction and one two-electron oxidation waves. Electrochemical quasireversibility of the TTFAQ(2+) state and a low E(ox) - E(red) gap ( approximately 0.25 V) for 3-(9-dicyanomethylene-4,5,7-trinitrofluorene-2-sulfonyl)-propionic acid 2-[10-(4,5-dimethyl-[1,3]dithiol-2-ylidene)-9,10-dihydroanthracen-9-ylidene]-5-methyl-[1,3]dithiol-4-ylmethyl ester (10) has enabled the electrochemical generation of the hitherto unknown transient D(2+)-sigma-A(.-) state as observed in cyclic voltammetry and time-resolved spectroelectrochemistry. The ground state of compound 10 was shown to be ionic in the solid but is essentially neutral in solution (according to electron paramagnetic resonance). The X-ray structure of an intermolecular 1:2 complex between 2-[2,7-bis(2-hydroxyethoxy)-9,10-bis(4,5-dimethyl-[1,3]dithiol-2-ylidene)-9,10-dihydroanthracene and 2,5,7-trinitro-4-bromo-9-dicyanomethylenefluorene, 14.(17)(2), reveals, for the first time, full electron transfer in a fluorene charge-transfer complex.     

Efficient and simple colorimetric fluoride ion sensor based on receptors having urea and thiourea binding sites

[structure: see text] Novel colorimetric receptors for selective fluoride ion sensing containing anthraquinone as chromogenic signaling subunit and urea (N,N' '-(9,10-dihydro-9,10-dioxo-1,2-anthracenediyl)bis[N'-phenyl])/thiourea (N,N' '-(9,10-dihydro-9,10-dihydro-9,10-dioxo-1,2-antrhacenediyl)bis[N-phenyl]) binding sites have been reported. These receptors have shown no affinity for other halide ions (Cl-, Br-, and I- ions). Well-defined color change in the visible region of the spectrum was observed upon addition of fluoride ion in DMSO/CH3CN solution of the receptors 1 and 2.