- Multifunctional Cationic Iridium(III) Complexes Bearing 2-Aryloxazolo[4,5-f][1,10]phenanthroline (N^N) Ligand: Synthesis, Crystal Structure, Photophysics, Mechanochromic/Vapochromic Effects, and Reverse Saturable Absorption
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A series of 2-aryloxazolo[4,5-f][1,10]phenanthroline ligands (N^N ligands) and their cationic iridium(III) complexes (1-11, aryl = 4-NO2-phenyl (1), 4-Br-phenyl (2), Ph (3), 4-NPh2-phenyl (4), 4-NH2-phenyl (5), pyridin-4-yl (6), naphthalen-1-yl (7), naphthalen-2-yl (8), phenanthren-9-yl (9), anthracen-9-yl (10), and pyren-1-yl (11)) were synthesized and characterized. By introducing different electron-donating or electron-withdrawing substituents at the 4-position of the 2-phenyl ring (1-5), or different aromatic substituents with varied degrees of conjugation (6-11) on oxazolo[4,5-f][1,10]phenanthroline ligand, we aim to understand the effects of terminal substituents at the N^N ligands on the photophysics of cationic Ir(III) complexes using both spectroscopic methods and quantum chemistry calculations. Complexes with the 4-R-phenyl substituents adopted an almost coplanar structure with the oxazolo[4,5-f][1,10]phenanthroline motif, while the polycyclic aryl substituents (except for naphthalen-2-yl) were twisted away from the oxazolo[4,5-f][1,10]phenanthroline motif. All complexes possessed strong absorption bands below 350 nm that emanated from the ligand-localized 11ILCT (intraligand charge transfer) transitions, mixed with 1LLCT (ligand-to-ligand charge transfer)/1MLCT (metal-to-ligand charge transfer) transitions. At the range of 350-570 nm, all complexes exhibited moderately strong 1ILCT/1LLCT/1MLCT transitions at 350 450 nm, and broad but very weak 3LLCT/3MLCT absorption at 450 570 nm. Most of the complexes demonstrated moderate to strong room temperature phosphorescence both in solution and in the solid state. Among them, complex 7 also manifested a drastic mechanochromic and vapochromic luminescence effect. Except for complexes 1 and 4 that contain NO2 or NPh2 substituent at the phenyl ring, respectively, all other complexes exhibited moderate to strong triplet excited-state absorption in the spectral region of 440-750 nm. Moderate to very strong reverse saturable absorption (RSA) of these complexes appeared at 532 nm for 4.1 ns laser pulses. The RSA strength followed the trend of 7 > 11 > 9 > 3 > 2 4 > 5 10 6 8 > 1. The photophysical studies revealed that the different 2-aryl substituents on the oxazole ring impacted the singlet and triplet excited-state characteristics dramatically, which in turn notably influenced the RSA of these complexes.
- Zhu, Xiaolin,Cui, Peng,Kilina, Svetlana,Sun, Wenfang
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- Design, synthesis and antitumour evaluation of pyrrolo[1,2-f]-phenanthridine and dibenzo[f,h]pyrrolo[1,2-b]isoquinoline derivatives
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A series of 1,2-bis(hydroxymethyl)pyrrolo[1,2-f]phenanthridine derivatives and their alkyl (ethyl and isopropyl) carbamates and 12,13-bis(hydroxymethyl)-9,14-dihydro-dibenzo[f,h]pyrrolo[1,2-b]isoquinoline derivatives were synthesized for antiproliferative evaluation. The preliminary antitumour studies revealed that these two types of bis(hydroxymethyl) derivatives showed significant antitumour activities and were able to inhibit the growth of various human tumour cell lines in vitro. Several of the derivatives were demonstrated to cause DNA interstrand cross-links by an alkaline agarose gel shifting assay. These conjugates were cytotoxic to a variety of cancer cell lines by inducing DNA damage, delaying cell cycle progression in the G2/M phase and triggering apoptosis. Compound 21a, dissolved in a vehicle suitable for intravenous administration, was selected for antitumour studies in animal models. We demonstrated that at a dose that did not cause body weight loss in mice, compound 21a could significantly suppress the growth of tumour xenografts of human lung cancer H460 and colorectal cancer HCT-116 cells in nude mice. Our present results confirm the antitumour activities of these conjugates.
- Jain, Vicky,Lai, Kuo-Chu,Lee, Te-Chang,Lin, Yi-Wen,Patel, Anilkumar S.,Rao, Vaikar Navakanth,Shah, Anamik,Su, Tsann-Long
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- Systematic investigations on fused π-system compounds of seven benzene rings prepared by photocyclization of diphenanthrylethenes
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We studied the photoproducts of 1-(n-phenanthryl)-2-(m-phenanthryl)ethenes (nEm; n, m = 1, 3 and 9) for understanding photocyclization patterns based on NMR spectroscopy. The crystal structures of the photoproducts were analyzed by X-ray crystallography, and the photophysical features of the photocyclized molecules were investigated based on emission and transient absorption measurements. Phenanthrene derivatives substituted at the 1- and 3-positions were prepared for synthesizing nEm by photocyclization of stilbene derivatives. We obtained four types of primary photoproducts (n@m) from the corresponding nEm. Two of them were found to have racemic molecular structures in the single crystal determined by X-ray crystallography. Besides the primary photoproducts, two types of secondary photoproducts (n@mPP) were isolated. Fluorescence quantum yields and lifetimes of the obtained photoproducts were determined in solution whereas the definite fluorescence quantum yields were obtained in the powder. Observation of the triplet-triplet absorption spectra in solution by laser photolysis techniques showed that intersystem crossing to the triplet state competes with the fluorescence process.
- Fujino, Shota,Yamaji, Minoru,Okamoto, Hideki,Mutai, Toshiki,Yoshikawa, Isao,Houjou, Hirohiko,Tani, Fumito
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p. 925 - 934
(2017/07/10)
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- Construction of polyaromatics via photocyclization of 2-(fur-3-yl) ethenylarenes, using a 3-furyl group as an isopropenyl equivalent synthon
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The construction of different types of substituted arenes was demonstrated through the photocyclization of 2-(fur-3-yl)ethenylarenes using a 3-furyl group as an isopropenyl equivalent synthon in the photocyclization reaction. The furan portion of the photocyclization intermediate could be fragmented via a base-induced elimination reaction to yield a series of substituted polyaromatics, including naphthalene, benzofuran, benzothiophene, phenanthrene, phenalene, acenaphthene, and triphenylene. Using different reagents, this method made it possible to introduce methyl or 2-hydroxyethyl groups as substituents at specific positions in these arenes.
- Chen, Ying-Zhe,Ni, Ching-Wen,Teng, Fu-Lin,Ding, Yi-Shun,Lee, Tunng-Hsien,Ho, Jinn-Hsuan
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p. 1748 - 1762
(2014/03/21)
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- Macroscopic self-assembly based on molecular recognition: Effect of linkage between aromatics and the polyacrylamide gel scaffold, amide versus ester
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The interactions of polyacrylamide- (pAAm-) based gels possessing cyclodextrin (CD) residues (CD-gels) with pAAm-based gels modified with aromatic residues through amide and ester linkages (ArA-gels and ArE-gels, respectively) were investigated to examine the effect of linkage (i.e., amide and ester) between aromatic residues and the pAAm gel scaffold. In the present study, benzyl (Bz), 2-naphthylmethyl (Np), 9-phenanthrylmethyl (Ph), and 1-pyrenylmethyl (Py) residues were chosen as a series of aromatic residues. αCD-gel did not interact notably with the ArA-gels and ArE-gels in water. βCD-gel interacted with the ArA-gels and ArE-gels possessing smaller aromatic residues (i.e., Bz and Np residues) in water to form gel assemblies. γCD-gel showed different tendencies of its interactions with the ArA-gels and with the ArE-gels; γCD-gel interacted with the ArA-gels carrying larger aromatic residues (i.e., Ph and Py residues), while γCD-gel formed stable gel assemblies only with NpE-gel among the ArE-gels examined. This is because γCD residues in γCD-gel included favorably dimeric aromatic residues in the ArA-gels and ArE-gels. Reflection fluorescence spectra for the ArA-gels and ArE-gels possessing fluorescent aromatic residues (i.e., Np, Ph, and Py residues) in the presence of 10 mM γCD were indicative of weak selectivities of γCD toward NpE, PhA, and PyA residues. Such weak selectivities may be largely enhanced in the macroscopic observation of interaction of CD-gels with the ArA-gels and ArE-gels presumably because of multivalency.
- Hashidzume, Akihito,Zheng, Yongtai,Takashima, Yoshinori,Yamaguchi, Hiroyasu,Harada, Akira
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p. 1939 - 1947
(2013/04/24)
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- Triphenylene-Benzofuran/Benzothiophene/Benzoselenophene Compounds With Substituents Joining To Form Fused Rings
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Compounds comprising a triphenylene moiety and a benzo- or dibenzo-moiety are provided. In particular, the benzo- or dibenzo-moiety has a fused substituent. These compounds may be used in organic light emitting devices, particularly in combination with yellow, orange and red emitters, to provide devices with improved properties.
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- A New General Synthesis of Polycyclic Aromatic Compounds Based on Enamine Chemistry
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Alkylation of enamines and enamine salts by benzylic and (β-haloethyl)aryl halides, respectively, followed by acidic cyclodehydration and dehydrogenation provides an efficient synthetic approach to a wide range of polycyclic aromatic compounds of diverse structural types.Specific polycyclic hydrocarbons synthesized by this route include benzo- and benzofluorene, 7H-dibenzo-, 13H-dibenzo-, and 13H-dibenzofluorene, 15H-tribenzofluorene, dibenzochrysene, benzopentaphene, indenofluorene, fluorenofluorene, octahydrodibenzanthracene, dibenzanthracene, octahydrodibenzanthracene, dibenzanthracene, picene, benzopicene, 1H-benzaceanthrylene, and 4H-cyclopentachrysene.This method with appropriate modifications appears to be potentially broader in scope than established traditional methods of polycyclic hydrocarbon synthesis.
- Harvey, Ronald G.,Pataki, John,Cortez, Cecilia,Raddo, Pasquale Di,Yang, ChengXi
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p. 1210 - 1217
(2007/10/02)
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- Preparation and Chemical Behaviour of exo-Methylene Compounds: Isoelectronic Compounds of 5-Methylenecyclohexa-1,3-diene
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Some exo-methylene compounds such as 9-methylene-9,10-dihydrophenanthrene(2) were photolytically prepared and their chemical behaviour was investigated.Treatment of (2) with acid (CF3CO2H) or base (OBut(1-)) led to the formation of 9-methylphenanthrene, with bromine to 9-bromomethylphenanthrene.Reaction with dimethyl acetylenedicarboxylate did not give Diels-Alder adduct but give an ene adduct.Treatment with ethenetetracarbonitrile also gave an ene adduct.Reaction with carbene or carbenoids gave 9,10-dihydrophenanthrene-9-spirocyclopropanes.Reaction with ethenetetracarbonitrile was examined for other exo-methylene compounds, 1-methylene-1,2-dihydronaphtalene and 2-methylene-2,3-dihydrobenzothiophene.The aromatisation may be responsible for the reactions of these exo-methylene compounds except for the reaction with carbenes.
- Sugimoto, Akira,Yamano, Junzo,Yasueda, Masahiro,Yoneda, Shigeo
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p. 2579 - 2584
(2007/10/02)
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- The Synthesis of Polycyclic Thiophenes Derived From Phenanthrene Intermediates
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The synthesis of benzotriphenylenothiophene (9), benzotriphenylenothiophene (13), 5-methylbenzanthrathiophene (17), 1-methylchrysenothiophene (18), triphenylenodibenzothiophene (22), triphenylenodibenzothiophene (26), triphenylenodibenzothiophene (29), and triphenylenodibenzothiophene (30) is described.
- Baldwin, Larry J.,Tedjamulia, Marvin L.,Stuart, John G.,Castle, Raymond N.,Lee, Milton L.
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p. 1775 - 1779
(2007/10/02)
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- Studies in the Cycloproparene Series: Halogenation and Dehydrohalogenation of Some 1a,9b-Dihydrocyclopropaphenanthrenes
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Dehydrohalogenation of (1α,1aβ,9aβ)-1-chloro-1a,9b-dihydrocyclopropaphenanthrene (4b) yields products by way of the corresponding dibenzobicyclohepta-2,4,6-triene (5b) whilst under solvolytic conditions the 7-t-butoxydibenzocyclohepta-1,3,5-triene (11b) is formed by cyclopropyl-allyl ring expansion.When subjected to bromination the cyclopropaphenanthrenes (4a,c) yield halophenanthrenes (14a) and (15c) by cleavage of an external bond of the cyclopropane ring.
- Halton, Brian,Officer, David L.
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p. 1167 - 1175
(2007/10/02)
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