Cyclometalated platinum(II) diimine complexes: synthetically tuning the photophysical and electrochemical properties

Presented is the synthesis of an array of 16 heteroleptic phosphorescent diimine complexes of platinum(II) with electronically diverse ligand spheres and their full spectroscopic, photophysical, and electrochemical characterization. The complexes were found to exhibit luminescence (480-500 nm) in deaerated solutions at room temperature from a long-lived (3)LC state (τ = 2-3 μs) that exhibits significant metal character perturbed by a low-lying (1)MLCT state. Interestingly, emission from a (3)MLCT state was not observed as is the case with many other polypyridine-based d-block complexes. Electrochemical intermediates proved stable as multiple reversible reductions between -1 and -2 V vs. SCE were noted during cyclic voltammetry experiments unveiling the potential of these luminophores for use in a variety of optoelectronic and solar energy conversion applications.     

Zn(II)-containing metallo-supramolecular polymers: synthesis,photophysical and electrochemical properties

Abstract

Two novel building blocks M1, M2 with different electronic structures, were synthesized based on 2,2′:6′,2″-terpyridine modified with cyano-p-phenylenevinylene (CN-PV) and carbazole moieties through Knoevenagel condensation and Suzuki coupling, respectively. Directed by transition metal ion Zn²⁺, the metallo-homopolymers P1, P2 and metallo-copolymer P3 were obtained via self-assembly polymerization. The structures of the monomers and metallo-supramolecular polymers were fully characterized by MS, ¹H-NMR and ¹³C-NMR. Meanwhile, the UV–vis absorption, photoluminescence (PL) and electrochemical properties of these compounds were systematically investigated. With respect to that of the monomers, both the UV–vis absorption and PL spectra of the polymers are significantly red-shifted. The resulting metallo-supramolecular polymers show similar double absorption peaks (342, 418?nm for P1, 339, 410?nm for P2, and 332, 412?nm for P3), which is caused by the π–π* transition and intramolecular charge transfer (ICT). Further, all the polymers display red-orange emission in toluene and narrow electrochemical energy gaps of 1.46, 1.65 and 1.48?eV for P1, P2, and P3, respectively.     

Synthesis,photophysical, and electrochemical properties of wide band gap tetraphenylsilane-carbazole derivatives: Effect of the substitution position and naphthalene side chain

Four tetraphenylsilane-carbazole derivatives with wide bandgaps (3.38–3.55 eV) were synthesized. The effects of the substitution position and of the presence of naphthalene groups on the photophysical, electrochemical and thermal properties were investigated. The derivatives exhibited maximum absorption peaks ranging from 293 to 304 nm and maximum emission peaks ranging from 347 to 386 nm. Changing the carbazole substitution position on the tetraphenylsilane did not significantly change the photophysical and electrochemical properties. However, p-substituted compounds exhibited higher glass transition temperatures than m-substituted compounds. Naphthalene groups with bulky structures had extended the conjugation lengths that red-shifted both the absorption and emission spectra. The LUMO level was decreased, which reduced the optical bandgap and triplet energy level. However, the naphthalene groups significantly improved the thermal stability by increasing the glass transition temperature of the compounds.     

Electron impact induced fragmentation of ( p-substituted phenyl)-(4'-methylphenacyl) sulfones: contribution of sulfinate ester rearrangements

The molecular ions of the title compounds are usually very unstable. The main fragmentation corresponds to the formation of p-MeC(6)H(4)CO(+) as would be expected. Another abundant fragment ion was [M - SO(2)](+) which is formed both from the original sulfone and from the rearranged sulfinate esters. There are, however, three primary ions which can be traced back to each isomeric molecular ion: p-RC(6)H(4)SO(2)(+) to the original sulfone, p-RC(6)H(4)SO(+) to the.CH(2)S(=O)O-. type sulfinate ester and p-RC(6)H(4)OH(+.) to the.CH(2)OS(=O). type sulfinate ester of which the latter seems by far to dominate. Copyright 2000 John Wiley & Sons, Ltd.     

Ring-opening polymerization of 1-(p-substituted phenyl)-2-vinylcyclopropanes by Ziegler–Natta catalysts

1-(p-Substituted phenyl)-2-vinylcyclopropanes such as 1-phenyl-2-vinylcyclopropane (I_a), 1-(p-chlorophenyl)-2-vinylcyclopropane (I_b), 1-(p-anisyl)-2-vinylcyclopropane (I_c), and 1-(p-tolyl)-2-vinylcyclopropane (I_d) were prepared and polymerized radically, cationically and with Ziegler–Natta catalysts. I_a and I_b polymerized exclusively in 1,5-fashion with radical initiators. However, I_c and I_d polymerized in 1,5-fashion only with Ziegler–Natta catalysts. All polymers were soluble in ordinary organic solvent and solution-cast films were clear and flexible, showing T_g values in the range of 39–71°C. Spectral data indicated that the double bonds of the polymer chains were in trans form in all cases. The difference between the polymerizabilities of different monomers are interpreted in terms of electronic properties of substituents.     

Dinuclear ReI complex based on 1,2,4,5-tetrakis(diphenylphosphino)- pyridine: synthesis and luminescence properties

The reaction of 1,2,4,5-tetrakis(diphenylphosphino)pyridine (L) with Re(CO)₅Br (in a molar ratio of 1:2) leads to the bis-chelated complex [Re₂(CO)₆(L)Br₂] in 95% yield. At ambient temperature, the solid complex exhibits green phosphorescence (λ_max = 535 nm) with a quantum yield of 12% and a lifetime of 90 μs.     

Effect of aza substitution on the formation of anhydro bases of quinolylindoles

The reaction of quaternary salts of 3-(2-quinoxalinyl) indoles with hydroxylamine was investigated. It was established that the presence of a second pyridine nitrogen atom in the ring increases the positive -electron charge on the nitrogen atom of the quinoxaline ring and, as a consequence of this, markedly increases the contribution of dealkylation.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1365–1368, October, 1980.     

Di(alkoxy)- and di(alkylthio)-substituted perylene-3,4;9,10-tetracarboxy diimides with tunable electrochemical and photophysical properties

Nucleophilic substitution of N,N'-dicyclohexyl-1,7-dibromoperylene-3,4:9,10-tetracarboxydiimide (PTCDI) with an excess of corresponding alkanol in the presence of sodium hydride or anhydrous potassium carbonate at 85-100 degrees C provided both di(alkoxy)- and mono(alkoxy)-substituted PTCDI compounds, namely, N,N'-dicyclohexyl-1,7-di(alkoxy)perylene-3,4:9,10-tetracarboxydiimide (3) and N,N'-dicyclohexyl-1-bromo-7-alkoxyperylene-3,4:9,10-tetracarboxydiimide (2). Starting from mono(alkoxy)-substituted PTCDI, nucleophilic substitution with thiol, thiophenol, or alkylamine led to the formation of unsymmetrical 1,7-di(substituted) PTCDI compounds (7-10). For the purpose of comparative studies, symmetrical di(substituted) N,N'-dicyclohexyl-1,7-di(alkylthio)perylene-3,4:9,10-tetracarboxydiimide (4), N,N'-dicyclohexyl-1,7-di(thiophenyl)perylene-3,4:9,10-tetracarboxydiimide (5), and N,N'-dicyclohexyl-1,7-di(alkylamine)perylene-3,4:9,10-tetracarboxydiimide (6) have also been prepared by a similar nucleophilic substitution. These newly prepared PTCDI compounds have been characterized by a wide range of spectroscopic methods in addition to elemental analysis. Electronic absorption and fluorescence studies revealed that the absorption and emission bands as well as the fluorescence quantum yield can be tuned continuously over a large range by incorporating substituents with different electron-donating abilities.     

New members of the [Ru(diimine)(CN)(4)](2-) family: structural, electrochemical and photophysical properties

A series of complexes of the type K(2)[Ru(NN)(CN)(4)] has been prepared, in which NN is a diimine ligand, and were investigated for both their structural and photophysical properties. The ligands used (and the abbreviations for the resulting complexes) are 3-(2-pyridyl)pyrazole (Ru-pypz), 2,2'-bipyrimidine (Ru-bpym), 5,5'-dimethyl-2,2'-bipyridine (Ru-dmb), 1-ethyl-2-(2-pyridyl)benzimidazole (Ru-pbe), bidentate 2,2':6',2'-terpyridine (Ru-tpy). The known complexes with = 2,2'-bipyridine (Ru-bpy) and 1,10-phenathroline (Ru-phen) were also included in this work. A series of crystallographic studies showed that the [Ru(NN)(CN)(4)](2-) complex anions form a range of elaborate coordination networks when crystallised with either K(+) or Ln(3+) cations. The K(+) salts are characterised by a combination of near-linear Ru-CN-K bridges, with the cyanides coordinating to K(+) in the usual 'end-on' mode, and unusual side-on pi-type coordination of cyanide ligands to K(+) ions. With Ln(3+) cations in contrast only Ru-CN-Ln near-linear bridges occurred, affording 1-dimensional helical or diamondoid chains, and 2-dimensional sheets constituted from linked metallamacrocyclic rings. All of the K(2)[Ru(CN)(4)] complexes show a reversible Ru(II)/Ru(III) couple (ca.+0.9 V vs. Ag/AgCl in water), the exception being Ru-tpy whose oxidation is completely irreversible. Luminescence studies in water showed the presence of (3)MLCT-based emission in all cases apart from Ru-bpym with lifetimes of tens/hundreds of nanoseconds. Time-resolved infrared studies showed that in the (3)MLCT excited state the principal C-N stretching vibration shifts to positive energy by ca. 50 cm(-1) as a consequence of the transient oxidation of the metal centre to Ru(III) and the reduction in back-bonding to the cyanide ligands; measurement of transient decay rates allowed measurements of (3)MLCT lifetimes for those complexes which could not be characterised by luminescence spectroscopy. A few complexes were also examined in different solvents (MeCN, dmf) and showed much weaker emission and shorter excited-state lifetimes in these solvents compared to water.     

3-芳亚甲基联氨羰基-5-(对位取代苯基)-吡唑衍生物的 合成、结构和生物活性

以4-取代苯乙酮及草酸二乙酯为起始原料, 设计合成了20个新的3-芳亚甲基联氨羰基-5-(对位取代苯基)-吡唑衍生物, 产率较高. 所合成的化合物经元素分析, IR, 1H NMR对其结构进行了表征, 化合物4b, 4h还通过X-ray单晶衍射进一步确证了其结构. 初步生物活性实验结果表明, 所合成的化合物对绿豆发芽过程有着较好的生长调节作用.     

Synthesis,structures and photophysical properties of (o-carboranyl)-(pyridyl)methanols

The reaction of o-carboranyllithium with two equiv. of 2-pyridinecarboxaldehyde affords 1-[(hydroxy)(pyridyl)methyl]-o-carborane (1) and 1,2-bis[(hydroxy)(pyridyl)methyl]-o-carborane (2), which have been characterized by IR and NMR spectroscopy, mass spectrometry and single-crystal X-ray diffraction. Compound 2 exhibits interesting polymorphism (monoclinic 2a and triclinic 2b). The solid state structures of the new carboranes feature intermolecular and intramolecular hydrogen bonding interactions involving all the N and O atoms, leading to one dimensional (1, 2b) or two-dimensional (2a) supramolecular structures. The photoluminescence of 1 and 2b was investigated in the solid and solution states at room temperature, respectively.     

Semiconducting 2,6,9,10-tetrakis(phenylethynyl)anthracene derivatives: effect of substitution positions on molecular energies

2,6-Bis((4-hexylphenyl)ethynyl)-9,10-bis(phenylethynyl)anthracene, 4, and 9,10-bis((4-hexylphenyl)ethynyl)-2,6-bis (phenyl ethynyl)anthracene, 5, have been synthesized to study their electronic and photophysical properties. It should be noted that the difference between these compounds is the substitution position of 1-ethynyl-4-hexylbenzene groups into an anthracene ring. In particular, substitution in the 9,10-positions of the anthracene ring enhanced J-aggregated intermolecular interactions. Since 5 has a lower bandgap energy and more compact film morphology, it exhibited higher hole mobility (～0.27 cm(2) V(-1) s(-1)) in thin-film transistor devices.     

Synthesis and acid-base and complex-forming properties of 1,4,7,10-tetrakis(dihydroxyphosphorylmethyl)-1,4,7,10-tetraazacyclododecane

Conclusions A new complexone, 1,4,7,10-tetrakis(dihydroxyphosphorylmethyl)-1,4,7,10-tetraazacyclododecane, has been synthesized and its acid-base and complex-forming properties have been studied. It shows a very high complexing capability and marked selectivity for cations of large ionic radius (Cd²⁺, Hg²⁺, Pb²⁺, La³⁺).Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 844–849, April, 1984.     

Aryl-diamide bridged binuclear ruthenium (II) tris(bipyridine) complexes: Synthesis, photophysical, electrochemical and electrochemiluminescence properties

Several new symmetrical aromatic hydrocarbon bridged bipyridine ligands and their binuclear Ru (II) complexes have been designed, synthesized and characterized on the basis of ¹H NMR, MS and HRMS. Their absorption and emission properties, electrochemical behaviors and electrochemical luminescence were investigated. All ruthenium complexes show characteristic MLCT absorption and similar redox potential. Among the three complexes reported, 4c has the best electrochemical luminescence property.     

Halogen atom effect on photophysical and photodynamic characteristics of derivatives of 5,10,15,20-tetrakis(3-hydroxyphenyl)porphyrin

Brominated and iodinated derivatives of 5,10,15,20-tetrakis(3-hydroxyphenyl)porphyrin were synthesised directly from the corresponding aldehydes. Photophysical and photochemical properties, singlet oxygen formation quantum yields, photobleaching and log P were measured. Cellular uptake measurements and cytotoxicity assays on WiDr and A375 tumour cell lines were performed. 5,10,15,20-Tetrakis(2-bromo-5-hydroxyphenyl)porphyrin showed the best cytotoxicity with values of IC(50) of 113 nM over WiDr cells and 52nM over A375 cells.     

1,6- and 1,7-regioisomers of dinitro- and diamino-substituted perylene bisimides: synthesis,photophysical and electrochemical properties

1,6- and 1,7-regioisomers of dinitro- (1,6-3 and 1,7-3) and diamino-substituted perylene bisimides (1,6-1 and 1,7-1) were synthesized. The regioisomers 1,6-3 and 1,7-3 were successfully separated by high performance liquid chromatography and characterized by 500 MHz ¹H NMR spectroscopy. Subsequently, the reduction of 1,6-3 and 1,7-3 afforded the corresponding diaminoperylene bisimides 1,6-1 and 1,7-1, respectively. This is the first time 1,6-regioisomers of dinitro- and diamino-substituted perylene bisimides are obtained in pure form. The photophysical and electrochemical properties of 1,6-3 and 1,7-3 were found to be almost the same. However, the regioisomers 1,6-1 and 1,7-1 exhibit significant differences in their optical characteristics. The absorption spectrum of 1,6-1 covers a larger part of the visible region compared to that of 1,7-1. Upon excitation, 1,6-1 also show larger dipole moment change than that of 1,7-1. Time-dependent density functional theory calculations are reported on these dyes in order to rationalize their electronic structure and absorption spectra.