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To construct novel ion receptors and D-A self-assembly systems for materials with better functions, the annulation of a tetrathiafulvalene donor with a magnesium norphthalocyanine core via a flexible tetrathiacrown ether bridge afforded a new triad 1. The structure of this product was characterized by 1H NMR and infrared spectroscopy, time-of-flight mass spectrometry, and elemental analysis. The optical and electrochemical properties were investigated using UV–vis spectroscopy and cyclic voltammetry. The complex of triad 1 and 2,3,5,6- tetrafluoro-7,7,8,8-tetracyanoquinodimethane produced electron transfer with a radical cationic character, as confirmed by UV–Vis and electron paramagnetic resonance analysis. Furthermore, the target compound presented evident intramolecular charge-transfer interactions in ground states, which were explained using density functional theory. Furthermore, norphthalocyanine 1 was able to coordinate Ag+ through the peripheral ligating oxathiaether crown. [ABSTRACT FROM AUTHOR]

A novel magnesium-base and metal-free norphthalocyanine ( 6 and 7 ) containing peripheral thiacrown ether-linked tetrathiafulvalene moieties have been synthesized and fully characterized. Electrochemical investigations showed two quasi-reversible one-electron oxidation waves, one irreversible one-electron oxidation wave and two irreversible one-electron reduction waves, indicating that these triads are good π-electron donors. Triad 6 reacted with 2,3,5,6-tetrafluoro-7,7,8,8-tetra-cyanoquinodimethane (F 4 TCNQ) to form a charge transfer complex that exhibited absorption bands in the vicinity of 750 and 960 nm. Compound 6 showed evident intramolecular charge transfer interactions in ground states and these may be explained on the basis of the density functional theory. [ABSTRACT FROM AUTHOR]

Abstract: We have reported a theoretical analysis of a series of heteroleptic iridium(III) complexes (mpmi)2Ir(pybi) [mpmi=1-(4-tolyl)-3-methyl-imidazole, pybi=2-(pyridin-2-yl)-benzo[d]imidazole] (1a), (fpmi)2Ir(pybi) [fpmi=1-(4-fluoro-phenyl)-3-methyl-imidazole] (1b), (tfpmi)2Ir(pybi) [tfpmi=1-methyl-3-(4-trifluoromethyl-phenyl)-imidazole] (1c), (pypmi)2Ir(pybi) [pypmi=3-(3-methyl-imidazol)-pyrazole] (2a), (phpymi)2Ir(pybi) [phpymi=3-(3-methyl-imidazol)-5-phenyl-pyrazole] (2b), and (inpymi)2Ir(pybi) [inpymi=3-(3-methyl-imidazol)-indeno[1,2-c]pyrazole] (2c) by using the density functional theory (DFT) method to investigate their electronic structures and photophysical properties and obtain further insights into the phosphorescent efficiency mechanism. By changing cyclometalated ligands, the conjugation length, and substituents of the cyclometalated ligands, one can tune the emission color from green (λ em=520nm) to orange (λ em=592nm). Complexes 1a, 1b, 2a, and 2b have the almost identical emission wavelength about 550nm, while 592nm for 1c and 520nm for 2c are red shifted and blue shifted, respectively, relative to 1a. The calculated results indicate that, for 1b and 1c, the substituents of −F and −CF3 at the phenyl moiety cause a poor hole-injection ability compared with that of 1a. For all these complexes studied, the hole-transporting performances are better than the electron-transporting ones. The difference between reorganization energies for hole transport (λ ih) and reorganization energies for electron transport (λ ie) for complex 1c are relatively smaller, indicating that the hole and electron transfer balance could be achieved more easily in the emitting layer. The alteration of cyclometalated ligands with different conjugation lengths and substituents has an impact on the optoelectronic properties of these complexes. It is believed that the larger metal to ligand charge transfer (MLCT) character, the highest and values, and the smallest value could result in the larger phosphorescent quantum efficiency for 2c than other complexes. [Copyright &y& Elsevier]

A series of ethylenedithiotetrathiafulvalene (EDT-TTF) compounds with cyanobiphenyl moieties attached with different length alkyl chains has been designed and synthesized. The phase behavior of these derivatives was investigated by a combination of polarizing optical microscopy, differential scanning calorimetry, and X-ray diffraction. Among the derivatives, the derivatives with spacer group lengths of n = 6–12 (3b–3d) show a distinct glassy transition during the heating and cooling processes, and 3c (n = 8) and 3d (n = 12) show liquid crystal (LC) phases below the isotropic temperature. An electrochemical study shows that the longer the spacer group, the more readily the target compound is oxidized. Density functional theory calculations show that the LC molecules are typical donor–σ-bridge–acceptor molecules. [ABSTRACT FROM AUTHOR]

Theelectronic structures and phosphorescent properties of a seriesof heteroleptic iridium(III) complexes (mpmi)2Ir(dmpypz)(1; mpmi = 1-(4-tolyl)-3-methylimidazolium, dmpypz =3,5-dimethyl-2-(pyrazol-3-yl)pyridine), (bpmi)2Ir(dmpypz)(2; bpmi = 1-biphenyl-4-yl-3-methylimidazole), (dfmi)2Ir(dmpypz) (3; dfmi = 1-(2,6-difluorobiphenyl)-3-methylimidazole),(mtmi)2Ir(dmpypz) (4; mtmi = 1-methyl-3-(4′-(trifluoromethyl)biphenyl-4-yl)imidazole),(fmmi)2Ir(dmpypz) (5; fmmi = 1-(fluoren-2-yl)-3-methylimidazole),and (mhmi)2Ir(dmpypz) (6; mhmi = 1-methyl-3-phenanthren-2-ylimidazole)have been investigated by using density functional theory (DFT) andtime-dependent density functional theory (TDDFT) methods. The influenceof different substituent groups and π-conjugation degrees onthe optical and electronic properties of Ir(III) complexes was alsoexplored by introducing phenyl, fluorophenyl, (trifluoromethyl)phenyl,and rigid construction on the phenylimidazole moiety of a cyclometalatedligand (C∧C) in complex 1. The calculatedresults show that the lowest energy absorption wavelengths of complexes 1–6are 387, 380, 378, 375, 391, and 384nm, respectively. The introduction of different substituent groupsleads to different degrees of red shift for complexes 2–6in emission spectra in comparison with thatof complex 1. It is believed that the highest tripletmetal to ligand charge transfer 3MLCT (%) contribution,smallest ΔES1–T1and higher μS1values,and larger 3MC–3MLCT energy gap for 3ensure its higher quantum yield in comparison with thatof other complexes. [ABSTRACT FROM AUTHOR]

A novel highly conjugated donor–acceptor dyad composed of a tetrathiafulvalene (TTF) moiety covalently attached to a magnesium norphthalocyanine (NPc) unit (1) has been synthesized and full characterized. Ultraviolet–visible spectroscopy and electron paramagnetic resonance data reveal that 1 forms an electron transfer complex with 2,3,5,6-tetrafluoro-7,7,8,8-tetra-cyanoquinodimethane (F 4 TCNQ). Detailed electrochemical investigations show one irreversible one-electron oxidation wave, two quasi-reversible one-electron oxidation waves, and two irreversible one-electron reduction waves, indicating that 1 is a good π-electron donor. Compound 1 shows clear intramolecular charge transfer (ICT) interactions from the tetrathiafulvalene fragments to the norphthalocyanine core. This phenomenon can be explained by density functional theory (DFT). A novel highly conjugated donor–acceptor dyad with tetrathiafulvalene (TTF) covalently attached to a magnesium norphthalocyanine (NPc) unit was synthesized. Image 1 • A novel highly conjugated donor–acceptor dyad was synthesized. • The electrochemical and optical properties of 1 are fully studied. • The results demonstrate that 1 is a good π-electron donor which has clear intramolecular charge transfer (ICT) interactions in molecule. [ABSTRACT FROM AUTHOR]