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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 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]