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Synthetic, structural, photophysical, and electrochemical study of [Ir(ppy)2(py)2](BF4) (1(BF4)) and four di‐N–N‐bridged complexes of [Ir(ppy)2(bpa)]2(BF4)2 (2A(BF4)2), [Ir(ppy)2((cis‐bpe))]2(BF4)2 (2B(BF4)2), [Ir(ppy)2(tmp)]2(BF4)2 (2C(BF4)2), and [Ir(ppy)2(bpy)]4(BF4)4 (3(BF4)4) are described with Hppy = 2‐phenylpyridine, py = pyridine, N–N = dipyridyl ligands of 1,2‐bis(4‐pyridyl)ethane (bpa), cis‐1,2‐bis(4‐pyridyl)ethylene (cis‐bpe), 1,3‐di(4‐pyridyl)propane (tmp), and 4,4'‐dipyridine (bpy). Five single‐crystal structures of 1(PF6), 2A(NO3)2, 2A(PF6)2, 2B(PF6)2, and 3(NO3)4 were determined, supporting the dibridged structures and presence of a variety of stereoisomers. Application of four luminescent complexes, 1(BF4), 2A(BF4)2, 2C(BF4)2, and 3(BF4)4, in solid‐state light‐emitting electrochemical cells (LECs) is reported. The work demonstrates an effective approach to realize efficient LECs based on dibridged di‐ and multinuclear cationic transition‐metal complexes with a suitably long alkyl spacer in the bridging ligand. [ABSTRACT FROM AUTHOR]

Abstract: Series of neutral and ionic non-conjugated metal-containing copolymers are readily prepared via the free-radical copolymerization of benzyl methacrylate (BzMA) with two phosphorescent Ir(III) complexes, [Ir(ppy)2(AIm)Cl](1) and [Ir(ppy)2(AIm)2]PF6 (2PF6), respectively. The copolymers are soluble in polar organic solvents, easily forming a film on glass, aluminum foil or plastic materials. The neutral copolymers have weight-average molecular weights (Mw) of ca. 30,000–60,000g/mol. Although the thermal stabilities of the neutral and ionic copolymers both increase with increasing amount of Ir(III) complex, the ionic copolymers are more thermally stable than their neutral analogs. With a suitable amount of Ir(III)-complex content, the neutral non-conjugated copolymerization between the Ir complex and BzMA can induce a blue shift in the max value of copolymer relative to that observed for complex 1. For the neutral and ionic copolymers, the observed max value in the film are red-shifted to those observed in solution. [Copyright &y& Elsevier]

The organic salts 1-(2-pyridylmethyl)-3-alkylbenzimidazolium halide (pm- RbH+X−) and 1-(2-pyridylmethyl)-3-alkylimidazolium halide (pm-R′ iH+X′−) were prepared (where R = 4-, 3-, 2-fluorobenzyl ( 4f, 3f, and 2f, respectively), 4-, 3-, 2-chlorobenzyl ( 4c, 3c, and 2c, respectively); 4-methoxybenzyl (4mo); 2,3,4,5,6-pentafluorobenzyl (f5); benzyl (b); and methyl (m)); X = Cl and Br; R′ = benzyl (b) and methyl (m); and X′ = Cl and I. From these salts, heteroleptic Ir( III) complexes containing one N-heterocyclic carbene ( NHC) ligand [Ir(κ2-ppy)2(κ2-(pm-Rb))] PF6 (R = 4f, 1( PF6); 3f, 2( PF6); 2f, 3( PF6); f5b, 4( PF6); 4c, 5( PF6); 3c, 6( PF6); 2c, 7( PF6); 4mo, 8( PF6); b, 9( PF6); m, 10( PF6)) and [Ir(κ2-ppy)2(κ2-(pm-R′i))] PF6 (R = b, 11( PF6); m, 12( PF6)), were synthesized, and the crystal structures of 1( PF6), 2( PF6), 3( PF6), 5( PF6), 6( PF6), 7( PF6), 9( PF6), 10( PF6), and 12( PF6) were determined by X-ray diffraction. The neutral NHC ligands 1-(2-pyridylmethyl)-3-alkylbenzimidazolin-2-ylidene (pm-Rb) and 1-(2-pyridylmethyl)-3-alkylimidazolin-2-ylidene (pm-R′i) of all cations were found to be involved in the intermolecular π−π stacking interactions with the surrounding cations in the solid state, thereby probably influencing the photophysical behavior in the solid state and in solution. The absorption and emission properties of all the complexes show only small variations. [ABSTRACT FROM AUTHOR]

Abstract: Treatment of cis-[Ir(η2-ppy)2(MeCN)2]NO3 (1, ppy=2-phenylpyridine) with isonicotinaldehyde, ethyl isonicotinate, and 4-aminopyridine afforded cis-[Ir(η2-ppy)2L2]NO3 (L=4-pyCHO (2), 4-pyCOOEt (3), 4-pyNH2 (4)). The photophysical properties of these complexes were determined. Complex 4 is a good light-emitting chemical sensor toward silver trifluoromethanesulfonate in methanol. Crystal structures of 2 and 3 as well as that of the adduct, formed between 4 and AgNO3, have been characterized by X-ray diffraction. [Copyright &y& Elsevier]

Abstract: Heating of [Ir(η2-ppy)2(MeCN)2]NO3 (1, ppy=2-phenylpyridine) in MeCN under reflux afforded [Ir(η2-ppy)2(η2-NO3)] (2). Treatment of 1 with 2-mercaptopyridine (Hmp), 6-methyl-2-hydroxypyridine (Hmhp), 6-chloro-2-hydroxypyridine (Hchp), trimethylacetic acid (Htma), benzoic acid (Hbz), 2-methylacrylic acid (Hma), and acetic acid (Hac) in the presence of excess Et3N produced [Ir(η2-ppy)2(η2-XZY)] (XZY− =mp− (3), mhp− (4), chp− (5), ac− (6), bz− (7), ma− (8), tma− (9)). Crystal structures of 2, 3, 7, 8, and 9 have been characterized by X-ray diffraction. The inherent strain contained in the four-member rings, {Ir(η2-XZY)}, is apparently reflected in the long Ir–X and Ir–Y distances. The absorption and emission properties of nearly all the new complexes except 2 show small variations. [Copyright &y& Elsevier]