The first molecular capsule based on an [Ir(ppy)(2)](+) unit (ppy = 2-phenylatopyridine) has been prepared. Following the development of a method to resolve rac-[(Ir(ppy)(2)Cl)(2)] into its enantiopure forms, homochiral Ir(6)L(4) octahedra where obtained with the tritopic 1,3,5-tricyanobenzene. Solution studies and X-ray diffraction show that these capsules encapsulate four of the six associated counteranions and that these can be exchanged for other anionic guests. Initial photophysical studies have shown that an ensemble of weakly coordinating ligands can lead to luminescence not present in comparable mononuclear systems.

This paper describes the synthesis of a new, yellow triphenylamine dye, 4-[2-(4-diphenylaminophenyl) vinyl]benzoic acid] (6), with a sorption maximum at 380 nm in solution for which EQE data show shifts to 420 nm on sorption to TiO 2 . The performance of this dye has been measured in dye-sensitized solar cell (DSC) devices, showing h ¼ 2.6% for 1 cm 2 devices. Light soaking of (6) shows excellent long-term stability with <10% variation in device performance over 1800 h. Full characterization data are reported for ( 6) and the intermediates used in its synthesis including single-crystal X-ray structural analysis of all compounds. The paper also describes the ultra-fast dye sensitization and co-sensitization of TiO 2 photo-electrodes in 5 minutes using one or two dyes and the first example of ultra-fast tri-sensitization. The dyes tested include the ruthenium dye N719, the squaraine dye SQ1, the red triphenylamine dye 2-cyano-3-{4-[2-(4-diphenylaminophenyl)vinyl]phenyl}acrylic acid ( 5) and ( 6). DSC efficiencies of 7.5% have been achieved for 1 cm 2 devices co-sensitized using (6) and N719. These efficiencies exceed those recorded for single dye devices and EQE measurements confirm efficient photon capture from two or more dyes in a single photo-electrode. Photo-acoustic calorimetry (PAC) has also been used to measure the energy of the charge separation states formed for (6) and N719, showing a larger value (1.47 eV) for (6) compared to N719 (1.08 eV), whilst a TiO 2 film co-sensitized with both (6) and N719 gave an intermediate value (1.28 eV). These data have been used to calculate dye HOMO, LUMO and l max levels for (6) and N719 leading to important insights for future successful co-sensitization.

D,L-Norleucine (2-aminohexanoic acid), C 6 H 13 NO 2 , has been the subject of many structural, spectroscopic, and thermoanalytical investigations 1 in the last half century as a result of its remarkable thermal behavior. In fact, D,L-norleucine is used as a reference system for thermal behavior in molecular organic materials, such as pharmaceuticals, and more recently has been a test case for the modeling of concerted phase transitions at the molecular level. 2,3 The interest has centered around the singlecrystal to single-crystal transitions and structures for a low temperature β-form, and a room temperature R-form, which can be found in the Cambridge Structural Database (DLNLUA, DLNUA01, DLNLUA02). [4][5][6] The existence of a high temperature γ-form, based on postulation from Weissenberg photographs, was proposed as long ago as 1953 4 and observed in Laue diffraction patterns 5 over a decade ago, but the structure has remained elusive. Recent work aimed at modeling the high temperature phase transition has also resulted in a prediction of the high temperature form. 2,3,7 Clearly, knowledge of the true high temperature form would enable the most accurate modeling of the transition, and this communication now reports the new experimentally determined single crystal structure of this γ-form.The transition temperature between the low and room temperature forms has not previously been reported. We have found that both the transition temperature and the transition behavior are extraordinarily variable. We have also confirmed the welldefined reversible single-crystal to single-crystal (R to γ) transition at 390-391 K, which is indefinitely repeatable, with a very narrow hysteresis. The range normally observable by differential scanning calorimetry (DSC), variable temperature vibrational spectroscopy, or X-ray diffraction is of the order of a few degrees. The range observable by very slow heating and cooling under a hotstage microscope is only 0.6 K, but the absolute temperatures vary by a few tenths of a degree between crystals, or between parts of the same crystal. We have now succeeded in solving this structure and examining the relationship of all the forms. A single crystal of the R-form was mounted on the diffractometer at room temperature and then subjected to a preliminary analysis of its thermal behavior by systematically raising the temperature and checking the unit cell parameters. A change in unit cell dimensions (full cell data are deposited as Supporting Information), indicating a phase transition and retention of crystalline structure, was observed at 390 K, showing precise agreement with hot stage microscopy results 8 (Figure 1) and also those from DSC 9 (Figure 2). As observed by Anwar 5 and Mnyunkh, 7 the high temperature phase transition causes crystal cracking; however, the degree of cracking can be reduced by slowing down the heating rate.For reliability of comparison, new structures of the βand Rforms were redetermined 10 close to the phase transition (at 198 and 385 K) and are also included a...

This paper reports the synthesis of a series of new half-squaraine dyes (Hf-SQ) based around a common chromophoric unit but with differently positioned linker groups.