60]fullerene-stoppered porphyrinorotaxanes: pronounced elongation of charge-separated-state lifetimes

A series of Sauvage-type porphyrinorotaxanes containing [60]fullerene stoppers have been synthesized by a convergent route. Photoinduced energy transfer and electron-transfer reactions in these rotaxanes yield long-distance charge-separated radical-pair states, whose lifetimes in solution at ambient temperatures are as high as 32 mus, depending on the distance between the fullerene and zinc porphyrin chromophores.     

Metal coordination to the formal P=N bond of an iminophosphorane and charge-density evidence against hypervalent phosphorus(V)

The iminophosphorane Ph(2)P(CH(2)Py)(NSiMe(3)) (1) was treated with deprotonating alkali metal reagents to give [(Et(2)O)Li[Ph(2)P(CHPy)(NSiMe(3))]] (2), [[Ph(2)P(CH(2)Py)(NSiMe(3))]Li[Ph(2)P(CHPy)(NSiMe(3))]] (3) and [[Ph(2)P(CH(2)Py)(NSiMe(3))]Na[Ph(2)P(CHPy)(NSiMe(3))]] (4). We report their coordination behaviour in solid-state structures and NMR spectroscopic features in solution. Furthermore, we furnish experimental evidence against hypervalency of the phosphorus atom in iminophosphoranes from experimental charge-density studies and subsequent topological analysis. The topological properties, correlated to the results from NMR spectroscopic investigations, illustrate that the formal P=N double bond is better written as a polar P(+)--N(-) single bond. Additionally, the effects of metal coordination on the bonding parameters of the iminophosphorane and the related anion are discussed.     

Multicomponent redox gradients on photoactive electrode surfaces

Redox gradients have been used to tailor the arrangement of photoactive ITO-electrodes at the molecular level.     

Selective synthesis of U-shaped terpyridines. Versatile ligands for the preparation of platinum complexes

The development of a simple and highly selective method for the preparation of substituted U-shaped terpyridines is described. The treatment of imine 5 with ternary iminium salts 2 leads to the terpyridines 4. A possible mechanism is discussed. The terpyridine derivatives are used for the preparation of several platinum(II) complexes 14. Complex 14e is characterized by single-crystal X-ray analysis.     

Convergent synthesis and photophysics of [60]fullerene/porphyrin-based rotaxanes

A series of Sauvage-type rotaxanes containing [60]fullerene and tetraarylporphyrin moieties has been synthesized by a convergent route. Photoinduced energy-transfer and electron-transfer reactions in these rotaxanes yield long-lived change-separated states, in agreement with the large distance between the fullerene and porphyrin chromophores.     

Capillary electrochromatography of peptides and proteins

This review surveys the accomplishments in the separation of peptides and proteins by capillary electrochromatography (CEC) over the last decade. A significant number of research articles have been published on this topic since the last review. Peptide and proteins separations have been carried out in all three formats of CEC, i.e., packed bed, continuous bed and open-tubular (OT) format. In addition to electrophoresis, different chromatographic modes have been successfully exploited with the most prevalent being reversed-phase mode followed by ion-exchange. Although many researchers continue to use model proteins and peptides primarily to evaluate the performance of novel stationary phases some researchers have also applied CEC to the analysis of real-life samples. The potential of CEC to yield complementary information and sometimes a superior separation with respect to established techniques, i.e., microbore HPLC and capillary electrophoresis has been demonstrated. Instrumental modifications in order to facilitate coupling of CEC to mass spectrometry have further upgraded the value of CEC for proteomic analysis. Capillaries are still the separation vehicle of choice for most researchers yet the microfluidic platform is gaining momentum, propelled particularly by its potential for multitasking, e.g., performing different chromatographic modes in series.