- Synthesis, characterisation, electrochemistry and Ion-Binding studies of ruthenium (II) and rhenium(I) bipyridine/Crown ether receptor molecules
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A number of molecular receptors containing a ruthenium(II)/ rhenium(I) bipyridine moiety as fluorophore and a crown ether, connected to the 4,4'-positions of the bipyridine/phenanthroline unit through >C=0 and -HC=N- spacers, as ionophore have been synthesised and characterised. The luminescence and electrochemical properties of these receptors have been studied. The cation-binding properties of these molecules have been investigated with the cations Na+, K+,Rb2+, Mg2+, Ca 2+, Zn2+, Cd2+, Hg2+, Pb 2+and Cu2+ and the recognition event monitored by H NMR spectroscopy, luminescence, the oxidation potential of the metal ion and UV7 Vis absorption studies. The emission intensities of complexes 1 3 are strongly quenched by the addition of Pb2+, Cu2+,Hg2+ and Na2+, whereas a significant enhancement of the emission intensities is observed for 4 in the presence of Cu2+ and Hg2+ and for 5 in the presence of Cd2+and Hg2+ Luminescence titrations for 1-5 with the above-mentioned metal ions have been carried out. The binding constants (Ks) and stoichiometry of the complexes have been calculated from titration data, with values of Ks ranging from 9.97 × 103 to 1.28 × 102 M-1 in the decreasing order Pb2+ > Na+ > Cu2+ > Hg2+ > Cd2-. The stoichiometries found for 1-3 and 5 are in the range 1.85-2.09 and for 4 0.99-1.04. A1H NMR spectroscopic study with selected metal ions exhibits significant spectral changes for the protons attached to the crown moiety; a few significant changes are also noted in the aromatic region. Among the ions studied, the highest change is observed with Na+and Pb2+, whereas K+ does not show any significant change. The electrochemical study exhibits a significant cathodic shift: of the oxidation potentials of the RuII centre in the presence of Na+ and Pb2+, thereby indicating complexation of these ions with the crown moiety. The electronic spectra, however, do not show significant spectral changes with various metal ions except for that: of the Re1 complex 6, which exhibits some change upon addition of Na+. The results obtained are presented and discussed in light of selectivity and intramolecular energy-transfer.
- Borieha, Vinod P.,Patra, Subrata,Chouhan, Yogendra S.,Sanavada, Pankaj,Suresh,Paul, Parimal
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- Shape-Memory Platinum(II) Complexes: Intelligent Vapor-History Sensor with ON-OFF Switching Function
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A novel platinum(II)-diimine complex, [Pt(CN)2(H2dcphen)] (1; H2dcphen=4,7-dicarboxy-1,10- phenanthroline), was synthesized and its vapochromic shape-memory behavior was evaluated. The as-synthesized amorphous purple solid, [Pt(CN)2(H2dcphen)]·2 H2O (1 P), exhibited vapochromic behavior in the presence of alcoholic vapors through transformation to a red, crystalline, porous, vapor-adsorbed form, 1 R?vapor. The obtained 1 R?vapor complex released the adsorbed vapors upon heating without collapse of the porous structure. The vaporfree, porous 1 R?open could detect water or n-hexane vapor, although these vapors could not induce 1 P-to-1 R?vapor transformation, and 1 R?open could easily be converted to the initial 1 P by manual grinding. These results indicate that 1 is a new shape-memory material that functions through formation and collapse of the porous framework with an emission change upon vapor-adsorption and grinding; this enables it to exhibit vapor history and ON-OFF switching sensing functions.
- Shigeta, Yasuhiro,Kobayashi, Atsushi,Ohba, Tadashi,Yoshida, Masaki,Matsumoto, Takeshi,Chang, Ho-Chol,Kato, Masako
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- Selenous Acid in an Aromatic Framework: Insights Into a Temperature-Sensitive Internal Redox System from the Solid State
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We report on a new compound composed of a phenanthroline network in which emerging channels are alternately occupied by selenous acid (H2SeO3) and dioxane molecules. The material undergoes a variety of structural changes due to both its redox activity as well as its thermal decomposition. We investigate an internal redox system of the incorporated selenous acid and the aldehyde groups of the phenanthroline framework. The reduction process of the selenium species was further elucidated by cyclic voltammetry, while the oxidation process was also monitored by1H NMR spectra. The thermal behavior reveals that the material can undergo a reversible, topotactic transition due to dioxane and water (de)intercalation.
- Straub, Laura C.,Wickleder, Mathias S.,Rasche, Bertold
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p. 3641 - 3648
(2022/03/03)
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- Surface immobilized copper(i) diimine photosensitizers as molecular probes for elucidating the effects of confinement at interfaces for solar energy conversion
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Heteroleptic copper(i) bis(phenanthroline) complexes with surface anchoring carboxylate groups have been synthesized and immobilized on nanoporous metal oxide substrates. The species investigated are responsive to the external environment and this work provides a new strategy to control charge transfer processes for efficient solar energy conversion.
- Eberhart, Michael S.,Phelan, Brian T.,Niklas, Jens,Sprague-Klein, Emily A.,Kaphan, David M.,Gosztola, David J.,Chen, Lin X.,Tiede, David M.,Poluektov, Oleg G.,Mulfort, Karen L.
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p. 12130 - 12133
(2020/10/21)
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- A new efficient photosensitizer for nanocrystalline solar cells: Synthesis and characterization of m-bis(4,7-dicarboxy-l,10phenanthroline)dithiocyanato ruthenium(n)
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The complexes [NBu4]2-n[a.y-Ru(H2-xdcphen)2X 2 (n = 0 or 1; H2dcphen; =4,7-dicarboxy-l,10-phenanthroline; X = Cl, CN or SCN) were synthesized and spectroscopically characterized as a new class of photosensitizers. The energy levels of the LUMO and HOMO of ra-[Ru(H2dcphen)2(NCS)2] were estimated to be -1.02 and 0.89 V (vs. SCE), respectively, slightly more positive than those of [NBu4]2n[m-Ru(H2-xdcbpy)2(NCS) 2] (x = 0 or 1 ; H2dcbpy = 4,4'-dicarboxy-2,2'-bipyridine). A more intense and broader MLCT absorption of [NBu4]2[raeRu(H2-xdcphen)2(NCS)2] (;; = 0 or 1 ) than that of [NBu4]2-x[rae-Ru(H1-xdcbpy) 2(NCS)2] (;; = 0 or 1) was observed in ethanol solution at around 525 nm in the visible region. It is demonstrated that the new complexes act as efficient light harvesting antennae for dye-sensitized solar cells. A [NBu4]2-x[cw-Ru(Hdcphen)2(NCS)2] sensitized nanocrystalline TiO2 film shows a remarkable solar light to electrical power conversion efficiency of 6.1% at 100mWcm-2of AM 1.5. The Royal Society of Chemistry 2000.
- Yanagida, Masatoshi
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p. 2817 - 2822
(2007/10/03)
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- Diporphyrinyl Derivatives of 1,10-Phenanthroline and 2,2'-Bipyridyl
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The title derivatives were synthesized containing two meso-tri-p-tolylphenyleneporphyrin units attached via amide bridges to 4,7- and 4,4' positions of the respective heteroatomatic spacers.
- Kus, Piotr,Knerr, Gary,Czuchajowski, Leszek
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