[Show abstract][Hide abstract] ABSTRACT: In the crystal structure of the title compound, [Sn(C(44)H(28)N(4))(CH(3)O(3)S)(2)]·3CHCl(3), the Sn(IV) ion is located on an inversion center and is octa-hedrally coordinated. The porphyrin N atoms occupy the equatorial positions while the axial positions are occupied by the O atoms of the methane-sulfonate anions. The phenyl rings make dihedral angles of 77.02 (13) and 87.89 (14)° with the porphyrin ring. Of the three solvent chloro-form mol-ecules, one is disordered over a twofold rotation axis. In the crystal a three-dimensional assembly is accomplished via C-H⋯O hydrogen bonds between the H atoms of the phenyl groups in the porphyrin ring and the O atoms of the methane-sulfonate ligands.
[Show abstract][Hide abstract] ABSTRACT: In the title compound, C(31)H(34)N(2)O(4), the two pyrrole rings are bent around the central methyl-ene C atom, making a dihedral angle of 64.83 (7)°. In the crystal, mol-ecules are linked into dimers via N-H⋯O=C hydrogen bonds. These dimers are packed through π⋯π inter-actions between neighboring pyrrole rings with a separation between the mean planes of symmetry-related pyrrole rings of 3.61 (2) Å and a centroid-centroid distance of 4.33 Å. Parallel phenyl groups in neighboring dimers also exhibit efficient π⋯π inter-actions, characterized by an inter-plane separation of 3.378 (8) Å and a centroid-centroid distance of 3.97 Å.
[Show abstract][Hide abstract] ABSTRACT: ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
[Show abstract][Hide abstract] ABSTRACT: In the centrosymmetric title compound, C(64)H(62)N(4), the two phenyl-ethynyl groups lie at diagonal meso positions. The 24-membered porphyrin has in-plane distortion with respect to the mean plane of the macrocycle and two intra-ring bifurcated N-H⋯(N,N) hydrogen bonds occur. The dihedral angles between the phenyl rings in the phenyl-ethynyl group and the 3,5-bis-(tert-but-yl)phenyl group with respect to the mean plane of the porphyrin are 17.2 (2) and 59.2 (3)°. The tert-butyl groups are disordered over two sets of sites in a 0.661 (13):0.339 (13) ratio.
[Show abstract][Hide abstract] ABSTRACT: Photochromic fluorophore Sn(TTP)(DTE)2 , in which two phenolic derivatives of 1,2-dithienylethene are axially coordinated to (5,10,15,20-tetratolylporphyrinato)tin(IV) in trans position, has been synthesized and fully characterized by various spectroscopic methods. We have also investigated the photoregulated fluorescence switching behavior of Sn(TTP)(DTE)2 . The fluorescence of the porphyrin macrocycle in Sn(TTP)(DTE) 2 greatly depends on the state of the 1,2-dithienyletene photochromic switch. In the open state (Sn(TTP)(o-DTE)2), the porphyrin exhibits high fluorescence intensity at 609 and 664 nm when excited at 410 nm. When the photocyclization reaction was carried out by irradiating Sn(TTP)(o-DTE)2 with the UV light (approximately 365 nm), the fluorescence intensity of the porphyrin macrocycle decreased. Back irradiation with visible light at wavelengths greater than 500 nm regenerated Sn(TTP)(o-DTE)2 and almost restored the original fluorescence spectrum. The fluorescence intensity of the porphyrin fluorophore is efficiently regulated by photochromic switching between Sn(TTP)(o-DTE)2 and Sn(TTP)(c-DTE)2 in several cycles, clearly demonstrating that the Sn(TTP)(DTE)2 can act as a system for reversible data processing using fluorescence as the detection method.
[Show abstract][Hide abstract] ABSTRACT: We report octupolar trisporphyrin conjugates, derived from the symmetrical functionalization of a triphenylamine core with three ethynylporphyrin wings, exhibiting largely enhanced two-photon absorption (TPA) compared to the porphyrin monomers. Octupolar trisporphyrin conjugate tris-H2P was synthesized by the Pd(0)-catalyzed Sonogashira cross-coupling reaction of tris(4-iodophenyl)amine with 5,10,15-tri-(p-tolyl)-20-ethynylporphyrin, and fully characterized by various spectroscopic methods and elemental analysis. The optimized geometry of tris-H2P obtained by semi-empirical AM1 calculations reveals that tris-H2P adopts a propeller-shaped structure. Our photophysical studies strongly manifest that the trisporphyrin conjugates are promising octupolar fluorophores with effective π-conjugation over the porphyrin wings through the octupolar core. The trisporphyrin conjugates exhibit much larger TPA cross-section values in comparison with the monomers; the TPA cross-section σ(2) value of tris-ZnP (11,800 GM) exceeds that of mono-ZnP (630 GM) by about 20 times.Graphical abstract
[Show abstract][Hide abstract] ABSTRACT: The reversible formation of cucurbituril (CB)-stabilized charge-transfer (CT) complex on gold, which can be regulated by electrochemical stimuli, is reported. A viologen-based thread molecule with a thiol terminus was designed to synthesise a stable CB-threaded pseudorotaxane (5 ). A mixed self-assembled monolayer (SAM) of 5 and 3-mercaptopropionic acid (3-MPA) on gold was prepared and characterised by reflectance FT-IR spectroscopy. The formation and disruption of a CT complex on surface was investigated by cyclic voltammetry with the SAM on gold as a working electrode in a supporting electrolyte solution containing 2,6-dihydroxynaphthalene (DHNp). The cathodic peak was shifted to a more negative potential (ΔE∼40 mV) when compared with that measured without DHNp in the electrolyte, which confirmed the formation of a CT complex on gold upon immersion of the SAM of 5 on gold in the supporting electrolyte containing DHNp. When the viologen unit was reduced, the CT complex was destroyed and the electron-rich guest molecule was released. Upon reoxidation of the reduced viologen unit, however, the CT complex was slowly reformed.
[Show abstract][Hide abstract] ABSTRACT: Photophysical properties of a newly-synthesized porphyrin derivative, trans-bis(ferrocene carboxylato)-
(5,10,15,20-tetraphenylporphyrinato)tin(IV) [Sn(TPP)(FcCOO)2] were investigated by means of steady-state
and fs-time resolved laser spectroscopic techniques, and compared with those of a standard molecule, transdichloro(
5,10,15,20-tetraphenyl-porphrinato)tin(IV) [Sn(TPP)Cl2]. The fluorescence spectrum of Sn(TPP)-
(FcCOO)2 was observed to exhibit dual emission bands originating from the S2-state and the S1-state, which
was greatly quenched as compared to those of Sn(TPP)Cl2. The fs-time resolved fluorescence and transient
absorption spectroscopic measurements revealed that the fluorescence quenching is due to formation of the
long-lived charge transfer state by intramolecular electron transfer from ferrocene to the S2-excited SnTPP in
addition to the enhanced non-radiative deactivation processes.
Bulletin- Korean Chemical Society 11/2007; 28(11):1967-72. · 0.84 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: trans-Bis(ferrocenecarboxylato)(5,10,15,20-tetraphenylporphyrinato)tin(IV) complex Sn(TPP)(FcCOO)2 has been synthesized and fully characterized. The X-ray structural analysis of Sn(TPP)(FcCOO)2 reveals that the tin(IV) center is octahedrally coordinated by the porphyrin occupying the square base and axial coordination of two ferrocenecarboxylato ligands in an anti orientation with respect to each other. The Fe(II) center of the ferrocenecarboxylato ligand lies 5.7Å from the tin(IV) center of the porphyrin ring. The cyclic voltammogram of Sn(TPP)(FcCOO)2 exhibits three distinctive redox couples consisting of one oxidative wave and two reductive waves due to the ferrocenecarboxylato ligands and the porphyrin ring, respectively.
[Show abstract][Hide abstract] ABSTRACT: A new class of nanostructures were fabricated by one-step hydrothermal reaction of a mixture solution
of TiO2 anatase powder and a Sn-porphyrin, trans-dihydroxo[5,10,15,20-tetrakis(p-tolyl)porphyrinato]-
tin(IV) [SnTTP], and they were found to be well-crystalline trititanate (H2Ti3O7)-type multilayered
nanofibers (TiNFs) intercalated by SnTTP which have lengths in the range of 0.5-1 ím with an average
diameter of approximately 50 nm. Based on the femtosecond-diffuse reflectance transient absorption
and photoluminescence spectroscopic measurements, the SnTTP-intercalated TiNFs were observed to
exhibit efficient optoelectronic properties such as photoinduced electron transfer from deep surface states
of trititanate layer to SnTTP, forming an anion radical SnTTP.¥- rapidly in a few picoseconds. These
results infer that electrons and holes are effectively separated in the SnTTP-TiNFs upon illumination,
and consequently remarkable UV-visible light-sensitive photocatalytic activities as compared to those
of free TiNFs and SnTTP, suggesting that the SnTTP-intercalated TiNFs have potential application in
development of efficient artificial photosynthetic systems and photoelectronic materials.
Chemistry of Materials 06/2007; 19:1984. · 8.54 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Angewandte Chemie International Edition 02/2007; 46(1-2):210-3. · 11.34 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: A novel thermochromic organic compound, 1,5-bis(hydroxyethylamino)-2,4-dinitrobenzene (BDB), was synthesized and characterized using X-ray diffraction, differential scanning calorimetry, visible and infrared spectroscopy. It was observed that BDB exists in two different crystal structures of A- and B-forms at room temperature. In each crystal structure, there exist intra- and intermolecular hydrogen bonds between hydroxy, amino, and nitro groups. As the temperature is increased, the color of BDB crystalline powder changes from yellow to orange. The yellow color was recovered for a specific period of time when it is cooled again, indicating that thermochromism of BDB in the solid state is reversible. Both crystals of A- and B-forms are transformed to the C-form crystal at the transition temperature. From the results of X-ray diffraction, thermal data, and infrared spectra, it is suggested that the thermochromism of BDB originates from the crystal-to-crystal transition accompanying with the configurational transformation between nitro-form and acid-form via intramolecular hydrogen transfer.
Journal of Molecular Structure 12/2006; 825(1):70-78. · 1.60 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The conformational (cis and trans) stability and electronic structures of (C(60)CHCOO)(2)-Sn(IV) porphyrin, recently synthesized as a novel fullerene-porphyrin-fullerene triad linked by metal axial coordination, have been studied by ab initio calculations. The cis conformer was found to be slightly more stable than the trans by 1.38 kcal/mol in the neutral compound. Upon the addition of an electron to the triad, the relative stability of the cis conformer was found to be higher (3.29 kcal/mol) than that in the neutral one. From the investigation of frontier molecular orbitals, for the cis conformer, it was found that the electrons are localized in HOMO of the porphyrin, while the electrons are localized in LUMO of the syn-fullerene. For the trans conformer, it was found that the electrons are localized in HOMO of the porphyrin, while the electrons are localized in LUMO of one of the two fullerene moieties, and the electrons are localized in LUMO2 of the other fullerene moiety, but the LUMO and LUMO2 have the same orbital energy. Thus, the PET may take place unidirectionally in the cis conformer from the porphyrin to the syn-fullerene, while it is bidirectional from the porphyrin to both of the fullerene moieties.
The Journal of Physical Chemistry B 04/2006; 110(11):5337-42. · 3.38 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Thread-in-hole complexation of cucurbituril (CB) with spermidine and spermine either enhances or reduces the activity of the polyamine on the enzymatic reactions of DNA.
Chemical Communications 04/2005; · 6.72 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The supramolecular assembly of tin(IV) porphyrin equipped with six pyridyl groups, trans-diisonicotinate[meso-tetrakis(4-pyridyl)porphyrinato]tin(IV), generates a uniform channel lined with the pyridyl groups, in which the lattice water molecules are ordered into a single-file chain by hydrogen bonding between neighboring water molecules along the chain as well as hydrogen bonding between water molecules and the pyridyl lining of the channel.
[Show abstract][Hide abstract] ABSTRACT: A novel fullerene-porphyrin-fullerene triad linked by the axial coordination of tin(IV) porphyrin is reported, exhibiting strong pi-pi interactions between the tin porphyrin and fullerene moieties owing to their close proximity.
Chemical Communications 12/2004; · 6.72 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: trans-Dihydroxo[5,10,15,20-tetrakis(n-pyridyl)porphyrinato]tin(IV) (n = 3 and 4) complexes have been synthesized and fully characterized. X-ray structural analysis of trans-dihydroxo[5,10,15,20-tetrakis(4-pyridyl)porphyrinato]tin(IV) reveals that the supramolecular hydrogen bondings between the hydroxotin(IV) porphyrins and lattice water molecules form a hydrogen-bonded two-dimensional network. The hydrogen bonding mode between the tin(IV) porphyrins and the water molecules closely resembles that of the hydrogenbonded outer-sphere intermediate in the acidolysis of dihydroxotin(IV) porphyrins.
Bulletin- Korean Chemical Society 01/2004; 25(12). · 0.84 Impact Factor