다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

The molecular exciton model has received its most extensive development and application in the field of molecular crystals1'2. More recently, numerous applications to non-crystalline molecular composite systems have been made, including van der Waals and hydrogen-bonded dimers, trimers, and higher order aggregates. Another type of composite system has also been investigated, namely the composite molecule consisting of covalently bonded molecular units, with intrinsic individual unsaturated electronic systems so isolated by single bonds that but little or insignificant electronic overlap between units may occur. It is now well established that in molecular aggregates and in composite molecules, exciton effects may be observed if sufficiently strong electronic transitions exist in the component sub-units. The result of exciton splitting of excited states in the composite molecule may be the appearance of strong spectral shifts or splittings (which may be of the order of 2000 cm—1) of the absorption bands for the component molecules. At the same time, as a consequence of the exciton splitting of the excited state manifold, an enhancement of triplet state excitation may result. The purpose of this paper is to present a summary of the various type cases for molecular dimers, trimers and double and triple molecules in the description of the molecular exciton strong-coupling model. Then it will be shown by new experimental examples that, even in those cases where no significant exciton effect is observable in the singlet—singlet absorption spectrum for the composite molecule (intermediate and weak coupling cases), the enhancement of lowest triplet state excitation may still be conspicuous and significant. The ideas which are summarized in this paper have a curious history. Long ago, Kautsky and Merkel3 demonstrated experimentally that aggregation of dyes facilitated their action as photophysical sensitizers in photochemical reactions, at the same time diminishing their fluorescence efficiency. Kautsky attributed these easily demonstrated effects to enhancement of metastable state excitation in the aggregate dye. There is no doubt today that the metastable state he described is the lowest triplet state of the molecules studied. However, he did not distinguish between intrinsic and enhanced metastable (triplet) state excitation, so his interpretations were largely overlooked. Forster in l946 used the quasi-classical vector model to

/pdf/the-exciton-model-in-molecular-spectroscopy-2vwkowivjh.pdf

The exciton model in molecular spectroscopy

Over the last decade, substantial research has led to the introduction of an impressive number of efficient procedures which allow the selective construction of CC bonds by directly connecting two different CH bonds under oxidative conditions. Common to these methodologies is the generation of the reactive intermediates in situ by activation of both CH bonds. This strategy was introduced by the group of Li as cross-dehydrogenative coupling (CDC) and discloses waste-minimized synthetic alternatives to classic coupling procedures which rely on the use of prefunctionalized starting materials. This Review highlights the recent progress in the field of cross-dehydrogenative C sp 3C formations and provides a comprehensive overview on existing procedures and employed methodologies.

The Cross-Dehydrogenative Coupling of C sp 3H Bonds: A Versatile Strategy for CC Bond Formations

Iron Catalysis in Organic Synthesis

Perylene Bisimide Dye Assemblies as Archetype Functional Supramolecular Materials

5,10-Bis(pentafluorophenyl)corrole (5) and 5,15-bis(pentafluorophenyl)corrole (9) have been synthesized as meso-free corroles by rational synthetic routes. Both the structures of these corroles have been unambiguously revealed by X-ray diffraction analysis and their optical and electrochemical properties have been studied. Chlorination and oxidative dimerization of 5 and 9 have been explored, which revealed a marked different reactivity of the free meso-positions in 5 and 9. 10-Chlorinated corrole 11 was effectively prepared by the reaction of 9 with Palau‘chlor in the presence of 1 % pyridine whereas 5-chlorinated corrole 12 was obtained in a trace amount from similar chlorination of 5. 5,5′-Linked corrole dimer 13 was produced by reaction of 5 with AgNO2 in a good yield, whereas 10,10′-linked corrole dimer 14 was formed in a moderate yield by the reaction of 9 with [bis(trifluoroacetoxy)iodo]benzene. Observed large electronic interaction between the two corroles in 13 as compared with that in 14 has been ascribed mainly to conformational flexibility of the former, which allows more coplanar conformation.

meso-Free Corroles: Syntheses, Structures, Properties, and Chemical Reactivities.

A long-standing question in porphyrin chemistry is why pyrrole monomers selectively form tetrapyrrolic macrocycles, whereas the corresponding tripyrrolic macrocycles are never observed. Calix[3]pyrrole, a tripyrrolic porphyrinogen-like macrocycle bearing three sp3-carbon linkages, is a missing link molecule that might hold the key to this enigma; however, it has remained elusive. Here we report the synthesis and strain-induced transformations of calix[3]pyrrole and its furan analogue, calix[3]furan. These macrocycles are readily accessed from cyclic oligoketones. Crystallographic and theoretical analyses reveal that these three-subunit systems possess the largest strain energy among known calix[n]-type macrocycles. The ring-strain triggers transformation of calix[3]pyrrole into first calix[6]pyrrole and then calix[4]pyrrole under porphyrin cyclization conditions. The present results help explain the absence of naturally occurring three-pyrrole macrocycles and the fact that they are not observed as products or intermediate during classic porphyrin syntheses.

Calix[3]pyrrole: A Missing Link in Porphyrin-Related Chemistry.

FeCl3 in combination with t-BuOOt-Bu as an oxidant was found to catalyze oxidative coupling of alkylamines with arenes, nitroalkanes, and 1,3-dicarbonyl compounds to give arylmethylamines, β-nitroa...

Iron-catalyzed Oxidative Coupling of Alkylamines with Arenes, Nitroalkanes, and 1,3-Dicarbonyl Compounds

A recent surge in the chemistry of expanded porphyrins is largely due to their attractive optical, electrochemical, and coordination properties, which arise from their large p-conjugated frameworks. The unique chemical reactivity of expanded porphyrins means that they often undergo metalation-induced skeletal rearrangements, as metalation reactions require specific coordination structures and expanded porphyrins have flexible electronic systems that are reactive toward such structural distortions. 3] The first examples of expanded porphyrins were the octaphyrins(1.1.1.0.1.1.1.0) reported by Vogel et al. , which were followed by our reports on 1) the splitting reaction of a bis(Cu octaphyrin) into two Cu porphyrins, 2) the boron(III)-triggered splitting reaction of Cu heptaphyrins to Cu porphyrins and B subporphyrins, and 3) the boron(III)-induced rearrangement of a hexaphyrin(1.1.1.1.1.1) to form a hexaphyrin(2.1.1.0.1.1). These skeletal rearrangements are intriguing in making “chemical connections” between important porphyrinoids such as octaphyrins, heptaphyrins, hexaphyrins, porphyrins, and subporphyrins. Despite these results, N-confused porphyrins (NCPs), which have a key position in porphyrin chemistry, 5] have not been included in this approach to date. Herein, we report that an NCP-type conjugated system is formed from [32]heptaphyrin(1.1.1.1.1.1.1) upon rearrangement triggered by metalation with Pd ions. meso-Aryl-substituted [32]heptaphyrins(1.1.1.1.1.1.1) are interesting macrocycles in terms of their flexible conformations, multiple N-fusion reactions, facile formation of twisted M bius aromatic species upon protonation, formation of three-coordinated Cu complexes, and oxidative ring opening to form conjugated helical molecules. We have previously reported that a M bius aromatic complex, 2, was formed in 88 % yield from meso-heptakis(2,6-dichlorophenyl)-substituted [32]heptaphyrin 1 upon treatment with Pd(OAc)2 in CH2Cl2. [7c] Careful examination of this reaction led to an isolation of brown complex 3 as a side-product in 9% yield. When the metalation reaction was carried out in acetone, the yield of 3 was improved to 22 % at the expense of the yield of 2 (Scheme 1). High-resolution electrospray ionization time-of-flight mass spectroscopy (HR-ESI-TOF MS) indicated the parent ion peak of 3 at m/z 1659.7423 (calcd for C77H34N7Cl14Pd [M H] : 1659.7485). The structure of 3 was unambiguously determined by single-crystal X-ray

Palladium(II)-Triggered Rearrangement of Heptaphyrins to N-Confused Porphyrins†

A Zn(II) -Cu(I) -Zn(II) heterotrimetal complex of decaphyrin was synthesized by stepwise metalations: metalation of a [46]decaphyrin with Zn(II) ions to produce a 46π decaphyrin bis(Zn(II) ) complex and its subsequent metalation with Cu(II) ion. In the second metalation step, it has been shown that Cu(II) ion is reduced to a Cu(I) ion in the complex and a dianionic bis(Zn(II) ) containing [46]decaphyrin ligand is oxidized to the corresponding monoanionic [45]decaphyrin ligand, indicating a non-innocent nature of the decaphyrin ligand. Despite the radical nature, the heterotrimetal complex is fairly stable under ambient conditions and exhibits almost no intermolecular magnetic interaction, owing to extensive delocalization of an unpaired electron in the large π-conjugated circuit of decaphyrin moiety.

A Stable Organic π-Radical of a Zinc(II)–Copper(I)–Zinc(II) Complex of Decaphyrin

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