이승중 교수

Chiralsupramolecular systems have attracted a great deal of interest from synthetic chemists over the past two decades because of their ability to mimic complex biological processes and their potential applications in enantioselective events such as asymmetric catalysis and chiral sensing. Chiral metallocycles, among the simplest forms of chiral supramolecular systems, are of particular interest because of their relative ease of synthesis. In this Account, we survey recent developments in the ra

A family of chiral molecular squares based on fac-Re(CO)3Cl metallocorners and enantiopure atropisomeric bipyridine bridging ligands (L1-4) have been synthesized in high yields by refluxing ClRe(CO)5 and L1-4 in 1:1 molar ratio. These novel chiral metallocycles have been characterized by 1H and 13C{1H} NMR, UV-vis, luminescence, and circular dichroism (CD) spectroscopies, FAB mass spectrometry, and microanalysis. Molecular square 4 which contains four 1,1'-bi-2-naphthol functionalities exhibits

This communication describes the discovery of air-stable and highly versatile B-protected haloalkenylboronic acid building blocks for iterative cross-coupling. These reagents enable the total synthesis of polyene natural products with extraordinary levels of simplicity, efficiency, and modularity. Specifically, all-trans-retinal, β-parinaric acid, and one-half the amphotericin B macrolide skeleton were prepared using only the Suzuki-Miyaura reaction in an iterative manner to bring together colle

A family of chiral organometallic triangles based on cis-Pt(PEt3)2 metallocorners and enantiopure atropisomeric bis(alkynyl) bridging ligands (L1-4) has been synthesized and characterized by 1H, 13C{1H}, and 31P{1H} NMR, UV-vis, and circular dichroism (CD) spectroscopies, FAB and MALDI-TOF mass spectrometry, and microanalysis. Metallocycle 4 which contains three 1,1'-bi-2-naphthol functionalities in combination with Ti(iOPr)4 has been shown to be an excellent catalyst for highly enantioselective

Using a steric self-sorting strategy, the assembly of highly ordered and rigid supramolecular boxes possessing catalytic properties has been achieved in one step. The formation of these assemblies, comprising up to 18 porphyrin centers, was readily confirmed by solution X-ray scattering in conjunction with fluorescent spectroscopy. Size-selective and enantioselective oxidation catalysis were both demonstrated.

Anthracene-based conjugated molecules are synthesized and J-aggregations are clearly observed in a single-crystal structure study. Single-crystal-based field-effect transistors (FETs) exhibit high field-effect mobility. They displayed dramatic photoinduced enhancement of the drain current and showed unusually high photoresponsivity under extremely low intensity light. Due to the photoinduced enhancement of excitons, single and multiple-stage memory operations are achieved.

Not so complex: A novel iterative cross-coupling strategy provides access to useful building blocks that enable the simple preparation of complex polyene natural-product motifs in all possible stereoisomeric forms. The method was used to synthesize the polyene core of vacidin A (see structure). Aiming to maximally harness the inherent modularity of small molecules, we are pursuing the development of a synthesis strategy based on the iterative cross-coupling (ICC) of bifunctional building blocks

The self-assembly of amphiphilic (porphyrin)Sn 1 in an aqueous Pluronic F127 media results in the formation of narrowly dispersed nanowires. Variation of aqueous Pluronic concentrations allows for a systematic variation of porphyrin nanowire lengths while keeping their widths constant. These nanowires can be further assembled into secondary macroscopic columns.

Highly conjugated porphyrin derivatives, H(2) TP and ZnTP, are synthesized. J-aggregations of the H-aggregated dimeric porphyrin pairs are clearly observed by their single crystal structures that facilitate slip-stacked charge transport phenomenon. In particular, their SC-FETs show the highest field-effect mobilities of 0.85-2.90 cm(2) V(-1) s(-1) . Furthermore, the ZnTP-based OPT displays a dramatic photoinduced current enhancement with a high photoresponsivity of 22 000 A W(-1) under a very lo

Combining linear Zn porphyrin trimers with orthogonally derivatized porphyrin dimers leads rapidly and spontaneously to the formation of monodisperse, torsionally constrained boxes comprising six components and a total of 16 metalloporphyrins. In situ X-ray scattering measurements confirm the formation of monodisperse assemblies of precisely the size expected from model box structures. While simple subunits yield highly symmetrical boxes, we find that sterically demanding subunits produce unusua

A new class of narrowly dispersed nanosize hexagonal MOF rods from Mn(III)-porphyrin and In(III) was obtained. The length of MOF rods was controlled by simple change of reaction times. Furthermore, the oxidation of styrene has been successfully demonstrated with Mn(III)-porphyrin MOF rods and their reusability has been also tested.

A hierarchical strategy for producing mesoscopic objects from discrete amphiphilic (porphyrin)Sn molecules is demonstrated. Vigorous stirring and/or microwave heating produced uniform porphyrin nanocrystals, whose morphology can be easily modulated. These nanocrystals can then be assembled together into macroscopic prisms with a simple surfactant or selectively partitioned into hydrophobic patterns on glass surfaces.

A new pyrene-cored π-conjugated molecule has been synthesized through Sonogashira coupling reaction. The single-crystalline microribbon-based FET exhibited the highest mobility of 0.7 cm(2) V(-1) s(-1) (I(on)/I(off) > 10(6)). Single-crystalline microribbons were employed to operate in an organic phototransistor (OPT) under very low light intensity (I = 5.6 μW cm(-2)).