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Moonhyun Oh

Publications and source records attributed to Moonhyun Oh.

9 recordsLinked to original sources
PubMed2006

Pi-bonded quinonoid transition-metal complexes.

Coordination of the carbocyclic ring of hydroquinones to electrophilic transition-metal fragments such as Mn(CO)3+ and Rh(COD)+ produces stable pi-bonded eta6-complexes that are activated to facile reversible deprotonation of the -OH groups. The deprotonations are accompanied by electron transfer to the transition metal, which acts as an internal oxidizing agent or electron sink. With manganese as the metal, the resulting eta5-semiquinone and eta4-quinone complexes have been used to synthesize one- two- and three-dimensional polymeric metal-organometallic coordination networks. With rhodium as the metal, the pi-quinonoid complexes have been demonstrated to play a unique role in multifunctional C-C coupling catalysis and in the synthesis of new organolithium reagents. Both classes of pi-quinonoid complexes appear to have significant applications in nanochemistry by providing an excellent vehicle for templating the directed self-assembly of nanoparticles into functional materials.

Catalysis↗
PubMed2005

Chemically tailorable colloidal particles from infinite coordination polymers.

Micrometre- and nanometre-sized particles play important roles in many applications, including catalysis, optics, biosensing and data storage. Organic particles are usually prepared through polymerization of suitable monomers or precipitation methods. In the case of inorganic materials, particle fabrication tends to involve the reduction of a metal salt, or the controlled mixing of salt solutions supplying a metal cation and an elemental anion (for example, S2-, Se2-, O2-), respectively; in some instances, these methods even afford direct control over the shape of the particles produced. Another class of materials are metal-organic coordination polymers, which are based on metal ions coordinated by polydentate organic ligands and explored for potential use in catalysis, gas storage, nonlinear optics and molecular recognition and separations. In a subset of these materials, the use of organometallic complexes as ligands (so-called metalloligands) provides an additional level of tailorability, but these materials have so far not yet been fashioned into nano- or microparticles. Here we show that simple addition of an initiation solvent to a precursor solution of metal ions and metalloligands results in the spontaneous and fully reversible formation of a new class of metal-metalloligand particles. We observe initial formation of particles with diameters of a few hundred nanometres, which then coalesce and anneal into uniform and smooth microparticles. The ease with which these particles can be fabricated, and the ability to tailor their chemical and physical properties through the choice of metal and organic ligand used, should facilitate investigations of their scope for practical applications.

Journal Article↗
PubMed2005

Coordination polymers from silver(I) and bifunctional pyridyl ligands.

Coordination polymers and a macrocycle formed from the reactions between flexible bis(2-pyridyl) ligands and AgCF(3)SO(3) are reported. The type of structure formed depends on the choice of ligand and the stoichiometry of the reaction. When 1 equiv of 1,4-bis(pyridin-2-ylmethoxy)benzene (L2), 4,4'-bis(pyridin-2-ylmethoxy)biphenyl (L4), or bis((4-pyridin-2-ylmethoxy)phenyl)methane (L5) is used, 1D chain coordination polymers held together via Ag-N bonds are generated. When a 2:1 ratio of L2 and silver ion is used, a 2D porous network is formed. The reaction between silver ions with a mixture of ligands (L1 and L2 in 1:1 ratio, L1 = 1,4-bis((pyridin-2-yl-methyl)thio)benzene) results in a novel 1D ABAB type coordination copolymer where L1 and L2 act as a bis-bidentate and a bis-monodentate ligand, respectively. The reaction of 1-(pyridin-2-ylmethoxy)-4-((pyridin-2-yl-methyl)thio)benzene (L3) with silver ions in a 1:1 ratio gives a bimetallic macrocycle rather than a polymeric species. Structural analyses of the polymeric compounds suggest that interactions between the aromatic rings play a significant role in stabilizing the polymeric structures.

Journal Article↗
PubMed2004

Supramolecular metal-organometallic coordination networks based on quinonoid pi-complexes.

The use of organometallic pi-complexes in the coordination-directed self-assembly of polymeric structures is a new area with many potential applications. Supramolecular metal-organometallic coordination networks (MOMNs), which are described herein, consist of metal ion or metal cluster nodes connected by bifunctional "organometalloligands" that serve as spacers. The organometalloligand utilized in this work is the stable anionic complex (eta(4)-benzoquinone)Mn(CO)(3)(-) (p-QMTC), which binds through both quinone oxygen atoms to generate MOMNs having both backbone and pendant metal sites. In many cases the MOMNs are obtained as neutral and thermally stable solids, with molecular structures that depend on the geometrical and electronic requirements of the metal nodes, the solvent, and the presence of organic spacers. Redox-active quinone-based organometallic pi-complexes permit the construction of an impressive range of coordination network architectures and hold much promise for the development of functional materials.

Cadmium↗