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Jason A C Clyburne

Publications and source records attributed to Jason A C Clyburne.

11 recordsLinked to original sources
PubMed2006

Structure of organic and metal-organic networks based on a bifunctional m-terphenyl carboxylic acid.

A series of metal-organic frameworks (MOFs) based upon the ligand 2,6-diphenyl-1,4-dibenzoic acid [Ph2C6H2(CO2H)2]infinity have been prepared and characterized by X-ray crystallography. The networks exhibit a variety of topologies and coordination modes at the metal center. The reaction of the ligand with cobalt(II) nitrate or zinc(II) nitrate in methanol/pyridine results in the formation of isostructural 1-D chains [(Ph2C6H2(CO2)2)M(py)2(MeOH)]infinity, where M = Zn, Co; however, in the presence of ethanol and triethylamine, Zn(NO3)2 reacts to form a 2-D clay-like network, [(Ph2C6H2(CO2)2)Zn(EtOH)2]infinity. 2-D networks are also formed in similar reactions with copper(II) nitrate or silver(I) nitrate to give [(Ph2C6H2(CO2)(CO2H))2Cu(py)2]infinity, [(Ph2C6H2(CO2)CO2H))2Cu(py)4.2H2O](infinity), and [(Ph2C6H2(CO2)2)Ag2]infinity, respectively. The hydrogen-bonded chains formed by the ligand alone and with 4,4'-dipyridyl are also described.

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PubMed2006

From the reactivity of N-heterocyclic carbenes to new chemistry in ionic liquids.

N-Heterocyclic carbenes have numerous applications in synthetic chemistry. We detail the reactivity and chemistry of these molecules including investigations into their reactions with small reagents, their use for the preparation of polarised azines and their potential application as NLO materials. The chemistry of imidazolium salts, which are related to NHCs by the addition of a proton, is also discussed. New chemistry for ionic liquids is also revealed.

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PubMed2005

A zinc carboxylate network containing metal sites with low coordination numbers.

A bifunctional m-terphenyl, 2,6-diphenyl-1,4-dibenzoic acid (Ph2BDC), was synthesized and used in the preparation of a 2-D metal-organic coordination polymer. The steric hindrance of the bulky bifunctional linker forces low coordination at the Lewis-acidic zinc center. A zinc carboxylate dimer was prepared as a model compound to examine the unusual tricoordinate geometry at the metal site.

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PubMed2005

A computational study of the reactions of a beta-diketiminatoaluminium(I) complex with the hydrogen atom and the electron.

A computational study has been performed to examine the reactions of a model beta-diketiminatoaluminium (I) complex with the hydrogen atom and with the electron. It was found that the hydrogen atom adds to the metal centre exothermically (DeltaH(rxn)=-202 kJ mol(-1)), and the spin density in the resulting radical resides entirely on the beta-diketiminato ligand. The spin density of the corresponding radical anion is very similar to the H-adduct.

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PubMed2004

Phosphonium ionic liquids as reaction media for strong bases.

Phosphonium ionic liquids are compatible with strong bases; for example, solutions composed of commercially available phenylmagnesium bromide in THF are persistent in tetradecyl(trihexyl)phosphonium chloride for several hours-days: their stability appears to be couched in kinetic terms.

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PubMed2004

Azines possessing strong push-pull donors/acceptors.

Azines (R(2)C[double bond, length as m-dash]N-N[double bond, length as m-dash]CR(2)) are 2,3-diaza analogues of 1,3-butadiene. In this report we show that strong polarisation of the azine imparts structural features consistent with delocalization within the azine fragment; NLO properties for the azines are also reported.

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PubMed2003

The reactions of imidazol-2-ylidenes with the hydrogen atom: a theoretical study and experimental confirmation with muonium.

The possible radicals resulting from hydrogen atom addition to the imidazole rings of 1,3-bis(isopropyl)-4,5-dimethylimidazol-2-ylidene (1) and 1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene (2) have been studied by means of density functional calculations (B3LYP). The calculations included solvent effects estimated via the polarized continuum model (PCM) and an empirical treatment of vibrational averaging of hyperfine constants. Addition of a hydrogen (or muonium) atom to the carbeneic carbon of 1,3-bis(isopropyl)-4,5-dimethylimidazol-2-ylidene was found to give a radical 60.46 kJ mol(-)(1) more stable than the radical resulting from addition to the double bond. Estimation of the activation barriers for reaction at the two sites shows that addition at the carbeneic carbon is favored. The site of addition was confirmed experimentally using muonium (Mu), which can be considered a light isotope of hydrogen. Muon spin rotation and muon level-crossing spectroscopy were used to determine muon, (13)C, and (14)N hyperfine coupling constants (hfc's) for the radical products of addition to the two carbenes. Good agreement between the experimental and calculated hfc's confirms that Mu (and hence H) adds exclusively to the carbeneic carbon. The radicals that are produced have nonplanar radical centers with most of the unpaired electron spin density localized on the alpha-carbon.

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PubMed2003

A monomeric imidazol-2-ylidene-silver(I) chloride complex: synthesis, structure, and solid state 109Ag and 13C CP/MAS NMR characterization.

The structure of 1,3-bis(2,4,6-trimethylphenyl)-imidazol-2-ylidene-silver(I) chloride, 1, has been determined to be a monomer with weak head-to-tail H...Cl interactions in the solid state. A multinuclear NMR study using a (13)C(carbene) labeled derivative, 1((13)C), exhibits (13)C-(107,109)Ag coupling in solution. Further, the solid state CP/MAS NMR parameters, including the principal components of the chemical shift tensors for both the (13)C and (109)Ag centers, have been determined. With the aid of DFT calculations, the orientation of the chemical shift tensors have been assigned.

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