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Chengyun Guo

Publications and source records attributed to Chengyun Guo.

7 recordsLinked to original sources
PubMed2006

Carbon-halide oxidative addition and carbon-carbon reductive elimination at a (PNP)Rh center.

An unsaturated (PNP)Rh fragment can be generated by means of C-C reductive elimination from (PNP)Rh(Me)(Ar) or (PNP)Rh(Ar)(Ar). This fragment undergoes carbon-halogen oxidative addition with aryl chlorides, bromides, and iodides at room temperature. The C-H oxidative addition products in reactions with haloarenes are not observed, and evidence is presented that carbon-halogen oxidative addition is thermodynamically preferred. C-C reductive elimination from (PNP)Rh(Me)(Ar) and (PNP)Rh(Ar)(Ar) proceeds near quantitatively as a clean, first-order reaction.

Journal Article↗
PubMed2005

Conformational polymorphism of methacrylamide.

The industrially important compound methacrylamide crystallizes as concomitant conformational polymorphs; the monoclinic form contains only the s-cis conformer, while the orthorhombic form contains only the s-trans conformer.

Acrylamides↗
PubMed2004

Facile oxidative addition of N-C and N-H bonds to monovalent rhodium and iridium.

An investigation of room-temperature oxidative addition of N-C and N-H bonds to RhI and IrI in solution and in the solid state is presented. The rigid, product-adapted framework of the pincer bis(ortho-phosphinoaryl)amine (PNP) ligand may contribute to the ease of the N-C and N-H cleavage. The migration of Me from N of the coordinated amine moiety to Rh proceeds with near-zero entropy of activation in solution. In the solid state, this transformation is a crystal-to-crystal reaction, transforming only one of the two independent molecules of (PN(Me)P)RhCl into (PNP)Rh(Me)Cl.

Journal Article↗
PubMed2004

Diiminoisoindoline: tautomerism, conformations, and polymorphism.

Two polymorphs of the industrially important compound diiminoisoindoline occur in the amino tautomeric form as a conformational isomorph with a 1 : 1 mixture of the syn- and anti-isomers, and a conformational polymorph containing only the syn-isomer.

Journal Article↗