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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 217 records · Page 12
All sourcesNASA NTRSDOE OSTI
DOE OSTI2012

Surface functionalization of metal-organic polyhedron for homogeneous cyclopropanation catalysis

A super-paddlewheel (comprised of two paddlewheels) metal-organic polyhedron (MOP) containing surface hydroxyl groups was synthesized and characterized. Condensation reactions with linear alkyl anhydrides lead to new MOPs with enhanced solubility. As a result, the surface-modified MOP 4 was demonstrated as a homogeneous Lewis-acid catalyst.

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DOE OSTI2014

Oxy-functionalization of Group 9 and 10 transition metal methyl ligands: use of pyridine-based hemi-labile ligands

Hemi-labile ligands (HLLs) are interesting candidates for catalysts since they may facilitate bond activation and bond formation through facile ligand dissociation/association. DFT studies are reported of hemi-labile ligands in conjunction with Group 9 and 10 metals for oxygen atom insertion into metal–methyl bonds. Analysis of the reaction of pyridine- N -oxide with d 8 -[L n M (Me)(THF)] q + (M = Co, Rh, Ir, Ni, Pd, Pt; L n = 2-(CH 3 OCH 2 )Py; q = 0 and +1 for Group 9 and 10 metals, respectively; Py = pyridine; THF = tetrahydrofuran) indicates that oxy-insertion for Group 9 complexes occurs with lower free energy barriers than their Group 10 congeners. Analysis of structural changes along the reaction coordinate indicates that the initial oxygen atom transfer and subsequent methyl migration steps are favored by a reduction and increase, respectively, in coordination number. This emphasizes that HLLs could be uniquely positioned to assist both transformations within a single complex. Additionally, such ligands are worthy of experimental study due to their ability to meet the disparate coordination demands for two-step, redox-based oxy-insertion.

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