Adocobinamide, the Base-off Analog of Coenzyme B12(Adocobalamin). 2.1Probing the “Base-on” Effect in Coenzyme B12via Cobalt−Carbon Bond Thermolysis Product and Kinetic Studies as a Function of Exogenous Pyridine Bases

1996 ◽  
Vol 118 (45) ◽  
pp. 11142-11154 ◽  
Author(s):  
Cheryl D. Garr ◽  
Jeanne M. Sirovatka ◽  
Richard G. Finke
Keyword(s):  
Thermolysis Product ◽  
Kinetic Studies ◽  
Coenzyme B12 ◽  
Carbon Bond ◽  
Pyridine Bases

Kinetics of Plasmon-Driven Hydrosilylation of Silicon Surfaces: Photogenerated Charges Drive Silicon- Carbon Bond Formation

2021 ◽  
Author(s):  
Chengcheng Rao ◽  
Brian Olsen ◽  
Erik Luber ◽  
Jillian Buriak
Keyword(s):  
Green Light ◽  
Kinetic Studies ◽  
Silicon Surfaces ◽  
Moderate Intensity ◽  
Carbon Bond ◽  
Silicon Carbon ◽  
Set Up ◽  
Kinetics Of ◽  
Insight Into

Optically transparent PDMS stamps coated with a layer of gold nanoparticles were employed as plasmonic stamps to drive surface chemistry on silicon surfaces. Illumination of a sandwich of plasmonic stamps, an alkene ink, and hydride-terminated silicon with green light of moderate intensity drives hydrosilylation on the surface. The key to the mechanism of the hydrosilylation is the presence of holes at the Si-H-terminated interface, which is followed by attack by a proximal alkene and formation of the silicon-carbon bond. In this work, detailed kinetic studies of the hydrosilylation on silicon with different doping levels, n++, p++, n, p, and intrinsic were carried out to provide further insight into the role of the metal-insulator-semiconductor (MIS) junction that is set up during the stamping.

A study of the cage mechanism for the homolytic cleavage of the cobalt-carbon bond in coenzyme B12 by varying the solvent viscosity

1991 ◽  
Vol 190 (1) ◽  
pp. 47-53 ◽  
Author(s):  
Leonard E.H. Gerards ◽  
Huibert Bulthuis ◽  
Martinus W.G. de Bolster ◽  
Sijbe Balt
Keyword(s):  
Coenzyme B12 ◽  
Homolytic Cleavage ◽  
Carbon Bond ◽  
Solvent Viscosity

Protein–coenzyme interactions in adenosylcobalamin-dependent glutamate mutase

2001 ◽  
Vol 355 (1) ◽  
pp. 131-137 ◽  
Author(s):  
Marja S. HUHTA ◽  
Hao-Ping CHEN ◽  
Craig HEMANN ◽  
C. Russ HILLE ◽  
E. Neil G. MARSH
Keyword(s):  
Gel Filtration ◽  
Visible Spectrum ◽  
Titration Calorimetry ◽  
Coenzyme B12 ◽  
Glutamate Mutase ◽  
Carbon Bond ◽  
Coenzyme Binding ◽  
Radical Intermediates ◽  
Bond Stretching ◽  
Uv Visible

Glutamate mutase catalyses an unusual isomerization involving free-radical intermediates that are generated by homolysis of the cobalt–carbon bond of the coenzyme adenosylcobalamin (coenzyme B12). A variety of techniques have been used to examine the interaction between the protein and adenosylcobalamin, and between the protein and the products of coenzyme homolysis, cob(II)alamin and 5′-deoxyadenosine. These include equilibrium gel filtration, isothermal titration calorimetry, and resonance Raman, UV-visible and EPR spectroscopies. The thermodynamics of adenosylcobalamin binding to the protein have been examined and appear to be entirely entropy-driven, with ∆S = 109 Jċmol-1ċK-1. The cobalt–carbon bond stretching frequency is unchanged upon coenzyme binding to the protein, arguing against a ground-state destabilization of the cobalt–carbon bond of adenosylcobalamin by the protein. However, reconstitution of the enzyme with cob(II)alamin and 5′-deoxyadenosine, the two stable intermediates formed subsequent to homolysis, results in the blue-shifting of two of the bands comprising the UV-visible spectrum of the corrin ring. The most plausible interpretation of this result is that an interaction between the protein, 5′-deoxyadenosine and cob(II)alamin introduces a distortion into the ring corrin that perturbs its electronic properties.

Kinetics of Plasmon-Driven Hydrosilylation of Silicon Surfaces: Photogenerated Charges Drive Silicon- Carbon Bond Formation

2021 ◽  
Author(s):  
Chengcheng Rao ◽  
Brian Olsen ◽  
Erik Luber ◽  
Jillian Buriak
Keyword(s):  
Green Light ◽  
Kinetic Studies ◽  
Silicon Surfaces ◽  
Moderate Intensity ◽  
Carbon Bond ◽  
Silicon Carbon ◽  
Set Up ◽  
Kinetics Of ◽  
Insight Into

Optically transparent PDMS stamps coated with a layer of gold nanoparticles were employed as plasmonic stamps to drive surface chemistry on silicon surfaces. Illumination of a sandwich of plasmonic stamps, an alkene ink, and hydride-terminated silicon with green light of moderate intensity drives hydrosilylation on the surface. The key to the mechanism of the hydrosilylation is the presence of holes at the Si-H-terminated interface, which is followed by attack by a proximal alkene and formation of the silicon-carbon bond. In this work, detailed kinetic studies of the hydrosilylation on silicon with different doping levels, n++, p++, n, p, and intrinsic were carried out to provide further insight into the role of the metal-insulator-semiconductor (MIS) junction that is set up during the stamping.

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