Reactivity of the B-H Bond in tris(pyrazolyl)hydroborato zinc complexes: unexpected example of zinc hydride formation in a protic solvent and its relevance towards hydrogen transfer to NAD(+) mimics by tris(pyrazolyl)hydroborato zinc complexes in alcoholic media.
Solutions of the zinc hydroxide complex [Tp(Bu(t),Me)]ZnOH in alcohols (ROH; R = Me, Et, Pr(i)) achieve hydride transfer to the NAD(+) model, 10-methylacridinium perchlorate. Deuterium labeling studies, however, demonstrate that the source of the hydride is not the alcohol but, rather, the B [bond] H group of the [Tp(Bu(t),Me)] ligand. A further example in which a [Tp(Bu(t),Me)] ligand acts as a hydride donor is provided by the reaction of the aqua complex [[Tp(Bu(t),Me)]Zn(OH(2))][HOB(C(6)F(5))(3)] with MeOH to generate the zinc hydride complex [Tp(Bu(t),Me)]ZnH. The present study therefore provides a caveat for the often assumed inertness of the B [bond] H group in tris(pyrazolyl)hydroborato ligands, especially in the presence of reactive cationic species.
Bergquist
Catherine
C
Department of Chemistry, Columbia University, New York, New York 10027, USA.
Koutcher
Lawrence
L
Vaught
Amanda L
AL
Parkin
Gerard
G
D000166:Acridines / Q000737:chemistry; D000426:Alcohol Dehydrogenase / Q000737:chemistry / Q000378:metabolism; D000473:Alkanes / Q000737:chemistry; D001896:Boron Compounds / Q000737:chemistry; D002384:Catalysis; D002412:Cations / Q000737:chemistry; D003903:Deuterium / Q000737:chemistry; D004563:Electrochemistry; D006878:Hydroxides / Q000737:chemistry; D008099:Liver / Q000201:enzymology; D008958:Models, Molecular; D015394:Molecular Structure; D009243:NAD / Q000737:chemistry* / Q000378:metabolism; D009536:Niacinamide / Q000031:analogs & derivatives / Q000737:chemistry; D009942:Organometallic Compounds / Q000737:chemistry* / Q000378:metabolism; D015032:Zinc / Q000737:chemistry*; D017967:Zinc Compounds / Q000737:chemistry
C453120:1-benzylnicotinamide; C453119:10-methylacridinium perchlorate; D000166:Acridines; D000473:Alkanes; D001896:Boron Compounds; D002412:Cations; D006878:Hydroxides; D009942:Organometallic Compounds; D017967:Zinc Compounds; D009243:NAD; C028189:N-methylacridine; D009536:Niacinamide; D003903:Deuterium; D000426:Alcohol Dehydrogenase; D015032:Zinc; C052745:zinc hydroxide