Metal complexes as models for vitamin B₆ catalysis

Chapter I. Historical introduction to Vitamin B₆ Complexes. Chapter II. The aldimine complexes N(Salicylidene)glycinato and valinatozinc(II), N,~pyridoxylidene)valinatocopper(II) monohydrate and N-(3-Hydroxypyridyl-2-methylene)valinatocopper( II) hemihydrate have been prepared from L̳-valine. Synthetic methods and characterization data are given. Also prepared were the bis-chelate amino acid ester complexes, Bis[N- (2-ethoxycarbonyl-l-propyl)salicylaldiminato]copper(II) and Bis[N-(3-ethoxycarbonyl-2-propyl)salicylaldiminato]copper(II). The inertness of these two complexes to H-D exchange contrasts with the ready exchange in the absence of base of the complexes derived from a-amino acids. This result shows that facile exchange and racemization properties of Bis[N-(alkoxycarbonylalkyl)salicylaldimino] metal(II) complexes derive principally from the direct attachment of the electron-withdrawing HC=NM and COOC₂H₅ groups to the asymmetric center. The base-catalyzed racemization rates of four copper(II)-aldimine complexes in 95% ethanol at 50° were found to increase in the order N-Salicylidene-L̳-valinatocopper( II), Cu(sal-L̳-val) << N-Pyridoxylidene-L̳-valinatocopper(II) </- N-3-Hydroxypyridyl-2-methylene-L̳-valinatocopper(II) <N-4-NO₂ - Salicylidene-L̳-valinatocopper(II). This order is essentially the same as that of qualitative catalytic effectiveness of the constituent o̲-hydroxyarylcarbonyl compounds in nonenzyrnatic transamination and reinforces in semiquantitative fashion the prevailing model of ligand electronic features requisite to catalytic activity of these compounds.

Name thesis:degree_name

Master

Department dc:contributor.department

Massachusetts Institute of Technology. Department of Nutrition and Food Science

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

1972

Author dc:creator

• Weinstein, Georgia Nan.

Advisor dc:contributor.advisor

• Sanford Miller.

• Nutrition and Food Science.

Statement dc:rights

• MIT theses may be protected by copyright. Please reuse MIT thesis content according to the MIT Libraries Permissions Policy, which is available through the URL provided.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

https://hdl.handle.net/1721.1/154250

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/154250