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The Syntheses and Characterization of Binuclear Clathrochelate Complexes

Citation

Marritt, William Alan (1983) The Syntheses and Characterization of Binuclear Clathrochelate Complexes. Dissertation (Ph.D.), California Institute of Technology. http://resolver.caltech.edu/CaltechTHESIS:10302018-160040560

Abstract

A series of binuclear clathrochelate complexes, MA(II)MB(II)L+, have been synthesized and characterized for the purpose of examining electrostatic, magnetic, and electronic delocalization effects in binuclear complexes. The clathrochelating ligand, L3-, is a bicyclic Schiff-base compound derived from 3 equiv of 2-hydroxy-5-methylisophthalaldehyde and 2 equiv of 2,2',2"-triaminotriethylamine (tren). The following MA(II)MB(II)L+ complexes were prepared by combinations of metal-ion template, metathesis, and insertion reactions: homonuclear complexes with MA = MB = Mn, Fe, Co, Cu, Zn, and Cd; heteronuclear complexes with MA = Mn, MB = Co, Ni, Zn, Cd, and Mg; MA = Fe, MB = Mn, Co, Ni, Cu, Zn, Cd, and Mg; MA = Cu, MB = Mn, Co, Ni, Zn, Cd, and Mg. In addition, syntheses and characterization are reported for the binuclear Cu(II)Cu(II)LH2+ complex and mononuclear complexes of the non-deprotonated ligand, MLH3n+, with M = Na(I), Mn(II), Mn(III), Fe(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), and Mg(II).

The MA redox potentials of the Mn(III)/Mn(II), Fe(III)/Fe(II), and Cu(II)/Cu(I) couples were determined by cyclic voltammetry and differential pulse voltammetry for three series containing both homonuclear and heteronuclear complexes, Mn(II)MB(II)L+, Fe(II)MB(II)L+, and Cu(II)MB(II)L+. Within experimental error, the average of the MA redox potentials for each series of heteronuclear complexes was the same as that for the corresponding homonuclear complex. This result suggests that there is no measurable stabilization of Mn(III)Mn(II)L2+, Fe(III)Fe(II)L2+, and Cu(I)Cu(II)L with respect to mixed-valent heteronuclear analogues.

The magnetic properties of a series of four homonuclear MA(II)MB(II)L+ complexes were examined by variable temperature susceptibility measurements (MA = MB = Mn, Fe, Co, and Cu). In all cases, weak antiferromagnetic coupling between the metal centers was observed (-33.5 cm-1 < J < -0.8 cm-1). The weakness is attributed to limited overlap of metal orbitals with those of the bridging atoms.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:Chemistry
Degree Grantor:California Institute of Technology
Division:Chemistry and Chemical Engineering
Major Option:Chemistry
Thesis Availability:Restricted to Caltech community only
Research Advisor(s):
  • Grubbs, Robert H.
Thesis Committee:
  • Bercaw, John E. (chair)
  • Gray, Harry B.
  • Gagne, Robert R.
  • Grubbs, Robert H.
Defense Date:2 August 1982
Funders:
Funding AgencyGrant Number
CaltechUNSPECIFIED
Record Number:CaltechTHESIS:10302018-160040560
Persistent URL:http://resolver.caltech.edu/CaltechTHESIS:10302018-160040560
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:11252
Collection:CaltechTHESIS
Deposited By: Benjamin Perez
Deposited On:31 Oct 2018 18:50
Last Modified:31 Oct 2018 18:50

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