Doctoral Dissertations
Date of Award
8-1996
Degree Type
Dissertation
Degree Name
Doctor of Philosophy
Major
Chemistry
Major Professor
Craig Barnes
Committee Members
Clifton Woods, Jim Chambers
Abstract
A number of alkyne adduct complexes have been prepared from the trinuclear cyclopentadienyl-based cluster (CpCo)3(CO)2. The most frequently observed products of the reaction of Co3 with alkynes are (CpCo)3(CO)(µ3η2-RC≡CR) alkyne complexes. For the terminal alkyne t-butyl acetylene, a second type of complex with the formula (CpCo)3(CO)(OCC(R)CH) (R = C(CH3)3) is isolated from the reaction in which a carbonyl ligand is coupled with the coordinated alkyne to form an acyl group. Single crystal X-ray, electrochemical and variable temperature nuclear magnetic resonance studies are reported for these complexes. A number of complexes have been prepared which contain alkyne adduct clusters joined by a phenyl linking group. Structural and electrochemical studies have been conducted on these complexes to determine the extent of electronic interaction between the linked cluster centers.
The high temperature reactivity of the (CpCo)3(CO)(alkyne) complexes has been studied extensively. The pyrolysis of these complexes in refluxing decalin generally results in the formation of (CpCo)3(µ3-CR)2 bis-carbyne complexes. The molecular structures and electrochemical properties of several new bis-carbyne complexes, including a number of complexes containing linked bis-carbyne clusters, are reported. Pyrolysis of the butynediol complex (CpCo)3(CO) (HOCH2C≡CCH2OH) gave a quite different product from the bis- carbyne complexes normally observed in these reactions. Intramolecular dehydration and cyclization of the alkyne unit occurs in refluxing decalin resulting in the formation of the furyne ligand, CH2C≡CCH2O. Prolonged heating of the butynediol complex or the furyne complex (CpCo)3 (µ3-η2-CH2C≡CCH2O) results in the formation of the tetranuclear furyne complex, (CpCo)4(µ4-η2-CH2C≡CCH2O). The trinuclear and tetranuclear furyne complexes have been structurally characterized and the trinuclear complex has been studied by electrochemical techniques.
Recommended Citation
King, William D., "The chemistry of alkyne adduct complexes of the cyclopentadienyl-based cobalt cluster (CpCo)₃(CO)₂. " PhD diss., University of Tennessee, 1996.
https://trace.tennessee.edu/utk_graddiss/9775