Pettit, Rowland

Rowland Pettit (1927-19811 was born in Port Lincoln, Australia. He received two doctoral degrees, one from the University of Adelaide in 1952 and the second from the University of London in 1956, working with Michael Dewar. He then became professor of chemistry at the University of Texas, Austin (1957-1981). 

Cyclo butadiene is highly reactive and shows none of the properties associated with aromaticity. In fact, it was not even prepared until 1965, when Rowland Pettit of the University of Texas was able to make it at low temperature. Even at —78 °C, however, cyclobutadiene is so reactive that it dimerizes by a Diels-Alder reaction. One molecule behaves as a diene and the other as a dienophile. 

Jonathan L. Sessler is the Rowland K. Pettit Professor of Chemistry at the University of Texas-Austin. His research involves the design and constmction of molecules carefully tailored so as to accomplish specific objectives. These molecules often have architectural elegance and interesting chemical, physical, and/or biological properties. He has made important contributions to the synthetic chemistry of porphyrins and related compounds [44-46], New drags have resulted from his efforts [47],... 

Fig. 5.17 Rowland Pettit exercising his passion after giving his Plenary Lecture at the X. Sheffield-Leeds Symposium on Organometallic Chemistry in July 1979 (photo by courtesy from Professor Peter Maitlis)...

LEWIS WATTS and ROWLAND PETTIT Department of Chemistry, University of Texas, Austin, Tex. 

The behaviour of iron in CO-CO2 atmospheres was studied by Pettit and Wagner over the temperature range 700-1000 °C, where wustite is stable. They found that the kinetics were controlled by reactions at the scale-gas interface, but carbon pickup was not observed. In contrast, Surman oxidized iron in CO-CO2 mixtures in the temperature range 350-600 °C, where wustite was not stable and magnetite exists next to the iron. He observed breakaway oxidation whose onset, after an incubation period, coincided with the deposition of carbon within the scale. This was explained by Gibbs and Rowlands by the penetration of the scale by CO2 which achieved equilibrium in the scale, dissolved carbon in the metal substrate, and then deposited carbon within the scale, which split open the scale and left the system in a state of rapid breakaway oxidation. The incubation period observed corresponded to the time required to saturate the metal substrate with carbon. 

As we saw in Section 11.17, cyclobutadiene is antiaromatic and exceedingly difficult to prepare and study. Its successful preparation by Rowland Pettit (University of Texas) in 1965 demonstrated how transition-metal organometallic cbemistry can provide access to novel reactions and structures. His approach was to prepare cyclobutadiene as a transition-metal complex, then destabilize the complex to trigger its dissociation. The sequence for cyclobutadiene begins with the reaction of cis-3,4-dichlorocyclobutene with diiron nonacarbonyl [Fe2(CO)9]. The resulting iron-cyclobutadiene complex satisfies the 18-electron rale, is stable, and undo-goes a variety of reactions. Most importantly, oxidation with ceric ammonium nitrate (a source of Ce ) lowers the electron count Irom 18 to 16, causing the complex to dissociate and Ubo-ate free cyclobutadiene. 

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