Under the cardon spell: Diborane's puzzling structure and the emergence of boron chemistry

Tipo de prova

Mestrado em História e Filosofia das Ciências (FCUL)

Resumo (em inglês)

Nowadays, boron chemistry is one of the most promising fields of chemistry, with pervading and exciting applications to chemical and pharmaceutical industry, to nanotechnology and medicine. However, during their first three decades, the hydrides of boron had no application whatsoever and it was their puzzling structure that sustained all research on them. Since the isolation of the first hydride of boron in 1912 they had been considered one of the most puzzling phenomena in chemistry and they managed to keep their irreducibility until the 1950’s. In the process, they forced bond theory to abandon one of its most fundamental paradigms: the atom-to-atom bond. The present work offers the first systematic historical account of the borane’s route to industrialization since their discovery, with a strong focus on the role played by the structural debate. The analysis is supported by a very thorough and comprehensive study of the technical questions involved in the dispute. The historical investigation of any scientific field/discipline/specialty can be guided by numerous hopefully complementary approaches and plural methodological commitments. However, in any given area, no truly consistent historical account can exist without an initial systematic and comprehensive assessment of the evolution of its technical problems. It is my contention that this starting point should be the basis upon which social, cultural and intellectual approaches can later (or simultaneously) find their unquestionable grounding and utility. Thus, the present work is clearly assumed to provide such a groundbreaking point of departure. The present work proves that the chemistry of the hydrides of boron was an integral and important part of theoretical chemistry in the twentieth century. No diachronic account of the history of chemistry in the twentieth century can ignore the history of the hydrides of boron. The history of these compounds is essential to put into a more inclusive perspective the history of chemical bond. The history of diborane raises the question of how ideas are able to evolve and be appropriated by other participants in new theoretical contexts. Ignoring the history of the hydrides of boron can only lead to a mistaken perception of their own identity. Such is the case with the presently prevailing idea that up until their use outside the academic environment, they had been laboratory curiosities. The present work demonstrates that during their laboratory phase they were rather seen as a pressing theoretical problem and this perception entirely guided all investigations. An interesting historiographic issue raised by the history of the hydrides of boron is the dramatic role played by war in their mutation into industrial and commercial products. Diborane’s history also has important bearings on the debates over the reducibility of chemistry to physics and the true nature of quantum chemistry. It is in complete agreement with the historiographic vision expressed a few years ago by Jed Buchwald and Allan Franklin and in fact it proves its fertility, at least on what concerns relatively recent historical processes.

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