Chemistry Reference
In-Depth Information
the NMR era (50s and 60s) when
1
H NMR thrived by itself, not yet com-
plemented by
13
C NMR, the hydrocarbon skeleton was primarily re-
vealed by the spectrum.
Matter, when in a magnetic field and tickled by RF waves, gained in
meaningfulness. NMR was a micro-scope of a different order. It dis-
played inter-relationships between atoms in a molecule (Barton 1972).
Couplings among nuclei, whether scalar or dipolar couplings, were the
silk threads in the spider web that the NMR spectrum revealed. NMR
was truly the Ariadne's thread guiding chemists to their Holy Grail of
structure elucidation.
The web of interactions thus revealed in turn mapped molecular
structure. Spectral analysis (the NMR tube) had replaced chemical analy-
sis (the test tube). Analyzing a spectrum, furthermore, was an exact sci-
ence, not an interpretation fraught with uncertainty, open to skepticism
and dispute.
How did chemists greet the new tool made suddenly available to them
towards the mid-1950s? Their obvious alacrity was tinged with ambiva-
lence. Chemists of the old school did not always embrace the new situa-
tion that they were dependent on young upstarts, called 'NMR special-
ists'. They retrained themselves. They had to. In addition, they had to
contend with the shadow cast by physics, which obscured the cherished
notion of the autonomy of chemistry, of its non-reducibility to physics.
The mixed feeling expressed itself in a catch phrase of those times,
'physical methods'.
With the advent of NMR, new values - in the strongest sense of
moral, ethical, and axiological values - came to dominate chemistry,
while more traditional values were made redundant and obsolete (Camp-
bell 1960). Take the example of elemental analyses. Before NMR came
on the scene, they were the equivalent of a moral obligation. They linked
laboratory notebooks to the final publication of the results. Now, elemen-
tal analyses became dispensable by the information from the new spec-
troscopies, high-resolution mass spectrometry (Laidler 2004) even more
so than NMR. In spite of this new aspect of laboratory life, journals in-
sisted for a long time (measured not in years but in decades) on the con-
tinued insertion of elemental analytical data in the experimental part of
manuscripts submitted for publication.
