From C&EN Archives: Chemical Bonding

Throughout its 90-year history, C&EN has explored new developments in chemical bonding and their impact on science, as these three examples reveal.

Aromatic Character In 1965, to celebrate the 100th anniversary of August Kekulé’s elucidation of the structure of benzene, C&EN published a special feature on aromaticity, complete with hand-drawn structures, written by Columbia University’s Ronald Breslow, an authority on organic ring compounds and reaction mechanisms. In the review, Breslow notes that 100 years after Kekulé, “chemists are still trying to understand aromatic character. Modern techniques and the increasing application of quantum mechanics to organic chemistry have led to the preparation of many new aromatic systems and to a deeper understanding of conjugated systems generally” (C&EN, June 28, 1965, page 90).

Metals and Enzymes “Multiple juxtapositional fixedness (MJF) is the tongue-in-cheek term that Dr. Daryle H. Busch has coined to describe the unusually strong bonding that occurs between metal ions and some ligands, and to account for certain aspects of metal-enzyme activity. Nevertheless, Dr. Busch notes that he was serious in his search for a phrase that would describe the principle of kinetic and thermodynamic stabilization that occurs whenever certain groups are so arranged in space that they can’t undergo stepwise dissociation from a metal ion by the usual pathways. The Ohio State University professor of chemistry described the principle at the 25th annual Northwest Regional ACS Meeting in Seattle” (C&EN, June 29, 1970, page 9).

The Chemical Side of the Double Helix “The double helix. That two-word phrase is so firmly planted in our scientific lexicon that even a good number of nonscientists recognize the reference to the structure of DNA. Many of us can’t remember a time when DNA wasn’t recognized as being the genetic material or as taking the form of two hydrogen-bonding complementary strands of base-pairing nucleotides wound around a single axis. Although the B-form DNA structure that James D. Watson and Francis H. C. Crick proposed in their April 25, 1953, letter to Nature made only a limited splash at the time, the subsequent ripples revolutionized biology—particularly genetics—turning it into a molecular science” (C&EN, March 10, 2003, page 49).