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A long time in the waiting: In 1960 Wanzlick brought N-heterocyclic carbenes to the point of take off. Experimental shortcomings, misunderstanding, and prejudgments, however, hindered their take off. Only 30 years later, with the isolation and structural elucidation of N-heterocyclic carbenes by Arduengo, did the flight begin.
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Wolfgang Kirmse (2010) studied this question.
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