Coordination-induced weakening of ammonia, water, and hydrazine X–H bonds in a molybdenum complex

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Science  11 Nov 2016:
Vol. 354, Issue 6313, pp. 730-733
DOI: 10.1126/science.aag0246

Coordinated scission of N–H or O–H bonds

Ammonia and water both have well-explored acid-base chemistry at room temperature, revolving around proton exchange. In contrast, radical chemistry involving H-atom exchange is comparatively rare in these molecules in the absence of a high-energy stimulus. Bezdek et al. now show that coordination of ammonia or water to a molybdenum complex substantially weakens the N–H or O–H bonds, so much so that heating to 60°C liberates hydrogen (see the Perspective by Hoover). Theoretical and electrochemical analyses reveal the underpinnings of the bond-weakening phenomenon.

Science, this issue p. 730; see also p. 707