An anatomy of the two-state reactivity concept: Personal reminiscences in memoriam of Detlef Schröder

Two-state reactivity (TSR) has become a widely used concept in bioinorganic and metallo-enzymatic chemistry. This concept was conceived in response to puzzling data on the reactivity of FeO+ with H2[1], and in the reactivity patterns of the enzyme Cytochrome P450. The TSR concept has been developed through a very intense interaction of the author with Helmut Schwarz and the late Detlef Schröder between the years 1993 and 1998. The paper is written as a tribute to Detlef Schröder who passed away untimely, and is still remembered by his many friends as a wonderful scientist with scintillating energy, goodness and enthusiasm.