Hydrogenase Enzyme Reactivity Modeling with a Transition-Metal Dihydrogen Complex

Noyori's Hydrogenation Catalyst Needs a Lewis Acid Cocatalyst for High Activity We thank Mr. Christian Dambouwy, Thales Technologies AG, Zürich, Switzerland, for experimental work to compare the effects of various combinations of bases and salts. Additionally, we thank Mr. Holgar Sellner in the group of Prof. D. Seebach for assistance in ee measurements, and Sebastian D. Friess for carefully correcting the German version of this manuscript.

“…Dicationic Ru II complexes21 show even more extreme behavior with respect to H 2 . The same effect has been suggested to be operative in certain hydrogenases 22…”

Catalytic Processes Involving Dihydrogen Complexes and Other Sigma-bond Complexes

“…The r coordinated H-Si distance in 12 is 1. 91(2) Å , at the higher limit for r-Si-H bonds [121]. The SISHA interaction H-Si has a distance of 1.…”

“…Possible mechanisms could involve 7-or 8-coordinate 20e intermediates such as a (H 2 )(D 2 ) complex or species such as WH 2 (D 2 )(CO) 3 (PR 3 ) 2 , but no evidence exists for these. Trace quantities of adventitious water may lead to exchange since isotopic scrambling of W(CO) 3 (PR 3 ) 2 (D 2 ) with H 2 O occurs in solution within days [85] or less for other D 2 complexes [86][87][88][89][90][91][92]. A reasonable exchange mechanism for complexes with one open coordination site is deprotonation of g 2 -H 2 by the weak base water followed by reprotonation with H 2 DO + .…”

Hydridic reactivity of W(CO)(H)(NO)(PMe3)3 – Dihydrogen bonding and H2 formation with protic donors

“…Distances r(HÁÁÁH) in [Å] can be obtained from Eq. (11) [12,27,[91][92][93][94][95] where m is the NMR frequency in MHz and DR 1 (min) = 1/T 1 (min)(add) -1/T 1 (min)(WH). rðH Á Á Á HÞ ¼ 5:817ðm Á DR1ðminÞÞ À1=6 ð11Þ…”