Stephan Schenk

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Carbonic anhydrase (CA) is known to react with carbonyl sulfide, an atmospheric trace gas, whereby H(2)S is formed. It has been shown that, in the course of this reaction, the active catalyst, the His(3)ZnOH structural motif, is converted to its hydrosulfide form: His(3)ZnOH+COS-->His(3)ZnSH+CO(2). In this study, we elucidate the mechanism of reactivation(More)
In this work, we investigate the mechanism of the ammonia-dinitrogen exchange reaction, which is the decisive step to close the catalytic cycle of Schrock's dinitrogen reduction sequence under ambient conditions. We identify several viable pathways for the approach of dinitrogen to the five-coordinate molybdenum center of the ammonia complex by means of(More)
In this work, we investigate with density functional methods mechanistic details of catalytic dinitrogen reduction mediated by Schrock's molybdenum complex under ambient conditions. We explicitly take into account the full HIPTN 3N ligand without approximating it by model systems. Our data show that replacement of the bulky HIPT substituent by smaller(More)
We have extended our investigations of the carbonic anhydrase (CA) cycle with the model system [(H(3)N)(3)ZnOH](+) and CO(2) by studying further heterocumulenes and catalysts. We investigated the hydration of COS, an atmospheric trace gas. This reaction plays an important role in the global COS cycle since biological consumption, that is, uptake by higher(More)
This Perspective starts with the discussion of the properties of an interesting metalloenzyme (carbonic anhydrase, CA) that performs extremely successfully the activation of carbon dioxide. Conclusions from that are important for many synthetic procedures and include experimental and theoretical investigation (DFT calculations) of such metal mediated(More)
Catalytic dinitrogen reduction with the Schrock complex is still hampered by low turn-over numbers that are likely to result from a degradation of the chelate ligand. In this work, we investigate modifications of the original HIPTN(3)N ligand applied by Schrock and co-workers in catalytic reduction of dinitrogen with density functional methods. We focus on(More)
In this article we performed an extensive density functional [BP86/6-311++G(3df,3pd) level] investigation of the hypersurface of the Mitsunobu reaction. Reaction of a phosphine with a dialkyl azodicarboxylate (first step in the Mitsunobu conversion) leads to either a five-membered oxadiazaphosphole ring (more stable) or a betaine. The subsequent formation(More)
The macrocyclic ligand [13]aneN 4 ( L1, 1,4,7,10-tetra-azacyclotridecane) was reacted with Zn(II) perchlorate and CO 2 in an alkaline methanol solution. It was found that, by means of subtle changes in reaction conditions, two types of complexes can be obtained: (a) the mu 3 carbonate complex 1, {[Zn( L1)] 3(mu 3-CO 3)}(ClO 4) 4, rhombohedral crystals,(More)
CeO2-x nanorods are functional mimics of natural haloperoxidases. They catalyze the oxidative bromination of phenol red to bromophenol blue and of natural signaling molecules involved in bacterial quorum sensing. Laboratory and field tests with paint formulations containing 2 wt% of CeO2-x nanorods show a reduction in biofouling comparable to Cu2 O, the(More)