TY  - JOUR
A1  - Noll, Niklas
A1  - Krause, Ana-Maria
A1  - Beuerle, Florian
A1  - Würthner, Frank
T1  - Enzyme-like water preorganization in a synthetic molecular cleft for homogeneous water oxidation catalysis
JF  - Nature Catalysis
N2  - Inspired by the proficiency of natural enzymes, mimicking of nanoenvironments for precise substrate preorganisation is a promising strategy in catalyst design. However, artificial examples of enzyme-like activation of H\(_2\)O molecules for the challenging oxidative water splitting reaction are hardly explored. Here, we introduce a mononuclear Ru(bda) complex (M1, bda: 2,2’-bipyridine-6,6’-dicarboxylate) equipped with a bipyridine-functionalized ligand to preorganize H\(_2\)O molecules in front of the metal center as in enzymatic clefts. The confined pocket of M1 accelerates chemically driven water oxidation at pH 1 by facilitating a water nucleophilic attack pathway with a remarkable turnover frequency of 140 s\(^{−1}\) that is comparable to the oxygen-evolving complex of photosystem II. Single crystal X-ray analysis of M1 under catalytic conditions allowed the observation of a 7th H\(_2\)O ligand directly coordinated to a RuIII center. Via a well-defined hydrogen-bonding network, another H\(_2\)O substrate is preorganized for the crucial O–O bond formation via nucleophilic attack.
KW  - water oxidation
KW  - enzyme
KW  - catalysis
KW  - molecular
KW  - catalyst synthesis
KW  - catalytic mechanisms
KW  - homogeneous catalysis
KW  - photocatalysis
KW  - supramolecular chemistry
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-302897
N1  - This version of the article has been accepted for publication, after peer review and is subject to Springer Nature’s AM terms of use (https://www.springernature.com/gp/open-research/policies/accepted-manuscript-terms), but is not the Version of Record and does not reflect post-acceptance improvements, or any corrections. The Version of Record is available online at: https://doi.org/10.1038/s41929-022-00843-x
ET  - accepted version
ER  - 
TY  - JOUR
A1  - Karak, Suvendu
A1  - Stepanenko, Vladimir
A1  - Addicoat, Matthew A.
A1  - Keßler, Philipp
A1  - Moser, Simon
A1  - Beuerle, Florian
A1  - Würthner, Frank
T1  - A Covalent Organic Framework for Cooperative Water Oxidation
JF  - Journal of the American Chemical Society
N2  - The future of water-derived hydrogen as the “sustainable energy source” straightaway bets on the success of the sluggish oxygen-generating half-reaction. The endeavor to emulate the natural photosystem II for efficient water oxidation has been extended across the spectrum of organic and inorganic combinations. However, the achievement has so far been restricted to homogeneous catalysts rather than their pristine heterogeneous forms. The poor structural understanding and control over the mechanistic pathway often impede the overall development. Herein, we have synthesized a highly crystalline covalent organic framework (COF) for chemical and photochemical water oxidation. The interpenetrated structure assures the catalyst stability, as the catalyst’s performance remains unaltered after several cycles. This COF exhibits the highest ever accomplished catalytic activity for such an organometallic crystalline solid-state material where the rate of oxygen evolution is as high as ∼26,000 μmol L\(^{–1}\) s\(^{–1}\) (second-order rate constant k ≈ 1650 μmol L s\(^{–1}\) g\(^{–2}\)). The catalyst also proves its exceptional activity (k ≈ 1600 μmol L s\(^{–1}\) g\(^{–2}\)) during light-driven water oxidation under very dilute conditions. The cooperative interaction between metal centers in the crystalline network offers 20–30-fold superior activity during chemical as well as photocatalytic water oxidation as compared to its amorphous polymeric counterpart.
KW  - water oxidation
KW  - sustainable energy source
KW  - covalent organic framework
KW  - catalyst
KW  - crystalline
KW  - catalysis
KW  - nanoparticles
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-287591
UR  - https://pubs.acs.org/doi/10.1021/jacs.2c07282
SN  - 0002-7863
VL  - 144
IS  - 38
ER  -