220339-96-8Relevant articles and documents
A metal ion regulated artificial metalloenzyme
Bersellini, Manuela,Roelfes, Gerard
, p. 4325 - 4330 (2017)
Regulation of enzyme activity is essential in living cells. The rapidly increasing number of designer enzymes with new-to-nature activities makes it necessary to develop novel strategies for controlling their catalytic activity. Here we present the development of a metal ion regulated artificial metalloenzyme created by combining two anchoring strategies, covalent and supramolecular, for introducing a regulatory and a catalytic site, respectively. This artificial metalloenzyme is activated in the presence of Fe2+ ions, but only marginally in the presence of Zn2+.
Rotaxane synthesis exploiting the M(i)/M(III) redox couple
Emerson-King, Jack,Knighton, Richard C.,Gyton, Matthew R.,Chaplin, Adrian B.
, p. 11645 - 11655 (2017/09/18)
In the context of advancing the use of metal-based building blocks for the construction of mechanically interlocked molecules, we herein describe the preparation of late transition metal containing [2]rotaxanes (1). Capture and subsequent retention of the interlocked assemblies are achieved by the formation of robust and bulky complexes of rhodium(iii) and iridium(iii) through hydrogenation of readily accessible rhodium(i) and iridium(i) complexes [M(COD)(PPh3)2][BArF4] (M = Rh, 2a; Ir, 2b) and reaction with a bipyridyl terminated [2]pseudorotaxane (3·db24c8). This work was underpinned by detailed mechanistic studies examining the hydrogenation of 1p;:p;1 mixtures of 2 and bipy in CH2Cl2, which proceeds with disparate rates to afford [M(bipy)H2(PPh3)2][BArF4] (M = Rh, 4a[BArF4], t = 18 h @ 50 °C; Ir, 4b[BArF4], t 2Cl2 (1 atm H2). These rates are reconciled by (a) the inherently slower reaction of 2a with H2 compared to that of the third row congener 2b, and (b) the competing and irreversible reaction of 2a with bipy, leading to a very slow hydrogenation pathway, involving rate-limiting substitution of COD by PPh3. On the basis of this information, operationally convenient and mild conditions (CH2Cl2, RT, 1 atm H2, t ≤ 2 h) were developed for the preparation of 1, involving in the case of rhodium-based 1a pre-hydrogenation of 2a to form [Rh(PPh3)2]2[BArF4]2 (8) before reaction with 3·db24c8. In addition to comprehensive spectroscopic characterisation of 1, the structure of iridium-based 1b was elucidated in the solid-state using X-ray diffraction.
Reductive couplings of 2-halopyridines without external ligand: Phosphine-free nickel-catalyzed synthesis of symmetrical and unsymmetrical 2,2'-bipyridines
Liao, Lian-Yan,Kong, Xing-Rui,Duan, Xin-Fang
, p. 777 - 782 (2014/04/03)
An unexpectedly facile synthetic approach for symmetrical and unsymmetrical 2,2'-bipyridines through the Ni-catalyzed reductive couplings of 2-halopyridines was developed. The couplings were efficiently catalyzed by 5 mol % of NiCl2.6H2O without the use of external ligands. A variety of 2,2'-bipyridines including caerulomycin F have been efficiently synthesized.