Ni complexes of N 2 S ligands with amine/imine and amine/amide donors with relevance to the active site of Ni superoxide dismutase

Nickel(II)‐Mediated Reversible Thiolate/Disulfide Conversion as a Mimic for a Key Step of the Catalytic Cycle of Methyl‐Coenzyme M Reductase

“…[25] TheS ÀSd istance of 1 Cl is in the range of typical SÀSd istances found with Ar-S-S-Ar disulfides. [26] TheN i II -coordinated Cl of 1 Cl is eliminated following reaction with AgClO 4 in CH 3 CN to form as olvent ligated complex 1 Solv .This transformation of 1 Cl to 1 Solv was monitored using UV/Vis spectroscopy (Figure S19). Theisolated solid of 1 Solv displays no n CN of CH 3 CN in its FTIR spectrum (Figure S9A, see synthesis) but exhibits an intense stretch at 3400 cm À1 that probably corresponds to the n O-H of H 2 O, either coordinated to Ni II or present as solvent of crystallization.…”

Model Complexes for the Nip Site of Acetyl Coenzyme A Synthase/Carbon Monoxide (CO) Dehydrogenase: Structure, Electrochemistry, and CO Reactivity

“…Mono- and binuclear complexes as models of the Ni d , Ni p –Ni d , and Cu p –Ni d subunits of the A cluster of ACS/CODH are known. , In addition to these, a few trinuclear ,− ,,,, and heteromultinuclear , complexes, containing metal cores such as Ni 3 Cu 2 , Ni 2 Cu 2 , and Ni 3 Zn 2 , related to the A-cluster modeling of ACS are reported. In all of these models, either amidato-N-containing or tert -amine-N-containing thiol ligands are used to mimic the Ni d part, which, in turn, utilizes its thiolato S to bridge another metal ion such as Ni II , Cu I , or Zn II , hence producing a M p site. Employment of such N donors ( tert -amine or amide) is reasonable because these can stabilize the Ni II state of Ni d to a great extent and prevent its reduction to Ni I , ensuring that the modeled Ni p is the sole reducible site.…”

“…The Ni p site is able to bind substrates such as CO following reduction and may proceed further to acetyl thioester formation such as acetyl CoA, produced by ACS/CODH. Unfortunately, however, only a few models are reported to exhibit CO binding to reduced Ni I of the Ni p model site, ,− ,, and even fewer are known to produce acetyl thioester. , A literature survey surprisingly revealed no model complex with an imine-N-containing thiol ligand that may generate a S-rich coordination environment surrounding a Ni II center that can mimic the properties of the Ni p site like other models. ,− ,, Also, a six-coordinate metallothiolate synthon that generates a Ni p model is unknown. , As a continuing interest to investigate the donor-strength-dependent stabilization of various Ni oxidation states (0, 1+, 2+, and 3+) in NS donor environments and to study their reactivity, herein, we first report the use of pyridine-/imine-N-containing thiol ligands to synthesize thiolato-S-bridged bi- and trinuclear nickel complexes. These yield Ni p site models by employing a six-coordinate NiN 4 S 2 metallothiolate synthon.…”

Could boron-containing compounds (BCCs) be effective against SARS-CoV-2 as anti-viral agent?

“…O-C and C-C bond lengths are calculated to be nearly 1.37 and 1.40 Å, respectively. The carbon-carbon bond length in the benzene ring has been reported to be about 1.38 Å (19,20). The whole structures are planar except for the compound B5.…”