An experimental and computational study of sulfur-modified nucleophilicity in a dianionic NiN2S2 complex.
The dianionic NiN2S2 complex, Ni(ema)2-, ema=N,N'-ethylenebis-2-mercaptoacetamide, known as a reasonable model of the tripeptide complex Ni(CGC)2- (C=cysteine; G=glycine) with respect to the two carboxyamido nitrogens and cis-dithiolates in a (N2S2)4- ligand scaffold as found in acetyl CoA synthase, has been explored for S-based reactivity toward oxygenation and alkylation. The isolation and structural characterization of a sulfinato species, [Et4N]2[Ni(ema).O2], prepared through a unique direct reaction of molecular O2 with crystalline [Et4N]2[Ni(ema)] is described. Reaction of [Et4N]2[Ni(ema)] with Br(CH2)3Br yields a neutral N2S2 macrocyclic complex shown by DFT computations and electrostatic-potential mapping to be opposite in electron distribution from the neutral NiN2S2 complexes in which the anionic charge is localized on sulfur.
Department of Chemistry, Texas A&M University, College Station, Texas 77845, USA.
Kayla N
KN
Green
Scott M
SM
Brothers
Roxanne M
RM
Jenkins
Cody E
CE
Carson
Craig A
CA
Grapperhaus
Marcetta Y
MY
Darensbourg
D000081:Acetamides / Q000737:chemistry; D000838:Anions / Q000737:chemistry; D003198:Computer Simulation; D004563:Electrochemistry; D004578:Electron Spin Resonance Spectroscopy; D005030:Ethylenes / Q000737:chemistry; D008958:Models, Molecular; D008968:Molecular Conformation; D009532:Nickel / Q000737:chemistry; D009942:Organometallic Compounds / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry; D000644:Quaternary Ammonium Compounds / Q000737:chemistry; D055672:Static Electricity; D013455:Sulfur / Q000737:chemistry*; D013457:Sulfur Compounds
D000081:Acetamides; D000838:Anions; D005030:Ethylenes; D009942:Organometallic Compounds; D000644:Quaternary Ammonium Compounds; D013457:Sulfur Compounds; C421484:ethylammonium; D013455:Sulfur; D009532:Nickel; C030686:acetamide; C036216:ethylene; D010100:Oxygen