Zinc/nickel exchange and ligand cannibalism in N2S2O(1,2) donor ligand sets.
To explore the displacement of Zn(2+) by Ni(2+) from within N-, S-, and O-chelate ligands, (N-(3-thiabutyl)-N'-(3-thiapentaneoate)-1,4-diazacycloheptane)zinc(II), Zn-1'-Ac, and 1,4-diazacycloheptane-1,4-diylbis(3-thiapentanoato) zinc(II), Zn-1'-Ac(2), were reacted with Ni(BF(4))(2) in a methanol solution and were found to yield, in both cases, the bright blue, hexa-coordinate Ni-1'-Ac(2) metal-exchanged product. The latter conditions imply an intact-ligand unwrapping process as the hexadentate N(2)S(2)O(2) ligand is transferred from zinc to nickel. The former involves transfer of the pentadentate N(2)S(2)O ligand generating a green, penta-coordinate nickel intermediate which engages in CH(2)CO(2) fragment scavenging from a second zinc unit. This conclusion is supported by the observed analogous reformulation of the stable Zn-1'-Ac complex into Zn-1'-Ac(2) and the dithiolato [Zn-1'](2) dimer. To our knowledge, this is a rare (possibly the first) example of cannibalism reported in such ligand systems. The M-1'-Ac(2) complexes were characterized by X-ray diffraction and compared to the directly synthesized products.
Department of Chemistry, Texas A&M University, College Station, Texas 77843, USA.
Elky
E
Almaraz
Jason A
JA
Denny
William S
WS
Foley
Joseph H
JH
Reibenspies
Nattamai
N
Bhuvanesh
Marcetta Y
MY
Darensbourg
D002614:Chelating Agents / Q000737:chemistry*; D018360:Crystallography, X-Ray; D008024:Ligands; D008958:Models, Molecular; D008968:Molecular Conformation; D009532:Nickel / Q000737:chemistry*; D009584:Nitrogen / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry*; D013455:Sulfur / Q000737:chemistry*; D015032:Zinc / Q000737:chemistry*
D002614:Chelating Agents; D008024:Ligands; D013455:Sulfur; D009532:Nickel; D015032:Zinc; D009584:Nitrogen; D010100:Oxygen