Asymmetric sulfur atom coordination in a copper(II) dipicolylamine (DPA) complex with a thioglycoside ligand.
The 2,2'-dipicolylamine (DPA)-tethered thioglycoside ligand, N,N-bis(2-pyridylmethyl)-2-aminoethyl 1-deoxy-1-thio-2,3,4,6-tetra-O-acetyl-beta-d-glucopyranoside (sL1), has been prepared and its copper(II) complex synthesized. Using copper(II) chloride, the copper complex was isolated as a chloride-bound species formulated as [Cu(sL1)Cl(ClO(4))](1). The corresponding O-glycoside complex ([Cu(L1)Cl](ClO(4)), 2) was also prepared using L1 (N,N-bis(2-pyridylmethyl)-2-aminoethyl 2,3,4,6-tetra-O-acetyl-beta-d-glucopyranoside), and both complexes were characterized and compared by means of X-ray crystallography, cyclic voltammetry, electronic absorption and circular dichroism (CD) spectra. Although both complexes exhibited similar copper coordination geometries, the absolute configuration of the O/S chiral center generated by the copper coordination was inverted. The electronic and CD spectra of acetonitrile solutions of 1 and 2 were different likely due to the presence of a copper-sulfur charge-transfer band for 1. Complex also exhibits a large Cotton effect around 700 nm. The corresponding d-d transition of the copper(II) center reveals that the asymmetric copper-sulfur (oxygen) coordination remains even in solution.
Sugai
Yuko
Y
Division of Functional Material Science, Nara Women's University, Nara, 630-8506, Japan.
Fujii
Shoko
S
Fujimoto
Tomomi
T
Yano
Shigenobu
S
Mikata
Yuji
Y
D000588:Amines / Q000737:chemistry*; D003300:Copper / Q000737:chemistry*; D018360:Crystallography, X-Ray; D004563:Electrochemistry; D008024:Ligands; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000737:chemistry*; D010848:Picolinic Acids / Q000737:chemistry*; D013455:Sulfur / Q000737:chemistry*; D013865:Thioglycosides / Q000737:chemistry*
C501847:2,2'-dipicolylamine; D000588:Amines; D008024:Ligands; D009942:Organometallic Compounds; D010848:Picolinic Acids; D013865:Thioglycosides; D013455:Sulfur; D003300:Copper