Synthesis and electronic characterization of bipyridine dithiolate rhodium(III) complexes.
Five new mixed diimine 1,1'-dithiolate or dithiocarbamate ligand complexes of the form [Rh(bpy)2(SS)][PF6]n, where bpy = 2,2'-bipyridine and SS = various substituted dialkyldithiocarbamates or 1,1'-dithiolates, were synthesized from cis-[Rh(bpy)2(OTf)2][OTf]. The triflate ligands are easily displaced by other ligands and allow these syntheses to proceed in high yields (80-90% overall) under relatively mild reaction conditions and to give high purity products. Electrochemistry shows irreversible two-electron reduction of Rh(III) to Rh(I) and a concomitant loss of one bipyridine ligand; this is followed by reversible one-electron reduction of the remaining 2,2'-bipyridine ligand. The electronic characterizations of these complexes are consistent with significant delocalization of the sulfur electron density onto the empty metal d orbitals. The 1,1'-dithiolate ligands induce larger red shifts in the absorption and emission spectra than the dithiocarbamates as the 1,1'-dithiolates have a more extensive conjugation system.
Amarante
Daniel
D
Chemistry Department, St. John's College, St. John's University, Queens, New York 11439, USA.
Cherian
Cheryl
C
Catapano
Anthony
A
Adams
Rebekah
R
Wang
Man Hoi
MH
Megehee
Elise G
EG
D015392:Chemistry, Inorganic / Q000379:methods*; D004563:Electrochemistry / Q000379:methods; D009682:Magnetic Resonance Spectroscopy; D011725:Pyridines / Q000138:chemical synthesis / Q000737:chemistry*; D012238:Rhodium / Q000737:chemistry*
D011725:Pyridines; D012238:Rhodium