Transition-Metal-Mediated Activation of Sulfur toward C–S Bond Formation Jan-Uwe Rohde, Department of Chemistry, The University of Iowa, Iowa City, IA 52242 Tunable N,N-dialkyl-N',N''-diarylguanidinates provide access to low- and high-valent iridium, ranging from IrI to IrIV: R''
N Ir R' R N R' N R
Absorbance
1. IrI complexes react with O2 and S8 under ambient conditions, and the reactivity can be modulated through substituent effects (right).
R'
R' R''
Current
0
-0.5
-1
Potential (V) vs. [FeCp2]/[FeCp2]+
2. IrIII complexes can be oxidized at unusually low redox potentials.
0 350
1 Time (h)
450 Wavelength (nm)
N
Ar N R2N N Ar 0.5
0
NR2
Ar
1
1
N Ir N
Ar Ar
+ [FeCp2]PF6 – [FeCp2]
N Ar
NR2
3. IrIV can be stabilized in a nitrogendonor ligand environment.
550
2
