Synthesis, characterization, and O2 reactivity of iridium(I) complexes supported by guanidinato ligands.
Mononuclear [Ir{ArNC(NR(2))NAr}(C(8)H(12))] complexes (where R = Me or Et; Ar = Ph, 4-MeC(6)H(4), or 2,6-Me(2)C(6)H(3); and C(8)H(12) = 1,5-cyclooctadiene) were synthesized from the neutral N,N-dialkyl-N',N''-diarylguanidines via deprotonation and transmetalation. As confirmed by single-crystal structure determinations, the guanidinato(1-) ligands coordinate the low-valent d(8) Ir(I) center in an N,N'-chelating binding mode, and the (13)C NMR chemical shifts of the alkene carbon atoms establish that these ligands function as stronger donors than related monoanionic, bidentate nitrogen-based ligands. In the reactions of the complexes with O(2), the observed reactivity trends correlate with the electronic and steric influences of the substituents of the guanidinato ligands.
Rohde
Jan-Uwe
JU
Department of Chemistry, The University of Iowa, Iowa City, Iowa 52242, USA. jan-uwe-rohde@uiowa.edu
Kelley
Matthew R
MR
Lee
Wei-Tsung
WT