Mechanism of Me-Re Bond Addition to Platinum(II) and Dioxygen Activation by the Resulting Pt-Re Bimetallic Center.
Unusual cis-oxidative addition of methyltrioxorhenium (MTO) to [PtMe2(bpy)], (bpy = 2,2'-bipyridine) (1) is described. Addition of MTO to 1 first gives the Lewis acid-base adduct [(bpy)Me2Pt-Re(Me)(O)3] (2) and subsequently affords the oxidative addition product [(bpy)Me3PtReO3] (3). All complexes 1, MTO, 2, and 3 are in equilibrium in solution. The structure of 2 was confirmed by X-ray crystallography, and its dissociation constant in solution is 0.87 M. The structure of 3 was confirmed by extended X-ray absorption fine structure and X-ray absorption near-edge structure in tandem with one- and two-dimensional NMR spectroscopy augmented by deuterium and13C isotope-labeling studies. Kinetics of formation of compound 3 revealed saturation kinetics dependence on [MTO] and first-order in [Pt], complying with prior equilibrium formation of 2 with oxidative addition of Me-Re being the rate-determining step. Exposure of 3 to molecular oxygen or air resulted in the insertion of an oxygen atom into the platinum-rhenium bond forming [(bpy)Me3PtOReO3] (4) as final product. Density functional theory analysis on oxygen insertion pathways leading to complex 4, merited on the basis of Russell oxidation pathway, revealed the involvement of rhenium peroxo species.
Brown Laboratory, Department of Chemistry, Purdue University , 560 Oval Drive, West Lafayette, Indiana 47907, United States.
Kothanda Rama
KR
Pichaandi
Qatar Environment and Energy Research Institute, Hamad Bin Khalifa University, Qatar Foundation , Doha, Qatar.
Lara
L
Kabalan
Department of Chemistry, College of Sciences, Shiraz University , Shiraz, 71467-13565 Iran.
Hashem
H
Amini
School of Chemical Engineering, Purdue University , Forney Hall of Chemical Engineering, 480 Stadium Drive, West Lafayette, Indiana 47907, United States.
Guanghui
http://orcid.org/0000-0002-5854-6909
G
Zhang
Brown Laboratory, Department of Chemistry, Purdue University , 560 Oval Drive, West Lafayette, Indiana 47907, United States.
Hanyu
H
Zhu
Brown Laboratory, Department of Chemistry, Purdue University , 560 Oval Drive, West Lafayette, Indiana 47907, United States.
Hilkka I
HI
Kenttämaa
Brown Laboratory, Department of Chemistry, Purdue University , 560 Oval Drive, West Lafayette, Indiana 47907, United States.
Phillip E
PE
Fanwick
School of Chemical Engineering, Purdue University , Forney Hall of Chemical Engineering, 480 Stadium Drive, West Lafayette, Indiana 47907, United States.
Jeffrey T
JT
Miller
Brown Laboratory, Department of Chemistry, Purdue University , 560 Oval Drive, West Lafayette, Indiana 47907, United States.|Qatar Environment and Energy Research Institute, Hamad Bin Khalifa University, Qatar Foundation , Doha, Qatar.
Sabre
S
Kais
Department of Chemistry, College of Sciences, Shiraz University , Shiraz, 71467-13565 Iran.
S Masoud
SM
Nabavizadeh
Department of Chemistry, College of Sciences, Shiraz University , Shiraz, 71467-13565 Iran.
Mehdi
M
Rashdi
Brown Laboratory, Department of Chemistry, Purdue University , 560 Oval Drive, West Lafayette, Indiana 47907, United States.|School of Chemical Engineering, Purdue University , Forney Hall of Chemical Engineering, 480 Stadium Drive, West Lafayette, Indiana 47907, United States.
Mahdi M
http://orcid.org/0000-0002-4412-1985
MM
Abu-Omar