TY - JOUR
T1 - Exceedingly facile Ph-X activation (X=Cl, Br, I) with ruthenium(II)
T2 - Arresting kinetics, autocatalysis, and mechanisms
AU - Miloserdov, Fedor M.
AU - Mckay, David
AU - Muñoz, Bianca K.
AU - Samouei, Hamidreza
AU - Macgregor, Stuart A.
AU - Grushin, Vladimir V.
N1 - "S.A.M. and D.M. thank the EPSRC for support through award EP/J010677/1."
PY - 2015/7/13
Y1 - 2015/7/13
N2 - [(Ph3P)3Ru(L)(H)2] (where L=H2 (1) in the presence of styrene, Ph3P (3), and N2 (4)) cleave the Ph-X bond (X=Cl, Br, I) at RT to give [(Ph3P)3RuH(X)] (2) and PhH. A combined experimental and DFT study points to [(Ph3P)3Ru(H)2] as the reactive species generated upon spontaneous loss of L from 3 and 4. The reaction of 3 with excess PhI displays striking kinetics which initially appears zeroth order in Ru. However mechanistic studies reveal that this is due to autocatalysis comprising two factors: 1) complex 2, originating from the initial PhI activation with 3, is roughly as reactive toward PhI as 3 itself; and 2) the Ph-I bond cleavage with the just-produced 2 gives rise to [(Ph3P)2RuI2], which quickly comproportionates with the still-present 3 to recover 2. Both the initial and onward activation reactions involve PPh3 dissociation, PhI coordination to Ru through I, rearrangement to a η2-PhI intermediate, and Ph-I oxidative addition.
AB - [(Ph3P)3Ru(L)(H)2] (where L=H2 (1) in the presence of styrene, Ph3P (3), and N2 (4)) cleave the Ph-X bond (X=Cl, Br, I) at RT to give [(Ph3P)3RuH(X)] (2) and PhH. A combined experimental and DFT study points to [(Ph3P)3Ru(H)2] as the reactive species generated upon spontaneous loss of L from 3 and 4. The reaction of 3 with excess PhI displays striking kinetics which initially appears zeroth order in Ru. However mechanistic studies reveal that this is due to autocatalysis comprising two factors: 1) complex 2, originating from the initial PhI activation with 3, is roughly as reactive toward PhI as 3 itself; and 2) the Ph-I bond cleavage with the just-produced 2 gives rise to [(Ph3P)2RuI2], which quickly comproportionates with the still-present 3 to recover 2. Both the initial and onward activation reactions involve PPh3 dissociation, PhI coordination to Ru through I, rearrangement to a η2-PhI intermediate, and Ph-I oxidative addition.
KW - Ar-X activation
KW - Autocatalysis
KW - DFT calculations
KW - Kinetics
KW - Ruthenium
UR - http://www.scopus.com/inward/record.url?scp=84930410867&partnerID=8YFLogxK
U2 - 10.1002/anie.201501996
DO - 10.1002/anie.201501996
M3 - Article
C2 - 26036691
SN - 1433-7851
VL - 54
SP - 8466
EP - 8470
JO - Angewandte Chemie International Edition
JF - Angewandte Chemie International Edition
IS - 29
ER -