TY - JOUR
T1 - Experimental and Computational Studies of Ruthenium Complexes Bearing Z-Acceptor Aluminum-Based Phosphine Pincer Ligands
AU - Isaac, Connie J.
AU - Wilson, Cameron I.
AU - Burnage, Arron L.
AU - Miloserdov, Fedor M.
AU - Mahon, Mary F.
AU - Macgregor, Stuart A.
AU - Whittlesey, Michael K.
PY - 2022/12/19
Y1 - 2022/12/19
N2 - Reaction of [Ru(C6H4PPh2)2(Ph2PC6H4AlMe(THF))H]
with CO results in clean conversion to the Ru−Al heterobimetallic complex
[Ru(AlMePhos)(CO)3] (1), where AlMePhos is the novel
P–Al(Me)–P pincer ligand (o-Ph2PC6H4)2AlMe.
Under photolytic conditions, 1 reacts with H2 to
give [Ru(AlMePhos)(CO)2(μ-H)H] (2) that is characterized by
multinuclear NMR and IR spectroscopies. DFT calculations indicate that 2 features
one terminal and one bridging hydride that are respectively anti and syn to
the AlMe group. Calculations also define a mechanism for H2 addition
to 1 and predict facile hydride exchange in 2 that
is also observed experimentally. Reaction of 1 with B(C6F5)3 results
in Me abstraction to form the ion pair [Ru(AlPhos)(CO)3][MeB(C6F5)3]
(4) featuring a cationic [(o-Ph2PC6H4)2Al]+ ligand,
[AlPhos]+. The Ru–Al distance in 4 (2.5334(16) Å)
is significantly shorter than that in 1 (2.6578(6) Å),
consistent with an enhanced Lewis acidity of the [AlPhos]+ ligand.
This is corroborated by a blue shift in both the observed and computed νCO stretching
frequencies upon Me abstraction. Electronic structure analyses (QTAIM and
EDA-ETS) comparing 1, 4, and the previously reported
[Ru(ZnPhos)(CO)3] analogue (ZnPhos = (o-Ph2PC6H4)2Zn)
indicate that the Lewis acidity of these pincer ligands increases along the
series ZnPhos < AlMePhos < [AlPhos]+.
AB - Reaction of [Ru(C6H4PPh2)2(Ph2PC6H4AlMe(THF))H]
with CO results in clean conversion to the Ru−Al heterobimetallic complex
[Ru(AlMePhos)(CO)3] (1), where AlMePhos is the novel
P–Al(Me)–P pincer ligand (o-Ph2PC6H4)2AlMe.
Under photolytic conditions, 1 reacts with H2 to
give [Ru(AlMePhos)(CO)2(μ-H)H] (2) that is characterized by
multinuclear NMR and IR spectroscopies. DFT calculations indicate that 2 features
one terminal and one bridging hydride that are respectively anti and syn to
the AlMe group. Calculations also define a mechanism for H2 addition
to 1 and predict facile hydride exchange in 2 that
is also observed experimentally. Reaction of 1 with B(C6F5)3 results
in Me abstraction to form the ion pair [Ru(AlPhos)(CO)3][MeB(C6F5)3]
(4) featuring a cationic [(o-Ph2PC6H4)2Al]+ ligand,
[AlPhos]+. The Ru–Al distance in 4 (2.5334(16) Å)
is significantly shorter than that in 1 (2.6578(6) Å),
consistent with an enhanced Lewis acidity of the [AlPhos]+ ligand.
This is corroborated by a blue shift in both the observed and computed νCO stretching
frequencies upon Me abstraction. Electronic structure analyses (QTAIM and
EDA-ETS) comparing 1, 4, and the previously reported
[Ru(ZnPhos)(CO)3] analogue (ZnPhos = (o-Ph2PC6H4)2Zn)
indicate that the Lewis acidity of these pincer ligands increases along the
series ZnPhos < AlMePhos < [AlPhos]+.
UR - http://www.scopus.com/inward/record.url?scp=85143688732&partnerID=8YFLogxK
U2 - 10.1021/acs.inorgchem.2c03665
DO - 10.1021/acs.inorgchem.2c03665
M3 - Article
C2 - 36475641
SN - 0020-1669
VL - 61
SP - 20690
EP - 20698
JO - Inorganic Chemistry
JF - Inorganic Chemistry
IS - 50
ER -