9 Frustrated Lewis Pairs Based on Transition Metals
347
9.4 Conclusion
Since the foremost reports around a decade ago, the field of transition metal FLPs has
enjoyed an outstanding expansion, particularly in the last five years. The vast amount
of examples described in this Chapter cover the majority of transition metals, as well
as a great variety of ligand frameworks. Besides, the field is continuously attracting
the attention of new audiences, evidencing its current great shape. A rising number of
research groups with complementary backgrounds and approaches are invigorating
the area in numerous ways and into novel scientific avenues. Not only homogeneous TMFLPs have been described, but also heterogeneous versions are more and
more often identified. The introduction of transition metals into FLPs, an area that
rapidly became an emblem of metal-free catalysis, is somehow serving to reconnect
main group and transition metal chemistry research, sometimes oddly segmented.
Advanced computational work has proved essential to delineate a more solid analogy
between frustrated Lewis pairs and cooperative transition metal systems whose reactivity can easily be understood in terms of ‘frustration’. The barrier between TMFLPs
and the broader area of transition metal cooperative systems has become rather
diffuse, even more if we assume a definition of an FLP as a combination of a Lewis
acid and a base that exhibits FLP chemistry [187]. The identification of key transition states by computational means is rendering insightful information that will be
decisive to develop novel architectures with desired properties.
The number of contributions in which authors are specifically stating the analogy
between FLPs and cooperative transition metal complexes is also continuously
growing. The concept of TMFLP has clearly permeated to other research areas and
fruitful inputs from those will surely boost up the potential of the field. Indeed, despite
being still in a sort of advanced infancy, all these aspects substantiate the notion of
some degree of maturity in the area. We are currently in a lively state of development
in which both very fundamental studies and also applications to catalysis, sensing or
materials designs may rapidly expand to address important scientific challenges. In
terms of catalysis, we believe that the combined virtues of transition metal complexes
and the concept of frustration will make it possible to functionalize inert molecules
that would otherwise remain unaltered. For instance, the efficient functionalization
of inert C–H bonds or the hydrogenation of dinitrogen, which could both be considered ‘holy-grail’ reactions for any synthetic chemist, are currently out of the scope of
main group FLPs, while remaining a difficult challenge for transition metal systems.
Taking advantage of the rich chemistry of transition metals along with the powerful
activating capacity of FLPs could provide original solutions to these and many other
unresolved problems faced by modern chemistry.
347
9.4 Conclusion
Since the foremost reports around a decade ago, the field of transition metal FLPs has
enjoyed an outstanding expansion, particularly in the last five years. The vast amount
of examples described in this Chapter cover the majority of transition metals, as well
as a great variety of ligand frameworks. Besides, the field is continuously attracting
the attention of new audiences, evidencing its current great shape. A rising number of
research groups with complementary backgrounds and approaches are invigorating
the area in numerous ways and into novel scientific avenues. Not only homogeneous TMFLPs have been described, but also heterogeneous versions are more and
more often identified. The introduction of transition metals into FLPs, an area that
rapidly became an emblem of metal-free catalysis, is somehow serving to reconnect
main group and transition metal chemistry research, sometimes oddly segmented.
Advanced computational work has proved essential to delineate a more solid analogy
between frustrated Lewis pairs and cooperative transition metal systems whose reactivity can easily be understood in terms of ‘frustration’. The barrier between TMFLPs
and the broader area of transition metal cooperative systems has become rather
diffuse, even more if we assume a definition of an FLP as a combination of a Lewis
acid and a base that exhibits FLP chemistry [187]. The identification of key transition states by computational means is rendering insightful information that will be
decisive to develop novel architectures with desired properties.
The number of contributions in which authors are specifically stating the analogy
between FLPs and cooperative transition metal complexes is also continuously
growing. The concept of TMFLP has clearly permeated to other research areas and
fruitful inputs from those will surely boost up the potential of the field. Indeed, despite
being still in a sort of advanced infancy, all these aspects substantiate the notion of
some degree of maturity in the area. We are currently in a lively state of development
in which both very fundamental studies and also applications to catalysis, sensing or
materials designs may rapidly expand to address important scientific challenges. In
terms of catalysis, we believe that the combined virtues of transition metal complexes
and the concept of frustration will make it possible to functionalize inert molecules
that would otherwise remain unaltered. For instance, the efficient functionalization
of inert C–H bonds or the hydrogenation of dinitrogen, which could both be considered ‘holy-grail’ reactions for any synthetic chemist, are currently out of the scope of
main group FLPs, while remaining a difficult challenge for transition metal systems.
Taking advantage of the rich chemistry of transition metals along with the powerful
activating capacity of FLPs could provide original solutions to these and many other
unresolved problems faced by modern chemistry.