Finally, the third section of the book is devoted to computational approaches to
catalysis by transition metal compounds, with enzymatic and biomimetic systems
allocated as the last, separate part. The section opens with Chapter “Mechanism and
Kinetics in Homogeneous Catalysis: A Computational Viewpoint” where
Jeremy N. Harvey critically reviews the use of computational methods based on
electronic structure theory and statistical mechanics to study reaction mechanisms
and kinetics in homogeneous catalysis, especially organometallic catalysis and
organocatalysis. The chapter is based on suitably selected examples from the
authors’ own group, which are discussed in the perspective of progress and still
open challenges for computational chemistry to model actual chemistry. A careful
reading of this chapter may be especially recommended as a warning to researches
pursuing this domain of computational modeling because it draws their attention to
still existing (and occasionally even growing) number of doubts and pitfalls
awaiting inexperienced users of “user-friendly” computational, half-automated
tools. The main line set in the introductory chapter for this part is actually followed
in consecutive three chapters which are devoted to complicated reaction patterns
found in catalytic systems and summarize attempts to allow various extended
environments into the modeling.
Chapter “Computational Modelling of Structure and Catalytic Properties of
Silica-Supported Group VI Transition Metal Oxide Species” by Jarosław Handzlik
deals with chromium, molybdenum, and tungsten oxides supported on amorphous
silica, the catalysts for many reactions, including large-scale industrial processes.
Although these systems have been extensively studied for many years, there are still
unresolved issues, concerning mainly the nature of the active sites and mechanisms
of their formation. Computational studies, using carefully selected cluster or periodic models to represent the catalyst surface, are helpful in interpretation of
spectroscopic data and can provide complementary information about the catalytic
process and lead to complex structure–activity relationships. Nevertheless, even if a
great progress has been achieved in modeling of these systems, theoretical determining of complex reaction mechanisms using surface models with representative
distribution of metal sites is still a challenge for computational catalysis. Chapter
“Catalytic Properties of Selected Transition Metal Oxides—Computational Studies”
by Witold Piskorz and Filip Zasada constitutes the review of computational
methods applied specifically to transition metal oxides (most abundant in heterogeneous catalysis, used as bulk or supported oxides) and is focused on the influence
of the environment on the transition metal cation properties. The shortcomings
of the DFT level of theory, most commonly used for modeling, are discussed, and
its extensions toward more realistic environment are presented. The modern reactive force field methods are also mentioned, and the embedding schemes most
commonly found in the quantum chemical or classical description of the heterogeneous processes are discussed. It is shown that in all discussed systems, the
appropriately applied Hubbard DFT GGA+U methods are successful provided that
the Hubbard correction is carefully tuned for modeling of particular properties. In
turn, Chapter “Molecular Electrochemistry of Coordination Compounds—A
Correlation Between Quantum Chemical Calculations and Experiment” by
viii
Preface
catalysis by transition metal compounds, with enzymatic and biomimetic systems
allocated as the last, separate part. The section opens with Chapter “Mechanism and
Kinetics in Homogeneous Catalysis: A Computational Viewpoint” where
Jeremy N. Harvey critically reviews the use of computational methods based on
electronic structure theory and statistical mechanics to study reaction mechanisms
and kinetics in homogeneous catalysis, especially organometallic catalysis and
organocatalysis. The chapter is based on suitably selected examples from the
authors’ own group, which are discussed in the perspective of progress and still
open challenges for computational chemistry to model actual chemistry. A careful
reading of this chapter may be especially recommended as a warning to researches
pursuing this domain of computational modeling because it draws their attention to
still existing (and occasionally even growing) number of doubts and pitfalls
awaiting inexperienced users of “user-friendly” computational, half-automated
tools. The main line set in the introductory chapter for this part is actually followed
in consecutive three chapters which are devoted to complicated reaction patterns
found in catalytic systems and summarize attempts to allow various extended
environments into the modeling.
Chapter “Computational Modelling of Structure and Catalytic Properties of
Silica-Supported Group VI Transition Metal Oxide Species” by Jarosław Handzlik
deals with chromium, molybdenum, and tungsten oxides supported on amorphous
silica, the catalysts for many reactions, including large-scale industrial processes.
Although these systems have been extensively studied for many years, there are still
unresolved issues, concerning mainly the nature of the active sites and mechanisms
of their formation. Computational studies, using carefully selected cluster or periodic models to represent the catalyst surface, are helpful in interpretation of
spectroscopic data and can provide complementary information about the catalytic
process and lead to complex structure–activity relationships. Nevertheless, even if a
great progress has been achieved in modeling of these systems, theoretical determining of complex reaction mechanisms using surface models with representative
distribution of metal sites is still a challenge for computational catalysis. Chapter
“Catalytic Properties of Selected Transition Metal Oxides—Computational Studies”
by Witold Piskorz and Filip Zasada constitutes the review of computational
methods applied specifically to transition metal oxides (most abundant in heterogeneous catalysis, used as bulk or supported oxides) and is focused on the influence
of the environment on the transition metal cation properties. The shortcomings
of the DFT level of theory, most commonly used for modeling, are discussed, and
its extensions toward more realistic environment are presented. The modern reactive force field methods are also mentioned, and the embedding schemes most
commonly found in the quantum chemical or classical description of the heterogeneous processes are discussed. It is shown that in all discussed systems, the
appropriately applied Hubbard DFT GGA+U methods are successful provided that
the Hubbard correction is carefully tuned for modeling of particular properties. In
turn, Chapter “Molecular Electrochemistry of Coordination Compounds—A
Correlation Between Quantum Chemical Calculations and Experiment” by
viii
Preface