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Current
Organic Chemistry
ISSN: 1385-2728
Current Organic
Chemistry
Volume 11, Number 16, November 2007
Contents
Organometallic Chemistry, Coordination Chemistry and
Catalysis thematic
Guest Editor: Julio Perez
Editorial Pp. 1400
Recent Advances in the Platinum-mediated CH Bond Functionalization
Pp. 1401-1416
Andrei N. Vedernikov
[Abstract]
Transmetallation Reactions Involving Group 10 Metals
Pp. 1417-1433
Ola F. Wendt
[Abstract]
Cooperation of Metals and Hydrogen Bonding Groups
in Metal Promoted Reactions Pp. 1434-1449
Juan C. Mareque Rivas
[Abstract]
Site-Selective Artificial Ribonucleases and their
Applications Pp. 1450-1459
Akinori Kuzuya and Makoto Komiyama
[Abstract]
Small Molecule Luminescent Lanthanide Ion Complexes
– Photophysical Characterization and Recent Developments
Pp. 1460-1480
Ana de Bettencourt-Dias
[Abstract]
Abstracts
[Back to top]
Editorial
The Number 16, 2007 Organometallic Chemistry, Coordination
Chemistry and Catalysis thematic issue of Current Organic
Chemistry comprises five review papers having synthesis,
reactivity and applications of metal complexes as the unifying
theme. Organometallic catalysis, activation of C-H and C-C
bonds, cooperation of hydrogen bonds and metals, recognition
and selective cleavage of nucleic acids by metal-based systems,
and the luminiscence of lanthanide complexes are some of the
topics dealt with in this issue.
Andrei N. Vedernikov (University of Maryland,
USA) authored Recent advances in the platinum-mediated
C-H bond functionalization. Metal-mediated C-H activation
is a topic of intense research activity, and one that has
been the subject of several previous reviews. Most of the
79 references of the present paper come from the 2005-06 period.
The Pt(II)-catalyzed oxidation of methane by stoichiometric
hexachloroplatinic (IV) acid in water to MeOH or MeCl (Shilov
reaction) was historically important in homogeneous C-H functionalization
by metal complexes. Subsequent efforts to use practical oxidants,
protect the products from overoxidation, achieve high activity,
and employ mild conditions, continue up to the present time.
Examples of catalytic formation of C-O, C-C and C-Si bonds,
and functionalization of relevant Pt-C bonds are discussed,
as well as selectivity issues and mechanistic studies. Finally,
current efforts to improve the design of Pt catalysts for
C-H activation based on mechanistic information and theoretical
calculations are summarized.
Ola F. Wendt (Lund University, Sweden) wrote
Transmetallation reactions involving group 10 metals,
an account that focuses on the transfer of an organic group
from a main group metal (including boron and group 12 metals)
to group 10 metals. The paper provides an overview of two
areas that have been dealt with separately in most previous
publications: (a) applications of the stoichiometric transmetallation
reaction to the synthesis of group 10 organometallic complexes,
and (b) transmetallation as one step of the group 10-catalyzed
cross-coupling between organic electrophiles and main group
(mainly B, Si and Sn) nucleophiles.
Juan C. Mareque Rivas (University of Edinburgh,
UK) is the author of the review Cooperation of metals
and hydrogen bonding groups in metal-promoted reactions.
Selected examples are used to illustrate how the presence
of groups able to participate in the formation of hydrogen
bonds can contribute to a higher efficiency of metal-based
catalysts, in an approach to the mode of action of enzymes.
While most examples are taken from areas reminiscent of the
activity of some enzymes (peptide and phosphodiester bonds,
the reaction of carbon dioxide and water, or oxidations catalyzed
by metal complexes, notably by iron-porphyrin complexes),
others come from reactions that are typically catalyzed by
organometallic complexes.
Akinori Kuzuya (New York University, USA)
and Makoto Komiyama* (University of Tokyo,
Japan) wrote Site-selective Artificial Ribonucleases and
Their Applications. In this case, the target of the artificial
nucleases is RNA, and the emphasis is on systems in which
the elements, the “sequence-recognizing moieties”
(that bind to a particular region of RNA), and the “molecular
scissors” (either a metal complex or a metal-free polyamine)
that catalyze RNA hydrolysis) are not covalently bonded. Applications
to genotyping are discussed.
Ana de Bettencourt-Dias (Syracuse University;
currently at the University of Nevada, Reno, USA) contributed
Small Molecule Luminiscent Lanthanide Ion Complexes-Photophysical
Characterization and Recent Developments. This paper
provides an introduction to the luminiscence displayed by
lanthanide ions and their complexes and some of their most
important applications. Then, recent examples of the solid
state structure of the complexes of the Ln3+
ions (which often reach high coordination numbers) with a
variety of ligands (that also act as sensitizers), their solution
speciation, and the luminiscent behavior are discussed.
It has been a privilege and a pleasure to help in putting
together this issue. I wish to express my deepest appreciation
to the authors, and to the many anonymous reviewers, for their
great job.
Julio Perez
University of Oviedo
Spain
[Back to top]
Recent Advances in the Platinum-mediated CH Bond Functionalization
Andrei N. Vedernikov
Platinum complexes have played an important role in our understanding
the mechanisms of arene and alkane CH activation and developing
catalytic methods for hydrocarbon CH functionalization. Knowledge
of the factors controlling the reactivity of the metal center
acquired over the past few years enabled significant progress
in the field. Among the most challenging problems which have
to be solved yet are i) the use of more readily available
oxidants, ideally, oxygen from the air; ii) selective functionalization
of CH bonds, iii) protection of the oxygenation products against
overoxidation and iv) designing more water-tolerant systems.
The most recent examples of platinum mediated catalytic functionalization
of alkane and arene CH bonds in water and non-polar solvents,
mechanistic studies of alkane and arene CH activation, computational
and experimental design of new efficient platinum complexes
are reported. The review covers mostly publications appeared
in 2005-2006.
[Back to top]
Transmetallation Reactions Involving Group 10 Metals
Ola F. Wendt
This review gives an overview of the early development of
transmetallation reactions for synthetic purposes and presents
some recent results on the transmetallation reaction as a
part of cross-coupling reactions and the mechanism of these
reactions.
[Back to top]
Cooperation of Metals and Hydrogen Bonding Groups
in Metal Promoted Reactions
Juan C. Mareque Rivas
A major challenge in chemistry is the design of catalysts
that can carry out important chemical transformations with
the extraordinary efficiency of enzymes. In many cases nature
does this by making metals and hydrogen bonding groups to
work cooperatively. This review provides a description of
recent work inspired by nature where the combination of metal
ions and hydrogen bonding groups has been used to enhance
the properties of synthetic metal complexes in metal-mediated
reactions. It covers a range of strategies, hydrogen bond
types, effects and chemical transformations.
[Back to top]
Site-Selective Artificial Ribonucleases and their
Applications
Akinori Kuzuya and Makoto Komiyama
Recent developments in artificial enzymes for site-selective
scission of RNA have been reviewed, and their advantages over
ribozymes are discussed. Most of previous reports involve
covalent fixation of molecular scissors to sequence-recognizing
moieties. However, non-covalent strategy, in which these two
components are never covalently bound each other, has made
remarkable progresses. When oligonucleotide bearing an acridine
(site-selective activator) forms duplex with RNA substrate,
the phosphodiester linkage of the RNA in front of the acridine
is selectively activated and hydrolyzed by various metal ions
(e.g., Lu(III). These non-covalent artificial ribonucleases
are simple enough to be used for various more complicated
systems. For example, tandem activator for clipping of desired
fragment from long RNA substrate is obtained by attaching
two acridines to an oligonucleotide. By analyzing the resultant
RNA fragment with MALDI-TOFMS, the RNA substrate is accurately
genotyped in terms of both single nucleotide polymorphisms
(SNPs) and insertion/deletion polymorphisms (Indels).
[Back to top]
Small Molecule Luminescent Lanthanide Ion Complexes
– Photophysical Characterization and Recent Developments
Ana de Bettencourt-Dias
The luminescence of lanthanide ions makes them interesting
for a wide variety of applications and several researchers
try to optimize this property. In this paper we give a brief
overview of the luminescence process and of the techniques
utilized to characterize the photophysical properties. Several
recent examples of luminescent complexes with small molecule
sensitizers will also be discussed.
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