Editorial [Hot Topic:Organometallic Chemistry, Coordination Chemistry and Catalysis thematic (Guest Editor: Julio Perez)]

The present issue, Number 17, is the second part of Volume 11, corresponding to the 2007 Organometallic Chemistry, Coordination Chemistry and Catalysis thematic issue of Current Organic Chemistry. The need to publish two separate numbers due to the large overall length reflects that Curr. Org. Chem. is increasing its attractiveness as a venue for publication of midsize reviews by some of the lead authors in the field. The generous effort of the many anonymous reviewers, to whom I wish to express my sincere appreciation, made possible to publish a larger number of contributions while maintaining a high standard of quality. This issue comprises five review papers dealing with synthesis, application of new ligands, catalysis and molecular recognition by coordination and organometallic complexes. Pamela J. Shapiro (University of Idaho, USA) contributed the paper titled The Elusive Chemistry of Bent-sandwich Chromocene. Bis(cyclopentadienyl)chromium was first synthesized by pioneers such as Fischer and Wilkinson in the nineteen fifties; however, due to the low stability, the reactivity studies of chromocenes have developed at a very slow pace compared with those of metallocenes of other early metals, or with half-sandwich chromium complexes. The review, with an emphasis on ansa-chromocenes, an area to which the author's group has made significant contributions, covers the efforts of several groups to synthesize chromocenes of sufficient stability to permit an exploration of their chemistry. The reactions studied include oxidation, addition of Lewis bases, in some cases with concomitant ring-slippage, protonation to afford a chromocenium hydride, and ring borylation. Hon Man Lee,* Chun-Chin Lee, and Pi-Yun Cheng (National Changhua University of Education, Taiwan) wrote the paper Recent Development of Functionalized N-heterocyclic Carbene Ligands: Coordination Chemistry and Catalytic Applications. Due to their strongly σ donor character, that affords highly electron-rich metal centers, their high steric profile, and the thermal stability of their metal complexes, N-heterocyclic carbene ligands have become, after the seminal work by Arduengo, who showed that the free carbenes were indeed stable enough to be isolable, some of the most widely employed ligands in transition metal coordination chemistry and, in particular, in catalysis. As a result, the topic have been reviewed many times. In this paper, with 152 references, Lee and co-workers focus on recent advances in the chemistry of polydentate ligands that combine N-heterocyclic carbenes with classical donor groups such as phosphines, N donors (pyridine, oxazoline, pyrazole, imine, amine, amido), and O- or S-donors. Literature is covered up to August 2006. David Necas (Charles University, Czech republic) amd Martin Kotora* (Charles University and Academy of Sciences, Czech republic) have reviewed the field of rhodium-catalyzed C-C bond cleavage reactions. High selectivity, atom economy and mild conditions are attractive features of these reactions. The authors look first at the C-C cleavage in carbocyclic compounds: cyclopropanes (including alkylidenecyclopropanes and vinylcyclopropanes), cyclobutanes, cyclobutanones, vinylcyclobutanones, cyclobutenones, and non-strained cyclic ketones, and then discuss acyclic substrates such as allyl malonates, alkylaromatic phosphines, and unsaturated nitriles. Finally, decarbonylation of aldehydes and acid derivatives are considered. Susanne Striegler (Auburn University, USA) wrote Binuclear metal complexes in molecular recognition and catalysis. The review highlights recent developments in several areas: (a) selective recognition and hydrolysis of phosphate monoester, mainly using dizinc (II) complexes (as found in the alkaline phosphatase enzyme), (b) the recognition and hydrolysis of double stranded DNA with dinuclear complexes of Zn(II), Ru(II), Cu(II), etc., (c) recognition of DNA with Pt(II) complexes showing antitumor activity, (d) metal complexes as components of self-assembled structures that display allosterism in their host-guest behavior, and (e) dicopper complexes as carbohydrate recognition agents......