m‐Metallaphenol: Synthesis and Reactivity Studies

Abstract

What was the inspiration for the cover design?According to the Chinese lunar calendar, this year is the Year of the Horse. In China, the horse is symbolic of passion, endurance, freedom, and vigorous spirit. In the past decade, we have concentrated on synthetic strategies for metallaaromatics, with a particular focus on their reactivity that would lead to new metallaaromatic species. The image of a running horse represents our wonderful journey through the chemistry of metallaaromatics.What is the most significant result of this study?In this contribution, we present the synthesis of the first examples of m-metallaphenols as well as reactivity studies for the complex. Both experimental and theoretical studies suggest that these metallacycles have aromatic character. They can undergo typical reactions of aromatic systems (e.g., nucleophilic substitution reaction) as well as phenols (e.g., formation of urethane linkage with isocyanates).What other topics are you working on at the moment?Our synthetic efforts have led to a large family of metallaaromatics with surprisingly excellent stability towards air, water, and heat. Their stability, together with their unprecedented structures, made it possible to study their properties, such as optical, electrochemical, magnetic, and chiral properties. Furthermore, these methods have also created a series of new topologies, such as metallapentalynes with Mçbius aromaticity, metallapyridynes, five-membered metallacycloallenes, and a number of metallaaromatics with fused rings. On account of these results, we are attempting to employ some valuable classic organic reactions in our metallacycles, which might allow us to capture certain key intermediates. Further advances are expected, not only for new insights into the classic organic reactions, but also for the expansion of metallaaromatic chemistry. Feifei HanHong Zhang Haiping XiaInvited for the cover of this issue is the group of Haiping Xia at the University of Xiamen. The image depicts their recent work on the chemistry of transition-metal-containing metallaaromatics, organometallic compounds derived from formal replacement of a (hydro)carbon segment in an organic aromatic ring by an isolobal transition-metal fragment. Read the full text of the article at

Recent Advances in Metallaaromatic Chemistry

“…Since these early reports the study of metallabenzenes has flourished. [39][40][41][42][43][44] The third row transition metalsa re well-represented with examples incorporating osmium, [45][46][47][48][49][50][51][52][53][54][55][56][57][58][59][60][61] iridium, [62][63][64][65][66][67][68][69][70][71][72][73][74][75][76][77][78][79][80] platinum [81][82][83][84] and, most recently,r henium. [85][86][87] Metallabenzenes of one second row transition metal, ruthenium, are also known.…”

“…They are dependent on (but do not have ac lear correlation with changes in) the metal, ligands, charge and ring substituents. [16,86,[100][101][102] Through other computational studies, metallabenzenes have been shown to exhibit negative nucleus-independent chemical shift (NICS) values, [60,94,96,97] diatropic ring currents [96,103,104] and relatively large absolute hardness, [100,105] each of whichi sc onsistent with aromaticity.I th as been noted, however,t hat many of these latter methods may have limited applicability to met-allabenzenes due to the influence of the ancillary ligands and metal anisotropy. [18,97] Although many metallabenzenes have an early planar structure, ac onsiderable number do not.…”

“…These go on to form osmabenzoxolone derivatives 10,v ia an intramolecular nucleophilics ubstitution process. [60] Although it is standard practice in organicc hemistry,s ynthesizingn ew metallabenzene derivatives through chemical modification of the ring substituents remains ar elatively underexplored area. The scope of derivatives that potentially could be accessed in this way is, however,l arge.…”

“…Since these early reports the study of metallabenzenes has flourished . The third row transition metals are well‐represented with examples incorporating osmium, iridium, platinum and, most recently, rhenium . Metallabenzenes of one second row transition metal, ruthenium, are also known .…”

Syntheses of Amino‐Substituted Iridabenzofurans and Subsequent Selective N‐Functionalisation

“…Although the isolation and study of a considerable number of metallabenzenes and fused‐ring metallabenzenes has been reported, much remains to be explored regarding the reactivity of these compounds. Studies carried out so far have demonstrated that the transition metal modifies significantly the delocalized π‐system and the chemical reactivity compared to the corresponding organic analogues . Theoretical studies have shown that the nature and position of ring substituents can have a large influence on the stability and reactivity of metallabenzenes …”