Aromaticity as a cornerstone of heterocyclic chemistry.

Metals and organic molecules are at the opposite sides in chemistry. Thus one may think that chemical bonding models, such as aromaticity, developed in organic chemistry will not be applicable in systems involving metallic elements. Yet in recent years there have been significant advances in extending the aromaticity and antiaromaticity concepts into the realm of metal clusters and alloys. These new developments have shown that aromaticity and antiaromaticity in metal systems have frequently multiple nature, being o-aromatic/antiaromatic and n-aromatic/antiaromatic, which is not found in organic aromatic/antiaromatic molecules.

http://casey.brown.edu/chemistry/research/LSWang/publications/209.pdf

All-Metal Aromaticity and Antiaromaticity

A quantitative model is proposed for the analysis of the thermodynamic parameters of multivalent interactions in dilute solutions or with immobilized multimeric receptor. The model takes into accou...

On the Nature of the Multivalency Effect: A Thermodynamic Model

Structure and Reactivity of Earlyminus signLate Heterobimetallic Complexes.

Research into aromatic metallacycles, though discussed in the literature over the last quarter century, has undergone a major expansion since 2000. A wide variety of new metallabenzenes, encompassing new synthetic methods and new metal centers, is now available. New aromatic metallacycle topologies (iridanaphthalene, osmabenzynes) have been isolated and characterized. The first metallabenzene valence isomers (iridabenzvalenes, rhodabenzvalenes) and constitutional isomers (isoosmabenzenes) are now known. This review discusses the synthesis, chemistry, and physical properties of these intriguing aromatic compounds.

Recent Advances in Metallabenzene Chemistry

From the starting compound (I) (two-step preparation described earlier) a proton is abstracted to give the title complex (II), which crystallizes in the P21/n with Z=4.

Metallabenzene: synthesis, structure, and spectroscopy of a 1-irida-3,5-dimethylbenzene complex

Metallacyclohexadiene and metallabenzene chemistry. 5. Chemical reactivity of metallabenzene

«Iridabenzene», (Ir-CH-C(Me)-CH-C(Me)-CH)(PEt 3 ) 3 (1), displaces p-xylene from (η 6 -p-xylene)Mo(CO) 3 in tetrahydrofuran solvent, producing (η 6 -iridabenzene)Mo(CO) 3 (2). The solid state structure of 2 has been determined by a single-crystal x-ray diffraction study (monoclinic, P2 1 /n)

Metallacyclohexadiene and metallabenzene chemistry. 6. Chemistry of an (.eta.6-metallabenzene)metal complex, [cyclic] [(.eta.6-Ir-CH-C(Me)-CH-C(Me)-CH)(PEt3)3]Mo(CO)3

Pentadienyl-metal-phosphine chemistry. 23. Pentadienyl-iridium-phosphine chemistry. Survey of the reactions of pentadienide reagents with ClIrL3 complexes

Metallacyclohexadiene and metallabenzene chemistry. 3. Synthesis, characterization, and reaction chemistry of a family of 1-iridacyclohexa-2,4-diene complexes

Yun Feng Xie

Papers

Metallabenzene: synthesis, structure, and spectroscopy of a 1-irida-3,5-dimethylbenzene complex

Metallacyclohexadiene and metallabenzene chemistry. 5. Chemical reactivity of metallabenzene

Metallacyclohexadiene and metallabenzene chemistry. 6. Chemistry of an (.eta.6-metallabenzene)metal complex, [cyclic] [(.eta.6-Ir-CH-C(Me)-CH-C(Me)-CH)(PEt3)3]Mo(CO)3

Pentadienyl-metal-phosphine chemistry. 23. Pentadienyl-iridium-phosphine chemistry. Survey of the reactions of pentadienide reagents with ClIrL3 complexes

Metallacyclohexadiene and metallabenzene chemistry. 3. Synthesis, characterization, and reaction chemistry of a family of 1-iridacyclohexa-2,4-diene complexes