Metallic System with Aromatic Character. Synthesis and Molecular Structure of Na2[[(2,4,6-Me3C6H2)2C6H3]Ga]3 The First Cyclogallane

Observation of d‐Orbital Aromaticity

“…This concept has been extended to metal-substituted organic molecules, [1,2] as well as main group organometallic complexes. [3][4][5][6] The recent discovery of aromaticity in allmetal clusters, for instance [Al 4 ] 2À in [MAl 4 ] À (M = Cu, Li, Na), [7] has led to a flurry of research activities [8][9][10][11][12][13][14][15][16] and predictions of new aromatic metal clusters, [17][18][19][20][21][22][23] among which is a class of interesting cyclic species containing Cu. [20,23] While main group clusters can give rise to s-and paromaticity, transition-metal-containing clusters can exhibit d-orbital aromaticity or, more interestingly, d-aromaticity due to d bonding interactions.…”

“…Our calculations show that the dianions are also unusually stable despite the strong intramolecular coulomb repulsion. In fact, [W 3 O 9 ] 2À is predicted to be a stable gas-phase dianion with a calculated electron binding energy of 0.03 eV relative to [W 3 À . To gain further insight into the 3c-1e and 3c-2e bonds in [M 3 O 9 ] À and [M 3 O 9 ] 2À , we estimated their resonance energies (see Supporting Information).…”

“…[31] We obtained NICS values of À21.5 and À20.5 at the ring center for [W 3 O 9 ] 2À and [Mo 3 O 9 ] 2À , respectively (see Supporting Information), that are much higher than those predicted for the cyclic Cu-containing clusters [20,23] [34,35] but that is very different from the d-orbital aromaticity in the [M 3 O 9 ] À and [M 3 O 9 ] 2À clusters discussed here. Aromaticity has also been considered in trinuclear Pt 3 and Os 3 metal complexes solely on the basis of molecular orbital topologies, [36,37] but it has not been verified using other criteria for aromaticity.…”

Sub‐Nano Clusters: The Last Frontier of Inorganic Chemistry

“…The discovery of aromaticity in all-metal clusters is one of the most remarkable developments in cluster science Kuznetsov et al 2003;Li et al 1995;Li et al 2001). It is also surprising that it took so long to discover.…”

Structural Dependence of Magnetic Shielding Properties in Al<SUB>4</SUB>Li<SUB>4</SUB> Clusters

“…The concept of aromaticity used to explain the additional stability of organic conjugated ring molecules was expanded to inorganic systems by the discovery of aromaticity in organometallic, [1][2][3] all-metal clusters, [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] and recently transition-metal-containing clusters with aromaticity. [21][22][23] Interest in this field has been increased by the finding of an antiaromatic all-metal cluster.…”