Evolution of Triangular All-Metal Aromatic Complexes from Bonding Quandaries to Powerful Catalytic Platforms

Abstract

This manuscript describes an overview on the literature detailing the observation of trinuclear complexes that present delocalized metal−metal bonds similar to those of regular aromatics, which are formed combining main group elements. A particular emphasis is given to the structural and electronic features of aromatic clusters that are sufficiently stable to allow their isolation. In parallel to the description of their key bonding properties, the work presents reported catalytic applications of these complexes, which already span from elaborated C−Cforming cascades to highly efficient cross-coupling methods. These examples present peculiar aspects of the unique reactivity exerted by all-metal aromatic complexes, which can often be superior to their established, popular mononuclear peers in terms of chemoselectivity and chemical robustness.

Core-electron contributions to the magnetic response of molecules with heavy elements and their significance in aromaticity assessments

“…In recent years, aromaticity has been extensively used to understand the stability of organometallic or transition metal compounds containing heavy elements. [1][2][3][4][5][6][7][8][9] Criteria based on the magnetic response of a molecule in the presence of an external magnetic field have become very popular among the experimental and theoretical communities due to their close relationship with nuclear magnetic resonance experiments. 10,11 However, determining aromaticity of inorganic molecules from a magnetic perspective is challenging because of the multiple delocalization characters and the presence of heavy elements.…”

Aryl sulfonate anion stabilized aromatic triangular cation [Pd3]+: syntheses, structures and properties

“…So, the substituted aryl sulfonate anions possessing different types of chromophores and auxochromes indeed brought variations in the maximum absorption wavelength and absorption intensities under identical conditions. 35 For comparison, we further measured the absorption for complexes (3)(4)(5)(6)(7) in MeOH (Fig. S8 †), their absorption intensity presented obvious solvent dependence.…”

“…Among multi-palladium composed complexes, aromatic triangular tri-palladium complexes [LPd] 3 + (L = ligand) [1][2][3][4][5] and their heteroaromatics 6,7 are excellent species as the metallic analogs of cyclopropene positive ion [C 3 H 3 ] + . The unique allmetal aromaticity and excellent stability endow such threemembered palladium cores with excellent molecular stability and Lewis alkalinity, which has brought them much attention in theoretical chemistry, [8][9][10][11] coordination chemistry, 12 catalytic reactions [13][14][15][16][17][18][19][20][21][22] and nanomaterials.…”

Advances for Triangular and Sandwich-Shaped All-Metal Aromatics

“…Later on, the advances in all-metal aromaticity were driven forcefully by several groups [ 20 , 21 , 22 , 23 ]. However, we are going to pay more attention to triangular all-metal aromatics and specifically summarize these group of organometallics due to its multiple theoretical predictions and existences, rapid developments and exciting application potentials [ 24 , 25 ].…”

“…Later on, the advances in all-metal aromaticity were driven forcefully by several groups [20][21][22][23]. However, we are going to pay more attention to triangular all-metal aromatics and specifically summarize these group of organometallics due to its multiple theoretical predictions and existences, rapid developments and exciting application potentials [24,25]. Triangular all-metal aromatics are a group of organometallic complexes that conform to the Hückel (4n + 2) π electrons rule and contain the smallest metallic ring core.…”