Which Is The Best Sandwich Compound? Hexaphenylbenzene Substituted By Sandwich Compounds Bearing Sc, Cr, and Fe

Abstract

The electronic properties of nine different hexaarylbenzene molecules substituted by sandwich compounds have been studied by applying density functional theory. Different structures and the particular electron donor power of these systems have been considered in order to analyze their oxidant capacity, using bis(ciclopentadienyl) scandium, ferrocene, and bis(benzene)chromium as sandwich compounds. Both monometallic and bimetallic combinations are investigated. According to the ionization energies and electron affinities, compounds with Cr are nucleophiles and represent the best electron donors, whereas compounds with Sc are electrophiles and represent the best electron acceptors. The worse electron donor or acceptor is hexakis(4-ferrocenyl phenyl) benzene. This is very significant, as it implies that the very well-known electronic properties of hexakis(4-ferrocenyl phenyl) benzene can be improved by substituting with other metals, such as Sc and Cr. This suggests several possible applications for these compounds.

Interlocking Mechanism between Molecular Gears Attached to Surfaces

“…Sandwich compounds have been studied in organometallic chemistry for several decades. − In the present work, we highlight that manganese and its congeners in the same column of the Periodic Table appear to be suitable intermediates for a five-membered carbon ring to stand firmly but rotate freely (the rotational barrier is less than 0.005 eV) on a graphene surface with significant barriers (see below for the binding energy) to lateral diffusion along the surface. The bonding mechanism is similar to that of ferrocene, a very stable chemical compound.…”

Hydrostatic Pressure on Toroidal Interaction and Propeller Chirality of Hexaarylbenzenes: Explicit Solvent Effects on Differential Volumes in Methylcyclohexane and Hexane

“…Amongt he various propeller-shaped molecules with distinctive features, [1][2][3][4][5] au nique intramolecular interaction between the peripheral aromatic blades in hexaarylbenzenes (HABs)h as attracted considerable attention, [6,7] as they demonstrateu nusually effective electron and/or excitond elocalization and hopping between the aromatic blades, which is known as toroidal interaction. [8,9] Although such interactions have been (semi)quantitatively discussed with various HAB derivatives, [10][11][12][13][14][15] it is imperative to take their dynamic behaviors into consideration, to comprehendt he exact nature of the toroidal interaction. In fact, X-ray crystal analysiso fh exaphenylbenzenes howeda propeller-like structure with the blade tilt angles of about 658, [16] which apparently contradicts with an electron diffrac-tion study in the gas phase, which implied as tructure with all the blades perpendicular to the central benzene ring.…”

Multi-functional switch effect in interlocking molecular rotators-on-graphene systems using electric fields

“…Since 1956, sandwich compounds, such as ferrocene, have been extensively investigated in organometallic chemistry. 29 According to the 18-electron principle, 16,18 sandwich compounds 34 can provide stable chemical bonds. Experimental studies have reported similar sandwich structures, such as benzene(cyclopentadienyl)manganese(I) 53 and (Z 6 -graphene) 2 Cr.…”

“…18 Since 1956, investigation on the structure of sandwich compounds have generated great interest in organometallic chemistry. [29][30][31][32][33][34] In particular, if the molecular gears are intended to rotate as motors, it is essential to adjust their rotational barrier or energy supply. Some of these molecular motors in the past decades have been powered by electrical currents through STM tips, [13][14][15]35 others by the energy supplied by chemical reactions, 2,3,36,37 by electromagnetic energy from light, 1,4,38 or by electric fields, [39][40][41][42][43] and so forth.…”

“…18 Since 1956, investigation on the structure of sandwich compounds have generated great interest in organometallic chemistry. 29–34…”