Chemical structures from the analysis of domain‐averaged fermi holes. Nature of the MnMn bond in bis(pentacarbonylmanganese)

Abstract

Abstract:Because of conflicting and contradictory classification based on traditional AIM characteristics, the nature of the Mn-Mn bond has been and still is the subject of continuing discussions. To overcome the existing inconsistencies in the interpretation of the nature of this bond, the bonding in Mn 2 (CO) 10 has been analyzed and discussed in terms of new recently proposed methodology known as the analysis of domain-averaged Fermi holes. It has been shown that this analysis is able to reconcile the conflicting conclusions of earlier AIM-based studies with traditional anticipations based on simple electron counting rules. According to Fermi hole analysis, the Mn-Mn bond has the character of the more or less ordinary covalent single bond, but the analysis also brings clear evidence in favor of Mn ⅐ ⅐ ⅐ (CO) intramolecular interactions between the metal atom and the ligands bonded to the other metal atom. These interactions could be responsible for the observed decrease of electron density at the bond critical point detected in AIM studies.

An Interacting Quantum Atoms Analysis of the Metal–Metal Bond in [M2(CO)8]n Systems

“…67 In fact, the presence of MC bridge bond paths, inwardly curved in the M-C-M ring was recognized as a clear sign of multi-center bonding. Moreover, this view is in agreement with the DAFH picture, later proposed by Ponec et al 32,34 The analysis of the individual E 136 au), in which the electrostatic part is overwhelming. Clearly, the observed molecular graph is able to reveal only the former, because produced by electron sharing and therefore with direct implications for the electron distribution, but not the latter, which is actually more effective.…”

“…[35][36][37] DAFH addresses a direct MM bond only for unsupported molecules, but M...CO interactions are also identified. 34 Multicenter bond is instead invoked for supported MM. This is a rephrasing of the original thesis proposed by Heijser et al 38 The almost continuous bonding encompassing the transformation from unsupported to supported MM was first rationalized by Macchi et al 28 using delocalization indexes and anticipating the arguments later proposed by Ponec with DAFH analysis.…”

Structure and bonding in binuclear metal carbonyls from the analysis of domain averaged Fermi holes. I. Fe2(CO)9and Co2(CO)8

“…[39][40][41][42] The most straightforward introduction of DAFH (originally called charge weighted Fermi holes in the studies 35,36 ) is via the definition eq. (1),…”

“…This analysis was repeatedly shown to provide a simple and chemically appealing picture of the bonding in various molecules with complicated bonding pattern including metal-metal bonds [40][41][42] and it was thus of interest to see whether or to what extent it can help in revealing and clarifying the final picture of bonding in the most stable binuclear iron and cobalt carbonyls. In the remainder of the article we first briefly summarize the theory and the technical details of DAFH analysis, then present the results of the analysis of the electronic structure of Fe 2 (CO) 9 and of Co 2 (CO) 8 , respectively.…”

Electron pairing and chemical bonds: Pair localization in ELF domains from the analysis of domain averaged Fermi holes

“…[29][30][31][32][33][34] The domain-averaged Fermi holes can most straightforwardly be introduced by eq. (1) in which (r 1 ,r 2 ) and (r 1 ) are the pair and first order density, respectively, and the averaging (integration) is performed over the finite domain O.…”