Electrophilic Double‐Sandwiches Formed by Interaction of [Cp₂Fe] and [Cp₂Ni] with the Tridentate Lewis Acid [(o‐C₆F₄Hg)₃]

Abstract

A sandwich in a sandwich: Electrophilic double‐sandwich compounds are readily formed by interaction of ferrocene and nickelocene with the tridentate Lewis acid 1 (see scheme; C gray, F light green, Hg orange, M dark green). These new supramolecules result from π interactions between the mercury centers of 1 and the C5H5 rings of the metallocenes. Surprisingly, the nickelocene derivative is dark red and air stable.

A comparative study of the coordination behavior of cyclo-P5 and cyclo-As5 ligand complexes towards the trinuclear Lewis acid complex (perfluoro-ortho-phenylene)mercury

“…The observed assembly resembles the weak Lewis acid/base adducts that are formed from 3 with several Lewis bases and significantly differs from a cofacial arrangement that was found for the double-sandwich complexes formed by [Cp 2 Fe] and 3 . 33 The closest Hg–P distance Hg1–P1 of 3.2878(9) Å is a bit longer than the closest Hg–P contact (3.195(3) Å) found in the polymeric chains of [( o -C 6 F 4 Hg)·{(CpMo) 2 (μ,η 6 :η 6 -P 6 )}] n but is comparable with other observed Hg–P distances of these compounds. 34 The shortest intermolecular P···P distance is 3.9443(13) Å and all of the others lie above 4 Å.…”

“…25,26 Additionally, it readily builds up alternating binary stacks with different electron rich aromatic hydrocarbons 27–32 and forms double sandwich complexes with the metallocenes [Cp 2 Ni] and [Cp 2 Fe] (Scheme 1b). 33 Accordingly, we reported the reaction of 3 with the triple decker complex [(CpMo) 2 (μ,η 6 :η 6 P 6 )] bearing two Cp rings and a cyclo P 6 middle deck. 34 In this case, the obtained products show a one dimensional polymeric structure which is based on weak P–Hg interactions and no Hg–Cp interactions are observed.…”

Lewis Acidic Behavior of Fluorinated Organomercurials

“…Simple mixing of 7 with ferrocene or nickelocene results in the formation of supramolecular electrophilic double-sandwiches in which each cyclopentadienyl ring of the metallocene is capped by a molecule of 7 (Figure ). The shortest Hg···C distances range from 3.20 to 3.24 Å and indicate that the carbon atoms of the Cp rings are in close contact with the mercury centers …”

Tenfold Metalation of Ferrocene: Synthesis, Structures, and Metallophilic Interactions in FeC10(HgX)10

“…[39] Therefore, thef inding of rather shortc rystallographicallyi ndependent Hg + II ÀHg + II contacts is surprising,s ince thec oordinationn umber of them ercury atoms is relatively high.S of ar,e xampleso fs trongH g + II ÀHg + II interactionsa re relatively rare. [40][41][42] Only as mall number of crystal structures contains horter contacts than theh erer eported 3.353(1) . [36,[43][44][45][46][47] Furthermore, only af ew examples of crystal structures of permercuratedc ompounds arek nown so far.…”