Chromium Complexes Containing Polycyclic Condensed Aromatic Ligands: Mono‐ and Bidirectional Synthesis from Chromium–Carbenes, Molecular Structures, and Rearrangement Reactions

Abstract

Chromium–pyrenylcarbenes accessible from halopyrene precursors undergo benzannulation upon gentle warming with 3‐hexyne to give hydroquinoid benzopyrene–Cr(CO)3 complexes. Kinetic benzannulation product 3 rearranges into thermodynamic haptotropomer 4 at 70 °C in octafluorotoluene under first‐order kinetics. Further complexation of 3 by Cr(NH3)3(CO)3 affords syn and anti dinuclear chromium–benzopyrene complexes. Bidirectional extension of the benzannulation protocol results in the formation of syn and anti dibenzopyrene–dichromium complexes, which are structurally characterized by X‐ray analysis.

[(η5-C5Me5)Ru]+ fragments ligated to polyaromatic hydrocarbons: an experimental and computational approach to pathways for haptotropic migration

“…[6][7][8] In this way, they can provide coordination sites with different geometries and different numbers of electrons, leading to a large number of advisable species, either mono or polymetallic, which are subjected under some circumstances to interconversion through inter-ring haptotropic rearrangements. 9 For instance, the η 6 -η 6 inter-ring haptotropic rearrangement, in which a 12-electron organometallic moiety migrates along the rim of a polyaromatic system as first proposed by Albright et al, 10 could, indeed, be thermally, 11,12 chemically, 13 photochemically 12,13 or electron-driven. 14 Organometallic complexes of the simplest PAHs like naphthalene, 15 pentalene, 16 azulene, 17 or indacene 18 are widely known, showing a variety of coordination modes.…”

“…including [(η 6 -pyrene)Cr(CO) 3 ], 20 [Cp*Ir(η 6 -pyrene)][BF 4 ] 2 , 21 [(η 6 -acenaphthylene)Cr(CO) 3 ], 22 [Cr(η 6 -fluoranthene) 2 ][I] 23 as well as the two isomers of [(η 6 -fluoranthene)Cr(CO) 3 ] 24 have been structurally characterized (Cp* = η 5 -C 5 Me 5 ). Although scarcer, bimetallic derivatives with an arenophile unit coordinated to each side of the polycyclic aromatic ligand such as [(µ-η 6 :η 6 -benzopyrene)(Cr(CO) 3 ) 2 ] 11 and [(Cp*Ru) 2 (µ-η 6 :η 6 -PAH)]-[PF 6 ] 2 (PAH = chrysene, 7c corannulene 25 ) have also been identified crystallographically. The doubly charged bis-[Cp*Ru + ] η 6coordinated phenanthrene, anthracene, pyrene and triphenylene cations were also prepared, 7a,b but no structural characterization by means of X-ray diffraction has been available so far.…”

The chemistry of the carbon-transition metal double and triple bond: Annual survey covering the year 2014

“…536), which underwent a haptotropic shift to the distal arene unit (e.g. formation of complex 537) upon heating to a higher temperature [922]. The analogous reaction using a bis(carbene) complex (e.g.…”