Binuclear Gold(I) and Mercury(II) Derivatives of Diethynylfluorenes

Abstract

A new series of bis(alkynyl) gold(I) and mercury(II) d10 complexes incorporating fluorenyl-based linking units are reported. The binuclear complexes [LAuC⋮CRC⋮CAuL] and their isoelectronic mercury(II) congeners [R‘HgC⋮CRC⋮CHgR‘] (L = tertiary phosphines; R = fluorene-2,7-diyl, dihexylfluorene-2,7-diyl, 9-((ferrocenylphenylene)methylene)fluorene-2,7-diyl, fluoren-9-one-2,7-diyl, 9-(dicyanomethylene)fluorene-2,7-diyl; R‘ = Me, Ph) were prepared in very good yields by the base-catalyzed dehydrohalogenation reaction of the corresponding metal chloride precursors with the appropriate diethynylfluorene derivatives HC⋮CRC⋮CH at room temperature. All the compounds have been fully characterized by FTIR, NMR and electronic absorption spectroscopies and FAB mass spectrometry. The solid-state molecular structures of [Ph3PAuC⋮CRC⋮CAuPPh3] (R = 9,9-dihexylfluorene-2,7-diyl, fluoren-9-one-2,7-diyl) and [MeHgC⋮CRC⋮CHgMe] (R = fluoren-9-one-2,7-diyl) have been determined crystallographically, the last of which represents the first dimercury diacetylide to be structurally characterized. Absorption studies suggest that it is possible to fine-tune the optical gap of this class of materials by modifying the electronic properties of the substituent at the 9-position of the central fluorene spacer. The solution redox chemistry of these fluorene-linked binuclear complexes as revealed by cyclic voltammetry indicates some degree of electronic communication between the 9-substituent of the fluorenyl ring and the terminal metal groups via the conjugated alkynyl bridge. Most of the complexes in this study have been shown to exhibit rich photophysical behavior, and a discussion on their emission properties in terms of the nature of metal groups and their auxiliary ligands as well as the fluorene spacer was made.

Syntheses, Structures and Photophysical Properties of Metal Carbonyl Clusters with Dansyl and Acridone Luminophores

“…Addition of polarization functions to C, N and O would increase the number of basis functions by more than a hundred. Previous molecular orbital calculations on other related systems [45,46] showed that the medium-size basis set provides reasonable results. In addition, we are interested in obtaining the qualitative picture of orbital patterns for the clusters and in comparing the relative HOMOϪLUMO gaps.…”

Synthesis and Luminescent Properties of Platinum-Containing Polyynes with Tetraacetylenic 9,9-Dihexylfluorene Units

“…The 0-0 absorption peak is assigned as the S 0 → S 1 transition from the highest occupied molecular orbital (HOMO) to the lowest unoccupied molecular orbital (LUMO), which are mainly delocalized π and π* orbitals. [34][35][36][37][38] Coordination of each of the platinum to the organic system results in enhanced π→π* transitions for the aryleneethynylene moiety. As compared to the band at 357 nm in CH 2 Cl 2 for I, we find that the position of the lowest energy absorption band is red-shifted after the inclusion of platinum in II and III.…”

Metall‐Alkinyl‐σ‐Komplexe: Synthesen und Materialien

“…Beschrieben wurde kürzlich die Struktur eines Diquecksilberdialkinylkomplexes (Abbildung 2), der durch klassische Dehydrohalogenierung aus einem Alkin und einem Alkylquecksilber(ii)-chlorid in Gegenwart einer Base hergestellt wurde. [262] Hg II -Alkinylkomplexe bilden im festen Zustand leicht Aggregate, deren Stabilisierung hauptsächlich auf mercurophilen und Hg···CC-Wechselwirkungen beruht. Die Aggregate wurden wegen ihrer Lumineszenzeigenschaften genutzt, [263] erlangten aber eine noch weitaus größere Bedeutung als Ligandentransferreagentien.…”