Metallacumulenes as Potential Electron Reservoir Devices

Abstract

This paper reviews recent work in the area of organomanganese chemistry whose purpose is the design of single-molecule components for electronics. This field has recently received much attention in the pursuit of continued miniaturization of electronics. Electron reservoirs and molecular wires are basic motifs of single-electron devices. Both can accept and release electrons in a reversible fashion, but the former can also store electrons. Our recent work in the field deals with complexes of two distinct types: mononuclear half-sandwich manganese(I) vinylidene complexes, designed for application as electron reservoirs, and half-sandwich dinuclear manganese complexes and the bis-dmpe dinuclear MnII/MnII compounds, which were designed to serve as molecular wires. However, this review will focus on the mononuclear half-sandwich manganese(I) vinylidene and butatrienylidene systems, which have been synthetically successful systems and are supported by extensive DFT calculations and further detailed investigations using NMR, IR, UV−vis, and Raman spectroscopy, CV, magnetic susceptibilities, and X-ray diffraction studies.

Ligand Redox Non‐Innocence in Transition‐Metal σ‐Alkynyl and Related Complexes

“…[101] A particularly well-explored aspect of C-C coupling reactions in redox-generated organometallic radicals relates to the oxidation chemistry of the manganese vinylidene complexes depicted in Scheme 12. [102,103] The reaction of the vinylidene complex 13 with [FeCp 2 ]PF 6 at room temperature affords varying mixtures of the bis(carbyne) complexes 14 and 17. The reaction proceeds by the initial oxidation of the vinylidene to give the radical cation [13] ·+ , which may then undergo immediate C β -C β coupling to afford complex 14.…”

Chemistry of chromium bis-acetylide complexes

“…Paramagnetic analogues of such species have electronic open-shell configurations and are therefore expected to have nonlinear optical properties in addition to having applications as electronic materials in single-electron devices [1][2][3]. Strongly r-donor ligandsubstituted complexes of this type are expected to have low energy work functions, which is expected to guarantee strong electronic delocalisation and coupling between the metal centres [34,35]. Only very recently a chromium bisacetylide complex has been reported [36].…”

Dcab2--Substituted Manganese Vinylidene Complexes as Better Electron Reservoirs: A DFT Study

“…Electron-rich manganese-centered vinylidene complexes have been exploited by many due to their low-energy work function. 16 Manganese vinylidene complexes of the type Mn(C 5 H 4 R′)(R′′ 2 PCH 2 CH 2 PR′′ 2 )dCdC(R 1 )(H) were designed and synthesized for application as molecular batteries. 16 Earlier reports by Terry et al 17 indicated that vinylidene complexes of the type Mn(C 5 H 5 )(CO) 2 dCdC(H) 2 were thermally unstable and thus had to be generated and studied at low temperature.…”

“…16 Manganese vinylidene complexes of the type Mn(C 5 H 4 R′)(R′′ 2 PCH 2 CH 2 PR′′ 2 )dCdC(R 1 )(H) were designed and synthesized for application as molecular batteries. 16 Earlier reports by Terry et al 17 indicated that vinylidene complexes of the type Mn(C 5 H 5 )(CO) 2 dCdC(H) 2 were thermally unstable and thus had to be generated and studied at low temperature. Later Venkatesan et al used bidentate phosphorus ligands Me 2 PCH 2 CH 2 PMe 2 (dmpe) and Et 2 PCH 2 CH 2 PEt 2 (depe) to obtain isolobal compounds that are thermally stable.…”

“…Later Venkatesan et al used bidentate phosphorus ligands Me 2 PCH 2 CH 2 PMe 2 (dmpe) and Et 2 PCH 2 CH 2 PEt 2 (depe) to obtain isolobal compounds that are thermally stable. 16 The complex Mn(C 5 H 4 R′)(R′′ 2 PCH 2 CH 2 P R′′ 2 )dCdC(R 1 )(H) can be oxidized to form radical cations, which can combine to form dinuclear carbyne complexes (C 5 H 4 R′)(R′′ 2 PCH 2 CH 2 PR 2 ′′)Mnt CC(R 1 )(H)C(R 1 )(H)CtMn(R′′ 2 PCH 2 CH 2 PR′′ 2 )(C 5 H 4 R′) 2+ (Scheme 1). The dinuclear carbyne complex can be reduced to get back the parent compound.…”