Iterative Synthesis of Oligoynes Capped by a Ru₂(ap)₄-terminus and Their Electrochemical and Optoelectronic Properties

Abstract

Cross-coupling reactions between terminal ethynes (HC⋮CY) and Ru2(ap)4(C2( k - 1)H) under Hay conditions, where ap is 2-anilinopyridinate and k = 2−5, resulted in compounds Ru2(ap)4(C2kY) (Y = Si i Pr3 and Ph) along with the homocoupling products YC4Y and [Ru2(ap)4]2(μ-C4( k - 1)). Compounds Ru2(ap)4(C2 k Y) display two reversible Ru2-based one-electron couples: an oxidation and a reduction. The HOMO−LUMO gaps (E g) estimated from electrode potentials correlate linearly with the number of acetylenic bonds (k) within each series. Both nonlinear absorption and degenerate four-wave mixing measurements were carried out at both 532 and 800 nm with nano- and femtosecond laser pulses.

Efficient Intramolecular Charge Transfer in Oligoyne‐Linked Donor–π–Acceptor Molecules

“…[20] Interestingly, an increment of + 30 to + 50 mV in the value of E ox was observed with each additional triple bond for compounds 1-4. As noted previously for 1 and 2, [23] and for some oligoyne-bridged binuclear organometallic compounds, [32,33] this can be ascribed to the electron-withdrawing nature of the extra triple bond. In the present D-(C C) n -A systems we cannot exclude the possibility that charge delocalisation across the bridge might play a role in causing these anodic shifts.…”

Synthesis of Uniform, Non-Natural Oligomers

“…38 Also very recently, Goodson, Ren et al reported the synthesis of a structurally related series of ruthenium-capped oligoynes. 39 These oligomers were prepared by a crosscoupling reaction between terminal acetylenes [HC≡CY, Y = Si(i-Pr 3 ), Ph] and Ru 2 (ap) 2 (C 2(k-1) H) (ap = 2-anilinopyridinate, k = 2-5).…”

Reactivity of Polyynes: Complex Molecules from Simple Carbon Rods

“…Very recently, Tykwinski and co-workers reported regioselective Diels-Alder reaction of different hexatriynes (14)(15)(16)(17)(18)(19)(20) with tetraphenylcyclopentadienone followed by further CO extrusion (Scheme 2). [60] As a result variety of hexasubstituted benzenes (21)(22)(23)(24)(25)(26)(27)(28) were obtained.…”

“…[63,64] Depending on polyyne end-groups and structure of the carbene, different types of products were observed. The use of bulkier TIPS group (14) led to product where the middle triple bond was involved in the reaction (45). The use of bulkier TIPS group (14) led to product where the middle triple bond was involved in the reaction (45).…”

“…[6] Polyynes may be regarded as model compounds of hypothetical linear allotropic form of carbon -carbyne. Polyynes also possess a remarkable application potential as molecular wires and switches in nanoelectronics, [7][8][9][10][11] as materials for optoelectronics due to their nonlinear optical response, [12][13][14][15][16][17][18] as precursors of conducting polymers [19,20] or even in live-cells imaging and sorting. Polyynes also possess a remarkable application potential as molecular wires and switches in nanoelectronics, [7][8][9][10][11] as materials for optoelectronics due to their nonlinear optical response, [12][13][14][15][16][17][18] as precursors of conducting polymers [19,20] or even in live-cells imaging and sorting.…”