Access to Functionalized Luminescent Multi-2,2′:6′,2″-terpyridine Ligands

Abstract

A one-pot synthesis of substituted multi-2,2':6',2″-terpyridines (multi-tpy) has been achieved using an acetylquaterpyridine precursor with various aryl aldehydes in basic media. This strategy enables ready access to functionalized tri-terpyridines. Utilizing a Suzuki-type cross-coupling, larger structures such as tetra- or even hexa-tpy were obtained from our tri-tpy precursor. These macromolecular units are ideal building blocks for the construction of transition-metal-based supramolecular assemblies.

1-{4-[(Hexyloxy)methyl]pyridin-2-yl}ethanone

“…The synthesis of 1-{4-[(hexyloxy)methyl]pyridin-2-yl}ethanone (3) is a two-step process, starting from alcohol derivative (1), which can be obtained either from methyl or ethyl 2-acetylisonicotinate [18][19][20] according to a procedure described in the literature [21] (Scheme 1). Deprotection of the ketone function was carried out in an acidic aqueous solution under reflux.…”

“…4-(hydroxymethyl)-2-(2-methyl-1,3-dioxolan-2-yl)pyridine (1) [21] (1.38 g, 7.07 mmol, 1 equiv) was dissolved in 20 mL of DMF. The mixture was cooled at 0 °C, NaH (60%) (7.78 mmol, 1.1 equiv) was added, and the mixture was stirred for 30 min.…”

“…Purification by flash chromatography (eluent: hexane/ethyl acetate: 90/10 to 70/30) yielded 3 as a colorless oil (2.65 g, 76%). 1 H-NMR (CDCl3, 400 MHz), δ (ppm) = 8.65 (d, 1H6, J = 4.9 4-(hydroxymethyl)-2-(2-methyl-1,3-dioxolan-2-yl)pyridine (1) [21] (1.38 g, 7.07 mmol, 1 equiv) was dissolved in 20 mL of DMF. The mixture was cooled at 0 • C, NaH (60%) (7.78 mmol, 1.1 equiv) was added, and the mixture was stirred for 30 min.…”

Synthesis and Photophysical Properties of Substituted 2,2′:6′,2′′‐Terpyridine Derivatives and Analogous Compounds with a Central Thiophene Ring

“…(E,E)- 6,2':6',: According to GP1, bis(nonaflate) 1 (300 mg, 0.378 mmol), K 2 CO 3 (105 mg, 0.756 mmol), (E)-2-phenylvinylboronic acid (123 mg, 0.832 mmol), and Pd(PPh 3 ) 4 (88 mg, 0.076 mmol) were reacted in 3mLo fD MF for 4hat 80 8C. After work-up, purification of the crude product by column chromatography (silica gel, hexanes/ethyl acetate, 3:1) pro- 3-H).…”

“…[2] The crucial intermediates are the corresponding nonaflates I (R = SO 2 C 4 F 9 ,X = Cl, Br,H ), which allow nucleophilic substitutions or palladium-catalyzed coupling reactions [3] at the 4-,4 '-, or 4''-positions of the heterocyclic system.T he methyl groups of these terpyridine derivatives allow further functionalization and introductiono fa dditional donor substituents. [4] As functionalized 2,2':6',2''-terpyridines are extremelyi mportant ligands andb uildingb locks for ab road range of applications, [5,6] we describe in this full account our efforts to further convert the obtained intermediates into new compounds.F ollowing the same syntheticm ethod, we also report the synthesis of related compounds bearing at hiophene ring insteado ft he centralp yridine core. [7] The photophysical properties of the new thiophenea nalogs will be compared with those of relatedt erpyridine derivatives and thiophene/pyridinehybrid compounds.…”