Synthesis and properties of a series of carboranyl-BODIPYs

Abstract

A series of four BODIPYs containing one or two ortho- or para-carborane clusters were synthesized using palladium(0)-catalyzed Suzuki cross-coupling or nucleophilic substitution reactions, at the 2,6- or the 8-positions of halogenated boron dipyrromethenes (BODIPYs). The spectroscopic, structural (including one X-ray) and in vitro BBB permeability of the BODIPYs using hCMEC/D3 brain endothelial cells were investigated.

Enhanced Hypsochromic Shifts, Quantum Yield, and π–π Interactions in a meso,β-Heteroaryl-Fused BODIPY

“…5 Their favorable properties include strong and narrow absorption and emission bands in the far-red or near-infrared (NIR) regions, high quantum yields, high chemical and physical stability, and high tunability that allows the design of specific targets for a particular application.…”

Substituent Effects on the Fluorescence Properties of ortho‐Carbor­anes: Unusual Emission Behaviour in C‐(2′‐Pyridyl)‐ortho‐carboranes

“…[9,15,16,17] No thin-film emissions were observed at room temperatures for the parent carboranes 1-3. Solid-state emissions at ambient temperatures were reported elsewhere for 1 (powder form: 395 nm; [53] silica gel form: 356 nm [5] ), 2 (silica gel: 380 nm [5] ) and 3 (silica gel: 345 nm [5] ). The different results are attributed to the different solid morphologies looked at.…”

“…Of the three carboranes with poorly resolved two-electron reversible waves observed, dipyridyl-ortho-carborane 14 and 1-phenyl-2-(2′-pyridyl)-ortho-carborane 17 are easier to reduce than diphenyl-ortho-carborane 16, [5,[61][62][63]67] and 1-phenyl-2-(2′-pyridyl)-ortho-carborane 17. This observation suggests that the carborane moiety is a suitable acceptor in 14 and thus gives charge-transfer emissions.…”

“…[4][5][6][7][8][9][10][11][12][13] The meta-or para-carborane cluster merely plays roles as a spectator, a spacer or an inductively electron-withdrawing group in these molecules or polymers. There are, however, rare exceptions where the clusters are actively involved in the excited states of bis(benzodiazaborolyl)-meta-and -para-carboranes.…”

“…[7][8][9][10][11][12][13][15][16][17][18][19][20][21][22][23][24][25][26][27][28] Dual fluorescence with CT and local transitions has been observed in some orthocarboranes. [12,13,[15][16][17][18][19][20]28] The ortho-carborane unit plays a role similar to meta-and para-carborane clusters in the photophysical process of a compound if there is a stronger electron acceptor than the cluster in these systems, [5,6,29,30] and if the ortho-carborane group is connected to a donor at one or more boron cluster atoms. [7,28,31] The ortho-carborane group is a much weaker electron acceptor when bonded at the boron atom (it may even be a donor depending on the position of the attached boron atom).…”