Functionalization of Biphenylcarbazole (CBP) with Siloxane-Hybrid Chains for Solvent-Free Liquid Materials

Abstract

We report herein the synthesis of siloxane-functionalized CBP molecules (4,4′-bis(carbazole)-1,1′-biphenyl) for liquid optoelectronic applications. The room-temperature liquid state is obtained through a convenient functionalization of the molecules with heptamethyltrisiloxane chains via hydrosilylation of alkenyl spacers. The synthesis comprises screening of metal-catalyzed methodologies to introduce alkenyl linkers into carbazoles (Stille and Suzuki Miyaura cross-couplings), incorporate the alkenylcarbazoles to dihalobiphenyls (Ullmann coupling), and finally introduce the siloxane chains. The used conditions allowed the synthesis of the target compounds, despite the high reactivity of the alkenyl moieties bound to π-conjugated systems toward undesired side reactions such as polymerization, isomerization, and hydrogenation. The features of these solvent-free liquid CBP derivatives make them potentially interesting for fluidic optoelectronic applications.

Control of the Organization of 4,4′-bis(carbazole)-1,1′-biphenyl (CBP) Molecular Materials through Siloxane Functionalization

“…The different siloxane-functionalized CBP derivatives investigated in this study were synthesized using optimized catalytic methodologies recently reported elsewhere (Scheme 1) [38]. Briefly, monobromocarbazole 1 was used to prepare the two CBP derivatives functionalized with two siloxane segments (short: CBP-2Si 3 and longer: CBP-2Si n ).…”

“…The detailed synthetic protocols can be found in Ref. [38] or in the Supplementary Materials. stoichiometry of reagents in the first and third steps, leading to intermediates 4, 7, and the final CBP derivative (CBP-4Si3) functionalized with 4 short siloxane segments instead of 2.…”

“…The synthetic procedure to prepare the siloxane-functionalized CBP has recently been reported elsewhere [38]. The latter focusses on the methodology we followed to introduce one or two short heptamethylsiloxane segments (via a propylene linker) at each of the carbazole end-units of CBP, to yield CBP-2Si 3 and CBP-4Si 3 , respectively (Figure 1).…”

Hydrogenation of Styrene-Butadiene Rubber Catalyzed by Tris(triisopropylphosphine)hydridorhodium(I)

“…Recently, several catalysts have been reported to be effective in the hydrogenation of SBR [11,12]. Barrios et al utilized a Ziegler-Natta-type catalyst made from a reaction between NiAcAc and n-BuLi to selectively hydrogenate 1,2-vinyl and 1,4-trans bonds in a styrene-butadiene copolymer [13].…”

Theoretical Study of Hydroxylation of α- and β-Pinene by a Cytochrome P450 Monooxygenase Model

“…CYPs are responsible for the metabolism of about 90% of administered drugs in men [ 4 ]. CYP enzymes were reported to catalyze a wide array of important chemical reactions such as arene oxidation, activation of inert C–H bonds, C–C coupling, epoxidation, hydroxylation, and N-dealkylation reactions [ 1 , 2 , 5 , 6 , 7 , 8 , 9 , 10 ]. In particular, hydroxylation reactions by CYP enzymes are among the most vital reactions in drug metabolism [ 3 , 11 , 12 ].…”