Catalytic Reductive Coupling of 9-Bromofluorene

Abstract

The reductive homocoupling of 9-bromofluorene is catalyzed by 0.1 mol % Ru 3 (CO) 12 in refluxing xylene, with a TON in excess of 3000. A stoichiometric reaction affords the novel cluster Ru 4 (µ 3 -OMe)-(µ 3 -OH)(µ-Br) 2 (CO) 10 , which is found to be even more catalytically active. Further reaction of this cluster with bromofluorene gives another novel cluster, Ru 4 (µ 4 -O)(µ-Br) 6 (CO) 8 , which is inactive. atoms, followed by difference maps for the light, non-hydrogen atoms. All non-hydrogen atoms were generally given anisotropic displacement parameters in the final model (except for 5 below). Cluster 2 exhibited disorder of two carbonyls on Ru(4) and one carbonyl on Ru(5). These were each modeled with two alternative sites of equal occupancies, and appropriate restraints on their anisotropic parameters and bond distances were placed.Cluster 5 contained three molecules in the asymmetric unit. It was refined as a racemic twin. The data quality was poor, and there appeared to be disorder in molecule A, which was not modeled.All the carbon atoms were given isotropic thermal parameters, as well as the µ 4 -O atom in molecule A.

A novel polyfluorene derivative electrodeposited by direct anodic oxidation of 9-bromofluorene in boron trifluoride diethyl etherate and trifluoroacetic acid

“…Although 9-bromofluorene (BFe) had been reported [17][18][19][20], up to now, there was not a systematic study of PBFe film electrodeposited by direct anodic oxidation of BFe and characterizations of corresponding polymers because the electropolymerization of BFe was more difficult in neutral solvent due to the electro-withdrawing group substitution (bromine) on the fluorenyl unit, leading to higher oxidation potential compared with Fe monomer. For example, Triebe and coworkers [17] studied the redox behavior of 9,9-dibromofluorene in dimethylformamide and found their redox behaviors were affected significantly by electrocatalysis from reduction products of the starting compounds.…”

“…Goodman and coworkers [19] investigated the synthesis and characterization of fluorine end-labeled polystyrene with BFe as the initiator by atom transfer radical polymerization. Recently, the reductive homocoupling of BFe was catalyzed by Ru 3 (CO) 12 in refluxing xylene and bifluorenyls were obtained by Sridevi et al [20]. The interest in BFe monomer was also due to its further modification by other functional groups through the reactions of bromine atom at C-9 position of the fluorenyl unit.…”

3,9′-Bi(9H-fluorene)

“…For the crystal structures of related compounds, see: Dougherty et al (1978); Sridevi et al (2006). For the synthesis of the compound, see: Stille et al (1993Stille et al ( , 1998; Grasa & Nolan (2001).…”

9,9′-Dibromo-9,9′-bifluorene

“…For related literature, see: Dougherty et al (1978); Graebe & Manz (1896); Olah et al (1981); Solans et al (1980); Sridevi et al (2006).…”

“…The dihedral angle of Br1-C9-C22-Br2 is 59.39 (16)°, indicating its gauche conformation. Although the bond length of C9-C22 [1.561 (3) Å] is longer than that of non-substituted 9,9′-bifluorene [1.542 (3) Å, Dougherty et al, 1978;1.539 (3) Å, Sridevi et al, 2006], it is one of the shortest C-C bonds between 9 and 9′ positions among the 9(,9′)-substituted 9,9′-bifluorenes (1.559-1.724 Å). The shortest intermolecular contacts were found to be C22-Br2…”