55718-44-0Relevant academic research and scientific papers
Controllable preparation of magnetic carbon nanocomposites by pyrolysis of organometallic precursors, similar molecular structure but very different morphology, composition and properties
Ruan, Zhijun,Ran, Jingwen,Liu, Shanshan,Chen, Yanmei,Wang, Xichao,Shi, Jie,Zhu, Lihong,Zhao, Shengfang,Lin, Junqi
, p. 2044 - 2052 (2021)
Four cobalt-containing organometallic compounds were synthesized for solid-state pyrolysis (SSP) to study the structure-property relationship between the precursors and the as-synthesized magnetic carbon nanocomposites (MCNs). In this research, the only s
Tuning the Electronic Properties of Acetylenic Fluorenes by Phosphaalkene Incorporation
Svyaschenko, Yurii V.,Orthaber, Andreas,Ott, Sascha
, p. 4247 - 4255 (2016)
Versatile synthetic protocols for 2,7- and 3,6-diacetylenic fluorene-9-ylidene phosphanes (F9Ps) were developed. Protodesilylation of trimethylsilyl-protected acetylenic F9Ps affords terminal acetylenes that can be employed in Sonogashira and Glaser-type C-C coupling reactions to give thienyl-decorated and butadiyne-bridged fluorene-9-ylidene phosphanes, respectively. As evidenced by UV/Vis spectroscopy and cyclic voltammetry and corroborated by ab initio calculations, the presence of the P center in the F9Ps induces a significantly reduced HOMO-LUMO splitting that originates from stabilization of the LUMO levels. Variation of the acetylene substitution pattern is an additional tool to influence the optical and electronic properties. Whereas 3,6-disubstituted F9Ps have strong absorptions around 400nm, mainly due to π-π? transitions, 2,7-diacetylenic F9Ps exhibit longest-wavelength absorptions that have significant charge-transfer character with an onset around 520nm. Bringing together the goodies: Fluorenes, acetylenes, and phoshosphaalkenes were combined in a novel class of compounds: acetylenic fluorene-9-ylidene phosphanes (F9Ps). Experimental and computational studies show that the exocyclic P center stabilizes the LUMO of the F9Ps and leads to significantly reduced HOMO-LUMO splittings. Variation of the acetylene substitution pattern is an additional tool to alter the optical and electronic properties.
Photophysics of arylene and heteroaryleneethinylenest
Birckner,Grummt,G?ller,Pautzsch,Egbe,Al-Higari,Klemm
, p. 10307 - 10315 (2001)
The absorption spectra and the stationary and time-resolved emissions of a series of the title compounds are investigated. Various combinations of ethinylene, p-phenylene, biphenyl-4,4'-diyl, fluorenyl-2,7-diyl, 3- or 4-pyridyl, phenanthroline-3,8-diyl, 2,2'- bipyridine-5,5'-diyl, and 2,2'- bipyridine-4,4'-diyl molecular units allow a systematic structure variation, e.g., size of n system, type of aza-substitution, linear or angular chains. Most compounds are highly fluorescent. Radiationless deactivation via internal conversion and to a lesser extend intersystem crossing become efficient if forbidden states exist close to the strongly allowed JTJTstates (proximity effect) which can be traced back to a smaller size of the JT system or reduced conjugation due to meta-linkages of heteroaromatic rings. Aza-substitution may change the deactivation behavior but it does insignificantly influence the absorption and fluorescence spectra. Replacing phenanthrene for 2,2'-bipyridine in the larger compounds does not alter the spectroscopic and the deactivation behaviors.
Fluorenes as new molecular scaffolds for carbon-carbon σ-bond cleavage reaction: Acylfluorenylation of arynes
Yoshida, Hiroto,Kishida, Takeshi,Watanabe, Masahiko,Ohshita, Joji
supporting information; experimental part, p. 5963 - 5965 (2009/05/06)
Acyl and fluorenyl moieties are facilely installed into neighbouring positions of aromatic skeletons via C-C bond cleavage reaction using arynes. The Royal Society of Chemistry.
