- Impact of deboronation on the electronic characteristics ofcloso-o-carborane: intriguing photophysical changes in triazole-appended carboranyl luminophores
-
5-Phenyl-1,2,4-triazole-appendedcloso- (CB1andCB2) andnido-o-carboranyl (nido-CB1andnido-CB2) compounds were prepared and fully characterized using multinuclear NMR spectroscopy and elemental analysis. The solid-state molecular structures of bothcloso-compounds were analyzed by X-ray crystallography. Although thecloso-compounds exhibited dual emissive patterns in the rigid state (in THF at 77 K), which were assignable to a π-π* local excitation (LE)-based emission (λem=ca. 380 nm) on the triazole moieties and to an intramolecular charge transfer (ICT)-based emission (ca. 460 nm) in which theo-carborane units acted as the acceptor (A), at 298 K in THF, the LE-based emission dominated. In contrast, thenido-compounds exhibited an intensive emission originating from ICT transitions in which theo-carborane units reversibly acted as the donor (D). In particular, the positive solvatochromic effects of bothnido-compounds and the results of theoretical calculations for theo-carboranyl compounds supported the electronic role of theo-carboranyl unit in each compound. Investigation of the radiative decay mechanism of thecloso- andnido-compounds using their quantum efficiency (Φem) and decay lifetime (τobs) suggested that the ICT-based radiative decay ofnido-compounds occurred more efficiently than the LE-based decay ofcloso-compounds. These results implied that emission from thecloso-compounds was drastically enhanced by the deboronation reaction upon exposure to an increasing concentration of fluoride anions, and finally became similar to the emission color (sky-blue) of thenido-compounds.
- Kim, Mingi,Im, Sehee,Ryu, Chan Hee,Lee, Seok Ho,Hong, Ju Hyun,Lee, Kang Mun
-
supporting information
p. 3207 - 3215
(2021/03/16)
-
- C-Au Covalently Bonded Molecular Junctions Using Nonprotected Alkynyl Anchoring Groups
-
We report on an approach to realize carbon-gold (C-Au) bonded molecular junctions without the need for an additive to deprotect the alkynyl carbon as endstanding anchor group. Using the mechanically controlled break junction (MCBJ) technique, we determine the most probable conductance value of a family of alkynyl terminated oligophenylenes (OPA(n)) connected to gold electrodes through such an akynyl moiety in ambient conditions. The molecules bind to the gold leads through an sp-hybridized carbon atom at each side. Comparing our results with other families of molecules that present organometallic C-Au bonds, we conclude that the conductance of molecules contacted via an sp-hybridized carbon atom is lower than the ones using sp3 hybridization due to strong differences in the coupling of the conducting orbitals with the gold leads.
- Olavarria-Contreras, Ignacio José,Perrin, Mickael L.,Chen, Zhi,Klyatskaya, Svetlana,Ruben, Mario,Van Der Zant, Herre S. J.
-
supporting information
p. 8465 - 8469
(2016/07/26)
-
- An easy route to (hetero)arylboronic acids
-
An unprecedented spontaneous reactivity between diazonium salts and diboronic acid has been unveiled, leading to a versatile arylboronic acid synthesis directly from (hetero)arylamines. This fast reaction (35 min overall) tolerates a wide range of functional groups and is carried out under very mild conditions. The radical nature of the reaction mechanism has been investigated.
- Erb, William,Hellal, Akila,Albini, Mathieu,Rouden, Jacques,Blanchet, Jerome
-
p. 6608 - 6612
(2014/06/09)
-
- Processes for preparing of glucopyranosyl-substituted (ethynyl-benzyl)-benzene derivatives and intermediates thereof
-
The present invention relates to processes for preparing the compounds of general formula I, wherein the groups R1, R2 and R3 are defined according to claim 1 and to intermediates of said processes.
- -
-
Page/Page column 28
(2010/11/26)
-
- Microwave-assisted synthesis of ethynylarylboronates for the construction of boronic acid-based fluorescent sensors for carbohydrates
-
A reliable and operationally simple procedure for the synthesis of 2,2-dimethylpropane-1,3-diyl ethynylaryl boronates 4 was developed. The key step is microwave-facilitated selective formation of 2,2-dimethylpropane-1,3-diyl trimethylsilylethynylaryl boro
- Zheng, Shi-Long,Reid, Suazette,Lin, Na,Wang, Binghe
-
p. 2331 - 2335
(2007/10/03)
-
- Anthracene - BODIPY cassettes: Syntheses and energy transfer
-
Compounds based on the 4,4-difluoro-1,3,5,7-tetramethyl-4-bora-3a,4a-diaza-s-indacene (BODIPY) framework are excellent fluorescent markers. When BODIPY dyes of this type are conjugated to functionalities that absorb at relatively short wave-lengths, those functionalities can, in some molecules, transmit the absorbed energy to the BODIPY which then fluoresces. In such cases the BODIPY fragment acts as an acceptor while the other group serves as a donor. Energy transfer efficiencies in such donor-acceptor cassette systems must vary with the relative orientation of the two components, and with the structure of the linkers that attach them. This study was designed to probe these issues for the special case in which the linkers between the donor and acceptor fragments are conjugated. To do this, the cassettes 3-10 were prepared. Electrochemical studies were performed to provide insight into the degree of donor -acceptor conjugation in these systems. X-ray Crystallographic studies on single crystals of compounds 7 and 9 revealed the favored conformations of the donor and acceptor fragments in the solid state. Absorption, fluorescence, and time-resolved fluorescence spectra of the compounds were recorded, and quantum yields for the cassettes excited at the donor λmax were measured. Fluorescence steady-state anisotropy data were determined for cassettes 3 and 9 to provide information about the mutual direction of the transition dipole moments.
- Wan, Chi-Wai,Burghart, Armin,Chen, Jiong,Bergstroem, Fredrik,Johansson, Lennart B.-A.,Wolford, Matthew F.,Kim, Taeg Gyum,Topp, Michael R.,Hochstrasser, Robin M.,Burgess, Kevin
-
p. 4430 - 4441
(2007/10/03)
-