Three differentp erfluoroalkylated borafluorenes (F Bf)w ere prepared and their electronic and photophysical properties were investigated. The systemsh ave four trifluoromethyl moieties on the borafluorene moiety as well as two trifluoromethyl groups at the ortho positions of their exo-aryl moieties. They differ with regard to the para substituents on their exo-aryl moieties, being ap roton(F Xyl F Bf, F Xyl:2 ,6-bis(trifluoromethyl)phenyl), at rifluoromethyl group (F Mes F Bf, F Mes:2 ,4,6-tris(trifluoromethyl)phenyl) or ad imethylamino group (p-NMe 2-F Xyl F Bf, p-NMe 2-F Xyl:4-(dimethylamino)-2,6-bis(trifluoromethyl)phenyl), respectively.A ll derivatives exhibit extraordinarily low reduction potentials, comparable to those of perylenediimides. The most electron-deficient derivative F Mes F Bf wasa lso chemically reduced and its radicala nion isolated and characterized. Furthermore, all compounds exhibit very long fluorescent lifetimes of about 250 ns up to 1.6 ms; however, the underlying mechanismsresponsible for this differ.T he donor-substitutedd erivative p-NMe 2-F Xyl F Bf exhibitst hermally activated delayedf luorescence (TADF) from ac harge-transfer (CT) state, whereas the F Mes F Bf and F Xyl F Bf borafluorenese xhibit only weakly allowed locally excited (LE) transitions due to their symmetry and low transition-dipole moments.
The reactivity of N-heterocyclic carbenes (NHCs) and cyclic alkyl amino carbenes (cAACs) with arylboronate esters is reported. The reaction with NHCs leads to the reversible formation of thermally stable Lewis acid/base adducts Ar-B(OR) ⋅NHC (Add1-Add6). Addition of cAAC to the catecholboronate esters 4-R-C H -Bcat (R=Me, OMe) also afforded the adducts 4-R-C H Bcat⋅cAAC (Add7, R=Me and Add8, R=OMe), which react further at room temperature to give the cAAC ring-expanded products RER1 and RER2. The boronate esters Ar-B(OR) of pinacol, neopentylglycol, and ethyleneglycol react with cAAC at RT via reversible B-C oxidative addition to the carbene carbon atom to afford cAAC (B{OR} )(Ar) (BCA1-BCA6). NMR studies of cAAC (Bneop)(4-Me-C H ) (BCA4) demonstrate the reversible nature of this oxidative addition process.
More than twelve blood group systems have been described in dogs, but little is known about their distribution frequencies within breed populations. Here, we report on an extensive typing survey carried out using available reagents and either established or new clinical kits in purebred dogs from Germany. Leftover anticoagulated blood samples were examined using an immunochromatographic strip method for DEA 1, a gel column technique for Dal and Kai 1/2, and new card agglutination tests for DEA 4 and DEA 5 (which were partially compared with the gel column technique). Monoclonal antibodies were used for DEA 1 and Kai 1/2 typing, and polyclonal antibodies were used for all other types. Among the 206 dogs, 59.2% were DEA 1+, 100% DEA 4+, 9% (Card)/11% (Gel) DEA 5+, 89.3% Dal+, 96.6% Kai 1+, and 2.9% Kai 2+. None of the dogs were Kai 1+/2+, and only one was Kai 1-/2-. Dal-dogs were found in several breeds. Erythrocytes from most DEA 1+ dogs bound strongly on the strips. The agglutination reactions for DEA 5 on the new card tests were generally less than those on the gel column. The blood group pattern DEA 4+, DEA 5-, Dal+, Kai 1+/2-and either DEA 1+ or DEA 1-was found among 80% of the dogs. In this first extensive blood typing survey of purebred dogs from Europe, the proportions of positive and negative blood types were similar to those found in the United States and, for DEA 1, were also similar to those from other European countries, with considerable breed variation in blood types. The newer typing techniques seem to work well and will likely be useful for detecting and preventing specific blood type incompatibilities in the clinic.
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