源自经典N-杂环卡宾的晶体自由基。
Crystalline Radicals Derived from Classical N-Heterocyclic Carbenes.
作者信息
Rottschäfer Dennis, Neumann Beate, Stammler Hans-Georg, van Gastel Maurice, Andrada Diego M, Ghadwal Rajendra S
机构信息
Anorganische Molekülchemie und Katalyse, Lehrstuhl für Anorganische Chemie und Strukturchemie, Centrum für Molekulare Materialien, Fakultät für Chemie, Universität Bielefeld, Universitätsstrasse 25, 33615, Bielefeld, Germany.
Max-Planck-Institut für Kohlenforschung, Kaiser Wilhelm Platz 1, 45470, Mülheim an der Ruhr, Germany.
出版信息
Angew Chem Int Ed Engl. 2018 Apr 16;57(17):4765-4768. doi: 10.1002/anie.201801596. Epub 2018 Mar 15.
One-electron reduction of C2-arylated 1,3-imidazoli(ni)um salts (IPr )Br (Ar=Ph, 3 a; 4-DMP, 3 b; 4-DMP=4-Me NC H ) and (SIPr )I (Ar=Ph, 4 a; 4-Tol, 4 b) derived from classical NHCs (IPr=:C{N(2,6-iPr C H )} CHCH, 1; SIPr=:C{N(2,6-iPr C H )} CH CH , 2) gave radicals [(IPr )] (Ar=Ph, 5 a; 4-DMP, 5 b) and [(SIPr )] (Ar=Ph, 6 a; 4-Tol, 6 b). Each of 5 a,b and 6 a,b exhibited a doublet EPR signal, a characteristic of monoradical species. The first solid-state characterization of NHC-derived carbon-centered radicals 6 a,b by single-crystal X-ray diffraction is reported. DFT calculations indicate that the unpaired electron is mainly located at the original carbene carbon atom and stabilized by partial delocalization over the adjacent aryl group.
源自经典氮杂环卡宾（IPr = :C{N(2,6-iPr₂C₆H₃)}CHCH，1；SIPr = :C{N(2,6-iPr₂C₆H₃)}CH₂CH₂，2）的C2-芳基化1,3-咪唑（鎓）盐（IPr）Br（Ar = Ph，3 a；4-DMP，3 b；4-DMP = 4-MeC₆H₄）和（SIPr）I（Ar = Ph，4 a；4-Tol，4 b）的单电子还原产生了自由基[(IPr)•]（Ar = Ph，5 a；4-DMP，5 b）和[(SIPr)•]（Ar = Ph，6 a；4-Tol，6 b）。5 a、b和6 a、b中的每一个都表现出双峰电子顺磁共振信号，这是单自由基物种的特征。本文报道了通过单晶X射线衍射对源自氮杂环卡宾的碳中心自由基6 a、b进行的首次固态表征。密度泛函理论计算表明，未成对电子主要位于原始卡宾碳原子上，并通过在相邻芳基上的部分离域而稳定。
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