The indenylidene-bearing family of complexes has exhibited a rapid growth in use in recent years and is quickly becoming a mainstream catalyst in metathesis-type reactions [-nitroaryl substituents were designed.
The average Ru–P, Ru-Cl(1), and Ru-Cl(2) bond lengths amount 2.52, 2.45, and 2.55 Å for 14a and 2.53, 2.48, and 2.54 Å for 14b, respectively.
Higher -selectivity of the synthesized 14a and 14b compared to the commercial complex 5 is mainly due to the unsymmetrical NHC ligand, which induces the indenylidene ligand to be located on the side of the mesityl group, but not the nitrobenzyl one.
As a result, we have chosen 6 conformers per isomer (see Supplementary Material) to show the structural diversity of the synthesized catalysts and influence of weak interactions on their catalytic activity.
The global minima structures of 14a and 14b are shown in Fig. Weak intramolecular interactions such as C–H···O, C–H···Cl, C–H···π hydrogen bonds and attractive π–π stacking interactions are among them.
Their activities were compared with that of commercially available indenylidene catalyst.
The structures of complexes and their stability were investigated using static DFT calculations with mixed basis set.], which are therefore attractive alternatives to well-known and more frequently used benzylidene catalysts.
The HMBC correlation of 14a confirmed the catalyst structure and showed good correlation of the attached proton signal from indenylidene group with the weak carbenic carbon peak.], they are reliable.
The experiments performed simultaneously with the same batch of reagents in air clearly showed differences in reactivity of 5, 14a, and 14b.
This issue will be the subject of further detailed investigations (e.g., including the Nolan and Cavallo method [H NMR spectrum confirmed the structure of the obtained catalysts.
The signals derived from the mesityl group protons (three singlets from the methyl groups and two singlets from the aromatic protons) have been well resolved in C NMR spectra signals from the carbenic carbons were weak.