A non-symmetric sulfur-basedO,C,O-chelating pincer ligand leading to chiral germylene and stannylene

Abstract

New chiral heteroleptic germanium(ii) and tin(ii) metallylenes were obtained using 1-(para-tolylsulfinyl)-3-tosyl-5-tert-butyl-benzene as a non-symmetric O,C,O-chelating pincer ligand.

Synthesis and Characterization of a Novel Bis‐Sulfoxide and Its Evaluation as a Ligand in p‐Block Chemistry

“…[40,42,59] The formation of product 5 was also confirmed by the 119 Sn NMR with the appearance of a sharp signal at 75 ppm and a broad one at 54 ppm. This is in agreement with the results previously observed in the case of the sulfone-sulfoxide stannylene, [43] where signals were seen at 49.3 and 72.5 ppm. This observation also suggests that coordination of the oxygen atoms of the sulfinyl groups is likely in compound 5, as it was proven for the sulfone-sulfoxide stannylene.…”

“…This is in agreement with the results previously observed in the case of the sulfone‐sulfoxide stannylene, where signals were seen at 49.3 and 72.5 ppm. This observation also suggests that coordination of the oxygen atoms of the sulfinyl groups is likely in compound 5 , as it was proven for the sulfone‐sulfoxide stannylene . The chemical shift for 5 observed at 75 and 54 ppm are downfield shifted compared to other O,C,O‐chelating chlorostannylenes (–99 ppm) , .…”

“…This observation also suggests that coordination of the oxygen atoms of the sulfinyl groups is likely in compound 5, as it was proven for the sulfone-sulfoxide stannylene. [43] The chemical shift for 5 observed at 75 and 54 ppm are downfield shifted compared to other O,C,O-chelating chlorostannylenes (-99 ppm). [60,61] at 939.2 can be observed (See S11 ESI), species that suggest the existence of the stannylene in the mixture.…”

“…The bis-thioether 1 was oxidized to obtain a mixture of 1,3-(para-tolylsulfinyl)-5-tert-butyl-benzene 2 together with the bis-sulfone [40] and sulfone-sulfoxide, [43] derivatives previously reported by our team. Though in the literature several studies are presented on the oxidation of sulfides to sulfoxides or sulfones using different solvents, catalysts and oxidants, on various substrates, [3][4][5]14,32,35,36,45] none of them mention the selective formation of a sole compound in the case when two sulfide groups are present in the molecule.…”

“…However, several methods were developed for selective oxidation, obtaining only a sulfoxide unit. [3,4] Following our scientific interest focused on the synthesis of new organic compounds that can function as O,C,O-chelating aryl-pincer-type ligands, containing either two sulfonyl groups in their structure (bis-sulfone), [40,42] or one sulfonyl and one sulfinyl moiety (sulfone-sulfoxide), [43] we have expanded our research on the bis-sulfoxides derivatives having in mind their ability to stabilize metallylenes. A significant feature of the sulfoxide groups connected to an aromatic ring, that is considered in this work, is their powerful directing effect in ortho position, as it is well known in the literature.…”