Hemilabile Properties of Sulfur‐Containing Cymantrene Derivatives

Abstract

Sulfur-containing cymantrene derivatives having one or two organometallic moieties were studied by NMR, IR, UV/Vis spectroscopic methods and CVA under irradiation conditions. Photolysis of compounds 1-3 leads to the formation of rare 4membered chelates 4, 5 and 8. In the presence of external ligand (L), dissociation of the MnÀ S bond occurred to form new dicarbonyl complexes with the MnÀ L bond, which demonstrates the hemilabile character of the chelates obtained. The results were confirmed by DFT calculations. CVA method showed manganese oxidation potential value increased in the case of dicarbonyls (1313 mV for 4) as compared to that of tricarbonyls (1067 mV for 1).

Synthesis, Spectral and Electrochemical Properties, and Computational Modeling of N‐Cymantrenylmethylphthalimide

“…When changing n ‐donor solvent, which is able to form stable dicarbonyl intermolecular complexes with manganese, there is a sharp change in the UV‐vis spectra. Thus, the appearance of a weak band from the chelate complex is observed in DMF, which completely disappears after 10 min of thermal reaction, while a slight increase in the intensity of bands at 403 and 467 nm was recorded ( Figure S19 , Table 2) belonging to dicarbonyl complex with the Mn−DMF bond [13] . Upon irradiation, the light yellow solution immediately turns to red‐violet and after thermal reaction for 10 min changes to dark red.…”

“…Earlier we showed that when a solutions of cymantrene derivatives containing a substituent with electron‐donating fragments in the cyclopentadienyl ring are irradiated, CO is released and chelates are formed due to coordination of donor substituent fragments with a manganese atom [13] …”

“…Upon irradiation, the light yellow solution immediately turns to red‐violet and after thermal reaction for 10 min changes to dark red. Only two bands appear at 376 and 428 nm in acetonitrile (Table 2) typical of dicarbonyl complexes with the manganese‐acetonitrile bond [13] …”

“…Only two bands appear at 376 and 428 nm in acetonitrile (Table 2) typical of dicarbonyl complexes with the manganese-acetonitrile bond. [13] The study of electrochemical properties of 1 and its photolysis products…”

“…Earlier we showed that irradiation of cymantrenylalkyl sulfides results in the formation of chelates, in which sulfur atom coordinates to manganese; in the presence of CO, the reverse thermal reaction occurs to give the initial tricarbonyls. [13] If the photolysis is carried out in the presence of an external ligand (PPh 3 ), a chelate is formed by a sulfur atom as a kinetic product, which gradually turns into a thermodynamically more advantageous dicarbonyltriphenylphosphine complex. Similar hemilabile properties were also revealed in the case of photolysis of complex 1 in benzene in the presence of triphenylphosphine as an external ligand.…”