Synthesis, characterization and electrochemical properties of phosphine-disubstituted diiron bis(monoselenolate) carbonyls

The properties of diiron dithiolates/diselenolates have been exhaustively studied, the substituted bis(monoselenolate) carbonyls are rarely described. In order to enrich the chemistry of diiron diselenolate compounds and synthesize new hydrogen evolution catalysts, a series of monosubstituted diiron bis(monoselenolate) carbonyls [Fe-2(mu-SeCH2Ph)(2)(CO)(5)L] (L= PPh3, 1a; PPh2Me, 1b; PPhMe2, 1c; PMe3, 1d), and two disubstituted diiron bis (monoselenolate) carbonyls [Fe-2(mu-SeCH2Ph)(2)(CO)(4)L-2] (L = PPh3, 2a; PPh2Me, 2b) have been prepared. That is, treatment of [Fe-2(mu-SeCH2Ph)(2)(CO)(6)] (1) with 1 equivalent of PR3 ligand in the presence of Me3NO center dot 2H(2)O afforded the 1a-1d in 47-63% yields. Alternately, treatment of [Fe-2(mu-SeCH2Ph)(2)(CO)(6)] (1) with 2 equivalents of PPh3 and PPh2Me under efficient one-pot UV-irradiation produced 2a and 2b in moderate yields. 1a-1d exist as two isomers, while only syn-isomer are found in 2a and 2b. All the new compounds were characterized by elemental analysis, IR, NMR spectroscopy and X-ray crystallography. In addition, the electrochemical and electrocatalytic properties of these models were studied by cyclic voltammetry (CV) in MeCN.

Automated summary

A series of monosubstituted and disubstituted diiron bis(monoselenolate) carbonyls were prepared to enrich the chemistry of diiron diselenolate compounds and synthesize new hydrogen evolution catalysts. The new compounds were characterized by various analytical techniques and their electrochemical properties were studied by cyclic voltammetry in MeCN.