85115-68-0Relevant academic research and scientific papers
Sulfinylaniline complexes of iron(0)
Ashton, Henry C.,Manning
, p. 1440 - 1445 (2008/10/08)
A number of synthetic routes have been utilized to prepare a series of [Fe(PR3)2(CO)2(ArNSO)] derivatives (I) (R = PhCH2, 4-MeOC6H4, 4-MeC6H4, Ph, 4-ClC6H4; Ar = 4-MeOC6H4, 4-MeC6H4, 4-FC6H4, Ph, 4-ClC6H4, 4-BrC6H4, 4-NO2C6H4). The most useful was the reaction of [Fe2(CO)9] with PR3 and ArNSO in tetrahydrofuran at 20°C, but its efficacy depended on both PR3 and Ar. In the absence of PR3, this reaction gave red oils tentatively formulated as [Fe(CO)4(η1-(N)-ArNSO)], which with PR3 rapidly form I. Trialkyl phosphite and alkyl isocyanide nucleophiles displace PPh3 and/or CO from I with the formation of, e.g., [Fe(PPh3)(P(OCH2)3CMe)(CO)2(PhNSO)], [Fe(P(OMe)3)2-(CO)2(4-NO2C 6H4NSO)], or [Fe(PPh3)2(CNMe)(CO)(4-NO2C6H 4NSO)], but CO displaces the ArNSO ligand. Compounds of type I fail to react with MeI or MeSO3F, but with other electrophiles such as [4-FC6H4N2]+ salts, tetracyanoethylene, or acetic acid, they suffer ArNSO loss with formation of, e.g., [Fe(PPh3)2(CO)2(NNC6H 4F-4)]BF4, [Fe(PPh3)2(CO)2-(C4(CN) 4)] with trans CO ligands, and [Fe(PPh3)2(CO)2(O2CMe)2] with cis CO groups. The IR spectra of I have been investigated and absorption bands due to their v(CO), v(NS), and v(SO) vibrations identified and assigned. ArNSO are very powerful electron-withdrawing ligands which thus form stable bonds only with relatively electron-rich metal centers. Metal-to-ligand back-donation appears to be an important, perhaps overwhelming, component of the Fe-ArNSO bond which, it is tentatively concluded, is of the η2-(NS) rather than the η1-(S) type. The N and S atoms probably lie in the equatorial plane of a trigonally bipyramidally coordinated iron atom while the R3P ligands occupy the apical coordination positions. The η1-(S)- and η2-(NS)-ArNSO-metal bonding are outlined in a qualitative fashion, and the reasons for the relative importance of the second as compared with η2-(SO)-SO2 coordination are discussed.
