A tetranuclear fluorido-bridged iron compound: Fluoride abstraction from the tetrafluoridoborate anion

Abstract

The novel iron(II) fluoride cluster [Fe II 4(L 1 SSL 1)2F6(MeCN)2](BF4)2 (L 1 SSL 1 = di-2-(bis(2pyridylmethyl)amino)ethyl disulfide) has been synthesized by reaction of the ligand L 1 SSL 1 with [Fe(MeCN)6](BF4)2. The crystal structure shows that a tetranuclear iron(II) compound is formed through the bridging of two dinuclear iron(II) units by four fluoride anions. The 19 F NMR spectrum distinguishes both the terminal and bridging fluoride ions in this compound. The new compound is a rare Fe II fluoride cluster with four Fe II and four F − ions arranged in a nearly perfect square plane, which obtained its fluoride ions from the tetrafluoridoborate anion.

Redox Interconversion between Cobalt(III) Thiolate and Cobalt(II) Disulfide Compounds

“…ESI-MS spectra of the final reaction mixture show the presence of a large number of species, including a peak at m / z 734.8 for [Fe 2 (L 1 SSL 1 )­Cl 3 ] + , indicating that the reaction does not simply yield the anticipated Fe­(III) thiolate compound. As described above, the direct reaction of L 1 SSL 1 with [Fe­(MeCN) 6 ]­(BF 4 ) 2 yielded a tetranuclear Fe­(II) compound of the disulfide ligand with bridging fluoride ions …”

“…As described above, the direct reaction of L 1 SSL 1 with [Fe(MeCN) 6 ](BF 4 ) 2 yielded a tetranuclear Fe(II) compound of the disulfide ligand with bridging fluoride ions. 25 …”

“…Reaction of 2 equiv of Co­(NCS) 2 with 1 equiv of ligand L 1 SSL 1 dissolved in acetonitrile provided a brown precipitate of the Co­(III) compound [Co III (L 1 S)­(NCS) 2 ] ( 3 ) in a yield of 70%. In contrast, reaction of 2 equiv of [Fe­(MeCN) 6 ]­(BF 4 ) 2 with 1 equiv of ligand L 1 SSL 1 dissolved in acetonitrile did not result in the anticipated Fe­(III) thiolate compound but instead yielded a tetranuclear iron­(II) fluoride compound . The cobalt and iron compounds were characterized by using 1 H NMR, UV–vis, Raman, and IR spectroscopy, electrospray ionization mass spectrometry (ESI-MS), elemental analysis, and single crystal X-ray crystallography.…”

“…Reaction of ligand L 1 SSL 1 with FeCl 2 ·4H 2 O results in the formation of the iron­(II) disulfide compound [Fe II 2 (L 1 SSL 1 )­Cl 4 ] ( 1 Fe ), showing a structure that is slightly different from that of [Co II 2 (L 1 SSL 1 )­Cl 4 ] ( 1 Co ). However, instead of the expected Fe­(III)-thiolate compound similar to 2 , reaction of 1 Fe with AgBF 4 did not give conclusive results, and reaction of ligand L 1 SSL 1 with [Fe­(MeCN) 6 ]­(BF 4 ) 2 resulted in the formation of a fluoride-bridged tetranuclear iron­(II) compound . Thus, the redox interconversion in the iron compound appears to be more difficult despite the fact that one of the thioether sulfurs in 1 Fe is coordinating.…”

“…However, instead of the expected Fe(III)-thiolate compound similar to 2 , reaction of 1 Fe with AgBF 4 did not give conclusive results, and reaction of ligand L 1 SSL 1 with [Fe(MeCN) 6 ](BF 4 ) 2 resulted in the formation of a fluoride-bridged tetranuclear iron(II) compound. 25 Thus, the redox interconversion in the iron compound appears to be more difficult despite the fact that one of the thioether sulfurs in 1 Fe is coordinating.…”