A new entry into ferraborane chemistry: Synthesis and characterization of heteroferraborane complexes

Abstract

Reaction of [CpFe(CO) 2I], 1 (Cp = η 5-C 5H 5) and di(organyl)dichalcogenides, E 2R 2 (E = S, Se; R = Ph, CH 2Ph, 2,6-( t Bu) 2-C 6H 2OH) with [LiBH 4·thf] at −70 °C in toluene, followed by stirring at room temperature for 18 h yielded heteroferraboranes, [CpFe(CO)B 2H 4(μ-L)], 2– 4 ( 2: L = SePh; 3: SeCH 2Ph and 4: S(2,6-( t Bu) 2-C 6H 2OH). Compounds 2– 4 are highly unstable and concurrent lose of boron atoms yielded organochalcogenolato-bridged complexes, [CpFe(CO)(μ-L)] 2, 5– 7, respectively ( 5: L = SePh; 6: SeCH 2Ph and 7: S(2,6-( t Bu) 2-C 6H 2OH). In contrast, the reaction of 1 with di(2-furyl)ditelluride, (C 4H 3O) 2Te 2, yielded organotellurato-bridged complex, [CpFe(CO)(μ-TeC 4H 3O)] 2, 8 and all of our attempts to isolate the boron precursor [CpFe(CO)B 2H 4(μ-TeC 4H 3O)] in pure form failed. The accuracy of these predictions in each case is established by IR, 1H, 11B, 13C, 77Se, 125Te NMR and mass spectrometry and complex 8 is further structurally confirmed by X-ray crystallography.