549502-66-1Relevant academic research and scientific papers
Molecular and electronic structures of iron(II)/(III) complexes containing N,S-coordinated, closed-shell o-aminothiophenolato(1-) and o-iminothiophenolato(2-) ligands
Ghosh, Prasanta,Begum, Ameerunisha,Bill, Eckhard,Weyhermuller, Thomas,Wieghardt, Karl
, p. 3208 - 3215 (2003)
The coordination chemistry of the ligands o-aminothiophenol, H(abt), 4,6-di-tert-butyl-2-aminothiophenol, H[LAP], and 1,2-ethanediamine-N,N′-bis(2-benzenethiol), H4(′N2S2′), with FeCl2 under strictly anaerobic and increasingly aerobic conditions has been systematically investigated. Using strictly anaerobic conditions, the neutral, air-sensitive, yellow complexes (μ-S,S)[FeII(abt)2]2 (1), (μ-S,S)[FeII(LAP)2]2 · 8CH3OH (2), and (μ-S,S)[FeII(′H2N2S2 ′)]2 · CH3CN (3) containing high spin ferrous ions have been isolated where (abt)1-, (LAP)1-, and (′H2N2S2′)2- represent the respective N,S-coordinated, aromatic o-aminothiophenolate derivative of these ligands. When the described reaction was carried out in the presence of trace amounts of O2 and [PPh4]Br, light-green crystals of [PPh4][FeII(abt)2(itbs)] · [PPh4]Br (4) were isolated. The anion [FeII(abt)2(itbs)]- contains a high spin ferrous ion, two N,S-coordinated o-aminophenolate(1-) ligands, and an S-bound, monoanionic o-iminothionebenzosemiquinonate(1-) π radical, (itbs)-. Complex 4 possesses an St = 3/2 ground state. In the absence of [PPh4]Br and presence of a base NEt3 and a little O2, the ferric dimer (μ-NH,NH)[FeIII(LAP)(LIP)]2 (5a) and its isomer (μ-S,S)[FeIII(LAP)(LIP)]2 (5b) formed. (LIP)2- represents the aromatic o-iminothiophenolate(2-) dianion of H[LAP]. The structures of compounds 2, 4, and 5a have been determined by X-ray crystallography at 100(2) K. Zero-field Moessbauer spectroscopy of 1, 2, 3, and 4 unambiguously shows the presence of high spin ferrous ions: The isomer shift at 80 K is in the narrow range 0.85-0.92 mm s-1, and a large quadrupole splitting, |ΔEQ|, in the range 3.24-4.10 mm s-1, is observed. In contrast, 5a and 5b comprise both intermediate spin ferric ions (SFe = 3/2) which couple antiferromagnetically in the dinuclear molecules yielding an St = 0 ground state.
