Sulfur Imide as bisdihapto‐Bridging Ligand in the Complex Fe₂(CO)₆(HNS)

Abstract

enzymatic meta-cleavage of pyrocatechol, both in alkaline solution (/2,,,=375 nm) as well as in acid solution (Lmax=316 nm). Since 2 is relatively unstable it was treated with NH3 for further characterization by the method of Fujiwara et al.L2'. After 3 days the yellow color RT, 72 h COOH QCOOMe 4 5 had disappeared and, as expected, the spectrum of picolinic acid 4 was obtained. The Rf value was identical with that of authentic picolinic acid, both in the thin-layer chromatography (toluene/dioxane/glacial acetic acid, 9 :2 :O.l) as well as in the HPLC (RP 8, 1% acetic acid). For final proof of the structure, the compound was esterified with methanol/POC13 according to the method described by Klo~a[~]. GC-MS gave a peak whose retention time and mass spectrum (m/z 137, 4%, M + ; 107, 23%, M-CH,O; 79, loo%, M-COOCH2) were identical to those of methyl picolinate 5.The mechanism of the meta-cleavage with K02/DMS0 is still unclear. Since the reaction does not take place under N2 it can be concluded that not only hyperoxide and pyrocatechol but also molecular oxygen must participate, and that not just a simple reaction of hyperoxide and pyrocatechol is involved.Several authors have discussed hyperoxide as a possible form of the reactive oxygen involved in dioxygenase reac-This would infer that the above mentioned reaction could be a model for dioxygenase reactions. Received: September 23, 1983 [Z 568 IE] German version: Angew. Chem. 96 (1984) 67 [I] L. Que, Strucr. Bonding 40 (1980) 39.[2] M.

NMR parameters of the tetrahedrane [Fe2(CO)6(μ-SNH)], studied by experiment and DFT

“…Previously, we have measured the 13 C and 15 N NMR spectra of 1 at room temperature and determined the coupling constant 1 J( 57 Fe, 15 N) = 6.1 Hz in natural abundance of the isotopes [18]. In the present work, we report lowtemperature 13 C NMR data of 1, including the coupling constants 1 J( 57 Fe, 13 C), and the first example of a 57 Fe chemical shift for a complex containing the (OC) 3 Fe-Fe(CO) 3 unit. After optimizing the geometry of 1 by DFT calculations [B3LYP/6-311 + G(d,p)], the NMR parameters such as chemical shifts and coupling constants of 1 were calculated at the same level of theory.…”

“…The complex 1 was prepared as described [13]. NMR spectra were recorded using Bruker ARX 250 (variable temperature .…”

“…Moreover, transformations B. Wrackmeyer ( ) · M. Herberhold Anorganische Chemie II, Universität Bayreuth, D-95440 Bayreuth, Germany e-mail: b.wrack@uni-bayreuth.de of this cluster [13][14][15][16][17], e.g. N-functionalisation of 1 [13][14][15][16], can be readily achieved (Scheme 1).…”

“…We have been interested for some time in aza-diferra-thiatetrahedranes, since the parent hexacarbonyl derivative 1 can be obtained in good yield (>50%) from the reaction of bis(trimethylsilyl)sulfur diimide with Fe 3 (CO) 12 , followed by chromatography on silica [13]. Moreover, transformations B. Wrackmeyer ( ) · M. Herberhold Anorganische Chemie II, Universität Bayreuth, D-95440 Bayreuth, Germany e-mail: b.wrack@uni-bayreuth.de of this cluster [13][14][15][16][17], e.g. N-functionalisation of 1 [13][14][15][16], can be readily achieved (Scheme 1).…”

Bridging (Thionylimido)metal Complexes

“…Sulfur–nitrogen transition-metal complexes have attracted many investigations in the past, and while bridging sulfur–nitrogen ligands are not unknown, they are relatively uncommon; complexes containing naked anions displaying different bridging modes, via nitrogen, sulfur, or both, have been reported. − (Thionylimido)metal complexes were first reported in the 1980s . To date, there are no examples of [NSO] − bridging between transition-metal centers; there are reports of a chromium complex where the [NSO] − anion coordinates to BF 3 as well as the metal and of Me 3 SiNSO coordinated to GaCl 3 .…”