Isolobal replacement of the metal fragments in [Fe3(μ3-Q)(μ3-AsCH3)(CO)9] (Q = Se and Te): Synthesis and structures of a number of Fe-Ir and Fe-Rh clusters simultaneously containing a chalcogen and arsenic

Dimerization of pentanuclear clusters [Fe3Q(AsMe)(CO)9] (Q = Se, Te) as a conversion pathway to novel cubane-like aggregates

“…Thus, its IR and mass spectra, as well as elemental analysis, could not be properly performed. Nevertheless, having the spectra of the Te-containing clusters for reference, the NMR spectra of corresponding pairs (2a and 2b, 3a and 3b) reveal practically the same signals both for 1 H and 13 C experiments. Analogously, the IR spectra in the n CO region contain practically the same pattern for each pair of compounds (weaker signals for 2a are hidden by the stronger ones of 1a impurities), with the shift of the n CO bands to higher frequencies for Se-containing analogs, according to the donor abilities of the chalcogen atoms.…”

“…Analogous behaviour was observed in the reactions of [Fe 3 S(PR)(CO) 8 (CRR¢)] with [Fe 2 (CO) 9 ] 15 and of [Fe 3 Q(AsMe)(CO) 9 ] with [Cp*M(CO) 2 ] (M = Rh, Ir). 13 Clusters with the core Fe 3 QQ¢ (with all combinations of Q, Q¢ = S, Se, Te, except QQ¢ = S 2 ) react with binuclear complex [CpMo(CO) 3 ] 2 to form insertion products containing the whole Mo 2 fragment in the cluster core. However, the final products contain only 2 Fe atoms (one Fe atom fewer), [Cp 2 Mo 2 Fe 2 (CO) n QQ¢] (n = 6-8 depending on the chalcogen atom combination 29 ).…”

“…The IR spectra were recorded on a Varian FTS 800 spectrometer, for the solutions in hexane. The NMR spectra were recorded on a Bruker Avance 400 spectrometer ( 1 H: 400.132 MHz, 13 C: 100.627 MHz), for the solutions in CD 2 Cl 2 . Chemical shifts (d, ppm) were referenced to the signals of the solvent ( 1 H and 13 In a typical experiment the starting compound 1a (0.200 g, 0.340 mmol), or 1b (0.200 g, 0.314 mmol) was placed in an ampoule with a Teflon stopcock.…”

“…The NMR spectra were recorded on a Bruker Avance 400 spectrometer ( 1 H: 400.132 MHz, 13 C: 100.627 MHz), for the solutions in CD 2 Cl 2 . Chemical shifts (d, ppm) were referenced to the signals of the solvent ( 1 H and 13 In a typical experiment the starting compound 1a (0.200 g, 0.340 mmol), or 1b (0.200 g, 0.314 mmol) was placed in an ampoule with a Teflon stopcock. About 10 ml of CH 3 CN were added, the vessel was shortly evacuated and placed in an oil bath (90 • C) for 2 days.…”