Reactions of M[(η5-C5Me5)Fe(CO)2] with ClSiMe2NR2 in THF, Et2O and toluene (M = Li and K; R = Me, Et, iPr and Ph)

Abstract

Treatment of K[Cp*Fe(CO) 2 ] (Cp* = η 5 -C 5 Me 5 ) with ClSiMe 2 NR 2 (R = Me, Et, i Pr, Ph) in THF afforded Cp*(CO) 2 -Fe(CH 2 ) 4 OSiMe 2 NR 2 accompanied with ring-opening and incorporation of a THF molecule between iron and silicon atoms. On the other hand, reactions between Li[Cp*Fe(CO) 2 ] and ClSiMe 2 NR 2 in diethyl ether (for R = Me, Et), or in toluene in the presence of N,N,NЈ,NЈ-tetramethylethylenediamine (TMEDA) (for R = i Pr, Ph) afforded the corresponding Cp*(CO) 2 FeSiMe 2 NR 2 (R = Me, Et, i Pr, Ph), where the anionic complex was freshly prepared by treatment of Cp*(CO) 2 FeH with n-BuLi. In the case of the reaction of Li[Cp*Fe(CO) 2 ] with ClSiMe 2 NPh 2 , although the formation of the diphenylamino derivative Cp*(CO) 2 FeSiMe 2 NPh 2 was confirmed by NMR spectroscopy, purification of the product was unsuccessful. Subsequently, the exclusive formation of Cp*(CO) 2 FeSiMe 2 NPh 2 was achieved by means of irradiation of Cp*(CO) 2 FeMe and HSiMe 2 NPh 2 in toluene.

Synthesis of N-Heterocycle Substituted Silyl Ligands within the Coordination Sphere of Iron

“…A related ring opening and incorporation of THF has previously been observed by Okazaki et al. 102 in the reaction between ClSiMe 2 NR 2 and the Fp-anion to form Fp(CH 2 ) 4 OSiMe 2 NR 2 . They explain this by initial coordination of THF to the silane, followed by nucleophilic attack of Fp – on the α-carbon.…”

Insertion of pyridine into an iron–silicon bond: structure of the product Cp*(CO)Fe{η3(C,C,C)-C5H5NSiMe2NPh2}

“…Ultraviolet irradiation of Cp*(CO) 2 FeSiMe 2 NPh 2 (1) 4 and pyridine in toluene was performed in a Pyrex sealed tube (eqn.…”

“…The Fe-Si bond distance (2.3330(4) Å) is shorter than that in 1 (2.3355(7) Å), while the Si-N1 bond distance (Si-N1 1.799(1) Å) is longer than that in 1 (1.787(2) Å). 4 These differences are attributable to enhanced back-donation from the iron dp orbital to the Si-N s* orbital by coordination of the strongly electron-releasing pyridine.…”

Reactions of Manganese Silyl and Silylene Complexes with CO2 and C(NiPr)2: Synthesis of Mn(I) Formate and Amidinylsilyl Complexes

“…The 29 Si NMR chemical shifts for 5 (vide supra) are comparable to those of base-stabilized silylene complexes, and a similarly high frequency resonance (65.4 ppm) has been used (in combination with crystallographic data) to suggest that the bonding environment in [Cp*­(OC) 2 Mo­(κ 2 { Si , N }-Si­{ p -Tol} 2 {N­(H)­C 5 H 4 N})] (which contains a comparable M–Si–N–C–N metallacycle) involves a contribution from a base-stabilized silylene resonance structure . However, 29 Si resonances at only slightly lower frequencies have also been reported for aminosilyl complexes such as [Cp*­(OC) 2 Fe­{SiMe 2 (NR 2 )}] (R = Me, i Pr, Ph; 29 Si δ = 53–47 ppm) …”

“…It is notable that CO 2 insertion into transition metal−hydride bonds is a key step in many catalytic processes, and is therefore the subject of considerable investigation. 25 NMR spectra of 3 feature a single 31 P NMR environment at 68.3 ppm, and only five 1 H NMR signals {four from the dmpe ligands between 1.23 and 1.90 ppm, and one (a quintet with J 31P−1H of 2 Hz) from the formyl proton at 8.68 ppm}.…”