Reversible Intramolecular Base Stabilization of a Low‐Coordinate Silicon Atom in the Silanediyl Complex [(o‐Me₂NCH₂C₆H₄)₂SiCr(CO)₅]

Synthesis and reactivities of dihydrosilanes tethered with two thioether moieties

“…The 29 Si NMR spectra of dichlorosilanes 3a, b showed signals at −3.6 and −3.2 ppm, respectively, which are shifted to higher field by −10.1 and −9.7 ppm, respectively, compared with the 29 Si NMR chemical shift of Ph 2 SiCl 2 (δ Si = 6.5 ppm) [10]. Since the 29 Si NMR chemical shift of a five-coordinate dichlorosilane, [2-(Me 2 NCH 2 )C 6 H 4 ] 2 SiCl 2 , (δ Si = −30.1 ppm) [13] has reportedly shown the large up-field shift ( δ Si = −36.6 ppm) compared with that of Ph 2 SiCl 2 , it may be suggested that the interaction between the silicon atom and thioether moieties in dichlorosilanes 3a, b is absent or very weak.…”

“…1 H NMR spectra of 1a-c, 3b, 4a-c, and 5a, b, 13 C NMR spectra of 1b, c, 3b, and 5a, b, and atomic coordinates for the calculated molecules, (2-MeSCH 2 C 6 H 4 ) 2 SiBr 2 and Ph 2 SiBr 2 are available from the corresponding author (ntakeda@chem-bio.gunma-u.ac.jp) on request.…”

“…The 1 H NMR (500 or 300 MHz) spectra were measured in CDCl 3 or C 6 D 6 with a JEOL JNM-λ500 or JEOL JNM-AL300 spectrometer using SiMe 4 (0 ppm) as internal standards. The 13 C NMR (126 MHz) and 29 Si NMR (99 MHz) spectra were measured in CDCl 3 or C 6 D 6 with a JEOL JNM-λ500 spectrometer using CDCl 3 (77.0 ppm) or C 6 D 6 (128.0 ppm) as those for 13 C NMR spectroscopy and SiMe 4 (0 ppm) as internal standards for 29 Si NMR spectroscopy. Infrared spectra were recorded on a Shimadzu FTIR-8400S spectrometer.…”

Facile syntheses, structural characterizations, and isomerization of disiloxane-1,3-diols

“…The reaction of bis[2-(dimethylaminomethyl)phenyl]dichlorosilane [10,14] with 2 equiv of water in the presence of triethylamine at room temperature for 1 h gave 1,3-dihydroxy-1,1,3,3-tetrakis[2-(dimethylaminomethyl)phenyl]disiloxane, 3, to be recrystallized from nhexane. The 1 H NMR resonance of hydroxy group for 3 was observed at 9.98 ppm.…”

Silver‐Catalyzed Silylene Transfer

“…While Fischer-type metal carbene complexes without solvent adducts have been extensively characterized, 48 most metal silylenoid complexes contain a bound solvent molecule or counterion on the silicon atom. The bond energy for donor silicon complex 22 was determined to be between 15 and 20 kcal/mol: 49,50 (OC) 5 The bonding picture of a metal with a divalent silicon atom emerged through computational studies to explain the need for the incorporation of a Lewis base at silicon. 51,52 Similar to the bonding scheme of a metal carbene, the Fischer-type silylene (OC) 5 Mo¼SiH 2 contains an sp s donor and p p acceptor.…”