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Amine treatment is commonly used to capture CO 2 from exhaust gases and from ambient air. The SiÀ N bond in aminosilanes is capable of reacting with CO 2 more readily than amines. In the current study we have synthesized trimethylsilylated ethanolamines, diethanolamines and piperazines and investigated their reaction toward CO 2. All products were characterized by 1 H, 13 C, and 29 Si NMR, RAMAN spectroscopy as well as mass spectrometry. The product of a twofold CO 2insertion into bis-trimethylsilylated piperazine was analysed by single-crystal X-ray diffraction. Furthermore, quantum chemical calculations (DFT) were used to supplement the experimental results. Geometry optimizations and NBO calculations for each starting material were carried out at the B3LYP level with different basis sets. DFT calculations at the B3LYP, WB97XD and M062x level were conducted for geometry optimization and frequency calculations to examine the thermochemical data. The calculations were carried out both for the gas phase and in solvent environment. The calculated reaction enthalpies varied between À 37 and À 107 kJ mol À 1 , while experimental values around À 100 kJ mol À 1 were determined.

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The aminosilanes MenSi(NRR′)4−n (n=2,3) with NRR′=ethylamino (NHEt), n-propylamino (NHnPr), sec-butylamino (NHsBu), n-octylamino (NHnOct), n-dodecylamino (NHnDodec), allylamino (NHAll), tert-butylamino (NHtBu), diethylamino (NEt2), and anilino (NHPh) were synthesized and their reactions with phenyl isocyanate were studied. In all cases of these silanes Me3SiNRR′ and Me2Si(NRR′)2 formal insertion of the –NCO group into their Si–N bonds was observed, i.e. formation of products with Si–N (rather than Si–O) bonds was found. In some cases, the products could be crystallized and their molecular structures have been elucidated with single-crystal X-ray diffraction analyses.

Lactamomethylsilanes of γ-butyrolactam, δ-valerolactam, ε-caprolactam, and 1-isoindolinone (phthalimidine) with up to three methyl moieties were synthesized according to the chemical formula Me x SiLac (4-x) (x = 0, 1, 2, and 3). Using the lactams as starting materials four synthetic routes were tested: salt elimination, transsilylation, transamination, and metallation of the lactames followed by reaction 377 with methylchlorosilanes. All products were analyzed by NMR ( 1 H, 13 C and 29 Si) and RAMAN spectroscopy. Selected solid products were crystallized and the molecular structure was determined by single-crystal X-ray diffraction. The reactivity of the lactamomethylsilanes towards phenylisocyanate and CO 2 was studied.Si-O bond but less reactive than a Si-Cl bond. The Si-N bond is prone towards hydrolysis and alkoholysis. Additionally, some substances containing Si-N bonds react with heteroallenes like CO 2 and isocyanates via insertion reactions yielding useful products such as ureas, carbamates, and polysiloxanes, among others. [23][24][25][26] Therefore, in the presented study we have synthesized lactamomethylsilanes of the type Me x SiLac (4-x) (x = 0, 1, 2, and 3) [Lac = γ-butyrolactam, δ-valerolactam, εcaprolactam, and 1-isoindolinone (phthalimidine)] in order to investigate their structures and reactivities.

A novel phosgene-free route to different isocyanates starts from CO 2 and aminosilanes (cf. silylamines) to form so-called carbamoyloxysilanes (O-silylcarbamates), i. e., compounds with the general motif R 1 R 2 NÀ COÀ OÀ SiR 3 R 4 R 5 as potential precursors. We focused on the insertion reaction of CO 2 into SiÀ N bonds of substrates with cyclic (mostly aromatic) amine substituents, i. e.

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