Transition metal-catalyzed polymerization of 1,3,5-trioxane

A new versatile binuclear seven-coordinate complex of molybdenum(II), [(μ-Cl)2{Mo(μ-Cl)(SnCl3)(CO)3}2]2−

“…Assignment of the proton and carbon signals of (nba) 2 O was done by combining the NMR data from 1 H-1 H COSY and 1 H- 13 C Table 3 Selected bond lengths (Å) and angles (°) for anion of 2. HMQC correlations and DEPT experiments.…”

“…Similar analysis of other proton signals reveals that most of them are very close double signals. Although their assignment to relevant carbons was done without difficulty by 1 H- 13 C HMQC correlations, the coupling constants could not be measured accurately.…”

“…What was very surprising and not seen before was the formation of the N-allylpiperidinium cation [(C 3 H 5 )pip] + in the above reaction. However, it was proved by X-ray diffraction studies in solid state and by 1 H and 13 C NMR measurements in solution (see Section 3). Additional evidence was obtained by ESI-MS analysis, where the signal of the cation C 8 H 16 N + , with M + = 126.1, was detected.…”

“…The proposed mechanism for the formation of [(C 3 H 5 )pip] + involves the splitting of the N-C and C-C bonds in one of the piperidine ligands due to synergic interactions with the molybdenum atom and the tin atom of the Lewis acid SnCl 4 , leading to the creation of an allyl ligand. This process can be compared to the ring-opening polymerization of cyclic ethers such as tetrahydrofurane [12] or 1,3,5-trioxane [13] or ring-opening of 2-phenylazetidines [14]. The formation of an intermediate allyl ligand of the molybdenum complex was detected by NMR spectroscopy analysis of the crude reaction mixture.…”

“…The 1 H NMR spectrum shows three signals for the allyl group from three sets of protons, central (H c ), syn (H s ), and anti (H a ) at d 3.90 (tt, 3 J H-H = 10 and 6.8 Hz, H c ), 3.61 (d, 3 J H-H = 6.8 Hz, H s ), and 1.12 (d, 3 J H-H = 10 Hz, H a ) with an integral intensity ratio of 1:2:2. In the 13 C NMR spectrum, two signals, at d = 74.4 (CH c ) and 58.0 (2CH 2 ), can be assigned to the allyl ligand. The NMR characteristics of this allyl ligand are very similar to those of other allyl ligands in molybdenum(II) complexes [15][16][17][18][19].…”