280-28-4

Upstream product

• 505-66-8 1,4-Diazacycloheptane 
• 50-00-0 formaldehyd 
• 67-56-1 methanol 

Relevant academic research and scientific papers

A reversible phase transition and dielectric anomaly in a spherical molecule [(3,2,1-dabco)2PbBr6]

Organic-inorganic hybrid materials were attracted most interests due to their potential applications in phase transition and photoelectric fields. Within this context, a spherical molecule 1, 5-diazabicyclo[3,2,1]octane (3,2,1-dabco) was used to react with PbBr2 in concentrated HBr acid and led to a discrete organic inorganic hybrid compound [(3,2,1-dabco)2PbBr6] (1). Thermodynamic DSC analyses and dielectric measurement of 1 showed an apparently reversible phase transition at about 427 K. The variable temperature X-ray single crystal diffraction demonstrated compound 1 underwent an order-disorder transition from orthorhombic to cubic systems at room and high temperatures.

Rational Design of Ceramic-Like Molecular Ferroelectric by Quasi-Spherical Theory

Molecular ferroelectrics are attracting tremendous interest because of their easy and environmentally friendly processing, light weight, low acoustical impedance, and mechanical flexibility, which are viable alternatives or supplements to conventional ceramic ferroelectrics. However, reports of ceramic-like molecular ferroelectrics that can be applied in the polycrystalline form have been scarce. Here, according to the "quasi-spherical theory", we successfully synthesized a ceramic-like molecular ferroelectric with an m3mFmm2 type phase transition at 357 K, 1,5-diazabicyclo[3.2.1]octonium tetrafluoroborate ([3.2.1-dabco]BF4), which can show excellent ferroelectric performance in the polycrystalline thin-film form at room temperature. On the basis of the reported molecular ferroelectric [2.2.2-dabco]BF4 (2.2.2-dabco = 1,4-diazabicyclo[2.2.2]octonium) with an Aizu notation of 4/mmmFmm2 and two polar axes, we changed the [2.2.2-dabco]+ cation to the [3.2.1-dabco]+ cation to reduce the molecular symmetry and keep the quasi-spherical shape simultaneously, making the number of polar axes up to six. Moreover, the spontaneous polarization Ps gets successfully increased from 4.9 μC cm-2 in [2.2.2-dabco]BF4 to 5.5 μC cm-2 in [3.2.1-dabco]BF4. This precise molecular design strategy offers an efficient pathway to design ceramic-like molecular ferroelectrics.

Using Methanol as a Formaldehyde Surrogate for Sustainable Synthesis of N-Heterocycles via Manganese-Catalyzed Dehydrogenative Cyclization

The development of an efficient and sustainable synthetic route for formaldehyde production from renewable feedstock, especially in combination with a subsequent transformation to straightforwardly construct valuable chemicals, is highly desirable. Herein, we report a novel manganese-catalyzed dehydrogenative cyclization of methanol as a formaldehyde surrogate with a variety of dinucleophiles for facile synthesis of N-heterocycles. The in situ generated formaldehyde via catalytic methanol dehydrogenation can be selectively trapped by diverse dinucleophiles to avoid several possible side reactions. The utility of this transformation is further highlighted by its successful application to the synthesis of 13C-labeled N-heterocycles using 13CH3OH as a readily accessible 13C-isotope reagent.

NMR study of stereoelectronic anomeric and homoanomeric effects on the axial and equatorial CH bonds in 1,3-diazacyclohexanes and 1,5-diazabicyclo[3.2.1]octanes

The 1H and 13C NMR spectra of a series of 1,3-di-tert-butyl-1,3-diazacyclohexanes 6, and of 1,5-diazabicyclo[3.2.1]octanes 7, have been investigated in an attempt to find evidence regarding a stereoelectronic interaction of the non-bonding electron pairs on nitrogen or of the C-N bonding electron pairs in the ring, with the axial and equatorial CH bonds of the α- or β-methylene groups. In 6, the orbital carrying the non-bonding electron pair lies antiperiplanar to the axial α-CH bond; a significant nN→σ*CH 3-orbital interaction (the anomeric effect) is sterically possible, and this shows up in the values of δH and of 1JCH. In 7, the doubly-occupied orbital is orientated gauche to both the axial and equatorial α-CH bonds, and no anomeric effect is apparent. In 7 however, in contrast to 6, the stereochemistry is appropriate for a W-plan nN→σ*CH 4-orbital interaction with the equatorial β-CH bond, and comparison of the NMR data of 6 and 7 suggests that such a homoanomeric effect may operate, though it is much weaker than in the analogous 1,3-dioxanes. No evidence could be found for a σCN→σ*CH 3-orbital interaction.