A newly formed bond of organic carbamato–carbonato emerged upon bubbling CO₂ in a low molecular weight chitosan hydrochloride oligosaccharide CS·HCl/DMSO binary mixture. The aforementioned bond was detected and confirmed using attenuated total reflectance-Fourier transform Infrared (ATR-FTIR) spectroscopy, with two prominent peaks at 1551 cm⁻¹ and 1709 cm⁻¹ corresponding to ionic organic alkylcarbonate (RCO₃⁻) and carbamate (RNH–CO₂⁻ NH₃⁺–R), respectively. ¹H–, ¹³C–, and ¹H–¹⁵N heteronuclear single quantum coherence (HSQC) NMR experiments were also employed. According to ¹³C NMR, two newly emerged peaks at 157.4 ppm and 161.5 ppm attributed for the carbonyl carbon within the sequestered species RCO₃⁻ and RNH–CO₂⁻ NH₃⁺–R, respectively. Upon CO₂ bubbling, cross peaks obtained from ¹H–¹⁵N HSQC at 84.7 and 6.8 ppm correlated to the ammonium counterpart chemical shift bound to the proton resonances. Volumetric uptake of CO₂ was measured using an ATR-FTIR autoclave equipped with a silicon probe. The equilibrium sorption capacity was 0.6 and 0.2 bars through the formation of RCO₃⁻ and RNH–CO₂⁻ NH₃⁺–R, respectively. Moreover, physisorption by the dried DMSO contributed to additional 0.4 bars. Density functional theory (DFT) calculations supported the occurrence of the suggested dual mechanisms and confirmed the formation of carbonate at C-6 of the glucosamine co-monomer. Moreover, CS·HCl/DMSO showed a slight impact on cell proliferation after 48 hours; this was a clear evidence of its non-toxicity. The biodegradation test revealed that a degradation of about 80% of CS·HCl/DMSO was achieved after 33 days; these results indicated that this method is suitable for green industry. CS·HCl/DMSO showed modest activities against Staphylococcus aureus and Escherichia coli. In addition, CS·HCl/DMSO demonstrated a significant antifungal activity against Aspergillus flavus in comparison with Fluconazole.

中文翻译：

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壳聚糖寡糖/ DMSO对CO ₂的化学吸附：形成有机氨基甲酸酯-氨基甲酸酯键

当在低分子量壳聚糖盐酸盐低聚糖CS·HCl / DMSO二元混合物中鼓吹CO _2时，出现了一个新形成的有机氨基甲酸酯基-氨基甲酸酯键。检测上述键和证实使用衰减全反射傅立叶在1551厘米变换红外（ATR-FTIR）光谱，具有两个显着的峰^-1和1709厘米^-1对应于离子有机烷基碳酸酯基（RCO ₃ ^- ）和氨基甲酸酯（RNH –CO ₂ ^- NH ₃ ⁺ –R）。¹ H–，¹³ C–和¹ H– ¹⁵还使用了N个异核单量子相干（HSQC）NMR实验。根据¹³ C NMR，在157.4 ppm的和161.5 ppm的2个新出现的峰归因于所述隔离物种内的羰基碳RCO ₃ ^-和RNH-CO ₂ ^- NH ₃ ⁺分别-R。在CO ₂鼓泡时，从¹ H– ¹⁵ N HSQC在84.7和6.8 ppm处获得的交叉峰与结合到质子共振上的铵态化学位移相关。CO _2的体积吸收使用装备有硅探针的ATR-FTIR高压釜来测量。平衡吸附容量为0.6和0.2巴通过RCO的形成₃ ^-和RNH-CO ₂ ^- NH ₃ ⁺ -R，分别。此外，干燥的DMSO的物理吸附贡献了另外的0.4 bar。密度泛函理论（DFT）计算支持所提出的双重机理的发生，并证实了C-6处碳酸盐的形成葡糖胺共聚单体。而且，CS·HCl / DMSO对48小时后的细胞增殖有轻微的影响。这是其无毒的明显证据。生物降解试验表明，经过33天的降解，CS·HCl / DMSO的降解率约为80％。这些结果表明该方法适用于绿色工业。CS·HCl / DMSO对金黄色葡萄球菌和大肠杆菌的活性中等。另外，与氟康唑相比，CS·HCl / DMSO对黄曲霉表现出显着的抗真菌活性。