[ 中文名 ]: | 葫芦[7]脲 |
---|---|
[ 英文名 ]: | cucurbituril |
CUCURBIT(7)URIL |
CUCURBIT[7]URIL (CB[7]) HYDRATE |
Cucurbit[7]uril |
常用名 | 葫芦[7]脲 | 英文名 | cucurbituril |
---|---|---|---|
CAS号 | 259886-50-5 | 分子量 | 1162.96000 |
密度 | N/A | 沸点 | N/A |
分子式 | C42H42N28O14 | 熔点 | N/A |
[ 中文名 ]: | 葫芦[7]脲 |
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[ 英文名 ]: | cucurbituril |
CUCURBIT(7)URIL |
CUCURBIT[7]URIL (CB[7]) HYDRATE |
Cucurbit[7]uril |
[ 分子式 ]: | C42H42N28O14 |
---|---|
[ 分子量 ]: | 1162.96000 |
[ 精确质量 ]: | 1162.34000 |
[ PSA ]: | 329.70000 |
[ Name ]: | cucurbituril |
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[ Synonym ]: | More Synonyms |
[ Molecular Formula ]: | C42H42N28O14 |
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[ Molecular Weight ]: | 1162.96000 |
[ Exact Mass ]: | 1162.34000 |
[ PSA ]: | 329.70000 |
Section 1: Product Identification Chemical Name:Cucurbit[7]uril (CB[7]) hydrate, 99+% CAS Registry Number:259886-50-5 Formula:C42H42N28O14.xH2O EINECS Number:none Chemical Family:macrocyclic compounds Synonym:CB[7] Section 2: Composition and Information on Ingredients IngredientCAS NumberPercentACGIH (TWA)OSHA (PEL) Title compound259886-50-5100%no datano data Section 3: Hazards Identification Emergency Overview:Irritating to skin, eyes and respiratory tract. Primary Routes of Exposure:Ingestion, inhalation, eyes Eye Contact:Causes slight to mild irritation of the eyes. Skin Contact:Causes slight to mild irritation of the skin. Inhalation:Irritating to the nose, mucous membranes and respiratory tract. Ingestion:No information available on the physiological effects of ingestion. May be harmful if swallowed. Acute Health Affects:Irritating to skin, eyes and respiratory tract. Chronic Health Affects:No information on long-term chronic effects. NTP:No IARC:No OSHA:No SECTION 4: First Aid Measures Immediately flush the eyes with copious amounts of water for at least 10-15 minutes. A victim may need Eye Exposure: assistance in keeping their eye lids open. Get immediate medical attention. Wash the affected area with water. Remove contaminated clothes if necessary. Seek medical assistance if Skin Exposure: irritation persists. Remove the victim to fresh air. Closely monitor the victim for signs of respiratory problems, such as difficulty Inhalation: in breathing, coughing, wheezing, or pain. In such cases seek immediate medical assistance. Seek medical attention immediately. Keep the victim calm. Give the victim water (only if conscious). Induce Ingestion: vomiting only if directed by medical personnel. SECTION 5: Fire Fighting Measures Flash Point:none Autoignition Temperature:none Explosion Limits:none Extinguishing Medium:carbon dioxide, dry powder or foam If this product is involved in a fire, fire fighters should be equipped with a NIOSH approved positive pressure Special Fire Fighting Procedures: self-contained breathing apparatus and full protective clothing. Hazardous Combustion andIf involved in a fire this material may emit irritating fumes. Decomposion Products: Unusual Fire or Explosion Hazards: No unusual fire or explosion hazards. SECTION 6: Accidental Release Measures Spill and Leak Procedures:Small spills can be mixed with vermiculite or sodium carbonate and swept up. SECTION 7: Handling and Storage Handling and Storage:Store in a tightly sealed container. Keep in a cool, dry, well-ventilated area. SECTION 8: Exposure Controls and Personal Protection Eye Protection:Always wear approved safety glasses when handling a chemical substance in the laboratory. Skin Protection:Wear protective clothing and gloves. Ventilation:Handle the material in an efficient fume hood. If ventilation is not available a respirator should be worn. The use of respirators requires a Respirator Respirator: Protection Program to be in compliance with 29 CFR 1910.134. Ventilation:Handle the material in an efficient fume hood. Additional Protection:No additional protection required. SECTION 9: Physical and Chemical Properties Color and Form:white powder Molecular Weight:1162.96 Melting Point:no data Boiling Point:no data Vapor Pressure:no data Specific Gravity:no data Odor:none Solubility in Water:insoluble SECTION 10: Stability and Reactivity Stability:air and moisture stable Hazardous Polymerization:no hazardous polymerization Conditions to Avoid:none Incompatibility:strong oxidizing agents Decomposition Products:carbon monoxide, carbon dioxide, nitrogen oxides, and organic fumes SECTION 11: Toxicological Information RTECS Data:No information available in the RTECS files. Carcinogenic Effects:no data Mutagenic Effects:no data Tetratogenic Effects:no data SECTION 12: Ecological Information Ecological Information:No information available SECTION 13: Disposal Considerations Disposal:Dispose of according to local, state and federal regulations. SECTION 14: Transportation Shipping Name (CFR):Non-hazardous Hazard Class (CFR):NA Additional Hazard Class (CFR):NA Packaging Group (CFR):NA UN ID Number (CFR):NA Shipping Name (IATA):Non-hazardous Hazard Class (IATA):NA Additional Hazard Class (IATA):NA Packaging Group (IATA):NA UN ID Number (IATA):NA SECTION 15: Regulatory Information TSCA:Not listed in the TSCA inventory SARA (Title 313):Not reportable under SARA 313 Second Ingredient:none SECTION 16 - ADDITIONAL INFORMATION N/A |
CUCURBIT(7)URIL |
CUCURBIT[7]URIL (CB[7]) HYDRATE |
Cucurbit[7]uril |
葫芦[7]脲做为纳米催化剂的最新突破
众所周知,生物体内的酶是自然界中活性最高的催化剂。这种特性除了与其本身的性质有关,还与其所处的环境息息相关:在反应前,酶及其所处的环境能通过弱的相互作用使反应底物呈现出一种“反应预备(reaction-ready)”状态,而处于这种状态下的底物不仅碰撞几率大大增加,其空间结构也会被诱导成有利于反应的构象。受到酶的启发,学者们试图合成具有空腔结构的大环化合物来模拟这种环境,使其不仅具有酶的功效,而且具有比酶更好的环境适应性。随着对酶性质的深入研究和主客体化学的出现及发展,超分子主体化合物催化有机反应的例子逐渐出现在化学及生物领域。从提出至今,超分子催化剂因其相对柔性的结构及优秀的识别性质而受到越来越多的关注,并在催化领域取得了一定的成果。
近日,清华大学化学系张希院士在对葫芦[7]脲识别性质的研究基础上将葫芦[7]脲(CB[7])与2,2,6,6 -四甲基哌啶氧化物(TEMPO)的包合物作为超分子催化剂成功催化了一系列醇类的氧化反应。相比于单独使用TEMPO,使用包合物不仅可以促进反应中间体TEMPO+的生成,并能在一定程度上抑制副反应的发生。该成果以“Highly Efficient Supramolecular Catalysis by Endowing the Reaction Intermediate with Adaptive Reactivity” 为题发表于《德国应用化学》(DOI: 10.1002/anie.201713351)。
图1. 葫芦[7]脲与TEMPO结合的ITC(左)及EPR(右)图谱
(图片来源:Angew. Chem. Int. Ed. 2018, Early View)
作者通过简单地混合葫芦[7]脲和TEMPO便得到了TEMPO/CB[7]超分子包合物,之后通过等温滴定量热法(ITC)和电子顺磁共振(EPR)对两者的结合进行了表征,发现TEMPO与葫芦[7]脲的结合比为1:1,结合常数为3.9 ×103 M-1。虽然核磁的结构不能体现出TEMPO上N原子所处的位置,但是EPR结果表明TEMPO上的N-O基团处于葫芦[7]脲的空腔内部。由于TEMPO与葫芦[7]脲的结合是由焓驱动的,并且它们之间的结合常数并不高,因此需要过量的葫芦[7]脲才能将溶液中的TEMPO完全包结。
图2. 葫芦[7]脲对TEMPO化学性质的影响
(图片来源:Angew. Chem. Int. Ed. 2018, Early View)
在确定了葫芦[7]脲可以与TEMPO结合之后,作者通过循环伏安法发现葫芦[7]脲的包结可以在一定程度上活化TEMPO,使得后者更容易发生氧化还原反应。作者推测这是因为葫芦[7]脲与反应中间体TEMPO+具有更高的亲和性,会促使反应向右移动。为了证实这种猜想,作者使用EPR监测NaClO与TEMPO的反应,并发现葫芦[7]脲的存在会使反应加速10倍。此外,TEMPO+这种活泼的中间产物并不稳定,在水中存在多种反应途径,其中,被水还原以及生成没有催化活性的副产物都会降低TEMPO的催化效率。而葫芦[7]脲与TEMPO+之间较高的亲和性会在一定程度上稳定这种活泼的中间产物。通过核磁等手段发现,即使在过量的氧化剂存在下,葫芦[7]脲也能使TEMPO+的寿命得到极大的延长。
表1. 葫芦[7]脲对TEMPO催化一系列醇的氧化反应的影响
(图片来源:Angew. Chem. Int. Ed. 2018, Early View)
最后,作者发现TEMPO+的催化活性可以在进入到有机相后得以恢复,并且葫芦[7]脲的存在并不会影响这个进程。以此为基础,作者对比了葫芦[7]脲的存在对TEMPO催化一系列醇的氧化反应的影响。结果表明,尽管葫芦[7]脲的存在对芳香醇的转化率的提升较大;而对于反应活性较低的脂肪醇类,葫芦[7]脲对转化率的提升有限。
全文作者:Yang Jiao, Bohan Tang, Yucheng Zhang, Jiang-Fei Xu, Zhiqiang Wang, and Xi Zhang