نتایج جستجو برای: دوتریوم nmr
تعداد نتایج: 58884 فیلتر نتایج به سال:
magnesium oxide nanoclusters have attracted much attention due to their potential applications to catalysis and novel optoelectronic materials. in the present study, we have studied the electronic and magnetic properties of the stoichiometric magnesium oxide nanoclusters (mgo)n for n = 2-20. although the binding energy increases with the size of the cluster, it reaches the asymptotic limit of...
a simple and green synthesis of α-hydroxy phosphonates has been performed by reaction between aldehydes and triethyl phosphite using sodium dodecylphosphonate as anionic surfactant in micellar media under reflux conditions. the novel structures were recognized by 1h nmr, 13c nmr and 31p-nmr. the employ of green media, clean reaction profiles, simple experimental and work up procedures and high ...
Natural products provide excellent potential leads for drug development because of their chemical diversity and biological functionality. However, the productivity of discovery of new, pharmacologically active natural products has traditionally been low due to inherent difficulties and costs associated with extract dereplication, i.e., isolation, purification and structure elucidation of indivi...
Natural products provide excellent potential leads for drug development because of their chemical diversity and biological functionality. However, the productivity of discovery of new, pharmacologically active natural products has traditionally been low due to inherent difficulties and costs associated with extract dereplication, i.e., isolation, purification and structure elucidation of indivi...
Since the development bloom in unconventional reservoirs in North America, total organic carbon (TOC) has become a more essential parameter, as the indicator of the efficiency of these reservoirs. In this paper, by using conventional well logs and NMR log data, the TOC content of an unconventional reservoir in West Africa is estimated. Passy’s, Issler’s, and Schmoker’s methods were used as indi...
نمودارگیری به روش تشدید مغناطیسی هستهای، روشی نوین برای دسترسی دقیق به پارامترهای پتروفیزیکی مخازن هیدروکربنی در صنعت نفت به شمار میآید. در این تحقیق با استفاده از حضور هسته هیدروژن در سیالات مخزن و با بهرهگیری از مزیت روش NMR در تعیین اندازه حفرهها، در ابتدا به دو شیوه حجم آب ناحیه مرزی و حجم سیال آزاد چاهی کربناته در جنوب غربی کشورمان تعیین شده و سپس نفوذپذیری NMR با استفاده از دو مدل SDR...
در این پایان نامه، محاسبات کوانتوم مکانیکی توسط روش های از اساس به کار گرفته شد برای تعیین پدیده دینامیک 1h nmr در یک دسته از ایلیدهای پایدار فسفر به عنوان محصول عمده از واکنش افزایشی 1:1:1، بین تری اتیل فسفیت (و یا تری فنیل فسفین) و دی متیل استیلن دی کربوکسیلات در حضور برخی n-h یا s-h اسیدها (واکنشهای ذیل). این ایلیدها? به صورت مخلوطی از 2 ایزومر هندسی در اثر چرخش محدود شده حول پیوند دوگانه کر...
abstractl density functional theory (dft) was used to investigate the effects of intra-moecular interactions and implicit water molecules on the relative stability and the nmr shielding tensors of hallucinogenic harmine in the monomeric and dimeric states. results represented that the relative stability and the nmr shielding tensors are dependent on the resonance interactions and chemical envir...
stable crystalline phosphorus ylides are obtained in excellent yields from the 1:1:1 addition reactionbetween hydantoins or thiohydantoins and dialkyl acetylenedicarboxylates in the presence oftriphenylphosphine. these phosphoranes undergo smooth intramolecular wittig reaction followedby an electrocyclic ring opening to produce dialkyl (e)-2-(2,5-dihydro-5,5-diaryl-2-thioxo-1h-imidazol-4-yl)fum...
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