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(2023-01-22 13:14:35)
(2023-01-22 12:45:49)
Wilkinson'scatalystisthecommonnameforchloridotris(triphenylphosphine)rhodium(I),acoordinationcomplexofrhodiumwiththeformula[RhCl(PPh3)3](Ph=phenyl).Itisared-browncoloredsolidthatissolubleinhydrocarbonsolventssuchasbenzene,andmoresointetrahydrofuranorchlorinatedsolventssuchasdichloromethane.Thecompoundiswidelyusedasacatalystforhydrogenationofalkenes.ItisnamedafterchemistandNobellaureateSirGeoff...[阅读全文]
(2023-01-21 21:52:47)
Acyclopentadienylcomplexisacoordinationcomplexofametalandcyclopentadienylgroups(C5H−
5,abbreviatedasCp−).Cyclopentadienylligandsalmostinvariablybindtometalsasapentahapto(η5-)bondingmode.Themetal–cyclopentadienylinteractionistypicallydrawnasasinglelinefromthemetalcentertothecenteroftheCpring.ExamplesBiscyclopentadienylcomplexesarecalledmetallocenes.Afamousexampleofthistype...[阅读全文]
(2023-01-21 19:21:59)
Martin'ssulfuraneistheorganosulfurcompoundwiththeformulaPh2S[OC(CF3)2Ph]2(Ph=C6H5).Itisawhitesolidthateasilyundergoessublimation.Thecompoundisanexampleofahypervalentsulfurcompoundcalledasulfurane.Assuch,thesulfuradoptsasee-sawstructure,withalonepairofelectronsastheequatorialfifthcoordinateofatrigonalbipyramid,likethatofsulfurtetrafluoride(SF4).Thecompoundisareagentinorganicsynthesis.Oneapplica...[阅读全文]
(2023-01-11 19:18:21)
1.元素周期表中所有元素都可以测出核磁共振谱吗？不是。首先，被测的原子核的自旋量子数要不为零；其次，自旋量子数最好为1/2（自旋量子数大于1的原子核有电四极矩，峰很复杂）；第三，被测的元素（或其同位素）的自然丰度比较高（自然丰度低，灵敏度太低，测不出信号）。2.关于样品管，要注意什么？对于5mm探头来说，其中探头内部隔离样品和线圈的石英管内径只有[阅读全文]
(2023-01-11 18:42:42)
据哈佛大学化学系教授消息，世界最杰出的有机化学家之一、美国哈佛大学化学与化学生物学系教授YoshitoKishi刚刚逝世，享年86岁。 KishiYoshito（岸义人），日本有机合成化学家，专长天然物化学，现任哈佛大学名誉教授，美国卫材株式会社副社长。 1937年4月13日，岸义人出生于日本爱知县名古屋市。1966年在名古屋大学获得理学博士。1966-1968年，在哈佛大学从事博士后[阅读全文]
(2023-01-06 21:22:43)
TheSakuraireaction(alsoknownastheHosomi–Sakuraireaction)isthechemicalreactionofcarbonelectrophiles(suchasaketoneshownhere)withallyltrimethylsilanecatalyzedbystrongLewisacids.Lewisacidactivationisessentialforcompletereaction.StrongLewisacidssuchastitaniumtetrachloride,borontrifluoride,tintetrachloride,andAlCl(Et)2arealleffectiveinpromotingtheHosomireaction.Thereactionisatypeofelectrophilicall...[阅读全文]
(2023-01-06 20:59:35)
(2023-01-06 20:31:21)
First-generationGrubbscatalystItissynthesizedfromRuCl2(PPh3)3,phenyldiazomethane,andtricyclohexylphosphineinaone-potsynthesis.Second-generationcatalystThesecond-generationcatalysthasthesameusesinorganicsynthesisasthefirstgenerationcatalyst,butgenerallywithhigheractivity.Thiscatalystisstabletowardmoistureandair,thusiseasiertohandleinthelab.Hoveyda–GrubbscatalystsFirst-generationHoveyda–...[阅读全文]
(2023-01-06 19:27:08)
Formorethanahalfofacentury,BarryTrosthasbeenahighlyinfluentialscientistinalmosteveryaspectoforganicsynthesis,includingmethodologyandtotalsynthesis.Hestartedhiscareerataremarkablyyoungage.AfterobtaininghisB.Sc.degreeinchemistryfromtheUniversityofPennsylvania(1962),hemovedtoMITwherehecompletedhisPh.D.withH.O.House,workingonfundamentalaspectsofenolatechemistry.Remarkably,attheageof24,immediatelyafter...[阅读全文]
