Molecular Tracer Dynamics in Crystalline Organic Films at the Solid−Liquid Interface
作者:David F. Padowitz、David M. Sada、Eric L. Kemer、Michael L. Dougan、W. Andrew Xue
DOI:10.1021/jp011790h
日期:2002.1.1
A molecular tracer method for scanning tunneling microscopy allowed the observation of individual molecular events at a crystal surface in solution. Long-chain alkanes or ethers were coadsorbed with similar length thioethers on a graphite surface. Due to the distinctive contrast of the sulfur atoms, it was possible to track individual thioether tracer molecules. The exchange of tracer molecules between the adsorbed monolayer and the overlying solution was measured at equilibrium. Rates depended on chain length, temperature, and neighboring molecules. Tracers at boundaries between crystal domains revealed specific molecular processes driving boundary fluctuations and domain growth. In addition to adsorption-desorption driven rearrangements, collective motion within the monolayer has been seen. Longer chain ethers exhibit two phases having different molecular configurations at grain boundaries and different microstructural. habits. Transition between phases was promoted by the scanning probe.
US5238980A
申请人:——
公开号:US5238980A
公开(公告)日:1993-08-24
Efficient catalytic activation of Suzuki–Miyaura C–C coupling reactions with recyclable palladium nanoparticles tailored with sterically demanding di-n-alkyl sulfides
作者:Satyendra Kumar、G. K. Rao、Arun Kumar、Mahabir P. Singh、Fariha Saleem、Ajai K. Singh
DOI:10.1039/c5ra00441a
日期:——
and its complex [Pd(L1)2Cl2] (1) have also been synthesized by the reaction of Na2PdCl4 with L1 and characterized with 1H and 13C1H} NMR spectroscopy. The NPs show good catalyticactivity for the Suzuki–Miyauracoupling (SMC) of various aryl chlorides/bromides with phenylboronic acid at low catalyst loading (0.1–0.5 mol% of Pd). The conversion is good for some aryl halides in a short reaction time
Ñ -Bromodocosane发生反应用Na 2 S,产生原位由元素硫用NaBH还原4,得到Ñ -didocosyl硫醚(L1),其充当用于钯纳米颗粒的保护器(2-7在使用不同的方法制备)L1(Pd: L1的比例为1:2和4:1)的情况下形成钯前体。NPs已通过粉末X射线衍射,SEM,EDX,紫外可见光谱和HRTEM进行了表征。大多数球形NP 2-7的尺寸(nm)范围分别是〜18-19、4-5、5-7、4-6、7-9和4-6。钯的前体会影响NP的大小,形状和分散度。当使用[Pd(CH 3 CN)2 Cl 2 ] / Na 2 PdCl 4作为前体时,获得了窄尺寸范围的均匀分散的NP。L1及其络合物[Pd(L1)2 Cl 2 ](1)也通过Na 2 PdCl 4与L1反应合成,并具有1 H和13 C 11 H NMR光谱。在低催化剂负载量(Pd的0.1-0.5 mol%)下,NPs对