诺贝尔化学奖简介原文及翻译

1. Phase-Switching Catalysis

By simply adding or removing carbon dioxide,

chemists in Scotland devised a neat trick for

reversibly shuttling a homogeneous catalyst

between the organic and aqueous phases in a

biphasic solvent system (C&EN, Jan. 26, page 11;

Angew. Chem. Int. Ed. 2009, 48, 1472). The

phase-switchable catalyst designed by Simon L.

Desset and David J. Cole-Hamilton of the

University of St. Andrews adds flexibility to the

often complicated techniques required to isolate

products and recycle catalysts during

homogeneous reactions. The secret to the

switchability is a weakly basic amidine group,

–N=C(CH 3)N(CH 3)2, that the researchers added to

the phenyl rings of triphenylphosphine. The

rhodium catalyst made with the modified

phosphine ligand is soluble in organic solvent. On bubbling CO 2 into an aqueous-organic reaction system containing the catalyst, the CO 2 reacts with water to form carbonic acid (H 2CO 3). The transient acid protonates the amidine groups and renders the catalyst water-soluble. Subsequently bubbling N 2 into the biphasic system drives off CO 2 and shifts the equilibrium of the catalyst-carbonic acid complex, leading the

catalyst to deprotonate and making it water-insoluble again. After a reaction is

completed in either organic solvent or water, the researchers separate the product and catalyst into different phases, remove the product, and then shuttle the catalyst back into the original phase for the next reaction cycle. Building switchability into basic chemicals in this manner could facilitate greener and less-energy-intensive industrial chemical processes.

能够转相的催化反应

通过简单的添加或除去二氧化碳，苏格兰的科学家发明了一种在两相系统中来回转运匀相催化剂的灵巧的把戏。St. Andrews 大学的Simon L. Desset and David J. Cole-Hamilton 发明的这种可以转相的催化剂使得通常需要复杂的技术来分离产品和重复利

Angew. Chem. Int. Ed. Switchphos Bubbling CO 2 and then N 2 into a reaction tube modifies the rhodium catalyst’s phosphine ligands, switching the catalyst (yellow) from the organic reaction phase to the aqueous phase while the organic product is removed, and then back to a fresh organic phase.

用催化剂的均相反应的灵活性增强了。催化剂的这种转相的能力的秘密是科学家在三苯基膦中的苯环上加上的弱碱性的脒基团，–N=C(CH3)N(CH3)2。用这种修改过的配位体配位的催化剂铑可溶于有机溶剂。当往水-有机含有催化剂的两相反应体系中通入CO2时，二氧化碳就和水反应生成碳酸。碳酸电离的氢离子与脒基团结合，使得催化剂变成水溶性的。之后，向两相体系通入氮气，赶走里面的二氧化碳，改变原有的平衡，从而使得催化剂再次变成疏水性的。通过这样，科学家们就可以在有机相内的反应结束后，把催化剂转移到水中，然后将产物取走，之后，又把催化剂转到有机溶剂中，开始催化新的反应。通过这种方式在基础化学上建立这种转换能力能够促进更环保和低能耗的化学工业。

W ater On The Moon

This year,

space

scientists were

finally able to

answer one of

the biggest

questions in

lunar science:

Is there water

on the moon?

The answer is

yes. NASA

announced last month that debris kicked up

during the deliberate crash of the Lunar Crater

Observation & Sensing Satellite (LCROSS)

spacecraft did contain a sprinkling of water and

possibly some organic compounds (C&EN, Nov.

23, page 31). LCROSS launched on June 18