Coordination Chemistry of H2 and N2 in Aqueous Solution. Reactivity and Mechanistic Studies Using trans-FeII(P2)2X2-Type Comple
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- 作者：John D. Gilbertson ; Nathaniel K. Szymczak ; Justin L. Crossland ; Warren K. Miller ; David K. Lyon ; Bruce M. Foxman ; Joclyn Davis ; David R. Tyler
- 刊名：Inorganic Chemistry
- 出版年：2007
- 出版时间：February 19, 2007
- 年：2007
- 卷：46
- 期：4
- 页码：1205 - 1214
- 全文大小：215K
- 年卷期：v.46,no.4(February 19, 2007)
- ISSN：1520-510X
文摘
The reactions of the trans-Fe(DMeOPrPE)2Cl2 complex (I; DMeOPrPE = 1,2-bis(bis(methoxypropyl)phosphino)ethane) and its derivatives were studied in aqueous and nonaqueous solvents with a particular emphasis on thebinding and activation of H2 and N2. The results show there are distinct differences in the reaction pathwaysbetween aqueous and nonaqueous solvents. In water, I immediately reacts to form trans-Fe(DMeOPrPE)2(H2O)Cl+. Subsequent reaction with H2 or N2 yields trans-Fe(DMeOPrPE)2(X2)Cl+ (X2=H2 or N2). In the case of H2,further reactivity occurs to ultimately give the trans-Fe(DMeOPrPE)2(H2)H+ product (III). The pathway for the reactionI 
III was spectroscopically examined: following the initial loss of chloride and replacement with H2, heterolysisof the H2 ligand occurs to form Fe(DMeOPrPE)2(H)Cl; substitution of the remaining chloride ligand by another H2molecule then occurs to produce trans-Fe(DMeOPrPE)2(H2)H+. In the absence of H2 or N2, trans-Fe(DMeOPrPE)2(H2O)Cl+ slowly reacts in water to form Fe(DMeOPrPE)32+, II. Experiments showed that this species forms byreaction of free DMeOPrPE ligand with trans-Fe(DMeOPrPE)2(H2O)Cl+, where the free DMeOPrPE ligand comesfrom dissociation from the trans-Fe(DMeOPrPE)2(H2O)Cl+ complex. In nonaqueous solvents, the chloride ligand inI is not labile, and a reaction with H2 only occurs if a chloride abstracting reagent is present. Complex III is a usefulsynthon for the formation of other water-soluble metal hydrides. For example, the trans-[Fe(DMeOPrPE)2H(N2)]+complex was generated in H2O by substitution of N2 for the H2 ligand in III. The trans-Fe(DHBuPE)2HCl complex(DHBuPE = 1,2-bis(bis(hydroxybutyl)phosphino)ethane, another water-solubilizing phosphine) was shown to be aviable absorbent for the separation of N2 from CH4 in a pressure swing scheme. X-ray crystallographic analysis ofII is the first crystal structure report of a homoleptic tris chelate of FeII containing bidentate phosphine ligands. Thestructure reveals severe steric crowding at the Fe center.
III was spectroscopically examined: following the initial loss of chloride and replacement with H2, heterolysisof the H2 ligand occurs to form Fe(DMeOPrPE)2(H)Cl; substitution of the remaining chloride ligand by another H2molecule then occurs to produce trans-Fe(DMeOPrPE)2(H2)H+. In the absence of H2 or N2, trans-Fe(DMeOPrPE)2(H2O)Cl+ slowly reacts in water to form Fe(DMeOPrPE)32+, II. Experiments showed that this species forms byreaction of free DMeOPrPE ligand with trans-Fe(DMeOPrPE)2(H2O)Cl+, where the free DMeOPrPE ligand comesfrom dissociation from the trans-Fe(DMeOPrPE)2(H2O)Cl+ complex. In nonaqueous solvents, the chloride ligand inI is not labile, and a reaction with H2 only occurs if a chloride abstracting reagent is present. Complex III is a usefulsynthon for the formation of other water-soluble metal hydrides. For example, the trans-[Fe(DMeOPrPE)2H(N2)]+complex was generated in H2O by substitution of N2 for the H2 ligand in III. The trans-Fe(DHBuPE)2HCl complex(DHBuPE = 1,2-bis(bis(hydroxybutyl)phosphino)ethane, another water-solubilizing phosphine) was shown to be aviable absorbent for the separation of N2 from CH4 in a pressure swing scheme. X-ray crystallographic analysis ofII is the first crystal structure report of a homoleptic tris chelate of FeII containing bidentate phosphine ligands. Thestructure reveals severe steric crowding at the Fe center.© 2004-2018 中国地质图书馆版权所有 京ICP备05064691号 京公网安备11010802017129号 地址：北京市海淀区学院路29号 邮编：100083 电话：办公室：(+86 10)66554848；文献借阅、咨询服务、科技查新：66554700 |