Studies of the Synthesis and Thermochemistry of Coordinatively Unsaturated Chelate Complexes (5-C5Me5
详细信息 查看全文
- 作者：Douglas B. Grotjahn ; H. Christine Lo ; Jason Dinoso ; Charles D. Adkins ; Chunbang Li ; Steven P. Nolan ; and John L. Hubbard
- 刊名：Inorganic Chemistry
- 出版年：2000
- 出版时间：June 12, 2000
- 年：2000
- 卷：39
- 期：12
- 页码：2493 - 2499
- 全文大小：110K
- 年卷期：v.39,no.12(June 12, 2000)
- ISSN：1520-510X
文摘
A comparative synthetic, structural, and thermochemical study on a series of chelate complexes containing thefragment (
5-C5Me5)Ir [(5-C5Me5)Ir(TsNCH2CH2NTs) (1), (5-C5Me5)Ir(TsNCH2CO2) (2), (5-C5Me5)Ir(CO2CO2) (3)] was performed to clarify the roles of carboxylato and sulfonamido ligands. Whereas 1 and 2 aremonomeric in solution and in the solid state, 3 appears to exist as an oligomer or polymer, (3)n, which can bebroken up by addition of a ligand L such as a phosphine, CO, or 2-methoxypyridine to form (5-C5Me5)Ir(L)(CO2CO2) (6). The synthesis of (3)n from [(5-C5Me5)IrCl(
-Cl)]2 required the use of silver oxalate in CH3CN, but ifother solvents were used, the bridging oxalato complex (5-C5Me5)IrCl(-2-2-C2O4)ClIr(5-C5Me5) (7) wasobtained and identified by X-ray diffraction. Enthalpies for reaction of THF-soluble monomers 1 and 2 withPMe3 were determined to be -28.7(0.5) and -28.5(0.4) kcal mol-1, respectively. The oligomerization behaviorof 3 may be a result of reduced 
- or 
-donation of carboxylato ligands compared to N-tosylamido ligands,because the values for 
CO in oxalato and bissulfonamido complexes 6-CO and (5-C5Me5)Ir(CO)(TsNCH2CH2NTs) (4-CO) were 2064 and 2042 cm-1, respectively.
5-C5Me5)Ir [(5-C5Me5)Ir(TsNCH2CH2NTs) (1), (5-C5Me5)Ir(TsNCH2CO2) (2), (5-C5Me5)Ir(CO2CO2) (3)] was performed to clarify the roles of carboxylato and sulfonamido ligands. Whereas 1 and 2 aremonomeric in solution and in the solid state, 3 appears to exist as an oligomer or polymer, (3)n, which can bebroken up by addition of a ligand L such as a phosphine, CO, or 2-methoxypyridine to form (5-C5Me5)Ir(L)(CO2CO2) (6). The synthesis of (3)n from [(5-C5Me5)IrCl(-Cl)]2 required the use of silver oxalate in CH3CN, but ifother solvents were used, the bridging oxalato complex (5-C5Me5)IrCl(-2-2-C2O4)ClIr(5-C5Me5) (7) wasobtained and identified by X-ray diffraction. Enthalpies for reaction of THF-soluble monomers 1 and 2 withPMe3 were determined to be -28.7(0.5) and -28.5(0.4) kcal mol-1, respectively. The oligomerization behaviorof 3 may be a result of reduced - or -donation of carboxylato ligands compared to N-tosylamido ligands,because the values for CO in oxalato and bissulfonamido complexes 6-CO and (5-C5Me5)Ir(CO)(TsNCH2CH2NTs) (4-CO) were 2064 and 2042 cm-1, respectively.