Synthesis, Characterization, and Transition-Metal Complexes of 3,4-Diazaphospholanes
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- 作者：Clark R. Landis ; Ryan C. Nelson ; Wiechang Jin ; and Amanda C. Bowman
- 刊名：Organometallics
- 出版年：2006
- 出版时间：March 13, 2006
- 年：2006
- 卷：25
- 期：6
- 页码：1377 - 1391
- 全文大小：373K
- 年卷期：v.25,no.6(March 13, 2006)
- ISSN：1520-6041
文摘
The steric, electronic, and synthetic characteristics of 3,4-diazaphospholanes are reported. Crystallographic structures of free and metal-complexed 3,4-diazaphospholanes provide steric metrics (coneangle, solid angle, etc.). Diazaphospholanes span a wide range of sizes with cone angles varying from135 to 188
f">. The electron-donating abilities of diazaphospholanes have been estimated using the carbonylinfrared stretching frequencies, 
fchars/nu.gif" BORDER=0 >(CO), of [trans-Rh(diazaphospholane)2(CO)Cl] complexes. Frequenciesfor the CO stretches range from 1975 to 2011 cm-1, thus indicating that 3,4-diazaphospholanes may beas electron rich as dialkylarylphosphines or as electron deficient as trialkyl phosphites. Reduction ofN,N'-phthalamido-3,4-diazaphospholanes with BH3·SMe2 yields diazaphospholanes that not only are moreelectron rich but also show a reorientation of the phospholane substituents that may affect catalyticproperties. Diazaphospholanes readily react with many Rh and Pd catalyst precursors to form complexes.Metal complexes of 3,4-diazaphospholanes exhibit reactivities different from those of common phosphinecomplexes, presumably due to the generally greater steric bulk and electron deficiency of 3,4-diazaphospholanes relative to phosphines. Cationic Rh(I) complexes of 3,4-diazaphospholanes abstractchloride ligands from chlorinated solvents to afford chloride-bridged dimers. The complex [(rac-17)Pd(Me)Cl] rearranges in solution-stereoselectively transferring methyl from palladium to phosphorus whilesimultaneously opening a diazaphospholane ring. Many of the 3,4-diazaphospholane-metal complexeshave extremely close Cl···H-C(P)(N) contacts, suggesting Cl···H hydrogen bonding.
f">. The electron-donating abilities of diazaphospholanes have been estimated using the carbonylinfrared stretching frequencies, fchars/nu.gif" BORDER=0 >(CO), of [trans-Rh(diazaphospholane)2(CO)Cl] complexes. Frequenciesfor the CO stretches range from 1975 to 2011 cm-1, thus indicating that 3,4-diazaphospholanes may beas electron rich as dialkylarylphosphines or as electron deficient as trialkyl phosphites. Reduction ofN,N'-phthalamido-3,4-diazaphospholanes with BH3·SMe2 yields diazaphospholanes that not only are moreelectron rich but also show a reorientation of the phospholane substituents that may affect catalyticproperties. Diazaphospholanes readily react with many Rh and Pd catalyst precursors to form complexes.Metal complexes of 3,4-diazaphospholanes exhibit reactivities different from those of common phosphinecomplexes, presumably due to the generally greater steric bulk and electron deficiency of 3,4-diazaphospholanes relative to phosphines. Cationic Rh(I) complexes of 3,4-diazaphospholanes abstractchloride ligands from chlorinated solvents to afford chloride-bridged dimers. The complex [(rac-17)Pd(Me)Cl] rearranges in solution-stereoselectively transferring methyl from palladium to phosphorus whilesimultaneously opening a diazaphospholane ring. Many of the 3,4-diazaphospholane-metal complexeshave extremely close Cl···H-C(P)(N) contacts, suggesting Cl···H hydrogen bonding.