First-Generation Chiral Metallodendrimers: Stereoselective Synthesis of Rigid D3-Symmetric Tetranuclear Ruthenium Complexes

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• 作者：Swamy Bodige ; Andrew S. Torres ; David J. Maloney ; David Tate ; Gary R. Kinsel ; Angela K. Walker ; and Frederick M. MacDonnell
• 刊名：Journal of the American Chemical Society
• 出版年：1997
• 出版时间：October 29, 1997
• 年：1997
• 卷：119
• 期：43
• 页码：10364 - 10369
• 全文大小：186K
• 年卷期：v.119,no.43(October 29, 1997)
• ISSN：1520-5126

文摘

Condensation reactions between the enantiopure,substitutionally inert building blockschars/Delta.gif" BORDER=0 >-[Ru(1,10-phenanthroline-5,6-dione)₃][PF₆]₂(2) andchars/Delta.gif" BORDER=0 >-[Ru(phen)₂(1,10-phenanthroline-5,6-diamine)][PF₆]₂(3) gave the D₃-symmetric tetramer[(chars/Delta.gif" BORDER=0 >-(phen)₂Ru(tpphz))₃-chars/Delta.gif" BORDER=0 >-Ru]⁸⁺(chars/Delta.gif" BORDER=0 >chars/Delta.gif" BORDER=0 >₃-1) in 68% isolated yield as thePF₆^- salt (where tpphz istetrapyrido[3,2-a:2',3'-c:3'',2''-h:2'',3''-j]phenazine).Reactions between appropriate enantiomers of 2and 3 also yieldedthe remaining D₃ isomerschars/Delta.gif" BORDER=0 >₃-1, chars/Delta.gif" BORDER=0 >₃-1, and₃-1 which collectively represent thehighest nuclearity Ru oligomersbased on bidentate type ligands prepared in a stereospecific fashion togive diasteromerically and enantiomericallypure products. The complexes were purified via cation-exchangeHPLC. ¹H and ¹³C NMR, COSY andHMQCNMR, and UV-visible spectroscopy were employed to characterize thesesupramolecular assemblies. MALDI-TOF mass spectrometry gave parent molecular ion peaks corresponding tothe species m/z 2638 [1 -8PF₆]⁺, 2783[1 - 7PF₆]⁺, 2928[1 - 6PF₆]⁺, 3073[1 - 5PF₆]⁺, 3218[1 - 4PF₆]⁺, and 3363 [M -3PF₆]⁺, proving the macromolecular structure. Circular dichroism spectroscopy was used todetermine the absolute stereochemistry and opticalpurity of each of these stereoisomers.