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Supramolecular Allosteric Cofacial Porphyrin Complexes

Supramolecular Allosteric Cofacial Porphyrin Complexes. Christopher G. Oliveri, Nathan C. Gianneschi, SonBinh T. Nguyen,*, Chad A. Mirkin,*, Charlotte L. Stern, Zdzislaw Wawrzak,and Maren Pink. J. Am. Chem. Soc. 2007 , 128 , 16286 - 16296. Speaker ： 鍾柏源. Allosteric Recognition.

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Supramolecular Allosteric Cofacial Porphyrin Complexes

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  1. Supramolecular Allosteric Cofacial Porphyrin Complexes Christopher G. Oliveri, Nathan C. Gianneschi, SonBinh T. Nguyen,*, Chad A. Mirkin,*, Charlotte L. Stern, Zdzislaw Wawrzak,and Maren Pink J. Am. Chem. Soc. 2007, 128, 16286 - 16296 Speaker：鍾柏源

  2. Allosteric Recognition The allosteric-effector-mediated shape change of a macrocycle. Chad A. Mirkinet. al.Angew. Chem. Int. Ed. 2006, 45, 941 –944

  3. Introduction-Porphyrin 丁裕生 碩士論文，國立中興大學物理研究所，93年

  4. Vitamin B12 Chlorophy11

  5. Supramolecular Coordination Chemistry Hydrogen bonding p-p interaction Metal to ligand binding van der Waals forces Holliday, B. J. et. al.Angew. Chem. Int. Ed.2001, 40, 2022-2043.

  6. The Directional-Bonding Approach Holliday, B. J. et. al.Angew. Chem. Int. Ed.2001, 40, 2022-2043.

  7. Dinuclear structures Tetranuclear structures The Symmetry-Interaction Approach • The symmetry-interaction synthetic strategy has granted researchers access • to a variety of elegant shapes andarchitectures (for example, helicates, • tetrahedra, and adamantoidstructures) through the predictable coordination • chemistry of multibranched chelating ligands with transition and main group • metal centers. Holliday, B. J. et. al.Angew. Chem. Int. Ed.2001, 40, 2022-2043.

  8. The Weak-Link Approach • A critical feature of this approach is that themetals used in the assembly • process are available forfurther reactions without destroying the • supramolecularstructure. • This approach targets condensed structures that contain strategically • placed strong(metal-phosphine) and weak (metal-X) bonds. Mirkin, C. A. Acc. Chem. Res. 2005,38,825-837.

  9. Schematic view of a proximity-catalyzed transfer reaction. Tetrahedral intermediate doubly-bound inside cavity of trimer. Catalytic Acyl Transfer by a Cyclic Porphyrin Trimer Sanders, J. K. M. et. al.J. Am. Chem. Soc. 1994,116, 3141-3142.

  10. Closed macrocycle Open macrocycle Design of Allosteric Porphyrin-Based Supramolecules PPh2 = diphenylphosphine MES = 1,3,5-trimethylbenzene

  11. 75% 86% 97% Y(OTf)3 Synthesis of Ether-Based Ligand 7 and Macrocycles 8a and 8b ( i ) 1-bromo-2-chloroethane, K2CO3, Acetone, Reflux ( ii) 1,3-propanedithiol, Y(OTf)3 (5 mol %), CH3CN (iii) KPPh2, THF (iv) S8, THF ( v) NaNO2,AcCl/H2O, CH2Cl2, 0 °C → rt

  12. 88% 41% 96% 5-mesityldipyrromethane (DDQ) ( vi ) 5-mesityldipyrromethane, BF3‧OEt2, DDQ, NEt3, CHCl3, 4 Å Molecular Sieves (vii ) Zn(OAc)2‧2H2O, 4:1 CHCl3/MeOH, Reflux (viii) Cp2ZrHCl, THF, 60 °C

  13. 8a：94% ； 8b：92% 89% (ix) [Rh(CO)2(Cl)]2, CH2Cl2/THF ( x) [Cu(CH3CN)4]PF6, CH2Cl2/THF

  14. DABCO X-ray crystal structure of 8a⊂DABCO as viewed (A) from the side and (B) from the top Zn-Zn distance of 7.09 Å Rh-Rh distance of 24.85 Å P-Rh-P distance of 4.64 Å Gray：C Pink：Rh, Red：O, Yellow：Cl, Green：P, Blue：N, Light Blue：Zn

  15. X-ray crystal structure of 8c⊂DABCO as viewed (A) from the side and (B) from the top Zn-Zn distance：6.99 Å Cu-Cu distance：22.6 Å Gray：C Brown：Cu, Red：O, Yellow：Cl, Green：P, Blue：N, Light Blue：Zn

  16. 92% 88% 44% Synthesis of Thioether-Based Ligand 13 and Macrocycles 14a-b, 15a-b • ( i ) ClCH2CH2PPh2, Cs2CO3, CH3CN, Reflux • ( ii) S8, THF • (iii) n-BuLi, DMF, THF, -78 °C • 5-mesityldipyrromethane, BF3‧OEt2, DDQ, • NEt3,CHCl3, 4 Å Molecular Sieves

  17. 98% 88% ( v ) Zn(OAc)2‧2H2O, 4:1 CHCl3/MeOH, Reflux ( vi ) Cp2ZrHCl, THF, 60 °C ( vii) for 14a: [Rh(NBD)Cl]2, AgBF4, CH2Cl2/THF (viii) for 14b: [Cu(CH3CN)4]PF6, CH2Cl2/THF

  18. 14a：90% ； 14b：90% Bis(triphenylphosphoranylidene) ammonium chloride  (PPNCl) (ix) for 15a: PPNCl/CO (1 atm) ( x) for 15b: C5D5N.

  19. NMR Data of 14a and 14b Comp. 2： 31P{1H} NMR (CD2Cl2)：δ64 ppm (d,JRh-P=161 Hz) Chad A. Mirkin et. al. Inorg. Chem. 2000, 39, 3432-3433 Comp. 14a： 31P{1H} NMR (CD2Cl2)：δ64.5 ppm (d,JRh-P=162 Hz)

  20. X-ray crystal structure of 15a⊂DABCO as viewed (A) from the side and (B) from the top Zn-Zn distance：7.02 Å Rh-Rh distance：22.59 Å P-Rh-P distance：4.60 Å Dihedral angles：17.8° Gray：C Pink：Rh, Red：O, Orange：S, Yellow：Cl, Green：P, Blue：N, Light Blue：Zn

  21. X-ray crystal structure of 15c⊂DABCO as viewed (A) from the side and (B) from the top Zn-Zn distance：7.05 Å Cu-Cu distance：22.38 Å Gray：C Brown：Cu, Red：O, Yellow：Cl, Green：P, Blue：N, Light Blue：Zn

  22. Closed macrocycle Open macrocycle Acyl transfer reactions catalyzed by a closed macrocycle vs. the corresponding open macrocycle.

  23. Formation of 4-(acetoxymethyl)pyridine (4-AMP) plotted as concentration vs. time for 14a and 15a.

  24. Formation of 4-(acetoxymethyl)pyridine (4-AMP) plotted as concentration vs. time for [Zn(TPP) + 16a] and [Zn(TPP) + 16b]

  25. Catalytic efficiency of 4-PC 15a：14a = 2：1 15a：monomer = 14：1 • 14a is probably dynamic when in solution and the observed catalytic activity may originate from the conformational flexibility around the S atoms.

  26. Formation of 3-(acetoxymethyl)pyridine (3-AMP) plotted as concentration vs. time for 14a and 15a.

  27. Formation of 3-(acetoxymethyl)pyridine (3-AMP) plotted as concentration vs. time for [Zn(TPP) + 16a] and [Zn(TPP) + 16b]

  28. Catalytic efficiency of 3-PC Drop slightly with respect to 4-PC => the cavities of 14a and 15a are still flexible enough to accommodate the change in transition state distance for acyl transfer from acetylimidazole upon binding.

  29. Formation of 2-(acetoxymethyl)pyridine (2-AMP) plotted as concentration vs. time for 14a and 15a.

  30. Formation of 2-(acetoxymethyl)pyridine (2-AMP) plotted as concentration vs. time for [Zn(TPP) + 16a] and [Zn(TPP) + 16b]

  31. Catalytic efficiency of 2-PC Drop significantly with respect to 3-PC and 4-PC Similar to those observed for the monomer => Unfavorable transition state (in comparison to those for 3-PC and 4-PC) for productive acyl transfer.

  32. Conclusion • They have developed a coordination chemistrybased synthetic approach for the quantitative preparation of flexible cofacial porphyrin assemblies in which the porphyrins act as functional sites within an allosteric framework that istunable via modulation of peripheral structure control domains. • This capability enables the cofacial porphyrin structuresto act as allosteric catalysts capable of discriminatingdifferent substrate combinations and selectively transformingthem into the desired products.

  33. Homework 1. paper中所合成出來的的15a及14b其催化機制是？ Ans：

  34. 2.Weak-link approach (WLA)其transition metal的選擇為？ Ans：Transition metal通常使用晚期過渡金屬，如Rh(Ι)及Pd(ΙΙ)，其可以和磷產生強建結而和醚基及硫醚基產生弱建結1。通常依照欲合成出的macrocycle來選定transition metal，這些性質有空氣和水的敏感性、電荷、孔洞的形狀小分子的反應性等等。常用的有d8的Rh(Ι)的平面四方結構，d10的Cu(Ι)四方角錐結構，d6的八面角錐結構。

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