一維金屬線結構之腙基吡啶配位雙螺旋銀錯合物

在本研究中，合成了亞胺腙基吡啶型配位子L1和L2，其中以L2與Ag(I)所形成的銀錯合物: [Ag9(L2)6]n[(ClO4)8] n (1)、 [Ag3(L2)2(CH2Cl2)(CH3OH)(H2O)](CF3SO3)3 (2) 、 [Ag9(L2)6]n[(BF4)9] n (3)，對其特性進行研究。 L2可與不同的銀鹽形成不同幾何構形的錯合物，依據銀鹽陰離子的不同，形成分別為九銀的雙螺旋金屬鏈錯合物和三銀螺旋錯合物這兩種不同的螺旋錯合物。雖然堆疊形式不同，但發現到有共通點在於這些螺旋錯合物的銀–銀距離約為2.85至3.29 Å之間，有明顯的親銀性作用力，再藉著配位子的末端吡啶環的分子間π–π作用力( 3.44 Å )堆疊串接，形成一維無限延伸的螺旋分子陣列。錯合物 1、2、3的二維核磁共振光譜 (H-H COSY、NOESY)結果，皆觀察到配位子L2末端的甲基與另一股螺旋單位上的配位子的吡啶環有長距離空間上的作用力，證實L2之銀錯合物在溶液中保持著螺旋結構。由DOSY得到的diffusion coefficient ( D1 = 1.12 × 10-10 m2s-1, D2 = 1.58 ×10-10 m2s-1, D3= 1.44 × 10-10 m2s-1 )，及ESI-MS推算出錯合物在溶液中的組成為 [Ag3(L2)2] X3。測量在不同濃度下的錯合物1、2、3的UV-Vis光譜，得知錯合物在溶液態時，沒有聚集的現象產生，與固態結構中觀察到的結果不同。本系列銀錯合物在溶液態的表現大致相似，證實陰離子效應在溶液態中不顯著，但在自組裝過程有很大的影響。在研究分子自組裝方面，利用UV-Vis滴定及核磁共振光譜滴定方法，測量以銀鹽滴定配位子的光譜變化，再以SPECFIT計算得知分子的反應機制是以L、AgL、AgL2、Ag2L2、Ag3L2逐步結合而成的。固態結構與自組裝反應的實驗結果一致，證明此系列的配位子在與銀形成錯合物時，可自組裝形成穩定的雙螺旋錯合物。

關鍵字

超分子；銀錯合物；自組裝；螺旋錯合物；腙基

並列摘要

In this research, a series of new ligands (L1 and L2) containing hydrazone and derivative pyridine moiety were synthesized. Three double helical complexes, [Ag9(L2)6](ClO4)8 (1), [Ag3(L2)2(CH2Cl2)(CH3OH)(H2O)](CF3SO3)3 (2), and [Ag9(L2)6](BF4)9 (3) have been prepared from the reactions of L2 with AgX ( X = ClO4-, CF3SO3-, BF4- ) and characterized by X-ray diffraction study. In particular, a strong influence of the counter-anions on the structures of helicates has been observed. Two type of polynuclear Ag+ ionic sequences: a continuous one for complex (1), complex (3), and a discontinuous one for complex (2) were observed. The Ag–Ag distances of polycationic Agn+ were observed in a range from 2.85 to 3.29 Å, which suggest the argentophilic interaction. The average distance between the terminal pyridines of each double helix unit is 3.4 Å, which suggest the π−π stacking interaction to form polymeric superstructure. The structures and composition of (1), (2) and (3) were examined by NMR method ( H-H COSY, NOESY and DOSY) and ESI-Mass, the results confirmed the double helix is maintained in the solution state. Detailed UV-Vis absorption spectroscopy, and diffusion-ordered spectroscopy ( DOSY ) NMR studies indicate the aggregating species in solution state were no longer exist. The self-assembling process and reaction mechanism were studied by NMR and UV-Vis titration. The step-wise and overall ability constant of L、AgL、AgL2、Ag2L2、Ag3L2 were investigated by systematic measurement. The results were consistent for the crystal and titration of L2 with AgX. Overall, double helical structure is the most stable conformation of L2 silver complex.

並列關鍵字

Supramolecule ； Silver complex ； Self-assembly ； Helicate ； Hydrazone

參考文獻

16. Dong, T.-Y.; Huang, C. H.; Chang, C. K.; Wen, Y. S.; Lee, S. L.; Chen, J. A.; Yeh, W. Y.; Yeh, A.

(b)Che, C.-M.; Tse, M.-C.; Chan, M. C. W.; Cheung, K.-K.; Phillip, D. L.; Leung, K.-H.

1. Lehn, J.-M. Angew. Chem. Int. Ed. Engl. 1988, 27, 89.

3. Sauvage, J.-P. Transition Metals in Supramolecular Chemistry; John Wiley: New York, 1999.

國際替代計量

一維金屬線結構之腙基吡啶配位雙螺旋銀錯合物

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