Anion Modulated Structural Diversification in the Assembly of Cd(II) Complexes Based on a Balance-like Dipodal Ligand

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• 作者：Zhi-Quan Yu ; Mei Pan ; Ji-Jun Jiang ; Zhi-Min Liu ; Cheng-Yong Su
• 刊名：Crystal Growth & Design
• 出版年：2012
• 出版时间：May 2, 2012
• 年：2012
• 卷：12
• 期：5
• 页码：2389-2396
• 全文大小：478K
• 年卷期：v.12,no.5(May 2, 2012)
• ISSN：1528-7505

文摘

Reaction of a balance-like dipodal ligand 2,6-bis(pyridiyl) hexahydro-4,8-ethenopyrrolo [3,4-f]isoindole-1,3,5,7-tetrone (3-pybtd) with various Cd(II) salts afforded eight complexes, namely, [Cd₂(3-pybtd)₂(NO₃)₄(C₂H₅OH)₂(H₂O)₂] (1), [Cd₂(3-pybtd)₂(SiF₆)₂(DMF)₄(H₂O)₂](H₂O)₄路(DMF)₂ (2), {[Cd(3-pybtd)₂(H₂O)₄](ClO₄)₂}_n (3), {[Cd(3-pybtd)₂(OTf)₂]路THF}_n (4), {[Cd(3-pybtd)₂(SCN)₂]路(H₂O)₂}_n (5), [Cd(3-pybtd)(OTs)₂(DMF)₂]_n (6), [Cd(3-pybtd)₂(OTs)₂]_n (7), and {[Cd₂(3-pybtd)₂Cl_10/3][CdCl_8/3]路(H₂O)₃}_n (8). Complexes 1 and 2 are zero-dimensional (0D) square-like or olive-like dimeric M₂L₂ metallacycles, showing a pair of shape-modified molecular rectangles due to different conformations of the ligands and coordination orientation of the metal centers. Complexes 3鈥?b>5 are one-dimensional (1D) looplike chains composed of olive-like M₂L₂ metallacycle building units as in 2, showing 0D 鈫?1D dimension increase via ligand addition, while complex 8 is a three-dimensional (3D) framework retaining the same olive-like M₂L₂ metallacycle, showing 0D 鈫?3D dimension increase via linkage of 渭₃-Cl bridged Cd(II) clusters. Complex 6 is a wave-like M_nL_n chain, possessing the same ML building units as in 1 but showing 0D 鈫?1D dimension increase via ring-opening polymerization. Replacement of DMF molecules from the coordination sphere in 6 by the ligands resulted in a two-dimensional (2D) (4, 4) network of 7, showing 1D 鈫?2D dimension increase from 6 via ligand addition or 1D 鈫?2D dimension increase from 3鈥?b>5 via ring-opening polymerization. Complexes 3鈥?b>5 also represent a series of supramolecular isomorphs displaying anion exchange properties. Electrospray ionization mass spectrometry (ESI-MS) studies in solution suggest that the discrete and infinite structures in 1, 6, and 7 are assembled from the same monomeric ML building blocks, which crystallize in a different way to lead to structural diversification via dimerization or polymerization during the crystallization.