Self‐Assembly of Water‐Soluble Platinum(II)‐Based Metallacalixarenes and Tuning Their Conformational Interconversion via Synergistic Effects between Solvents and Anions

• Published in: Chemistry, an Asian journal Vol. 13; no. 19; pp. 2805 - 2811
• Main Authors: Deng, Wei, Yu, Zheng‐Su, Ma, Hong‐Wei, Yu, Shu‐Yan
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 04.10.2018
• Subjects: Anions; Assembly; Chemistry; conformational conversion; Crystal structure; Encapsulation; Ethylenediamine; Imidazole; metallacalixarenes; NMR; Nuclear magnetic resonance; Platinum; Single crystals; Solvents; Synergistic effect
• ISSN: 1861-4728; 1861-471X
• DOI: 10.1002/asia.201800954

The aqueous self‐assembly of the flexible ligand L bis(1H‐benz[d]imidazole‐1‐yl)methane and cis‐coordinated PtII precursors [(en)Pt2+, (tmeda)Pt2+, en=ethylenediamine, tmeda=N,N,N′,N′‐tetramethylethylenediamine)] led to the formation of the metallacalixarenes with full alternative conformations (e.g., two novel water‐soluble metallacalixarenes [M2L2]4+ and [M3L3]6+ with D2 and D3 symmetry, respectively). Their molecular structures were determined by single crystal X‐ray analyses in solid state. The two metallacalixarenes present different cavity sizes and the [M3L3]6+ cavity encapsulates one NO3−. NOESY NMR revealed that the conformational interconversion between 1,3‐alternate conformer in methanol and cone conformer in DMSO was tuned via the synergistic effect between solvent and anion. Guest encapsulation is also discussed. Keep it contained: Two water‐soluble Pt‐coordinated metallacalixarenes with different cavity sizes were synthesized by metal‐directed self‐assembly. Conformational conversion between the 1,3‐alternate conformer in methanol and cone conformer in DMSO was finely tuned by synergistic effects between solvents and anions.