Reversible Phase Transformation and Mechanochromic Luminescence of Zn^II‐Dipyridylamide‐Based Coordination Frameworks

Abstract

A 1D double-zigzag framework, {[Zn(paps)(2)(H(2)O)(2)](ClO(4))(2)}(n) (1; paps = N,N'-bis(pyridylcarbonyl)-4,4'-diaminodiphenyl thioether), was synthesized by the reaction of Zn(ClO(4))(2) with paps. However, a similar reaction, except that dry solvents were used, led to the formation of a novel 2D polyrotaxane framework, [Zn(paps)(2)(ClO(4))(2)](n) (2). This difference relies on the fact that water coordinates to the Zn(II) ion in 1, but ClO(4)(-) ion coordination is found in 2. Notably, the structures can be interconverted by heating and grinding in the presence of moisture, and such a structural transformation can also be proven experimentally by powder and single-crystal X-ray diffraction studies. The related N,N'-bis- (pyridylcarbonyl)-4,4'-diaminodiphenyl ether (papo) and N,N'-(methylenedi-para-phenylene)bispyridine-4-carboxamide (papc) ligands were reacted with Zn(II) ions as well. When a similar reaction was performed with dry solvents, except that papo was used instead of paps, the product mixture contained mononuclear [Zn(papo)(CH(3)OH)(4)](ClO(4))(2) (5) and the polyrotaxane [Zn(papo)(2)(ClO(4))(2)](n) (4). From the powder XRD data, grinding this mixture in the presence of moisture resulted in total conversion to the pure double-zigzag {[Zn(papo)(2)(H(2)O)(2)](ClO(4))(2)}(n) (3) immediately. Upon heating 3, the polyrotaxane framework of 4 was recovered. The double-zigzag {[Zn(papc)(2)(H(2)O)(2)](ClO(4))(2)}(n) (6) and polyrotaxane [Zn(papc)(2)(ClO(4))(2)](n) (7) were synthesized in a similar reaction. Although upon heating the double-zigzag 6 undergoes structural transformation to give the polyrotaxane 7, grinding solid 7 in the presence of moisture does not lead to the formation of 6. Significantly, the bright emissions for double-zigzag frameworks of 1 and 3 and weak ones for polyrotaxane frameworks of 2 and 4 also show interesting mechanochromic luminescence.

Reversible Phase Transformation and Luminescence of Cadmium(II)–Dipyridylamide‐Based Coordination Frameworks

“…[10] Significantly, both double-zigzag and polyrotaxane structures can be interconverted by heating and grinding in the presence of moisture; such structural transformation is reversible and can be confirmed experimentally by powder and single-crystal X-ray diffraction studies. [10] Significantly, both double-zigzag and polyrotaxane structures can be interconverted by heating and grinding in the presence of moisture; such structural transformation is reversible and can be confirmed experimentally by powder and single-crystal X-ray diffraction studies.…”

“…Notably, we have shown the first reversible structural transformation and mechanochromic luminescence of ClO 4 ) 2 ] n , as well as of their papo analogues. [10] Significantly, both double-zigzag and polyrotaxane structures can be interconverted by heating and grinding in the presence of moisture; such structural transformation is reversible and can be confirmed experimentally by powder and single-crystal X-ray diffraction studies. Although heating the double-zigzag structure of…”

“…N,N'-Bis(pyridylcarbonyl)-4,4'-diaminodiphenyl thioether (paps), [10] N,N'bis(pyridylcarbonyl)-4,4'-diaminodiphenyl ether (papo), [9a] and N,N'-(methylenedi-p-phenylene)bispyridine-4-carboxamide (papc) [11] were prepared according to literature procedures. All solvents (analytical grade) were used without further purification.…”

Anion‐ and Solvent‐Induced Assembly and Reversible Structural Transformation of d10‐Metal Coordination Architectures Containing N‐(4‐(4‐Aminophenyloxy)phenyl)isonicotinamide

“…Based on our previous studies, [6] areversible structuraltransformationp rocess of the 1D double-zigzag {[Zn-(paps) 2 (H 2 O) 2 ](ClO 4 ) 2 } n and the 2D polyrotaxane [Zn-(paps) 2 (ClO 4 ) 2 ] n framework can be observed. Indeed, water plays av ital role for this structuralt ransformation process.…”

“…Reversible structural transformation and mechanochromic luminescence of the 1D double-zigzag {[Zn(paps) 2 (H 2 O) 2 ]-(ClO 4 ) 2 } n (paps = N,N'-bis(pyridylcarbonyl)-4,4'-diaminodiphenyl thioether) and the 2D polyrotaxane [Zn(paps) 2 (ClO 4 ) 2 ] n frameworksa sw ell as their respective N,N'-bis(pyridylcarbonyl)-4,4'diaminodiphenyl ether (papo)a nalogues have been investigated in our previous studies, [6] whereb oth the double-zigzag and the polyrotaxane frameworks were synthesized depending on the presence or absence of water in the reactionm edia, respectively.S ignificantly,b oth frameworks can be reversibly interconverted by heatinga nd grinding in thep resence of moisture, ands uch structural transformationi sa ble to be proven experimentally by powder and single-crystal X-ray diffraction studies. Significantly,w ater plays ak ey role in such an interesting structural transformation process.…”