Abstract
The spin-crossover properties of lipophilic, supramolecular Fe(II) complexes bridged by 4-(3-dodecyloxy)propyl-1,2,4-triazole [Fe(II)(1) 3Cl2] were investigated in chloroform and cast films. A purple low-spin (LS) complex in a powdery form was transformed into pale yellow high-spin (HS) polymers by dissolution in chloroform. The formation of lipophilic molecular wires in chloroform was observed with transmission electron microscopy. The casting of chloroform solutions onto solid supports produced purple, transparent films (LS state). The cast films exhibited sluggish spin-crossover (LS ⇌ HS) behavior without thermal hysteresis. On the other hand, the cocasting of equimolar dodecanol or tetradecanol with Fe(II)(1)3Cl2 produced composite films in which alcohol molecules were bound to the complex by ionic hydrogen bonding (ROH⋯Cl-) and van der Waals interactions. At room temperature, the cast films exhibited regular lamellar structures before and after alcohol doping; this was confirmed by wide-angle X-ray diffraction measurements. Interestingly, the Fe(II)(1)3Cl2/CnOH (n = 12 or 14) ternary films showed a reversible abrupt spin crossover accompanied by thermal hysteresis. The observed bistability was related to dynamic structural transformations between lamellar and hexagonal structures. This study provides a novel supramolecular approach to designing spin-crossover polymer films with controlled thermal bistability.
| Original language | English |
|---|---|
| Pages (from-to) | 5192-5202 |
| Number of pages | 11 |
| Journal | Journal of Polymer Science, Part A: Polymer Chemistry |
| Volume | 44 |
| Issue number | 17 |
| DOIs | |
| Publication status | Published - Sep 1 2006 |
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All Science Journal Classification (ASJC) codes
- Polymers and Plastics
- Organic Chemistry
- Materials Chemistry
Cite this
Supramolecular control of spin-crossover phenomena in lipophilic Fe(II)-1,2,4-triazole complexes. / Kuroiwa, Keita; Shibata, Tomoko; Sasaki, Sono; Ohba, Masaaki; Takahara, Atsushi; Kunitake, Toyoki; Kimizuka, Nobuo.
In: Journal of Polymer Science, Part A: Polymer Chemistry, Vol. 44, No. 17, 01.09.2006, p. 5192-5202.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Supramolecular control of spin-crossover phenomena in lipophilic Fe(II)-1,2,4-triazole complexes
AU - Kuroiwa, Keita
AU - Shibata, Tomoko
AU - Sasaki, Sono
AU - Ohba, Masaaki
AU - Takahara, Atsushi
AU - Kunitake, Toyoki
AU - Kimizuka, Nobuo
PY - 2006/9/1
Y1 - 2006/9/1
N2 - The spin-crossover properties of lipophilic, supramolecular Fe(II) complexes bridged by 4-(3-dodecyloxy)propyl-1,2,4-triazole [Fe(II)(1) 3Cl2] were investigated in chloroform and cast films. A purple low-spin (LS) complex in a powdery form was transformed into pale yellow high-spin (HS) polymers by dissolution in chloroform. The formation of lipophilic molecular wires in chloroform was observed with transmission electron microscopy. The casting of chloroform solutions onto solid supports produced purple, transparent films (LS state). The cast films exhibited sluggish spin-crossover (LS ⇌ HS) behavior without thermal hysteresis. On the other hand, the cocasting of equimolar dodecanol or tetradecanol with Fe(II)(1)3Cl2 produced composite films in which alcohol molecules were bound to the complex by ionic hydrogen bonding (ROH⋯Cl-) and van der Waals interactions. At room temperature, the cast films exhibited regular lamellar structures before and after alcohol doping; this was confirmed by wide-angle X-ray diffraction measurements. Interestingly, the Fe(II)(1)3Cl2/CnOH (n = 12 or 14) ternary films showed a reversible abrupt spin crossover accompanied by thermal hysteresis. The observed bistability was related to dynamic structural transformations between lamellar and hexagonal structures. This study provides a novel supramolecular approach to designing spin-crossover polymer films with controlled thermal bistability.
AB - The spin-crossover properties of lipophilic, supramolecular Fe(II) complexes bridged by 4-(3-dodecyloxy)propyl-1,2,4-triazole [Fe(II)(1) 3Cl2] were investigated in chloroform and cast films. A purple low-spin (LS) complex in a powdery form was transformed into pale yellow high-spin (HS) polymers by dissolution in chloroform. The formation of lipophilic molecular wires in chloroform was observed with transmission electron microscopy. The casting of chloroform solutions onto solid supports produced purple, transparent films (LS state). The cast films exhibited sluggish spin-crossover (LS ⇌ HS) behavior without thermal hysteresis. On the other hand, the cocasting of equimolar dodecanol or tetradecanol with Fe(II)(1)3Cl2 produced composite films in which alcohol molecules were bound to the complex by ionic hydrogen bonding (ROH⋯Cl-) and van der Waals interactions. At room temperature, the cast films exhibited regular lamellar structures before and after alcohol doping; this was confirmed by wide-angle X-ray diffraction measurements. Interestingly, the Fe(II)(1)3Cl2/CnOH (n = 12 or 14) ternary films showed a reversible abrupt spin crossover accompanied by thermal hysteresis. The observed bistability was related to dynamic structural transformations between lamellar and hexagonal structures. This study provides a novel supramolecular approach to designing spin-crossover polymer films with controlled thermal bistability.
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U2 - 10.1002/pola.21601
DO - 10.1002/pola.21601
M3 - Article
AN - SCOPUS:33748539666
VL - 44
SP - 5192
EP - 5202
JO - Journal of Polymer Science, Part A: Polymer Chemistry
JF - Journal of Polymer Science, Part A: Polymer Chemistry
SN - 0887-624X
IS - 17
ER -