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Mihara N, Iitsuka S, Shiga T, Nihei M. Reversible structural change of [Co 2Fe 2] complexes between diamagnetic hydrogen-bonded 1D chains and paramagnetic complexes within a layered structure of amphiphilic anions. Dalton Trans 2024; 53:7190-7196. [PMID: 38577769 DOI: 10.1039/d4dt00482e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/06/2024]
Abstract
The combination of amphiphilic ions and metal complexes may enable the construction of assemblies in which the assembly structure and electronic state of the metal complexes change concertedly. In this work, an alternating layered structure of [Co2Fe2] complexes and amphiphilic anions was constructed. In the crystal structure, [Co2Fe2] complexes and water molecules formed a hydrogen-bonded supramolecular one-dimensional (1D) chain in the hydrophilic layer. A reversible structural change between the 1D chain and discrete [Co2Fe2] complexes was found to occur concertedly with an electron transfer-coupled spin transition (ETCST) of the [Co2Fe2] complex and desorption/adsorption of water molecules.
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Affiliation(s)
- Nozomi Mihara
- Department of Chemistry, Institute of Pure and Applied Sciences, University of Tsukuba, Tennodai 1-1-1, Tsukuba, Ibaraki, 305-8571, Japan.
| | - Soyoka Iitsuka
- Department of Chemistry, Institute of Pure and Applied Sciences, University of Tsukuba, Tennodai 1-1-1, Tsukuba, Ibaraki, 305-8571, Japan.
| | - Takuya Shiga
- Department of Chemistry, Institute of Pure and Applied Sciences, University of Tsukuba, Tennodai 1-1-1, Tsukuba, Ibaraki, 305-8571, Japan.
| | - Masayuki Nihei
- Department of Chemistry, Institute of Pure and Applied Sciences, University of Tsukuba, Tennodai 1-1-1, Tsukuba, Ibaraki, 305-8571, Japan.
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2
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Mihara N, Shimamura T, Takayama R, Shiga T, Nihei M. Structural Conversion of Supramolecular Assembly in Solution by Thermally Induced Intramolecular Electron Transfer of [Co 2 Fe 2 ] Complex. Chemistry 2023; 29:e202300954. [PMID: 37208296 DOI: 10.1002/chem.202300954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2023] [Revised: 05/18/2023] [Accepted: 05/19/2023] [Indexed: 05/21/2023]
Abstract
Combining metal complexes with amphiphilic molecules leads to a wide variety of functional self-assembled nanostructures. Metal complexes exhibiting spin transitions can be good candidates as the trigger to cause structural conversion of such assembly because they respond to various external stimuli. In this work, we studied a structural conversion of a supramolecular assembly containing a [Co2 Fe2 ] complex through a thermally induced electron transfer-coupled spin transition (ETCST). With an amphiphilic anion, the [Co2 Fe2 ] complex formed reverse vesicles in solution and showed thermal ETCST. In contrast, thermal ETCST in the presence of a bridging hydrogen-bond donor caused structural conversion from the reverse vesicle structure to entangled one-dimensional chains through hydrogen bond formation.
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Affiliation(s)
- Nozomi Mihara
- Department of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba, Tennodai1-1-1, 305-8577, Tsukuba, Ibaraki, Japan
| | - Tomonari Shimamura
- Department of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba, Tennodai1-1-1, 305-8577, Tsukuba, Ibaraki, Japan
| | - Ryo Takayama
- Department of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba, Tennodai1-1-1, 305-8577, Tsukuba, Ibaraki, Japan
| | - Takuya Shiga
- Department of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba, Tennodai1-1-1, 305-8577, Tsukuba, Ibaraki, Japan
| | - Masayuki Nihei
- Department of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba, Tennodai1-1-1, 305-8577, Tsukuba, Ibaraki, Japan
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Hatakeda M, Toohara S, Nakashima T, Sakurai S, Kuroiwa K. Helical-Ribbon and Tape Formation of Lipid Packaged [Ru(bpy) 3] 2+ Complexes in Organic Media. Int J Mol Sci 2019; 20:E3298. [PMID: 31277518 PMCID: PMC6650996 DOI: 10.3390/ijms20133298] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 07/02/2019] [Accepted: 07/03/2019] [Indexed: 01/04/2023] Open
Abstract
Anionic lipid amphiphiles with [RuII(bpy)3]2+ complex have been prepared. The metal complexes have been found to form ribbon and tape structures depending on chemical structures of lipid amphiphiles. Especially, the composites showed hypochromic effect and induced circular dichroism in organic media, and flexibly and weakly supramolecular control of morphological and optical properties have been demonstrated.
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Affiliation(s)
- Miho Hatakeda
- Department of nanoscience, Faculty of engineering, Sojo University, 4-22-1, Ikeda, Kumamoto 860-0082, Japan
| | - Souta Toohara
- Department of nanoscience, Faculty of engineering, Sojo University, 4-22-1, Ikeda, Kumamoto 860-0082, Japan
| | - Takuya Nakashima
- Division of Materials Science, Nara Institute of Science and Technology, NAIST, 8916-5 Takayama, Ikoma, Nara 630-0192, Japan
| | - Shinichi Sakurai
- Department of Biobased Materials Science, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| | - Keita Kuroiwa
- Department of nanoscience, Faculty of engineering, Sojo University, 4-22-1, Ikeda, Kumamoto 860-0082, Japan.
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Ishiba K, Noguchi T, Iguchi H, Morikawa MA, Kaneko K, Kimizuka N. Photoresponsive Nanosheets of Polyoxometalates Formed by Controlled Self-Assembly Pathways. Angew Chem Int Ed Engl 2017; 56:2974-2978. [DOI: 10.1002/anie.201612473] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Indexed: 11/12/2022]
Affiliation(s)
- Keita Ishiba
- Department of Chemistry and Biochemistry; Graduate School of Engineering; Center for Molecular Systems (CMS); Kyushu University; 744 Moto-oka Nishi-ku Fukuoka 819-0395 Japan
| | - Takao Noguchi
- Department of Chemistry and Biochemistry; Graduate School of Engineering; Center for Molecular Systems (CMS); Kyushu University; 744 Moto-oka Nishi-ku Fukuoka 819-0395 Japan
| | - Hiroaki Iguchi
- Department of Chemistry and Biochemistry; Graduate School of Engineering; Center for Molecular Systems (CMS); Kyushu University; 744 Moto-oka Nishi-ku Fukuoka 819-0395 Japan
- Department of Chemistry; Graduate School of Science; Tohoku University; 6-3 Aramaki-Aza-Aoba Sendai 980-8578 Japan
| | - Masa-aki Morikawa
- Department of Chemistry and Biochemistry; Graduate School of Engineering; Center for Molecular Systems (CMS); Kyushu University; 744 Moto-oka Nishi-ku Fukuoka 819-0395 Japan
| | - Kenji Kaneko
- Department of Materials Science and Engineering; Kyushu University; Japan
| | - Nobuo Kimizuka
- Department of Chemistry and Biochemistry; Graduate School of Engineering; Center for Molecular Systems (CMS); Kyushu University; 744 Moto-oka Nishi-ku Fukuoka 819-0395 Japan
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Ishiba K, Noguchi T, Iguchi H, Morikawa MA, Kaneko K, Kimizuka N. Photoresponsive Nanosheets of Polyoxometalates Formed by Controlled Self-Assembly Pathways. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201612473] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Keita Ishiba
- Department of Chemistry and Biochemistry; Graduate School of Engineering; Center for Molecular Systems (CMS); Kyushu University; 744 Moto-oka Nishi-ku Fukuoka 819-0395 Japan
| | - Takao Noguchi
- Department of Chemistry and Biochemistry; Graduate School of Engineering; Center for Molecular Systems (CMS); Kyushu University; 744 Moto-oka Nishi-ku Fukuoka 819-0395 Japan
| | - Hiroaki Iguchi
- Department of Chemistry and Biochemistry; Graduate School of Engineering; Center for Molecular Systems (CMS); Kyushu University; 744 Moto-oka Nishi-ku Fukuoka 819-0395 Japan
- Department of Chemistry; Graduate School of Science; Tohoku University; 6-3 Aramaki-Aza-Aoba Sendai 980-8578 Japan
| | - Masa-aki Morikawa
- Department of Chemistry and Biochemistry; Graduate School of Engineering; Center for Molecular Systems (CMS); Kyushu University; 744 Moto-oka Nishi-ku Fukuoka 819-0395 Japan
| | - Kenji Kaneko
- Department of Materials Science and Engineering; Kyushu University; Japan
| | - Nobuo Kimizuka
- Department of Chemistry and Biochemistry; Graduate School of Engineering; Center for Molecular Systems (CMS); Kyushu University; 744 Moto-oka Nishi-ku Fukuoka 819-0395 Japan
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Yamamoto HM. Sheathed nanowires aligned by crystallographic periodicity: a possibility of cross-bar wiring in three-dimensional space. CrystEngComm 2014. [DOI: 10.1039/c3ce41015c] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Kuroiwa K, Masaki Y, Koga Y, Deming TJ. Self-assembly of discrete metal complexes in aqueous solution via block copolypeptide amphiphiles. Int J Mol Sci 2013; 14:2022-35. [PMID: 23337202 PMCID: PMC3565363 DOI: 10.3390/ijms14012022] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2012] [Revised: 01/09/2013] [Accepted: 01/17/2013] [Indexed: 11/29/2022] Open
Abstract
The integration of discrete metal complexes has been attracting significant interest due to the potential of these materials for soft metal-metal interactions and supramolecular assembly. Additionally, block copolypeptide amphiphiles have been investigated concerning their capacity for self-assembly into structures such as nanoparticles, nanosheets and nanofibers. In this study, we combined these two concepts by investigating the self-assembly of discrete metal complexes in aqueous solution using block copolypeptides. Normally, discrete metal complexes such as [Au(CN)(2)]-, when molecularly dispersed in water, cannot interact with one another. Our results demonstrated, however, that the addition of block copolypeptide amphiphiles such as K(183)L(19) to [Au(CN)(2)]- solutions induced one-dimensional integration of the discrete metal complex, resulting in photoluminescence originating from multinuclear complexes with metal-metal interactions. Transmission electron microscopy (TEM) showed a fibrous nanostructure with lengths and widths of approximately 100 and 20 nm, respectively, which grew to form advanced nanoarchitectures, including those resembling the weave patterns of Waraji (traditional Japanese straw sandals). This concept of combining block copolypeptide amphiphiles with discrete coordination compounds allows the design of flexible and functional supramolecular coordination systems in water.
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Affiliation(s)
- Keita Kuroiwa
- Department of Nanoscience, Faculty of Engineering, Sojo University, 4-22-1 Ikeda, Nishi-ku, Kumamoto 860-0082, Japan; E-Mails: (Y.M.); (Y.K.)
| | - Yoshitaka Masaki
- Department of Nanoscience, Faculty of Engineering, Sojo University, 4-22-1 Ikeda, Nishi-ku, Kumamoto 860-0082, Japan; E-Mails: (Y.M.); (Y.K.)
| | - Yuko Koga
- Department of Nanoscience, Faculty of Engineering, Sojo University, 4-22-1 Ikeda, Nishi-ku, Kumamoto 860-0082, Japan; E-Mails: (Y.M.); (Y.K.)
| | - Timothy J. Deming
- Department of Bioengineering, University of California, Los Angeles, CA 90095, USA; E-Mail:
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Self-assembly and functionalization of lipophilic metal-triazole complexes in various media. Polym J 2012. [DOI: 10.1038/pj.2012.142] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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9
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Kuroiwa K, Yoshida M, Masaoka S, Kaneko K, Sakai K, Kimizuka N. Self-Assembly of Tubular Microstructures from Mixed-Valence Metal Complexes and Their Reversible Transformation by External Stimuli. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/ange.201105080] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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10
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Kuwahara R, Fujikawa S, Kuroiwa K, Kimizuka N. Controlled polymerization and self-assembly of halogen-bridged diruthenium complexes in organic media and their dielectrophoretic alignment. J Am Chem Soc 2012; 134:1192-9. [PMID: 22224659 DOI: 10.1021/ja208958t] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Lipophilic paddlewheel biruthenium complexes [Ru(2)(μ-O(2)CR)(3)X](n) (O(2)CR = 3,4,5-tridodecyloxybenzoate, X = Cl, I) self-assemble in organic media to form halogen-bridged coordination polymers. The polymerization is accompanied by spectral changes in π(RuO,Ru(2)) → π*(Ru(2)) and π(axial ligand) → π*(Ru(2)) absorption bands. These polymeric complexes form lyotropic liquid crystals in n-decane at concentrations above ~100 unit mM. The bridging halogen axial ligands (X = Cl or I) exert significant influences on their electronic structures and self-assembling characteristics: the chloride-bridged polymers give hexagonally aligned ordered columnar structure (columnar hexagonal phase, Col(h)), whereas the iodide-bridged polymers form less ordered columnar nematic (Col(n)) phase, as revealed by small-angle X-ray diffraction measurements. Chloro-bridged coordination polymers dispersed in n-decane are thermally intact even at the elevated temperature of 70 °C. In contrast, iodo-bridged polymers show reversible dissociation and reassembly phenomena depending on temperature. These halogen-bridged coordination polymers show unidirectional alignment upon applying alternating current (ac) electric field as investigated by crossed polarizing optical microscopy and scanning electron microscopy. The unidirectionally oriented columns of chloro-bridged polymers are accumulated upon repetitive application of the ac voltage, whereas iodo-bridged coordination polymers show faster and reversible alignment changes in response to turning on-and-off the electric field. The controlled self-assembly of electronically conjugated linear complexes provide a potential platform to design electric field-responsive nanomaterials.
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Affiliation(s)
- Rempei Kuwahara
- Department of Chemistry and Biochemistry, Graduate School of Engineering, International Research Center for Molecular Systems (IRCMS), Kyushu University, 744 Moto-oka, Fukuoka 819-0395, Japan
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11
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KUROIWA K. Dynamic Self-Assembly from Mixed-Valence Metal Complexes and Their Reversible Transformations by External Stimuli. KOBUNSHI RONBUNSHU 2012. [DOI: 10.1295/koron.69.485] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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12
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Kuroiwa K, Yoshida M, Masaoka S, Kaneko K, Sakai K, Kimizuka N. Self-Assembly of Tubular Microstructures from Mixed-Valence Metal Complexes and Their Reversible Transformation by External Stimuli. Angew Chem Int Ed Engl 2011; 51:656-9. [DOI: 10.1002/anie.201105080] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2011] [Revised: 08/29/2011] [Indexed: 11/12/2022]
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14
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Effect of solvent on the gelation properties of a metallo-organic polymer of [Fe(II) (4-octadecyl-1,2,4-triazole)3(ClO4)2]n. Eur Polym J 2009. [DOI: 10.1016/j.eurpolymj.2009.10.013] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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15
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Tanaka K, Kaneko K, Watanabe Y, Shionoya M. A template-directed synthetic approach to halogen-bridged mixed-valence platinum complexes on artificial peptides in solution. Dalton Trans 2007:5369-71. [DOI: 10.1039/b711804j] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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16
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Kimizuka N, Yamada K, Kunitake T. Organization of One-Dimensional Mixed-Valence Platinum Complexes at the Air-Water Interface and in Langmuir-Blodgett Films. ACTA ACUST UNITED AC 2006. [DOI: 10.1080/10587250008038252] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Nobuo Kimizuka
- a Department of Chemistry and Biochemistry , Graduate School of Engineering, Kyushu University , Fukuoka , 812-8581
| | - Keiji Yamada
- a Department of Chemistry and Biochemistry , Graduate School of Engineering, Kyushu University , Fukuoka , 812-8581
| | - Toyoki Kunitake
- a Department of Chemistry and Biochemistry , Graduate School of Engineering, Kyushu University , Fukuoka , 812-8581
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Kuroiwa K, Shibata T, Sasaki S, Ohba M, Takahara A, Kunitake T, Kimizuka N. Supramolecular control of spin-crossover phenomena in lipophilic Fe(II)-1,2,4-triazole complexes. ACTA ACUST UNITED AC 2006. [DOI: 10.1002/pola.21601] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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18
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John NS, Thomas PJ, Kulkarni GU. Self-Assembled Hybrid Bilayers of Palladium Alkanethiolates. J Phys Chem B 2003. [DOI: 10.1021/jp027742u] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Neena Susan John
- Nanolaboratory, Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560 064, India
| | - P. John Thomas
- Nanolaboratory, Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560 064, India
| | - G. U. Kulkarni
- Nanolaboratory, Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560 064, India
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Luo X, Wang X, Wu S, Liang Y. Strong blue-fluorescence-emitted stable monolayers formed in organic solvents by a coordination polymer with long-chained bis-Schiff base. J Colloid Interface Sci 2003; 258:432-4. [PMID: 12618116 DOI: 10.1016/s0021-9797(02)00097-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The coordination polymer, P(ZnL) (L=N,N'-bis[2-hydroxy-4-(dodecyloxy)benzaldehyde)]-ethylenedimine), forms a novel uniform lamellar superstructure in organic liquids, which exhibits intense fluorescence in organic dispersions as well as in the corresponding cast films.
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Affiliation(s)
- Xuzhong Luo
- State Key Laboratory of Coordination Chemistry, Nanjing University, Nanjing 210093, People's Republic of China
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Chang-Soo L, Kimizuka N. Pillared honeycomb nanoarchitectures formed on solid surfaces by the self-assembly of lipid-packaged one-dimensional Pt complexes. Proc Natl Acad Sci U S A 2002; 99:4922-6. [PMID: 11929964 PMCID: PMC122695 DOI: 10.1073/pnas.062011099] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A highly lipophilic polyion complex [Pt(en)(2)][PtCl(2)(en)(2)](1)(4) (en, 1,2-diaminoethane) is prepared from one-dimensional mixed valence Pt(II)/Pt(IV) complex and newly designed chiral amphiphile 1. The powdery sample showed purple color, which is a result of the mixed valence absorption of the linear chlorobridged complex (Pt(II)-Cl-Pt(IV)-Cl-)(n). When the lipid complex is dispersed in dichloromethane, purple-colored dispersion is obtained at 0 degrees C, whereas the color disappears after heating the solution to 21 degrees C. The observed thermochromism is reversible with respect to the temperature changes and is ascribed to the reversible dissociation and reassembly of the self-assembling inorganic wires. Casting of the 0 degrees C-purple dispersion on solid substrates affords honeycomb nanostructures in addition to the nanowires with the width of about 20 nm. The honeycomb patterns seem to be templated by the condensed water droplets that are formed and aligned on the rapidly evaporating dichloromethane solution. On the other hand, more regular honeycomb structures are exclusively obtained by casting the 21 degrees C-colorless solution. These observations indicate that the ordered honeycomb structures are obtainable on solid surfaces by the self-assembly of molecularly dispersed components [Pt(en)(2)](1)(2) and trans-[PtCl(2)(en)(2)](1)(2.) Very interestingly, formation of double-layered honeycomb nanostructure is observed by scanning electron microscopy. The unit hexagons and pillars of the honeycombs are made of nanowires that are hierarchically assembled from the lipid-packaged Pt(II)/Pt(IV) complexes. The surface self-organization of lipophilic inorganic complexes has a potential to fabricate novel nanoarchitectures with conjugated electronic structures.
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Affiliation(s)
- Lee Chang-Soo
- Department of Chemistry and Biochemistry, Graduate School of Engineering, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan
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Wang K, Haga M, Monjushiro H, Akiba M, Sasaki Y. Luminescent Langmuir-Blodgett films of platinum(II) complex [Pt(L18)Cl](PF6) (L18 = 2,6-bis(1-octadecylbenzimidazol-2-yl)pyridine). Inorg Chem 2000; 39:4022-8. [PMID: 11198856 DOI: 10.1021/ic990880m] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A novel amphiphilic Pt complex containing 2,6-bis(1-octadecylbenzimidazol-2-yl)pyridine (L18), [Pt(L18)Cl](PF6), has been synthesized. The complex exhibits concentration-dependent absorption and emission spectra in solution. With increasing the concentration of the Pt complex, we observed a new absorption band centered at 550 nm derived from a metal-metal d sigma* to ligand pi* charge transfer (MMLCT) transition and the corresponding broad emission centered at 650 nm. The Pt complex is surface-active, and the surface pressure-area isotherm reveals three phase transitions. The three phases correspond to one liquid-expanding phase and two solid-condensed phases, respectively, with different intermolecular overlap in the "flat-on" orientation at the air-water interface. Without additives such as fatty acids, the complex forms a stable and reproducible Langmuir-Blodgett (LB) multilayer film above a surface pressure of 15 mN m-1. Strong emission from the LB films, even monolayer, was observed. Comparing the relative emission intensity of the MMLCT band for transferred LB monolayer film with that for cast films, we concluded that Pt-Pt interactions are suppressed in the LB film. Instead, the emission at 600 nm arising from the ligand-ligand pi-pi interacted excited state became dominant. The results would provide the insight into the control of molecular ordering for planar Pt complexes from the viewpoint of characteristic excited states.
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Affiliation(s)
- K Wang
- Department of Applied Chemistry, Faculty of Science and Engineering, Chuo University, 1-13-27 Kasuga, Bunkyo-Ku, Tokyo 112-8551, Japan
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