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Chen Q, Yao J, Hu X, Shen J, Sheng Y, Liu H. Monolayer effect of a gemini surfactant with a rigid biphenyl spacer on its self-crystallization at the air/liquid interface. J Appl Crystallogr 2015. [DOI: 10.1107/s1600576715004938] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
A gemini surfactant with a biphenyl spacer can spontaneously generate crystals at the air/solution interface. X-ray crystallography reveals that surfactant molecules exhibit an almost fully extended conformation with interdigitating alkyl chains, together with an approximate co-planarity of two C—C—C planes in two alkyl chains of one gemini molecule, and a prominent dihedral angle between the benzene rings and C—C—C planes of the alkyl chains. Infrared reflection–absorption spectroscopy shows that the gemini surfactant was stretched at the air/water interface, with the hydrocarbon chains oriented at a tilt angle of ∼75° with respect to the surface normal. In particular, the biphenyl group is more or less perpendicular to the water surface, and the C—C—C plane of the alkyl chain tends to be parallel to the water surface. Both results point out a remarkable similarity in the molecular conformation between the crystal and the monolayer. Meanwhile, dynamic light scattering and transmission electron microscopy results indicate that the crystallization of such gemini surfactants at the interface is contrary to the crystallization behavior in the bulk phase, meaning that the surfactant solution can only form a supersaturated solution as it is cooled, though the crystallization temperature of 296 K is lower than the Krafft temperature (∼303 K). Therefore, our findings indicate that the Gibbs monolayer of the gemini surfactant plays a critical role in its interfacial crystallization. Additionally, multiple weak intermolecular interactions, involving van der Waals interaction, π–π stacking and cationic–π interactions, as well as the hydrophobic effect during the aggregation of the gemini molecule in solution, are responsible for the formation of the interfacial crystal.
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Tang CY, Huang Z, Allen HC. Binding of Mg2+ and Ca2+ to Palmitic Acid and Deprotonation of the COOH Headgroup Studied by Vibrational Sum Frequency Generation Spectroscopy. J Phys Chem B 2010; 114:17068-76. [PMID: 21062085 DOI: 10.1021/jp105472e] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- Cheng Y. Tang
- Department of Chemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210, United States
| | - Zishuai Huang
- Department of Chemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210, United States
| | - Heather C. Allen
- Department of Chemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210, United States
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Wang H, Miao W, Liu H, Zhang X, Du X. Molecular Assemblies of 4-(Hexadecyloxy)-N-(pyridinylmethylene)anilines at the Air−Water Interface and Cu(II)-Promoted Vesicle Formation via Metal Coordination. J Phys Chem B 2010; 114:11069-75. [DOI: 10.1021/jp1059352] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Haibo Wang
- Key Laboratory of Mesoscopic Chemistry (Ministry of Education), State Key Laboratory of Coordination Chemistry, and School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, P. R. China, and School of Chemistry and Technology, Zhanjiang Normal University, Zhanjiang 524048, P. R. China
| | - Wangen Miao
- Key Laboratory of Mesoscopic Chemistry (Ministry of Education), State Key Laboratory of Coordination Chemistry, and School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, P. R. China, and School of Chemistry and Technology, Zhanjiang Normal University, Zhanjiang 524048, P. R. China
| | - Huijin Liu
- Key Laboratory of Mesoscopic Chemistry (Ministry of Education), State Key Laboratory of Coordination Chemistry, and School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, P. R. China, and School of Chemistry and Technology, Zhanjiang Normal University, Zhanjiang 524048, P. R. China
| | - Xianfeng Zhang
- Key Laboratory of Mesoscopic Chemistry (Ministry of Education), State Key Laboratory of Coordination Chemistry, and School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, P. R. China, and School of Chemistry and Technology, Zhanjiang Normal University, Zhanjiang 524048, P. R. China
| | - Xuezhong Du
- Key Laboratory of Mesoscopic Chemistry (Ministry of Education), State Key Laboratory of Coordination Chemistry, and School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, P. R. China, and School of Chemistry and Technology, Zhanjiang Normal University, Zhanjiang 524048, P. R. China
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Zheng H, Du X. Protein-Directed Spatial Rearrangement of Glycolipids at the Air−Water Interface for Bivalent Protein Binding: In Situ Infrared Reflection Absorption Spectroscopy. J Phys Chem B 2009; 114:577-84. [DOI: 10.1021/jp908559n] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Haifu Zheng
- Key Laboratory of Mesoscopic Chemistry (Ministry of Education), State Key Laboratory of Coordination Chemistry, and School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, People’s Republic of China
| | - Xuezhong Du
- Key Laboratory of Mesoscopic Chemistry (Ministry of Education), State Key Laboratory of Coordination Chemistry, and School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, People’s Republic of China
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Liu H, Zheng H, Miao W, Du X. In situ studies of metal coordinations and molecular orientations in monolayers of amino-acid-derived Schiff bases at the air-water interface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2009; 25:2941-2948. [PMID: 19437705 DOI: 10.1021/la803976c] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The surface behaviors of monolayers of amino-acid-derived Schiff bases, namely, 4-(4-(hexadecyloxy)benzylideneamino)benzoic acid (HBA), at the air-water interface on pure water and ion-containing subphases (Cu2+, Ca2+, and Ba2+) have been clarified by a combination of surface pressure-area isotherms and surface plasmon resonance (SPR) technique, and the metal coordinations and molecular orientations in the monolayers have been investigated using in situ infrared reflection absorption spectroscopy (IRRAS). The presence of metal ions gives rise to condensation of the monolayers (Cu2+, pH 6.1; Ca2+, pH 11; Ba2+, pH 10), even leading to the formation of three-dimensional structures of the compressed monolayer in the case of Ba2+ (pH 12). The metal coordinations with the carboxyl groups at the interface depend on the type of metal ions and pH of the aqueous subphase. The orientations of the aromatic Schiff base segments with surface pressure are elaborately described. The spectral behaviors of the Schiff base segments with incidence angle in the case of Ba2+ (pH 12) have so far presented an excellent example for the selection rule of IRRAS at the air-water interface for p-polarization with vibrational transition moments perpendicular to the water surface. The chain orientations in the monolayers are quantitatively determined on the assumption that the thicknesses of the HBA monolayers at the air-water interface are composed of the sublayers of alkyl chains and Schiff base segments.
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Affiliation(s)
- Huijin Liu
- MOE Key Laboratory of Mesoscopic Chemistry, State Key Laboratory of Coordination Chemistry, and School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, People's Republic of China
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