Hydrogen-bonding molecular ruler surfactants as probes of specific solvation at liquid/liquid interfaces

Siler, A. Renee; Brindza, Michael R.; Walker, Robert A.

doi:10.1007/s00216-009-2957-8

Cited by 12 publications

(11 citation statements)

References 50 publications

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“…45,46 The ability of interfacial water to act as a strong hydrogenbond donor has been confirmed by SSHG studies of N-methyl-pmethoxyaniline (NMMA) at the CCl 4 /water interface. 47 The SSHG spectra of NMMA, whose electronic absorption spectrum is sensitive to the hydrogen-bonding properties of the environment, were typical for strong hydrogen bonds with water.…”

Section: ' Results and Discussionmentioning

confidence: 99%

Hydrogen-Bond-Assisted Excited-State Deactivation at Liquid/Water Interfaces

2011

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' INTRODUCTIONOver the past few years, second-order nonlinear optical techniques, such as surface second harmonic generation (SSHG) 1À3 and surface sum frequency generation (SSFG), 4,5 have become powerful and extensively applied tools for studying the chemical and physical properties of interfaces. These methods are intrinsically insensitive to isotropic media, and they thus overcome the main difficulty of optical studies of interfaces, namely, the fact that the linear response from the relatively small number of molecules located in the interfacial region is completely hidden by the signal from the overwhelming number of bulk molecules.The information obtained in these experiments may have a significant value for various fields of chemistry and biochemistry, 6,7 because interfaces constitute the local environment of numerous chemical reactions and physical phenomena, including common and important processes for everyday life, such as the corrosion of metal surfaces or the formation of foams and emulsions. On the other hand, water interfaces play a key role in biological processes taking place at cell membranes, including the transport of medicines and the infection of cells by viruses. In this case, knowledge of the physical and chemical properties of the interface is essential for the design of more effective drugs.In most cases, the SSHG or SSFG experiments do not deliver straightforward information about interfaces, and the interpretation of the results is usually difficult and sometimes ambiguous. This especially applies to SSHG, which generally provides limited spectral information, although it is a convenient and relatively simple tool for studying the orientation, 8À13 the concentration, 14À16 and the dynamics of molecules at interfaces. 17À25 A powerful approach to investigate physical and chemical properties of interfaces is the use of a "dynamic probe", namely, a molecule with an excited-state dynamics (for instance, its S 1 lifetime) that depends on some properties of the environment. Once the dynamics of this molecule and its dependence upon a given environment property is well-characterized by bulk spectroscopy, information on this property at the interface can then be deduced from time-resolved SSHG (TRSSHG) experiments. A good example of this approach is the measurement of the S 1 state lifetime of malachite green to characterize the microscopic friction at air/liquid and liquid/liquid interfaces. 8,26 Because the deactivation pathways of the excited state of this dye were well-understood and the dependence of its S 1 state lifetime on solvent viscosity was established, it was possible to determine the friction exerted on this molecule at various interfaces by TRSSHG. In this approach, two aspects are simultaneously investigated: (1) the properties of the interface and (2) how these properties affect the behavior of solute molecules located at the interface. A proper understanding of the interfacial process requires both issues to be addressed.We report here on the application of the xanthene...

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Section: ' Results and Discussionmentioning

confidence: 99%

Hydrogen-Bond-Assisted Excited-State Deactivation at Liquid/Water Interfaces

2011

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“…Additional details about the SHG assembly can be found in previous reports. 35,36 C. Nonlinear spectroscopy VSFG is a 2nd order nonlinear optical process that measures vibrational spectra of molecules in environments lacking inversion symmetry. In a VSFG experiment, two high intensity elds (one visible and one infrared) induce a coherent, nonlinear polarization in molecules at a surface or interface.…”

Section: B Apparatusmentioning

confidence: 99%

Liquid organization and solvation properties at polar solid/liquid interfaces

Gobrogge

Woods

Walker³

2013

Faraday Discuss.

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Second order nonlinear optical spectroscopy has been employed to examine the organization of four different liquids at the hydrophilic silica/liquid interface. The liquids - cyclohexane, methylcyclohexane, 1-propanol, and 2-propanol - were chosen to isolate how intermolecular forces between the liquid and the substrate competed with steric effects to control liquid structure and solvating properties across the interfacial region. Vibrational sum frequency generation (VSFG) data showed that cyclohexane structure at the silica/liquid cyclohexane interface closely resembled the structure of a cyclohexane monolayer adsorbed to the silica/vapor interface. Methylcyclohexane, however, showed evidence of large structural reorganization between the silica/liquid and silica/monolayer/vapor interfaces. 1-Propanol at a silica/vapor interface formed a well-ordered, Langmuir-like monolayer due to strong hydrogen bonding with the surface silanols and cohesive van der Waals interactions between carbon chains. 1-Propanol at the silica/liquid interface retained the same ordered structure. In contrast, 2-propanol adopted different structures adsorbed to the solid/vapor and at the solid/ liquid interfaces. Specifically, the plane defined by 2-propanol's three carbon atoms changed orientation from being perpendicular to the surface (silica/vapor) to parallel to the surface (silica/liquid). Surface mediated liquid structure affected the solvation of adsorbed solutes. Resonance enhanced second harmonic generation (SHG) data showed that silica/alkane interfaces were significantly more polar than would be expected based on a solute's bulk solution solvatochromic behavior. Both silica/alcohol interfaces exhibited alkane-like polarity, a result that was interpreted in terms of a reduction in hydrogen bonding opportunities for adsorbed solutes.

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“…the interfacial properties of molecules at interfaces. [77][78][79][80][81][82][83][84][85][86][87][88][89][90][91][92][93][94][95] SHG is a second-order nonlinear process that involves the interaction of two photons with same frequency (o) in a noncentrosymmetric medium to produce a photon at frequency 2o. A niche application involves SHG at the interface between two isotropic bulk media, such as the surface of a centrosymmetric solid under water.…”

Section: Second Harmonic Generation Spectroscopymentioning

confidence: 99%

Water structure at solid surfaces and its implications for biomolecule adsorption

Jena

Hore

2010

Phys. Chem. Chem. Phys.

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The ordered arrangement of water molecules at solid surfaces is a consequence of hydrogen-bonding opportunities, electrostatic and dipolar interactions, and specific interactions with the surface. This perspective highlights recent understanding of this water structure at the solid-liquid interface. We discuss findings from three experimental techniques (attenuated total internal reflection infrared spectroscopy, second harmonic generation spectroscopy, and vibrationally-resonant sum-frequency generation spectroscopy) and two simulation approaches (molecular dynamics and Monte Carlo simulations). In each case, we also provide examples of how these techniques reveal the importance of interfacial water organization in rationalizing the structure of adsorbed biomolecules.

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Hydrogen-bonding molecular ruler surfactants as probes of specific solvation at liquid/liquid interfaces

Cited by 12 publications

References 50 publications

Hydrogen-Bond-Assisted Excited-State Deactivation at Liquid/Water Interfaces

Hydrogen-Bond-Assisted Excited-State Deactivation at Liquid/Water Interfaces

Liquid organization and solvation properties at polar solid/liquid interfaces

Water structure at solid surfaces and its implications for biomolecule adsorption

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