Hydrogen-Bonded Cluster Formation and Hydrophobic Solute Association in Aqueous Solutions of Ethanol

AbstractIt has been established that the electroviscosity effect of polyzwitterionic (PZI) aqueous solutions is more considerable than and acts in a direction opposite to that of aqueous polyelectrolyte solutions. Temperature and electric field strength influence the electroviscosity of PZI aqueous solutions in parallel, though the reasons for these effects are quite different. The unusual electroviscosity behaviour of PZI solutions is explained by a ‘core-shell’ model for the structural organization of PZI macromolecules, suggesting that cluster formation is due to intensive dipoledipole interactions between monomer units of the same or of different macromolecules.

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Vitrified dilute aqueous solutions. 3. Plasticization of water's hydrogen-bonded network and the glass transition temperature's minimum

The Journal of Physical Chemistry ◽

10.1021/j100348a053 ◽

1989 ◽

Vol 93 (11) ◽

pp. 4674-4677 ◽

Cited By ~ 30

Author(s):

Klaus Hofer ◽

Andreas Hallbrucker ◽

Erwin Mayer ◽

G. P. Johari

Keyword(s):

Glass Transition ◽

Aqueous Solutions ◽

Dilute Aqueous Solutions ◽

Hydrogen Bonded

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Enhanced Nonradiative Decay in Aqueous Solutions of Aminonaphthalimide Derivatives via Water-Cluster Formation

The Journal of Physical Chemistry A ◽

10.1021/jp964061o ◽

1997 ◽

Vol 101 (19) ◽

pp. 3461-3466 ◽

Cited By ~ 43

Author(s):

Dongwu Yuan ◽

Robert G. Brown

Keyword(s):

Aqueous Solutions ◽

Water Cluster ◽

Cluster Formation ◽

Nonradiative Decay

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Synthesis of Nanotubule-Forming Cyclic Octapeptides via an Fmoc Strategy

Australian Journal of Chemistry ◽

10.1071/c98006 ◽

1998 ◽

Vol 51 (7) ◽

pp. 535 ◽

Cited By ~ 14

Author(s):

Martina E. Polaskova ◽

John N. Lambert ◽

Nicholas J. Ede

Keyword(s):

Aqueous Solutions ◽

Infrared Absorption ◽

Structural Studies ◽

Protection Strategy ◽

Fmoc Chemistry ◽

Orthogonal Protection ◽

Fmoc Strategy ◽

Cyclic Octapeptide ◽

Head To Tail Cyclization ◽

Hydrogen Bonded

New syndiotactic cyclic octapeptides, namely cyclo(–D-Phe-L-Asp–D-Phe–L-Asn–D-Phe–L-Asp–D-Phe–L-Asn–) (1) and cyclo(–D-N-MeAla–L-Asp–D-N-MeAla–L-Asn–D-N-MeAla–L-Asp–D-N-MeAla–L-Asn–) (2), have been prepared, and preliminary structural studies have been conducted. The synthesis of the linear peptides was performed by using Fmoc chemistry, and head-to-tail cyclization was accomplished by using an orthogonal protection strategy and a support-bound cyclization step. Acidification of aqueous solutions of cyclic octapeptide (1) initiated formation of needlelike crystals whose morphology and infrared absorption behaviour suggested that they were hydrogen-bonded nanotubular aggregates of (1).

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Geometries and energetics of methanol–ethanol clusters: a VUV laser/time-of-flight mass spectrometry and density functional theory study

Canadian Journal of Chemistry ◽

10.1139/v07-104 ◽

2007 ◽

Vol 85 (10) ◽

pp. 843-852 ◽

Cited By ~ 9

Author(s):

Y Liu ◽

S Consta ◽

F Ogeer ◽

Y J Shi ◽

R H Lipson

Keyword(s):

Mass Spectrometry ◽

Dft Calculations ◽

Density Functional ◽

Vacuum Ultraviolet ◽

Single Photon ◽

Cluster Formation ◽

Time Of Flight ◽

Cluster Ions ◽

Flight Mass Spectrometry ◽

Hydrogen Bonded

Hydrogen-bonded clusters, formed above liquid methanol (Me) and ethanol (Et) mixtures of various compositions, were entrained in a supersonic jet and probed using 118 nm vacuum ultraviolet (VUV) laser single-photon ionization/time-of-flight mass spectrometry. The spectra are dominated by protonated cluster ions, formed by ionizing hydrogen-bonded MemEtn neutrals, m = 0–4, n = 0–3, and m + n = 2–5. The structures and energetics of the neutral and ionic species were investigated using both the all-atom optimized potential for liquid state, OPLS-AA, and the density functional (DFT) calculations. The energetic factors affecting the observed cluster distributions were examined. Calculations indicate that the large change in binding energy going from trimer to tetramer can be attributed more to pair-wise interactions than to cooperativity effects.Key words: alcohol clusters, cluster formation, DFT calculations, mass spectrometry, vacuum ultraviolet laser.

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