Raman Spectroscopic Observations of Anomalous Conformational Behavior of Short Poly(oxyethylene) Chains in Water

Masatoki, Sei; Takamura, M.; Matsuura, Hiroatsu; Kamogawa, Keiji; Kitagawa, Teizo

doi:10.1246/cl.1995.991

Cited by 22 publications

(34 citation statements)

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“…Meot-Ner et al 29 examined the complexing of H + from the formation of intramolecular or intermolecular hydrogen bonds with glymes (monoglyme, diglyme or triglyme) and 0–3 water molecules by pulsed high-pressure mass spectrometry; they found that the bonding of H 3 O + typically involve two or three hydrogen bonds, and complexes of H + and H 3 O + can be stabilized by interactions with bond dipoles of free ether groups of glymes and crown ethers whilst such a stabilization is enhanced by the decreasing constraints on the geometries of polar groups. Anomalous conformational behaviors of short glymes [CH 3 (OCH 2 CH 2 ) m OCH 3 with m = 2–6] in water were studied by FT-IR 30 and Raman spectroscopy; 31 both methods indicate that poly(ethylene oxide) chain progressively prefers the gauche ( g ) conformation for the OCH 2 –CH 2 O segment at the first stage, but this direction of the conformational preference is reversed for concentrations lower than a particular solution composition. Such an anomaly can be attributed to specific interactions and/or structures relevant to the glyme-water system.…”

Section: Physicochemical and Metal Complexing Properties Of Glymesmentioning

confidence: 99%

Glymes as versatile solvents for chemical reactions and processes: from the laboratory to industry

2014

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Glymes, also known as glycol diethers, are saturated non-cyclic polyethers containing no other functional groups. Most glymes are usually less volatile and less toxic than common laboratory organic solvents; in this context, they are more environmentally benign solvents. However, it is also important to point out that some glymes could cause long-term reproductive and developmental damages despite their low acute toxicities. Glymes have both hydrophilic and hydrophobic characters that common organic solvents are lack of. In addition, they are usually thermally and chemically stable, and can even form complexes with ions. Therefore, glymes are found in a broad range of laboratory applications including organic synthesis, electrochemistry, biocatalysis, materials, and Chemical Vapor Deposition (CVD), etc. In addition, glyme are used in numerous industrial applications, such as cleaning products, inks, adhesives and coatings, batteries and electronics, absorption refrigeration and heat pumps, as well as pharmaceutical formulations, etc. However, there is a lack of comprehensive and critical review on this attractive subject. This review aims to accomplish this task by providing an in-depth understanding of glymes’ physicochemical properties, toxicity and major applications.

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Section: Physicochemical and Metal Complexing Properties Of Glymesmentioning

confidence: 99%

Glymes as versatile solvents for chemical reactions and processes: from the laboratory to industry

2014

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“…A series of the Raman and infrared spectroscopy experiments for the DME/water and low molecular weight PEO/water systems have been made by Matsuura and co-workers. − These investigations reveal that the tgt conformer of DME becomes the most favorable in water solution. The reported intensity ratios of gauche and trans orientations around the C−C bond will be discussed below in our analysis of DME conformations.…”

Section: Theory Experiment and Previous Simulationsmentioning

confidence: 99%

Molecular Dynamics Simulations of 1,2-Dimethoxyethane/Water Solutions. 1. Conformational and Structural Properties

1998

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Molecular dynamics simulations of solutions of 1,2-dimethoxyethane (DME) and water have been performed in order to investigate the conformations of DME and the local solution structure as a function of solution composition and temperature. The simulations employ a previously developed force field based upon ab initio quantum chemistry calculations of DME/water interactions. The DME conformer populations show a strong dependence on temperature and solution composition and are quite different in aqueous solutions from those found in the gas phase or neat liquid. An analysis of the dependence of the conformer population distribution on temperature allows us to estimate the relative free energies of solvation for different conformers in water solution, which are found to be primarily energetic in origin for dilute solutions. The conformation dependence of the solvation free energy, resulting in "hydrophilic" and "hydrophobic" conformers, is explained in terms of differences in polar interactions between DME and neighboring water molecules. Analysis of the local structure of water around different DME conformers reveals that the degree of DME/water hydrogen bonding is nearly independent of the DME conformer for dilute solutions. The extent of water/water hydrogen bonding is also found to be nearly independent of composition over a wide composition range. To maintain a nearly constant level of water-water hydrogen bonding with increasing DME concentration, water is not randomly distributed in the system on a nearest-neighbor length scale but rather tends to form clusters of 4-5 molecules. The entropic penalty associated with this water structure increases with increasing DME concentration and temperature, thereby increasing the free energy of hydrophilic conformers relative to hydrophobic conformers.

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“…Effective permeation of the resin matrix occurs under the influence of a swelling solvent leading to good exposure of reactive group for peptide bond formation or enzymatic cleavage. There is strong evidence from Raman [48] infrared spectroscopy and from molecular dynamics simulation [47] that POE forms a helix in aqueous solution. There are three possible helical conformations of PEG having the low-energy gauche conformation of vicinal oxygen -carbon bond.…”

Section: Swelling Studies Of Various Pega Supportsmentioning

confidence: 99%

PEGA supports for combinatorial peptide synthesis and solid-phase enzymatic library assays

et al. 1998

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Permeable resins cross-linked with long PEG chains were synthesized for use in solid-phase enzyme library assays. High molecular weight bis-amino-polyethylene glycol (PEG) 4000, 6000, 8000 were synthesized by a three-step reaction starting from PEG-bis-OH. Macromonomers were synthesized by partial or di-acryloylation of bis-amino-PEG derivatives. Bis/mono-acrylamido-PEG were copolymerized along with acrylamide by inverse suspension copolymerization to yield a less cross-linked resin (Type I, compounds 6-9). Furthermore, acryloyl-sarcosin ethyl ester was co-polymerized along with bis-acrylamido PEG to obtain more crosslinked capacity resin (Type II, compounds 13-19). N,N-Dimethylacrylamide was used as a co-monomer in some cases. The polymer was usually obtained in a well-defined beaded form and was easy to handle under both wet and dry conditions. The supports showed good mechanical properties and were characterized by studying the swelling properties, size distribution of beads, and by estimating the amino group capacity. Depending on the PEG chain length, the monomer composition and the degree of cross-linking the PEGA supports showed a high degree of swelling in a broad range of solvents, including water, dichloromethane, DMF, acetonitril, THF and toluene: no swelling was observed in diethyl ether. The PEGA resins (Type I) with an amino acid group capacity between 0.07 and 1.0 mmol/g could be obtained by variation of the monomer composition in the polymerization mixture. Fluorescent quenched peptide libraries were synthesized on the new polymer using a multiple column library synthesizer and incubated with the matrix metalloproteinase MMP-9 after it had been activated by 4-aminophenyl mercuric acetate resulting in 67/83 kDa active enzyme. The bright beads were separated manually under a fluorescence microscope and sequenced to obtain peptide substrates for MMP-9. After treatment with ethylene diamine, high-loaded resins (Type II) have been employed in continuous flow peptide synthesis to yield peptides in excellent yield and purity.

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Raman Spectroscopic Observations of Anomalous Conformational Behavior of Short Poly(oxyethylene) Chains in Water

Cited by 22 publications

References 11 publications

Glymes as versatile solvents for chemical reactions and processes: from the laboratory to industry

Glymes as versatile solvents for chemical reactions and processes: from the laboratory to industry

Molecular Dynamics Simulations of 1,2-Dimethoxyethane/Water Solutions. 1. Conformational and Structural Properties

PEGA supports for combinatorial peptide synthesis and solid-phase enzymatic library assays

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