Thermal behaviour and electrochemical properties of bis(trifluoromethanesulfonyl)amide and dodecatungstosilicate viologen dimers.
Summary of "Thermal behaviour and electrochemical properties of bis(trifluoromethanesulfonyl)amide and dodecatungstosilicate viologen dimers."
We report the synthesis and characterization of dimeric viologen salts (1',1''-(alkane-1,n-diyl)bis(1-ethyl-4,4'-bipyridinium) with n = 4-10) with bis(trifluoromethanesulfonyl)amide (bistriflimide, Tf(2)N(-)) as a counteranion. For n = 4, 5 and 6, and for the nonylviologen cation (1,1'-dinonyl-4,4'-bipyridinium) we also prepared salts with the totally inorganic dodecatungstosilicate anion, SiW(12)O(40)(4-), featuring a poly-charged surface and nanosized dimensions. The materials have been characterized by means of calorimetric techniques, X-ray diffraction and solid state NMR and a comparison is made with analogous monomeric viologen salts exhibiting smectic mesophases. A strong odd-even effect is observed in the melting points and in the thermal behaviour of the bistriflimide dimeric systems, similar to what was reported for dipolar calamitic liquid crystal dimers, although the studied viologen dimers are not mesomorphic. By increasing the size of the counteranion we have observed a destabilization of the crystal phases and of the mesophases in favour of a glassy amorphous state. Implications on the design of novel ionic liquid crystals are discussed. The electrochemical behaviour in solution has been investigated by cyclic voltammetry measurements: interestingly, the odd-even effect is clearly visible also in the redox potentials. The spin-pairing of the viologen radical cations formed at each end of the dimer is responsible for the observed redox trend. Insights on the structure of the spin-paired dimer have been obtained by DFT calculations.
Affiliation
Istituto per la Tecnologia delle Membrane del CNR, Unità di Padova, Via Marzolo, 1 - 35131, Padova, Italy. giacomo.saielli@unipd.it.
Journal Details
This article was published in the following journal.
Name: Physical chemistry chemical physics : PCCP
ISSN: 1463-9084
Pages: 2710-7
Links
- PubMed Source: http://www.ncbi.nlm.nih.gov/pubmed/22274641
- DOI: http://dx.doi.org/10.1039/c2cp23580c
Medical and Biotech [MESH] Definitions
Amide Synthases
Enzymes that catalyze the joining of either ammonia or an amide with another molecule, in which the linkage is in the form of a carbon-nitrogen bond. EC 6.3.1.
Angiotensin Amide
The octapeptide amide of bovine angiotensin II used to increase blood pressure by vasoconstriction.
Polarography
An electrochemical technique for measuring the current that flows in solution as a function of an applied voltage. The observed polarographic wave, resulting from the electrochemical response, depends on the way voltage is applied (linear sweep or differential pulse) and the type of electrode used. Usually a mercury drop electrode is used.
Antiporters
Membrane transporters that co-transport two or more dissimilar molecules in the opposite direction across a membrane. Usually the transport of one ion or molecule is against its electrochemical gradient and is "powered" by the movement of another ion or molecule with its electrochemical gradient.
Symporters
Membrane transporters that co-transport two or more dissimilar molecules in the same direction across a membrane. Usually the transport of one ion or molecule is against its electrochemical gradient and is "powered" by the movement of another ion or molecule with its electrochemical gradient.
PubMed Articles
The ionic liquids (ILs) 1-ethoxyethyl-2,3-dimethylimidazolium bis(trifluoromethanesulfonyl)imide, [EtO(CH(2))(2)MMI][Tf(2)N], and N-(ethoxyethyl)-N-methylmorpholinium bis(trifluoromethanesulfonyl)imid...
Synthesis and characterization of oligonucleotide conjugates bearing electroactive labels.
Oxime bond formation has been applied to the preparation of oligonucleotides labeled with electrochemical ferrocene and viologen labels. Aminooxy functionalized ferrocene and viologen derivatives were...
Fluorosulfonyl-(trifluoromethanesulfonyl)imide ionic liquids with enhanced asymmetry.
New ionic liquids with an asymmetric anion, fluorosulfonyl-(trifluoromethanesulfonyl)imide (FTFSI), were prepared and their chemical-physical properties were investigated. The ionic liquids based on N...
The influence of the Zn(2+) concentration and temperature on the electrochemical reduction of O(2) in a solution of zinc bis(trifluoromethanesulfonyl)imide (Zn(TFSI)(2)) salt in 1-butyl-1-methylpyrrol...
Differential capacity-potential curves, C(E), were obtained from electrochemical impedance spectra (12 kHz-2 Hz) for the interfaces between Hg and a series of alkyl imidazolium-based room temperature...
Clinical Trials
Exendin(9-39)Amide as a Glucagon-Like Peptide-1 (GLP-1) Receptor Antagonist in Humans
The purpose of this study is to determine the dose of the GLP-1 receptor antagonist exendin(9-39) which blocks the insulinotropic action of synthetic GLP-1 by at least 95%.
This research is being done to see if giving a hormone called GLP-1 can improve heart function and reduce length of stay in the Cardiac Surgical Intensive Care Unit (CSICU) in people who h...
Thermal Signature of Patients Undergoing Radiation Therapy
The goal of this clinical research study is to evaluate whether thermal imaging (recording body temperature) can be used to check the body's response to cancer therapy. Primary Objective:...
This is a randomized, double-blind, placebo-controlled, parallel-group, single-dose study of the efficacy of REGN475 in patients with pain due to thermal injury.
The purpose of this study is to determine if the, MR guided, laser interstitial thermal therapy (LITT) treatment technique can be safety and efficiently used for the human liver metastasis
