scholarly journals Temperature- and Pressure-Induced Proton Transfer in the 1:1 Adduct Formed between Squaric Acid and 4,4′-Bipyridine

2009 ◽  
Vol 131 (11) ◽  
pp. 3884-3893 ◽  
Author(s):  
David M. S. Martins ◽  
Derek S. Middlemiss ◽  
Colin R. Pulham ◽  
Chick C. Wilson ◽  
Mark T. Weller ◽  
...  
Keyword(s):  
Proton Transfer ◽  
Squaric Acid ◽  
Temperature And Pressure

Antiferroelectric Phase Transition in a Proton-Transfer Salt of Squaric Acid and 2,3-Dimethylpyrazine

2019 ◽  
Vol 141 (41) ◽  
pp. 16279-16287 ◽  
Author(s):  
Jeff Lengyel ◽  
Xiaoping Wang ◽  
Eun Sang Choi ◽  
Tiglet Besara ◽  
Rico Schönemann ◽  
...  
Keyword(s):  
Phase Transition ◽  
Proton Transfer ◽  
Squaric Acid ◽  
Antiferroelectric Phase

scholarly journals High Pressure Spectroscopic Investigation on Proton Transfer in Squaric Acid and 4,4′-Bipyridine Co-crystal

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Zhiwei Ma ◽  
Juntao Li ◽  
Chunyu Liu ◽  
Chenglin Sun ◽  
Mi Zhou
Keyword(s):  
High Pressure ◽  
Proton Transfer ◽  
Spectroscopic Investigation ◽  
Squaric Acid

Tunneling proton transfer in biological systems. Role of temperature and pressure

2012 ◽  
Vol 86 (9) ◽  
pp. 1399-1406 ◽  
Author(s):  
L. I. Trakhtenberg ◽  
V. A. Nadtochenko
Keyword(s):  
Proton Transfer ◽  
Biological Systems ◽  
Temperature And Pressure

Proton transfer to the fluorine atom in fluorobenzene. Temperature and pressure dependence

1994 ◽  
Vol 90 (10) ◽  
pp. 1373 ◽  
Author(s):  
Rod S. Mason ◽  
Alyn J. Parry ◽  
Dafydd M. P. Milton
Keyword(s):  
Proton Transfer ◽  
Pressure Dependence ◽  
Fluorine Atom ◽  
Temperature And Pressure

Effect of temperature and pressure on proton transfer rate from a photoacid to ethanol solution

2003 ◽  
Vol 102-103 ◽  
pp. 676-681 ◽  
Author(s):  
Boiko Cohen ◽  
Pavel Leiderman ◽  
Dan Huppert
Keyword(s):  
Proton Transfer ◽  
Transfer Rate ◽  
Ethanol Solution ◽  
Effect Of Temperature ◽  
Temperature And Pressure

Proton-Transfer-Dependent Reversible Phase Changes in the 4,4′-Bipyridinium Salt of Squaric Acid

1994 ◽  
Vol 33 (2) ◽  
pp. 181-183 ◽  
Author(s):  
Manfred T. Reetz ◽  
Sigurd Höger ◽  
Klaus Harms
Keyword(s):  
Proton Transfer ◽  
Phase Changes ◽  
Squaric Acid ◽  
Reversible Phase

scholarly journals Core level crystallography: Probing H-bonding through nitrogen XPS and NEXAFS

2014 ◽  
Vol 70 (a1) ◽  
pp. C560-C560
Author(s):  
Joanna Stevens ◽  
Stephan Byard ◽  
Lauren Newton ◽  
Cherno Jaye ◽  
Colin Seaton ◽  
...  
Keyword(s):  
Proton Transfer ◽  
Photoelectron Spectroscopy ◽  
Disordered Systems ◽  
Structural Information ◽  
Chemical Shifts ◽  
Colour Change ◽  
Squaric Acid ◽  
X Ray ◽  
Bond Lengths ◽  
Donor And Acceptor

Determining the location of hydrogen is not always straightforward, despite its potential for wide-reaching effects, such as altering physicochemical properties and biological/chemical processes. Proton transfer can be considered a simple chemical reaction, with a continuum from neutral to protonated states, and short, strong H-bonds (SSHB) and disordered systems between the two extremes. X-ray Photoelectron Spectroscopy (XPS) and Near Edge X-ray Absorption Fine Structure (NEXAFS) intrinsically probe the local environment, with sensitivity to the chemical state of the atom and, importantly, nature of the local chemical and bonding environment. Organic molecular crystals have been studied by nitrogen XPS and NEXAFS, offering an alternative to X-ray and neutron diffraction. Strong chemical shifts occur with proton transfer to nitrogen (+N-H---O vs. N---H-O), unambiguously characterizing protonated and H-bonded systems,[1] leading to direct observation of an unusual solid-state colour change for 4,4'-bipyridine/squaric acid with heating[2] involving proton transfer to nitrogen with temperature-dependent measurements. Correlation between H-bond lengths and chemical shifts indicates potential for predicting H-bond lengths. SSHBs provide an interesting case, as hydrogen can reside midway between donor and acceptor, having a 3-centre, 4-electron bond with quasi-covalent character and atypical properties. Intermediate chemical shifts are found with hydrogen midway between donor and acceptor in 3,5-pyridinedicarboxylic acid, with increased peak width representative of hydrogen's broadened single minimum potential well.[3] This contrasts with conventional 2-site hydrogen disorder, in which signals from both donor and acceptor environments result in 2 peaks reflecting the % occupancy. Valuable electronic and structural information is obtained from the variety of organic systems investigated, with XPS clearly distinguishing different types of crystallographic materials (Fig 1).

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