Catalytic Activation of a Carbon–Chloride Bond by Dicationic Tellurium-Based Chalcogen Bond Donors

Synthesis ◽  
2021 ◽  
Author(s):  
Stefan M. Huber ◽  
Tim Steinke ◽  
Patrick Wonner ◽  
Elric Engelage

AbstractNoncovalent interactions such as halogen bonding (XB) and chalcogen bonding (ChB) have gained increased interest over the last decade. Whereas XB-based organocatalysis has been studied in some detail by now, intermolecular ChB catalysis only emerged quite recently. Herein, bidentate cationic tellurium-based chalcogen bond donors are employed in the catalytic chloride abstraction of 1-chloroisochroman. While selenium-based ChB catalysts showed only minor activity in this given benchmark reaction, tellurium-based variants exhibited strong activity, with rate accelerations of up to 40 relative to non-chalogenated reference compounds. In general, the activity of the catalysts improved with weaker coordinating counterions, but tetrafluoroborate took part in a fluoride transfer side reaction. Catalyst stability was confirmed via a fluoro-tagged variant.

2017 ◽  
Author(s):  
Manoj Kumar Kesharwani ◽  
Nitai Sylvetsky ◽  
Debashree Manna ◽  
Jan M.L. Martin

<p>We have re-evaluated the X40x10 benchmark for halogen bonding using conventional and explicitly correlated coupled cluster methods. For the aromatic dimers at small separation, improved CCSD(T)–MP2 “high-level corrections” (HLCs) cause substantial reductions in the dissociation energy. For the bromine and iodine species, (n-1)d subvalence correlation increases dissociation energies, and turns out to be more important for noncovalent interactions than is generally realized. As in previous studies, we find that the most efficient way to obtain HLCs is to combine (T) from conventional CCSD(T) calculations with explicitly correlated CCSD-F12–MP2-F12 differences.</p>


CrystEngComm ◽  
2021 ◽  
Author(s):  
Shouvik Chattopadhyay ◽  
Tanmoy Basak ◽  
Antonio Frontera

Two mononuclear iron(III) complexes, [FeL1Cl]∙CH3CN (1) and [FeL2(N3)] (2) {H2L1= N,N′-bis(5-chlorosalicylidene)diethylenetriamine and H2L2= N,N′-bis(5-bromosalicylidene)diethylenetriamine}, have been synthesized and characterized by X-ray crystallographic studies. In the solid state, there are strong...


2020 ◽  
Author(s):  
Rafael Nunes ◽  
Diogo Vila Viçosa ◽  
Paulo J. Costa

<div>Halogen bonds (HaBs) are noncovalent interactions where halogen atoms act as electrophilic species interacting with Lewis bases. These interactions are relevant in biochemical systems being increasingly explored in drug discovery, mainly to modulate protein–ligand interactions. In this work, we report evidence for the existence of HaB-mediated halogen–phospholipid recognition phenomena as our molecular dynamics simulations support the existence of favorable interactions between halobenzene derivatives and both phosphate (PO) or ester (CO) oxygen acceptors from model phospholipid bilayers, thus providing insights into the role of HaBs in driving the permeation of halogenated drug like molecules across biological membranes. This represents a relevant molecular mechanism, previously overlooked, determining the pharmacological activity of halogenated molecules with implications in drug discovery and development, a place where halogenated molecules account for a significant part of the chemical space. Our data also shows that, as the ubiquitous hydrogen bond, HaBs should be accounted for in the development of membrane permeability models.</div>


2015 ◽  
Vol 71 (10) ◽  
pp. 921-928 ◽  
Author(s):  
Kulsoom Kamal ◽  
Hardesh K. Maurya ◽  
Atul Gupta ◽  
Prema G. Vasudev

The revived interest in halogen bonding as a tool in pharmaceutical cocrystals and drug design has indicated that cyano–halogen interactions could play an important role. The crystal structures of four closely related δ-keto esters, which differ only in the substitution at a single C atom (by H, OMe, Cl and Br), are compared, namely ethyl 2-cyano-5-oxo-5-phenyl-3-(piperidin-1-yl)pent-2-enoate, C19H22N2O3, (1), ethyl 2-cyano-5-(4-methoxyphenyl)-5-oxo-3-(piperidin-1-yl)pent-2-enoate, C20H24N2O4, (2), ethyl 5-(4-chlorophenyl)-2-cyano-5-oxo-3-(piperidin-1-yl)pent-2-enoate, C19H21ClN2O3, (3), and the previously published ethyl 5-(4-bromophenyl)-2-cyano-5-oxo-3-(piperidin-1-yl)pent-2-enoate, C19H21BrN2O3, (4) [Maurya, Vasudev & Gupta (2013).RSC Adv.3, 12955–12962]. The molecular conformations are very similar, while there are differences in the molecular assemblies. Intermolecular C—H...O hydrogen bonds are found to be the primary interactions in the crystal packing and are present in all four structures. The halogenated derivatives have additional aromatic–aromatic interactions and cyano–halogen interactions, further stabilizing the molecular packing. A database analysis of cyano–halogen interactions using the Cambridge Structural Database [CSD; Groom & Allen (2014).Angew. Chem. Int. Ed.53, 662–671] revealed that about 13% of the organic molecular crystals containing both cyano and halogen groups have cyano–halogen interactions in their packing. Three geometric parameters for the C—X...N[triple-bond]C interaction (X = F, Cl, Br or I),viz.the N...Xdistance and the C—X...N and C—N...Xangles, were analysed. The results indicate that all the short cyano–halogen contacts in the CSD can be classified as halogen bonds, which are directional noncovalent interactions.


2019 ◽  
Vol 75 (3) ◽  
pp. 342-347 ◽  
Author(s):  
Aytan R. Asgarova ◽  
Ali N. Khalilov ◽  
Ivan Brito ◽  
Abel M. Maharramov ◽  
Namiq G. Shikhaliyev ◽  
...  

Cooperative action of hydrogen and halogen bonding in the reaction of 3-(3,5-di-tert-butyl-4-hydroxyphenyl)-1-phenylprop-2-en-1-one with HCl or HBr in alcohol medium under microwave irradiation (20 W, 80 °C, 10 min) allows the isolation of the haloetherification products (2S,3S)-3-(3-tert-butyl-5-chloro-4-hydroxyphenyl)-2-chloro-3-ethoxy-1-phenylpropan-1-one, C21H24Cl2O3, (2S,3S)-2-bromo-3-(3-tert-butyl-5-bromo-4-hydroxyphenyl)-3-methoxy-1-phenylpropan-1-one, C20H22Br2O3, and (2S,3S)-2-bromo-3-(3-tert-butyl-5-bromo-4-hydroxyphenyl)-3-ethoxy-1-phenylpropan-1-one, C21H24Br2O3, in good yields. Both types of noncovalent interactions, e.g. hydrogen and halogen bonds, are formed to stabilize the obtained products in the solid state.


2018 ◽  
Author(s):  
Manoj Kumar Kesharwani ◽  
Nitai Sylvetsky ◽  
Debashree Manna ◽  
Jan M.L. Martin

<p>We have re-evaluated the X40x10 benchmark for halogen bonding using conventional and explicitly correlated coupled cluster methods. For the aromatic dimers at small separation, improved CCSD(T)–MP2 “high-level corrections” (HLCs) cause substantial reductions in the dissociation energy. For the bromine and iodine species, (n-1)d subvalence correlation increases dissociation energies, and turns out to be more important for noncovalent interactions than is generally realized; ; (n-1)sp subvalence correlation is much less important. The (n-1)d subvalence term is dominated by core-valence correlation; with the smaller cc-pVDZ-F12-PP and cc-pVTZ-F12-PP basis sets, basis set convergence for the core-core contribution becomes sufficiently erratic that it may compromise results overall. The two factors conspire to generate discrepancies of up to 0.9 kcal/mol (0.16 kcal/mol RMS) between the original X40x10 data and the present revision.</p>


CrystEngComm ◽  
2021 ◽  
Vol 23 (39) ◽  
pp. 6821-6837
Author(s):  
Steve Scheiner

The heavier chalcogen atoms S, Se, and Te can each participate in a range of different noncovalent interactions. They can serve as both proton donor and acceptor in H-bonds. Each atom can also act as electron acceptor in a chalcogen bond.


2021 ◽  
Author(s):  
Rafael Nunes ◽  
Diogo Vila Viçosa ◽  
Paulo J. Costa

<div>Halogen bonds (XBs) are noncovalent interactions where halogen atoms act as electrophilic species interacting with Lewis bases. These interactions are relevant in biochemical systems being increasingly explored in drug discovery, mainly to modulate protein–ligand interactions, but are also found in engineered protein or nucleic acid systems. In this work, we report direct evidence for the existence of XBs in the context of biological membrane systems thus expanding the scope of application of these interactions. Indeed, our molecular dynamics simulations show the presence of favorable interactions between halobenzene derivatives and both phosphate or ester oxygen acceptors from model phospholipid bilayers, thus supporting the existence of XB mediated phospholipid–halogen recognition phenomena influencing the membrane insertion profile of the ligands and their orientational preferences. This represents a relevant interaction, previously overlooked, eventually determining the pharmacological or toxicological activity of halogenated compounds and hence with potential implications in drug discovery and development, a place where such species account for a significant part of the chemical space. We also provide insights into a potential role for XBs in water-to membrane insertion of halogenated ligands as XBs are systematically observed during this process. Therefore, our data strongly suggests that, as the ubiquitous hydrogen bond, XBs should be accounted for in the development of membrane partition models.</div>


Crystals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 71 ◽  
Author(s):  
Mariya Kryukova ◽  
Alexander Sapegin ◽  
Alexander Novikov ◽  
Mikhail Krasavin ◽  
Daniil Ivanov

Stabilization of specific crystal polymorphs of an active pharmaceutical ingredient is crucial for preventing uncontrollable interconversion of various crystalline forms, which affects physicochemical properties as well as physiological activity. Co-crystallization with various excipients is an emerging productive way of achieving such stabilization in the solid state. In this work, we identified an opportunity for co-crystallization of antiviral drug nevirapine (NVP) with a classical XB donor, 1,2,4,5-tetrafluoro-3,6-diiodobenzene (1,4-FIB), as well as 1,3-diiodobenzene (1,3-DIB), which has been seldom employed as an XB donor to date. In the X-ray structures of NVP·1,4-FIB and NVP·1,3-DIB co-crystals, different hydrogen and halogen bonding modes were detected and further investigated via DFT calculations as well as topological analysis of the electron density distribution within the framework of the QTAIM method at the M06/DZP-DKH level of theory. Estimated energies of these supramolecular contacts vary from 0.6 to 5.7 kcal/mol.


Author(s):  
Rui Liu ◽  
Yuan Jun Gao ◽  
Wei Jun Jin

Single-crystal X-ray diffraction reveals a series of phosphorescent cocrystals which were assembled by 1,4-diiodotetrafluorobenzene (1,4-DITFB) and either 4,7-dimethyl-1,10-phenanthroline (DMPhe), 4,7-diphenyl-1,10-phenanthroline (DPPhe) or 4,7-dichloro-1,10-phenanthroline (DClPhe)viaC—I...N halogen bonding. These cocrystals, labeled (1), (2) and (3), respectively, are phosphorescent and a distinct change in phosphorescent color can be observed from orange–yellow, green to yellow–green, with well defined vibrational band maxima at 587, 520 and 611 nm for (1), (2) and (3). Based on the dependence of halogen bonding in sites and strength, we discussed the impact of substituents with different electron-withdrawing effects and steric hindrance on intermolecular noncovalent interactions and phosphorescence. The method of inducing and modulating phosphorescence by halogen bonding and other weak non-covalent interactions through changing the substituent groups of molecules should be significant in both theory and the application of optical function materials with predictable and modulated luminescent properties.


Sign in / Sign up

Export Citation Format

Share Document