Naslov
Comparison of 1,3- and 1,4-diiodotetrafluorobenzene as halogen bond donors in crystal engineering

Autori
Bedeković, Nikola ; Stilinović, Vladimir ; Friščić, Tomislav ; Cinčić, Dominik

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
6th International School of Crystallography / Ruiz, Juan M. G. ; Morales, Jamie G. ; Lazarte, Duane C. ; Caballero, Alfonso G. ; Escamilla, Cristóbal V. ; Griesser, Ulrich ; Falini, Giuseppe - Granada, 2018, 145-145

Skup
6th International School of Crystallography

Mjesto i datum
Granada, Španjolska, 21.05.2018. - 25.05.2018

Vrsta sudjelovanja
Poster

Vrsta recenzije
Nije recenziran

Ključne riječi
halogen bonding

Sažetak
Halogen bond (XB) is an attractive noncovalent interaction between chemical entity with usually covalently bonded and partially positively charged Br or I atom (halogen bond donor) and some Lewis base.1 Positively charged domain on the halogen atom (known as -hole) steadily is formed in the continuation of the covalent bond, what makes halogen bond strong and directional interaction which also has attracted considerable attention of the solid state chemists, who recognized possibility of its application for synthesis of the new materials. The most usual halogen bond donors in solid state chemistry are perhalogenated hydrocarbons, of which 1, 4- diiodotetrafluorobenzene is probably the most extensively used halogen bond donor to date. On the contrary, its meta-isomer (1, 3-tfib) has remained almost completely unexplored (18 crystal structures in CSD).2 Herein, 3 we provide a systematic investigation of the structures and composition of halogen-bonded cocrystals involving the bent (meta) halogen bond donor 1, 3- diiodotetrafluorobenzene (1, 3-tfib), in comparison to analogous systems based on its linear (para) 1, 4-isomer. This study investigates the structures of 14 new cocrystals of 1, 3-tfib and 9 new, analogous cocrystals of 1, 4-tfib, with 9 monotopic and 7 ditopic nitrogen-based aliphatic and aromatic halogen bond acceptors. In particular, whereas our comparative study of 1, 3- tfib and 1, 4-tfib cocrystals with used halogen bond acceptors reveals a similarity in I···N halogen bond lengths and distribution of melting points of explored cocrystals, it also reveals differences in stoichiometric compositions of cocrystals and the structures of underlying halogen-bonded motifs (both halogen bond donors form topologically equivalent chains when combined with ditopic halogen bond acceptors, but with monotopic acceptors 1, 4-tfib preferably forms cocrystals of 2:1 stoichiometry, while 1, 3-tfib forms predominantly 1:1 complexes). Tentatively, the herein observed differences in halogen-bonded motifs and cocrystal composition are explained through changes in the efficiency of crystal packing upon switching from a linear halogen bond donor to the bent 1, 3-tfib. This implies that, at least in some cases, close packing, rather than halogen bonding strength may be the force that determines the supramolecular architecture and stoichiometric composition of the final the product.

Izvorni jezik
Engleski

Znanstvena područja
Kemija

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