engleski

Supramolecular architectures of halogen bonded cocrystals containing CoCl2L2 metal-organic units

The assembly of metal-organic units is an attractive target for crystal engineering by halogen bonding, due to their potential to provide new magnetic, optical or electrical properties [1]. Herein we present CoCl2L2 complexes (L = 1, 10 phenantroline, phen, or 2, 2’ bipyridine, bpy) as halogen bond acceptors and show their potential as building blocks for the construction of multicomponent materials by both liquid assisted grinding and conventional solution-based method. For cocrystal synthesis we selected commonly used, perfluorinated halogen bond donors: iodopentafluorobenzene (ipfb), 1, 4- diiodotetrafluorobenzene (14tfib), 1, 3- diiodotetrafluorobenzene (13tfib), 1, 2- diiodotetrafluorobenzene (12tfib), 1, 1, 2, 2, 3, 3, 4, 4-octafluoro-1, 4-diiodobutane (ofib) and 1, 3, 5-trifluoro-2, 4, 6-triiodobenzene (135tfib). Single crystal X-ray diffraction experiments have shown that cocrystals display different supramolecular architectures governed by Cl···I halogen bonds between halogen bond donor iodine atoms and metal complex chlorine atoms (varying from 3.088 to 3.471 Å). Halogen bonded architectures in the cocrystal can be grouped into discrete molecular complexes (0D), chains (1D), two- and three-dimensional networks (2D and 3D). As expected, discrete complexes are formed using ipfb, a monotopic halogen bond donor, as well as 12tfib, a ditopic donor. Halogen bonded chains were found in cocrystals with ditopic donors (14tfib, 13tfib, ofib) as well as with 135tfib, tritopic halogen bond donor. 2D and 3D networks are formed only using ditopic halogen bond donors 13tfib and ofib. In all cocrystals halogen bonded aggregates are further connected by C-H···F, C- H···Cl, C-H···C, C-H···I, C-F···C, I···C or I···I contacts.

cobalt(II), crystal engineering, halogen bonding, metal complexes

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