Find in Library

The title compound, C25H18F4P+·Br−·C2F4I2, is a 1:1 co-crystal of triphenyl(2,3,5,6-tetrafluorobenzyl)phosphonium (TTPB) bromide and 1,1,2,2-tetrafluoro-1,2-diiodoethane (TFDIE). The crystal structure consists of a framework of TTPB cations held together by C—H...Br interactions. In this framework, infinite channels along [100] are filled by TFDIE molecules held together in infinite ribbons by short F...F [2.863 (2)–2.901 (2)Å] interactions. The structure contains halogen bonds (XB) and hydrogen bonds (HB) in the bromide coordination sphere. TFDIE functions as a monodentate XB donor as only one I atom is linked to the Br− anion and forms a short and directional interaction [I...Br− 3.1798 (7) Å and C—I...Br− 177.76 (5)°]. The coordination sphere of the bromide anion is completed by two short HBs of about 2.8 Å (for H...Br) with the acidic methylene H atoms and two longer HBs of about 3.0 Å with H atoms of the phenyl rings. Surprisingly neither the second iodine atom of TFDIE nor the H atom on the tetrafluorophenyl group make any short contacts.