STRUCTURE AND THERMAL STABILITY OF THE BENZO-15-CROWN-5 WITH LANTHANUM (III) BROMIDE COMPLEX

Muhammad Idiris Saleh (School of Chemical Sciences, Universiti Sains Malaysia, Penang 11800)
Eny Kusrini (School of Chemical Sciences, Universiti Sains Malaysia, Penang 11800)
Abdulssalam Salhin (School of Chemical Sciences, Universiti Sains Malaysia, Penang 11800)
Rohana Adnan (School of Chemical Sciences, Universiti Sains Malaysia, Penang 11800)
Ismail Ab. Rahman (School of Chemical Sciences, Universiti Sains Malaysia, Penang 11800)
Bahruddin Saad (School of Chemical Sciences, Universiti Sains Malaysia, Penang 11800)
Bohari M. Yamin (School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor)

Indonesian Journal of Chemistry
Vol 4, No 3 (2004)

The reaction of benzo-15-crown-5 (C14H20O5) ligand with La(NO3)3.7H2O in the presence of HBr has resulted in the production of an exotic sandwich complex, [LaC28H36Br4O10][3Br]. The crystal system is triclinic with space group P1, a = 12.5834(14) Å, b = 13.5816(16) Å, c = 13.8403(16) Å, a = 70.751(2)°, b = 66.773(2)° and g = 67.631(2)°. The cation comprises of the lanthanum atom coordinated to two crowns via three oxygen atoms from each crown in a η3-sandwich fashion. The two phenyl groups of the crown are brominated. The La-OLigand bond lengths are between 2.857(7) and 2.949(7) Å. The trianion [3Br]3- is linear with Br-Br bond lengths of 2.518(2) and 2.560(2) Å respectively. The molecule is stabilized by intermolecular interactions of the type C-H...Br to form dimers and are arranged parallel to bc face.