NICKEL(2) COMPLEXES OF CYCLIC TETRADENTATE THIOETHERS

Three tetradentate ligands, 1,4,8,11-tetrathiacyclotetradecane (TTP), 2,5,9,12-tetrathiatridecane (TTT), and 13,14-benzo-1,4,8,11-tetrathiacyclopentadecane (TTX), have been prepared. The nickel(II) tetrafluoroborate complexes of these ligands are the first low-spin nickel(II) species reported having four thioethers as donors. Ni(TTP)2+ and Ni(TTX)2+ constitute the first reported complexes of tetradentate macrocyclic ligands containing only sulfur donor atoms. Tetragonal Ni(TTP)X2 species, where X = NCS, CI, Br, and I, have been prepared and their electronic spectra used to calculate a Dqxy of 1070 cm−1 for the macrocycle. The Ni(TTP)I2 complex exhibits behavior in nitromethane solution which is best interpreted as involving two consecutive ionization equilibria. The predominant species is low-spin, five-coordinate Ni(TTP)I+. © 1969, American Chemical Society. All rights reserved.