THE PREPARATION AND KINETICS OF AQUATION OF DIASTEREOISOMERIC COMPLEXES OF-TRANS-[CR(ME-8[14]ANEN(4))CL-2](-8[14]ANEN(4) = 4-OCTAMETHYL-1,4,8,11-TETRA-AZACYCLOTETRADECANE)() (ME)

1,2-Propanediamine monohydroperchlorate reacts with acetone to give th e dihydroperchlorate salt of ethyl-1,4,8,11-tetra-azacyclotetradeca-4, 11-diene, Me-8[14]dieneN(4). The reaction is stereospecific giving onl y the 3,10-C-meso diastereoisomer (L-1). Reduction of L-1 with NaBH4 i n methanol-water solution gives three isomeric Me-8[14]aneN(4) ligands (L-A, L-B and L-C). These saturated macrocycles give green trans-[CrL Cl2](+) complexes which have been characterised by infrared and visibl e spectra. The red chloroaqua complexes trans-[CrL(OH2)Cl]Cl-2 . H2O . H2SO4 have also been prepared and characterised. The aquation of the dichloro-complexes to the chloro-aqua derivatives has been studied kin etically over a temperature range and rate constants (k(aq)) and activ ation parameters are reported. The substantial negative values of Delt a S double dagger observed are consistent with an associative I-a mech anism. (C) 1998 Elsevier Science Ltd. All rights reserved.