Studies of Some Tetraazacyclopentadecadiene Complexes of Nickel(II). The Crystal and Molecular-Structure of (1RS,8SR)-(5,7,7,13,15,15-Hexamethyl-1,4,8,12-Tetraazacyclopentadeca-4,1 2-Diene)Nickel(II) Perchlorate Hydrate

Abstract

The crystal and molecular structure has been determined by X-ray diffractometry for the singlet ground state nickel(II) compound of a fifteen- membered tetraaza macrocyclic ligand , formed by reaction of a mixture of tris ( ethanediamine )nickel(II) and tris (propane-1,3- diamine )nickel(II) perchlorates with acetone. The compound, (1RS,8SR)- 5,7,7,13,15,15-hexamethyl-1,4,8,12-tetraazacyclopentadeca-4,12- diene )nickel(II) perchlorate hydrate, [Ni( hmpd )](ClO₄)₂.H₂O, is monoclinic, space group P2₁/C, a 1158.76(14), b 1319.53(22), c 1630.35(21) pm, β 96.209(10)°, R 0.046, R_w 0.062 for 2798 reflections. The nickel(II) ion is in tetrahedrally distorted square-planar coordination [mean Ni-N distances 188.9 pm ( imine ), 191.9 pm (amine), displacements of nitrogens c. ±20 pm from mean coordination plane]. Triplet ground state compounds [Ni( hmpd )( acac )]ClO₄ and [{Ni( hmpd )}₂C₂O₄](ClO₄)₂, with the macrocycle in folded coordination, were prepared and converted into an isomeric form of [Ni( hmpd )](ClO₄)₂. The 3,5,7,7,13,15,15-heptamethyl homologue of [Ni( hmpd )]²⁺ was prepared by reaction of tris (propane-1,2-diamine)- and tris (propane-1,3-diamine)- nickel(II) perchlorates with acetone. The electronic (d-d), ¹H N.M.R. and ¹³C N.M.R . spectra of compounds of these macrocyclic cations, and of (5,5,7,13,15,15-hexamethyl-1,4,8,12-tetraazacyclopentadeca-7,12-diene) nickel(II) are reported.