COMPLEMENTARITY AND INTERNAL CONSISTENCY BETWEEN MAGNETIC AND OPTICAL-PROPERTIES FOR THE MNIICUII HETERODINUCLEAR COMPOUND [MN(ME6-[14]ANE-N4)CU(OXPN)](CF3SO3)2 (ME6-[14]ANE-N4 = (+ 14,14-HEXAMETHYL-1,4,8,11-TETRAAZACYCLOTETRADECANE - OXPN = N,N'-BIS(3-AMINOPROPYL)OXAMIDE)/

A heterodinuclear compound of formula [Mn(Me6-[14]ane-N4)Cu(oxpn)](CF3 SO3)2 (hereafter abbreviated as MnCu), with Me6-[14]ane-N4 standing fo r 14,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane and oxpn for N,N' -bis(3-aminopropyl)oxamide, has been synthesized. Its crystal structur e has been solved. It crystallizes in the monoclinic system, space gro up P2(1)/a. The lattice parameters are a = 17.781(7) angstrom, b = 18. 202(5) angstrom, c = 12.893(4) angstrom, and beta = 105.48(3)-degrees with Z = 4. Its structure consists of oxamido-bridged Mn(II)Cu(II) dic ations and noncoordinated triflate anions. The Mn(II) ion is in distor ted octahedral surroundings, and the Cu(II) ion in square-planar surro undings. The intramolecular Mn --- Cu separation is equal to 5.436 ang strom. The temperature dependence of the magnetic susceptibility has b een investigated in the 300-2 K range and has revealed a ground quinte t-excited septet energy gap of 3J = -93.9 cm-1. It has also indicated that the zero-field splitting within the quintet state was too small t o be detected from the magnetic data. Both NMR and EPR properties have been investigated. The NMR spectrum in CD3CN solution is poorly resol ved. The X-band powder EPR study has allowed the estimation of values of the axial and rhombic zero-field splitting parameters within the S = 2 state. The absorption properties of MnCu have also been investigat ed. The main feature of the spectrum is a sharp and intense band corre sponding to the 6A1 --> 4A1 + 4E spin-forbidden transition for Mn(II) activated by an exchange mechanism. The temperature dependence of the intensity of this band has offered an alternative method to determine the quintet-septet energy gap.