HETERODINUCLEAR CUIIPBII AND CUIIMII (M = MN, FE, CO, NI, CU, ZN) COMPLEXES OF MACROCYCLES WITH DISSIMILAR 4-COORDINATION AND 5-COORDINATION SITES - SYNTHESIS, STRUCTURES, AND PROPERTIES

Heterodinucleating macrocycles with two 2,6-bis(iminomethyl)-4-methylphenolate entities combined through two lateral chains, -(CH2)2- and -(CH2)mNH(CH2)m- (m = 2, 3), at the imino nitrogens have been prepared as Cu(II)Pb(II) complexes of the formula [CuPb(L)]XY (L2- = L1 for m = 2 and L2 for m = 3; XY = (ClO4)2, (NO3)(PF6), (AcO)(BPh4)). [CuPb(L1)](AcO)(BPh4)-DMF crystallizes in the monoclinic crystal system, space group P2(1)/n, with Z = 4, a = 18.890(3)angstrom, b = 19.968(3)angstrom, c = 12.704(2)angstrom, beta = 91.61(l)-degrees, and V = 4790(1)angstrom3. The refinement converges with R = 0.0697 and R(w) = 0.0863 for 4945 reflections with \F(o)\ > 3sigma(\F(o)\). The crystal consists of a dimeric cation {CuPb(L1)(Ac)}2/2+ bridged by acetate groups, tetraphenylborate ions, and DMF molecules. The Cu is located at the 4-coordination site formed with the ethylene chain and assumes a planar environment. The Pb is at the 5-coordination site formed with the -(CH2)2NH(CH2)2-chain and assumes an eight-coordinate structure also involving three acetate oxygen atoms. The Cu- -Pb separation, bridged by two phenolic oxygens, is 3.577(2) A. In the crystal, the dimeric cations further interact through out-of-plane bonding between the {CuN2O2} entities forming a column along the a axis. The [CuPb(L1)]XY complexes react with metal(II) sulfates to form a series of Cu(II)M(II) complexes, [CuM(L1)]XY (M = Mn, Fe, Co, Ni, Cu, Zn). [CuMn(Ll)](AcO)(BPh4)crystallizes in the monoclinic space group P2(1)/n, with Z = 4, a = 17.508(8) angstrom, b = 15.539(5) angstrom, c = 16.515(5) angstrom, beta = 106.30(3)-degrees, and V = 4312(3) angstrom3. The refinement converges with R = 0.0689 and R(w) = 0.0563 for 2935 reflections with \F(o)\ > 3sigma(\F(o)\). The Cu(II) and Mn(II) ions reside at the 4- and 5-coordination sites of the macrocycle, respectively, and the acetate group bridges the two metal ions providing a nearly square-pyramidal geometry for the Cu and a highly distorted six-coordinate environment for the Mn. The Cu- -Mn separation is 3.122(2) angstrom. The cryomagnetic investigations (4.2-300 K) for the CuMn, CuFe, CuCo, CuNi, and CuCu complexes reveal the operation of an antiferromagnetic spin-exchange interaction within each molecule. The cyclic voltammograms of the CuM complexes show Cu(II)/Cu(I) reduction near-0.8 V (vs SCE) and oxidation at the ligand center near + 1.3 V. The oxidation of the Fe(II) of the CuFe complex occurs at +0.64 V whereas the Mn(II) ion of the CuMn complex and the Co(II) ion of the CuCo complex are hardly oxidized.