COPPER(II) AND NICKEL(II) COMPLEXES OF DIANIONIC AND TETRAANIONIC DINUCLEATING MACROCYCLES

With nickel(II) or copper(II) acetate, 2,6-bis(acetoximato)-4-methylph enol (H(2)Damox) and 2,6-bis(acetoximato)4-tert-butylphenol (H(2)Dabox ) afford molecular dinuclear complexes [Cu-2(Damox)(2)] (1), [Ni-2(Dam ox)(2)]MeOH)(2)]. MeOH (2), [Cu-2(Dabox)(2)] (5) and [Ni-2(Dabox)(2)(H 2O)(2)] (6). Salts of the macrocyclic tetraimine copper chelates from diacetylcresol with 1,3-diaminopropane and 1,4-diaminobutane, [Cu-2(Da mpn)](2+) and [Cu-2(Dambn)](2+), were also examined. Pyridine solution s of 2 yielded pink crystals of [Ni-2(Damox)(2)(Py)(4)].(Py)(2) (3a), which effloresce pyridine to form [Ni-2(Damox)(2)(Py)(2)]. Py (3). The pseudomacrocyclic complexes 1, 5, and 6 react with BF3 . Et2O to form BF2-bridged macrocyclic complexes [Cu-2(Damfb)] (4), [Cu-2(Dabfb)]. H 2O (7), and [Ni-2(Dabfb)] (8). Crystals of [Ni-2(Damox)(2)(Py)(4)].(Py )(2) (3a) are monoclinic (space group P2(1)/n), with a = 13.297(5) Ang strom, b = 11.240(5) Angstrom, c = 17.396(6) Angstrom, beta = 109.03 d egrees, V = 2458(3) Angstrom(3), Z = 2, R = 0.050, and R-w = 0.052. Th e [Ni-2(Dabfb] (8) crystals an orthorhombic (space group Pnma), with a = 11.558(6) Angstrom, b = 17.200(5) Angstrom, c = 16.058(2) Angstrom, V = 3192(3) Angstrom(3), Z = 4, R = 0.057, and R-w = 0.057. The saddl e-shaped molecules of 8 contain low-spin Ni(II). The copper(II) center s in 1, 5, 6, etc., are strongly antiferromagnetically coupled with -2 J values in the range 550-800 cm(-1). The nickel(II) centers in 2 and 3 are weakly (-2J = 3.2 cm(-1)) or moderately (-2J = 19.5 cm(-1)) anti ferromagnetically coupled, whereas 6 shows a moderate ferromagnetic in teraction with -2J = -5.1 cm(-1), All the complexes are electrochemica lly reducible in two 1-electron steps. In CH3CN, the mixed-valence com plexes [Cu-2(Dampn)](+) and [Cu-2(Dambn)](+) are valence-localized. Th e nature of the carbon monoxide interactions with the M(I) centers is dearest for [Cu-2(Dambn)](+/0), which in dimethylformamide solution bi nds two molecules of CO in a cooperative fashion.