Compounds of nickel(II) with 5RS,7RS,12SR,14SR-5,12-dimethyl-7,14-diphenyl-1,4,8,11-tetraazacyclotetradecane, mmL2; the structures of δ-[Ni(mmL2)](ClO4)2, trans-β-[Ni(mmL2)(NO2-N)2] and cis-α-[Ni(mmL2)(acac)]ClO4
作者:Donald F Cook、Neil F Curtis、Clifton E.F Rickard、Joyce M Waters、David C Weatherburn
DOI:10.1016/s0020-1693(03)00226-3
日期:2003.11
Reduction of the imine functions of 7RS,14SR-(5,12-dimethyl-7,14-diphenyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene)-nickel(II) gives the meso-meso (5RS,7RS,12SR,14SR) and rac-meso (5RS,7RS,12RS,14SR) isomers of (5,12-dimethyl-7,14-diphenyl-1,4,8,11-tetraazacyclotetradecane)nickel(II), [Ni(mmL(2))](2+) and [Ni(rmL(2))](2+), in approximately 6:1 proportions. Most compounds of [Ni(mmL(2))](2+) have the arnine in planar coordination with the 1RS, 4RS, 8SR, 11SR N-configuration III (labelled beta) of the nitrogen centres as square-planar singlet ground state salts beta-[Ni(mmL(2))]X-2 (X- = ClO4-, 1/2[ZnCl4](2-)) or as octahedral triplet ground state compounds trans-beta-[Ni(mmL(2))X-2] (X- = Cl-, Br-, I-, N-3(-) NO3-, HCO3-, MeCO3-, NCS-, NO2-, CN-), trans-beta-Ni(mmL(2))(CN)(ClO4), bis-adducts trans-beta-[Ni(mmL(2))Y-2]ClO4)(2) (Y = MeCN, DMSO, DMF, pyridine, MeNO2, NH3) and trans-mu-anion polymeric compounds [beta-Ni(mmL(2))Z] (Z(2-) = C2O42-, SO42-, CO32-, [Ni(CN)(4)](2-)). Centrosymmetrical trans-beta-[Ni(mmL(2))(NO2-N)(2)] has N-configuration III, with all chelate rings in optimum chair or gauche conformations, with all substituents equatorially oriented and with mean distances Ni-N-amine = 2.083(2), Ni-N-nitro = 2.183(2) Angstrom. Reaction of trans-beta-[Ni(mmL(2))(HCO3)(2)].H2O with alcohols form compounds of mono-alkyl carbonate esters, trans-beta-[Ni(mmL(2))(CO2OR)(2)]. Compounds cis-alpha-[Ni(mmL(2))(A)]ClO4 (A= pentane-2,4-dionato(-), 1/2C(2)O(4)(2-) have the macrocycle folded. The acac(-) compound has the 1RS, 4RS, 8RS, 11RS N-configuration V with mean distances Ni-N 2.121(3), Ni-O = 2.042(3) Angstrom and angles N(4)-Ni-N(11 1) = 173.2(1), N(1)-Ni-N(8) = 95.1(1)degrees, with one six-membered chelate ring in a chair conformation with the substituents equatorially oriented and the other in a boat conformation that orients the substituents pseudo-equatorially. The folded macrocycle compounds react with acid to form a metastable [Ni(mmL(2))](2+) cation, isolated as the perchlorate salt delta-[Ni(mmL(2))](ClO4)(2) with the 1RS,4RS,5SR,7SR,8SR,11RS,12RS,14RS configuration, N-configuration II. The square-planar cation is tetrahedrally twisted with N-atoms +/-0.103 Angstrom and Ni atom 0.043 Angstrom from the best N-4 plane, with mean Ni-N = 1.933(6) Angstrom. One six-membered chelate ring is in a chair conformation with the substituents equatorially oriented, and the other in a twist conformation with the methyl substituent axially and the phenyl substituent equatorially oriented. Relative strain energies for the isomeric cations were calculated by molecular mechanics. (C) 2003 Published by Elsevier B.V.