Coordination algorithms control molecular architecture (see abstract)

Yanhua Lan, Dietmar K. Kennepohl, Boujemaa Moubaraki, Keith S. Murray, John D. Cashion, Geoffrey B. Jameson, Sally Brooker

Research output: Contribution to journalJournal Articlepeer-review

57 Citations (Scopus)


The synthesis and characterisation of a pyridazine-containing two-armed grid ligand L2 (prepared from one equivalent of 3,6-diformylpyridazine and two equivalents of p-anisidine) and the resulting transition metal (Zn, Cu, Ni, Co, Fe, Mn) complexes (1-9) are reported. Single-crystal X-ray structure determinations revealed that the copper(I) complex had self-assembled as a [2 × 2] grid, [CuI4(L2)4][PF 6]4· (CH3CN)(H2O)(CH 3CH2OCH2CH3)0.25 (2·(CH3CN)(H2O)(CH3CH 2OCH2CH3)0.25), whereas the [Zn 2(L2)2(CH3CN)2(H2O) 2][ClO4]4·CH3CN (1·CH3CN), [NiII2(L2) 2(CH3CN)4][BF4]4· (CH3CH2OCH2CH3)0.25 (5a·(CH3CH2OCH2CH3) 0.25) and [COII2(L2)2(H 2O)2(CH3CN)2][ClO4] 4·(H2O)(CH3CN)0.5 (6a·(H2O)(CH3CN)0.5) complexes adopt a side-by-side architecture; iron(II) forms a monometallic cation binding three L2 ligands, [FeII(L2)3][FeIIICl 3OCl3FeIII]·CH3CN (7·CH3CN). A more soluble salt of the cation of 7, the diamagnetic complex [FeIII(L2)3][BF4] 2· 2H2O (8), was prepared, as well as two derivatives of 2, [CuI2(L2)2(NCS) 2]·H2O (3) and [CuI 2(L2)(NCS)2] (4). The manganese complex, [Mn II2(L2)2Cl4]·3H2O (9), was not structurally characterised, but is proposed to adopt a side-by-side architecture. Variable temperature magnetic susceptibility studies yielded small negative J values for the side-by-side complexes: J = -21.6 cm-1 and g = 2.17 for S = 1 dinickel(II) complex [Ni II2(L2)2(H2O)4][BF4] 4 (5b) (fraction monomer 0.02); J = -7.6 cm-1 and g = 2. 44 for S = 3/2 dicobalt(II) complex [CoII2(L2) 2(H2O)4][ClO4]4 (6b) (fraction monomer 0.02); J = -3.2 cm-1 and g = 1.95 for S = 5/2 dimanganese(II) complex 9 (fraction monomer 0.02). The double salt, mixed valent iron complex 7·H2O gave J = -75 cm-1 and g = 1.81 for the S = 1/2 diiron(III) anion (fraction monomer = 0.025). These parameters are lower than normal for FeIIIOFeIII m species because of fitting of superimposed monomer and dimer susceptibilities arising from trace impurities. The iron(II) centre in 7·H2O is low spin and hence diamagnetic, a fact confirmed by the preparation and characterisation of the simple diamagnetic iron(II) complex 8. Mössbauer measurements at 77 K confirmed that there are two iron sites in 7·H 2O, a low-spin iron(II) site and a high-spin diiron(III) site. A full electrochemical investigation was undertaken for complexes 1, 2, 5b, 6b and 8 and this showed that multiple redox processes are a feature of all of them.

Original languageEnglish
Pages (from-to)3772-3784
Number of pages13
JournalChemistry - A European Journal
Issue number16
Publication statusPublished - 18 Aug. 2003


  • Bridging
  • Electrochemistry
  • Ligand design
  • Ligands
  • Magnetochemistry
  • Self-assembly


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