Issue 12, 1977

Seven-co-ordination in metal complexes of quinquedentate macrocyclic ligands. Part 7. Synthesis and properties of some manganese(II), iron(III), iron(II), zinc(II), and cadmium(II) complexes of an N3O2 macrocycle and the crystal and molecular structure of {2,13-dimethyl-6,9-dioxa-3,12,18-triazabicyclo[12.3.1]octadeca-1(18),2,12,14,16-pentaene}di-isothiocyanatomanganese(II)

Abstract

Reaction of 2,6-diacetylpyridine and 3,6-dioxaoctane-1,8-diamine in methanol in the presence of a stoicheiometric amount of a salt of MnII, FeIII, FeII, ZnII, or CdII gives metal complexes of the 15-membered N3O2 macrocyclic ligand L4 in good yield. Vibrational and electronic spectra as well as electrical-conductance data for solutions provide strong evidence for a seven-co-ordinate, approximately pentagonal-bipyramidal, structure in each case with the macrocycle occupying the pentagonal plane and the axial positions being filled by halide or pseudohalide ion. This is confirmed by a single-crystal X-ray structure determination of the title complex [MnL4(NCS)2] which is triclinic, with a= 13.834(4), b= 7.403(2), c= 10.645(3)Å, α= 91.0(1), β= 71.3(1), γ= 100.8(1)°, Z= 2, space group P[1 with combining macron]. 1427 Independent reflections above background have been measured by counter methods and refined to R 0.075. Metal–nitrogen(macrocycle) distances are 2.244(9), 2.214(8). and 2.254(10)Å and the metal–oxygen distances are 2.296(8) and 2.270(7)Å. The metal–nitrogen(NCS) bond lengths are 2.254(13) and 2.277(13)Å with Mn–N–C bond angles of 130.4(10) and 126.1 (9)°. From magnetic and Mössbauer measurements, the complexes of FeIII, FeII, and MnII are shown to be high-spin. Electrochemical data for the iron and manganese complexes are reported; in the case of the iron complexes the oxidation state II is significantly stabilised relative to that in complexes of the analogous N5 macrocycle.

Article information

Article type
Paper

J. Chem. Soc., Dalton Trans., 1977, 1173-1180

Seven-co-ordination in metal complexes of quinquedentate macrocyclic ligands. Part 7. Synthesis and properties of some manganese(II), iron(III), iron(II), zinc(II), and cadmium(II) complexes of an N3O2 macrocycle and the crystal and molecular structure of {2,13-dimethyl-6,9-dioxa-3,12,18-triazabicyclo[12.3.1]octadeca-1(18),2,12,14,16-pentaene}di-isothiocyanatomanganese(II)

M. G. B. Drew, A. H. bin Othman, S. G. McFall, P. D. A. Mcllroy and S. M. Nelson, J. Chem. Soc., Dalton Trans., 1977, 1173 DOI: 10.1039/DT9770001173

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