Structural and spectroscopic characterisation of the holmium double-decker partially oxidised and bi-radical phthalocyanine complexes with iodine

摘要

Two crystals of holmium(III) double-decker iodine doped phthalocyanines, HoPc_2I_(5/3) (I) and HoPc_2I (II), were grown directly in the reaction of holmium chips with 1,2-dicyanobenzene under versatile quantity of iodine at 180-160 °C. The complex I crystallises in the P4/mcc space group of tetragonal system, while the complex II crystallises in the P2/c space group of monoclinic system. The space group of P4/mcc and z=1 requires that the Ho(III) atom is statistically disordered in the HoPc _2I_(5/3) structure. The iodine atoms form linear symmetrical triiodide I_3~- ions in I, while the I~- ions in II. Assignment of iodine species as I_3in the HoPc_2I _(5/3) and I~- in HoPc_2I complexes point to the +5/9 and +1 oxidation state of the HoPc_2 unit in these complexes. Thus one Pc macrocycle of the double-decker HoPc_2 units has a non-integer oxidation state of-1.222 in I, while both Pc-rings are one-electron oxidised radical Pc~- in II. Magnetic susceptibilities of HoPc _2I_(5/3) and HoPcI at room temperature are 4.56 × 10~(-2) and 5.12 × 10~(-2) emu/mol and the calculated magnetic moments are 10.46 and 11.08 μ_B, respectively. UV-Vis spectroscopic measurement of I and II in benzene solution were carried out and discussed.