Mercury complexes with 1,2,6,7-tetracyano-3,5-dihydro-3,5-diiminopyrrolizinide

摘要

The anion 2-(5-amino-3,4-dicyano-2H-pyrrol-2-ylidene)-1,1,2-tricyanoethanide (L', C_(11)H_2N_7~-), after isomerization to 1,2,6,7-tetracyano-3,5-dihydro-3,5-diimino-pyrrolizinide (L), forms different metal-complexes with mercury depending on the experimental conditions. Pure compounds were isolated from the reactions HL + CH_3HgAc in CH_3CN and NaL' + HgAc_2 in AcCH/H_2O. They are CH_3HgL and HgL_2. From their optical spectra, compared to those of phthalocyaninato- or other well-known pyrrolizinato-complexes, the coordination geometry of Hg(II) in these species is supposed to be trigonal planar and trigonal monopyramidal, respectively. CH_3HgL was characterized also by ~1H NMR: (CO_3CN, #delta#, ppm) 0.886 (CH_3), 8.733 (NH). From the reactions in water between NaL' and HgCl_2 or HgClO_4 complex mixtures of polynuclear complexes were isolated of composition: 0.826 [Hg_2ClL_2(OH)] centre dot 0.174 [Hg_4L_3(OH)_5] centre dot 2.06 H_2O (A) or 0.588 [Hg_2L_2] centre dot 0.412 [HgL(OH)_3] centre dot 3.35 H_2O (B), respectively. The formulae A and B were based on thermogravimetric and elemental analysis data. Indirect evidences, based on XPS data, for the existence of the pyrrolizinato-Hg(I) complex are also given.