Preparation and structural characterization of mercury 21-thiaporphyrin complex: HgII(Stpp)Cl (Stpp=tetraphenyl-21-thiaporphyrin anion)

Treatment of tetraphenyl-21-thiaporphyrin (StppH) with Hg(OAc)2 in CH2Cl2 yields diamagnetic HgII(Stpp)Cl complex. The coordination sphere around Hg2+ in the monomeric molecule is described as a five-coordinate distorted trigonal bipyramid with the bonding to the three pyrrole nitrogens [Hg(1)–N=2.104(4), 2.626(4), 2.640(4) Å], the thiophene sulfur [Hg(1)–S=2.801(1) Å], and one axial chloride ligand [Hg(1)–Cl(1)=2.318(1) Å]. The plane of the three pyrrole nitrogen atoms [i.e., N(1), N(2), N(3)] bonded to Hg2+ is adopted as a reference plane 3N. Because of its larger size, the Hg2+ is considerably out of the 3N plane; its displacement of 1.41 Å is in the same direction as that of the apical Cl− ligand. The thiophene ring is slightly folded so that the dihedral angle between the C(13)–C(14)–C(15)–C(16) and C(13)–S(1)–C(16) planes is 7.3°.