Syntheses, structural determination, and binding studies of nine-coordinate mononuclear (mnH)2[DyIII(Httha)]·3H2O and (enH2)3[DyIII(ttha)]2·9H2O

Abstract

Two dysprosium coordination compounds, (mnH)2[DyIII(Httha)]·3H2O (1) (H6ttha = triethylenetetramine-N,N,N′,N″,N′′′,N′′′-hexaacetic acid and mn = methylamine) and (enH2)3[DyIII(ttha)]2·9H2O (2) (en = ethylenediamine), were synthesized through direct heating and characterized by elemental analysis, FT-IR, thermal analysis, and single-crystal X-ray diffraction. X-ray diffraction analysis displays that 1 is a mononuclear nine-coordinate complex with a pseudo-monocapped square antiprismatic conformation (MCSAP) crystallizing in the monoclinic crystal system with P2(1)/c space group. The crystal data are as follows: a = 16.1363(19) Å, b = 13.9336(11) Å, c = 13.6619(14) Å, β = 102.2490(10)°, and V = 3001.8(5) Å3. There are two kinds of methylamine cation in 1. They connect [DyIII(Httha)]2−and crystal waters through hydrogen bonds, leading to formation of a 2-D ladder-like layer structure. The polymeric 2 also is a nine-coordinate structure with a pseudo-MCSAP crystallizing in the monoclinic crystal system with P2/c space group. The cell dimensions are: a = 17.7801(16) Å, b = 9.7035(10) Å, c = 22.096(2) Å, β = 118.874(2)°, and V = 3338.3(6) Å3. In 2 there are also two types of ethylenediamine cations. One connects three adjacent [DyIII(ttha)]3− complex anions through hydrogen bonds and the other is symmetrical forming hydrogen bonds with two neighboring [DyIII(ttha)]3− complex anions. These hydrogen bonds result in formation of a 2-D ladder-like layer structure as well.