Crystal Structure of [Cu₂(Edta)(Py)₂(H₂O)₂] 2H₂O
and [Cu(Im)₆]{Cu(Im)₄[Cu(Edta)(Im)]₂} 6H₂O,
Products of the Interaction
of (Ethylenediaminetetraacetato)diaquadicopper(II)
with Pyridine and Imidazole

A. S. Antsyshkina*, G. G. Sadikov*, A. L. Poznyak**, and V. S. Sergienko*

* Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences,
Leninskii pr. 31, Moscow, 119991 Russia

** Institute of Molecular and Atomic Physics, National Academy of Sciences of Belarus,
ul. F. Skaryna, Minsk, 220072 Belarus

Received June 27, 2005

Abstract—The crystals of [Cu₂(Edta)(Py)₂(H₂O)₂] · 2H₂O (I) and [Cu(Im)₆]{Cu(Im)₄[Cu(Edta)(Im)]₂} ·
6H₂O (II) were isolated as a result of the reaction of an aqueous solution of Cu₂(Edta) · 4H₂O with pyridine or
imidazole, respectively. The crystals were studied by X-ray diffraction. The crystals of I are monoclinic, a =
12.682 Å, b = 6.788 Å, c = 14.834 Å, = 91.44, Z = 2, space group P2₁/n. The crystals of II are triclinic, a =
9.118 Å, b = 14.889 Å, c = 15.130 Å, = 72.59, = 72.94, = 82.54, Z = 1, space group P . In the cen-
trosymmetric binuclear complex molecule of I, an N atom and two O atoms of the Edta ligand are coordinated
to each Cu atom (Cu–N, 2.046 Å; Cu–O, 1.941 and 1.954 Å). The N atom of the pyridine molecule (Cu–N,
1.993 Å) completes the base of an elongated tetragonal pyramid (4 + 1) with the O atom of the H₂O molecule
in the apex (Cu–O(w), 2.244 Å). The crystals of II are built of centrosymmetric complex cations [Cu(Im)₆]²⁺
(Cu(1)–N, 2.469, 2.021, and 2.056 Å), centrosymmetric trinuclear complex anions
{Cu(Im)₄[Cu(Edta)(Im)]₂}², and crystal water molecules. In the anion, the central fragment [Cu(Im)₄]²⁺
(Cu(2)–N, 1.985 and 2.023 Å) is bonded to two peripheral complexes [Cu(Edta)(Im)]^2– through atoms O of the
Edta ligand (Cu(2)–O, 2.615 Å). In the [Cu(Edta)(Im)]^2– fragment of the complex anion, the Cu(3) atom is
bonded to the Edta ligand through the two N atoms and three O atoms (Cu(3)–N, 1.970 and 2.071 Å; Cu(3)–O,
1.966, 1.969, and 2.238 Å) and with the imidazole molecule, through an N atom (Cu(3)–N, 2.397 Å). The coor-
dination polyhedra of the three copper atoms (Cu(1)–Cu(3)) in the structure of II are elongated tetragonal bipyr-
amids (4 + 2). In the structures studied, Edta^4– is a hexadentate chelating/bridging ligand. However, the coor-
dination mode of the ligand in these structures is different: in the binuclear complex I, the Edta ligand is coor-
dinated to each Cu atom through an N atom and two O atoms with the formation of two chelate rings
(symmetric (trans) coordination mode), whereas, in the trinuclear complex II, the Edta ligand is coordinated to
the Cu(2) atom through an O atom and to the Cu(3) atom through the two N atoms and three O atoms with the
formation of three chelate rings (asymmetric (cis) coordination mode).

Pleiades Publishing home page | journal home page | top

If you have any problems with this server, contact webmaster.