Synthesis and structural studies on three-dimensionally hydrogen-bonded metal perchlorate complexes with 1,3-dimethyllumazine and 1,3,6,7-tetramethyllumazine. Crystal structure of diaqua-bis(1,3,6,7-tetramethyl-pteridine2,4(1 H,3 H)-dione-O 4,N 5) copper(II) perchlorate dihydrate

• Published in: Inorganica Chimica Acta Vol. 268; no. 1; pp. 77 - 83
• Main Authors: Hueso-Ureña, Francisco, Jiménez-Pulido, Sonia B., Moreno-Carretero, Miguel N., Quirós-Olozábal, Miguel, Salas-Peregrín, Juan M.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 03-02-1998
• Subjects: Crystal structures; Lumazine complexes; Metal complexes; Pteridine complexes; Crystal structures; Pteridine complexes; Metal complexes; Lumazine complexes
• ISSN: 0020-1693; 1873-3255
• DOI: 10.1016/S0020-1693(97)05722-8

In aqueous solution, M
II(ClO
4)
2 (Mn  Mn, Co, Ni, Cu, Zn, Cd and Hg) reacted with 1.3-dimethyllumazine 9DLM) and 1,3,6,7-tetramethyllumazine (DLMD) (lumazine = (1
H,3
H)-pteridin-2,4-dione) to give complexes with general formula Mp
II(ClO
4)
2(LM)
2 ·
nH
2O. These compounds have been characterized by means of the analytical techniques (elemental analysis and thermogravimetry), spectral methods (IR,
13C and
1H NMR, UV-VIS-NIR, electron paramagnetic resonance) and magnetic measurements (77–290 K). Single-crystal X-ray diffraction studies have been made on the complex [Cu(DLMD)
2(H
2O)
2](ClO
4)
2·2H
2O. This compound crystallizes in the monoclinic system.
P2
1/
c space group,
Z = 2, with
a = 8.764(1), b = 13.7932(8), c = 14.792(1)
A
̊
, β = 116.02(1)°, V = 1602.9(3)
A
̊
3
, and
R = 0.0728 for 4648 independent reflections and 224 parameters. The metal ion occupies an center and exhibits a distorted octahedral coordination. The coordination octahedron is flattened, the equatorial plane consisting of two N(5) and two O(4) atoms of pteridine ligands: the two axial sites are occupied by two oxygen atoms from the coordinated water molecules. The monomeric units together with non-coordinated water molecules and perchlorate anions are involved in a complex three-dimensional H-bonds network, the pteridine moieties being packed following planes roughly parallel to
b axis, and perpendicular to the [5 4 21] direction. These planes are separated by a mean distance of 7.3 Å.