annual report annual report annual report annual report 2005

96
RADIOCHEMISTRY, STABLE ISOTOPES,
NUCLEAR ANALYTICAL METHODS, GENERAL CHEMISTRY
the packing diagram, Fig.3 – the coordination
around the barium(II) ion. A network of hydrogen
bonds is responsible for the stability of the crystal.
X-ray diffraction data collection was carried out
on a KUMA KM4 four circle diffractometer at the
Institute of Nuclear Chemistry and Technology.
Structure solution and refinement was performed
using SHELXL programme package.
Fig.3. The coordination around the barium(II) ion in the
structure of Ba[H(4,5-IDA)] 2
(H 2
O) 4·2H 2
O.
CRYSTAL CHEMISTRY OF COORDINATION COMPOUNDS
WITH HETEROCYCLIC CARBOXYLATE LIGANDS.
PART LIX. THE CRYSTAL STRUCTURE OF A CALCIUM(II) COMPLEX
WITH PYRIDAZINE-3-CARBOXYLATE AND WATER LIGANDS
Wojciech Starosta, Janusz Leciejewicz
The crystals of bis[(µ 2 -pyridazine-3-carboxylato-
-N,O, O’)-trisaqua-calcium(II)] are monoclinic,
Fig. The centrosymmetrical dimeric molecule of
Ca 2 (C 5 H 3 N 2 O 2 ) 4 (H 2 O) 6 with atom labelling scheme.
Unlabelled atoms are related by the symmetry code:
-x+1, -y+2, -z+1. Displacement ellipsoids are drawn
at the 50% probability level.
space group P2 1 /n with a=9.173(1) Å, b=10.539(2)
Å, c=14.984(3) Å, β=99.43(3) o and Z=4. The structure
contains centrosymmetric dimeric molecules
composed of two calcium(II) ions, each coordinated
by two pyridazine-3-carboxylate ligand molecules
(Ca 2
(C 5
H 3
N 2
O 2
) 4
(H 2
O) 6
) via their N,O bonding
moieties [Ca-O11 2.432(1) Å, Ca-N11 2.585(1) Å;
Ca-O21 2.404(1) Å, Ca-N21 2.606(1) Å] and three
water molecules [mean Ca-O 2.389(1) Å]. The calcium
ions are bridged by two carboxylate oxygen
atoms, each acting in a bidentate mode donated
by ligand molecules coordinated to different metal
ions forming a bridging path Ca-O11-Ca I (Fig.).
The coordination number of the calcium(II) ion is
eight, the coordination polyhedron is a strongly
deformed decahedron. Coordinated water molecules
participate in a hydrogen bond network linking
the dimers.
X-ray diffraction data collection was carried out
on a KUMA KM4 four circle diffractometer at the
Institute of Nuclear Chemistry and Technology.
Structure solution and refinement was performed
using SHELXL programme package