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25th Croatian meeting of chemists and chemical engineers, Poreč, 2017.
Stereochemistry of hexacoordinated transition metal complexes with
iminodiacetamide ligands
Stereokemija heksakoordiniranih kompleksa prijelaznih metala s
iminodiacetamidnim ligandima
Natalija P. Juraj,1 Neven Smrečki2, Zora Popovic2, Berislav Perić1, Srećko I. Kirin1,*
1
Division of Materials Chemistry, Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia
2
Laboratory of General and Inorganic Chemistry, Department of Chemistry, Faculty of Science,
University of Zagreb, Horvatovac 102a, 10000 Zagreb, Croatia
E-mail: [email protected]
Hexacoordinated transition metal complexes of tridentate ligands L with ML2 stoichiometry
can form several geometrical isomers: meridional, trans-facial, and delta or lambda cis-facial.
The configuration of isomers is affected by steric and electronic properties of the ligands and
coordinating ability of the counterions [1]. Derivatives of iminodiacetamide (imda) are
studied as tridentate ligands and in all known complexes the iminodiacetamides act as
O,N,O’ chelators. The Cambridge Structural Database (CSD) contains crystallographic data for
less than 20 metal complexes with iminodiacetamide or its N-substituted derivatives. All
reported complexes of N-substituted imda derivatives are trans-facial isomers [2].
In this communication we present the synthesis and characterization of phenyl
iminodiacetamide derivatives (L1-L6) and their ML2 complexes with transition metals, M =
Zn(II), Co(II), Ni(II) or Cd(II). The amide nitrogen atoms were substituted with phenyl groups
in order to increase their solubility in common organic solvents and enable characterization
of complexes in solution. To test the effect of the ligands electronic properties on the
complex configuration, ligands were prepared with electron donor or electron withdrawing
groups on the para-position of phenyl rings (R). The complexes were characterized in solid
state (single crystal X-ray diffraction, IR, TG) and in solution (1H and 13C NMR, IR, UV-Vis).
Figure 1: Synthesis of transition metal complexes (left) and crystal structure of trans-fac Zn(L2)2 complex (right).
References
[1] Đ. Škalamera, E. Sanders, R. Vianello, A. Maršavelski, A. Pevec, I. Turel, S. I. Kirin, Dalton Trans., 45
(2016) 2845–2858.
[2] See for example: N. Smrečki, B. M. Kukovec, M. Đaković, Z. Popović, Polyhedron, 93 (2015) 106–
117.