Author:
Dahlous Kholood A.,Soliman Saied M.,El-Faham Ayman,Massoud Raghdaa A.
Abstract
The trinuclear [Zn3(PMT)2(Cl4)(N3)2] complex of the N-pincer ligand, 2,4-bis(3,5-dimethyl-1H-pyrazol-1-yl)-6-methoxy-1,3,5-triazine (PMT), was obtained by self-assembly of the polydentate ligand (PMT) with ZnCl2 in the presence of azide ion as an auxiliary bridging ligand. The X-ray structure analysis revealed a monoclinic crystal system and centrosymmetric space group C2/c. There are two crystallographically independent Zn(II) sites where the Zn1 and Zn2 are tetra- and penta-coordinated with ZnN2Cl2 and ZnN4Cl coordination environments, respectively. The distortion τ4 and τ5 parameters for the Zn1 and Zn2 sites are 0.93 and 0.52, respectively. Hence, the Zn(1)N2Cl2 has a distorted tetrahedral configuration, while the Zn(2)N4Cl coordination sphere is intermediate between the square pyramidal and trigonal bipyramidal configurations. In this complex, the PMT is a tridentate N-chelate, while the chloride and azide anions are terminal and μ(1,1) bridged ligands, respectively. The %H…H, N…H, Cl…H, and C…H are 40.8, 17.2, 16.0, and 10.1%, respectively, based on Hirshfeld analysis. The charges at the Zn1 (+0.996 e) and Zn2 (+1.067 e) sites are calculated to be less than the official charge of the isolated Zn(II) ion. The μ(1,1) bridged azide has two asymmetric N–N bonds with clear covalent characters. In contrast, the Zn–N and Zn–Cl bonds have predominant closed-shell characters.
Subject
Inorganic Chemistry,Condensed Matter Physics,General Materials Science,General Chemical Engineering
Reference75 articles.
1. A Metal−Organic Framework with Entatic Metal Centers Exhibiting High Gas Adsorption Affinity;Ma;J. Am. Chem. Soc.,2006
2. Design of Frameworks with Mixed Triangular and Octahedral Building Blocks Exemplified by the Structure of [Zn4O(TCA)2] Having the Pyrite Topology;Hee;Angew. Chem. Int. Ed.,2003
3. Kepert, C.J., and Rosseinsky, M.J. (1999). Zeolite-like crystal structure of an empty microporous molecular framework. Chem. Comm., 375–376.
4. Wang, S.-N., Xing, H., and Li, Y.-Z. (2007). Unprecedented interweaving of single-helical and unequal double-helical chains into chiral metal–organic open frameworks with multiwalled tubular structures. Chem. Comm., 2293–2295.
5. Grayson, M., and Eckroth, D. (1978). Amino Resins and Plastics, in Kirk-Othmer’s Encyclopedia of Chemical Technology, Wiley. [3rd ed.].