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Discrete and Infinite Metallacyclic Coordination Architectures Based on a Conformationally Flexible Tripodal Aminotriazine‐Derived Polypyridyl Ligand
Author(s) -
Tsai MengRong,
Wu JingYun,
Lai LongLi
Publication year - 2011
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201001333
Subject(s) - chemistry , hexacoordinate , ligand (biochemistry) , moiety , coordination sphere , stereochemistry , crystallography , intramolecular force , coordination complex , pyridine , cobalt , crystal structure , metal , medicinal chemistry , inorganic chemistry , biochemistry , receptor , organic chemistry , silicon
Abstract A novel tripodal semi‐rigid ligand, 2,4,6‐tris(3‐picolylamino)‐1,3,5‐triazine ( m ‐H 3 tpat), consisting of a triazine central core and three pyridine donating functions attached to flexible –NHCH 2 – arms has been designed and synthesized. The self‐assembly reactions of m ‐H 3 tpat with copper(II) chloride and cobalt(II) chloride yielded discrete Cu II complex [Cu 2 Cl 4 ( m ‐H 3 tpat) 2 ] · 2H 2 O · 2EtOH ( 1· 2H 2 O · 2EtOH) and polymeric Co II complex [Co( m ‐H 3 tpat) 2 (H 2 O) 2 ]Cl 2 ( 2 ), respectively. Complex 1 has a metallacyclophane structure with a metal‐to‐ligand ratio of 2:2. Each copper(II) ion adopts a pentacoordinate square‐pyramidal geometry with a N 3 Cl 2 coordination sphere. Complex 2 exhibits an extended chain structure based on {Co 2 ( m ‐H 3 tpat) 2 } metallacyclic repeating units. Each cobalt(II) ion adopts a hexacoordinate octahedral geometry with a N 2 O 4 coordination environment. Note that the m ‐H 3 tpat ligand exists in a ci s– ci s– cis conformation in 1 and a ci s– trans – trans conformation in 2 , with the central aminotriazine moiety appearing to be an asymmetric‐configured all‐amino tautomer in both conformers. The stabilities of the two coordination‐directed structures may be enhanced by intramolecular π–π interactions between two pyridine rings from two different m ‐H 3 tpat ligands within the metallacyclophane structure of 1 and by a set of complementary double hydrogen bonds (DA–AD arrays) between two aminotriazine moieties of two m ‐H 3 tpat ligands within a metallacyclic unit for 2 .