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Self‐Assembly of Bis(pyrrol‐2‐ylmethyleneamine) Ligands with Cu II Controlled by Bridging [−(CH 2 ) n −] Spacers and Weak Intermolecular C−H···Cu Hydrogen Bonding
Author(s) -
Yang Lanying,
Chen Qingqi,
Li Yan,
Xiong Shaoxiang,
Li Genpei,
Ma Jin Shi
Publication year - 2004
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.200300639
Subject(s) - chemistry , crystallography , intermolecular force , monomer , linker , alkyl , stereochemistry , crystal structure , hydrogen bond , imine , helix (gastropod) , polymer , molecule , catalysis , organic chemistry , ecology , snail , computer science , biology , operating system
Bis(pyrrol‐2‐ylmetyhleneamine) ligands linked by alkyl spacers between the imine nitrogens are shown to give dinuclear dimers or mononuclear monomers, depending on the length of the alkyl linker, upon coordination with Cu II . Ligands containing ethylene or hexylene linkers −(CH 2 ) n − ( n = 2, 6) give dinuclear dimers 5 and 8 , while propylene and butylene chains ( n = 3, 4) give mononuclear monomers 6 and 7 . X‐ray crystal structural analysis reveals that 5 exists as two very similar isomers 5a and 5b , in which the two ligands are bound to two Cu II centers to form a distorted helical conformation. In the unit cells of 8 , two entirely different isomers 8a and 8b are found. In 8a two ligands are side‐by‐side bound to two Cu II centers to form a rectangular macrocycle, while in 8b they are bonded to two Cu II centers to form a distorted double‐stranded helix. Moreover, X‐ray structural analysis reveals that complexes 5 − 8 are further assembled into one‐dimensional polymers through weak, intermolecular C−H ··· Cu hydrogen bonding, which plays a crucial role in stabilizing the crystal lattice. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)