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Secondary Structures in Inorganic Helicates of an Octadentate Phenanthroline‐Type Schiff Base Ligand
Author(s) -
Begum Ameerunisha,
Seewald Oliver,
Seshadri Tarimala,
Flörke Ulrich,
Henkel Gerald
Publication year - 2016
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.201600055
Subject(s) - chemistry , stacking , ligand (biochemistry) , intramolecular force , intermolecular force , crystallography , supramolecular chemistry , stereochemistry , phenanthroline , topology (electrical circuits) , cationic polymerization , ion , folding (dsp implementation) , schiff base , molecule , crystal structure , receptor , polymer chemistry , biochemistry , mathematics , organic chemistry , combinatorics , electrical engineering , engineering
To analyze the contribution of supramolecular interactions to helical architectures and to investigate whether ligand folding can be induced by only protons in a similar fashion in the absence of metal ions, a new 1,10‐phenanthroline (phen)‐based extended ligand, C 12 H 6 N 2 [CHNC 6 H 4 NH(C 10 H 6 N)] 2 (L 1 ), its copper(I) complexes, [Cu 2 (C 12 H 6 N 2 {CHNC 6 H 4 NH(C 10 H 6 N)} 2 ) 2 ] [PF 6 ] 2 ( 1 ), [Cu 2 (C 12 H 6 N 2 {CHNC 6 H 4 NH(C 10 H 6 N)} 2 ) 2 ][BF 4 ] 2 ( 2 ), [Cu 2 (C 12 H 6 N 2 {CHNC 6 H 4 NH(C 10 H 6 N)} 2 ) 2 ][CuCl 2 ] 2 · CH 2 Cl 2 ( 3 ), and [Cu 4 (C 12 H 6 N 2 {CHNC 6 H 4 NH(C 10 H 6 N)} 2 ) 2 ][Cu 2 I 4 ] ( 4 ), were prepared and structurally characterized. Ligand L 1 wraps copper(I) ions in two intriguingly different fashions depending on the nature of the anions. Although dicopper helicates 1 – 3 and tetracopper helicate 4 show significant intermolecular interactions that show considerable structural relationships with DNA, helicate 4 more closely resembles the structural features of DNA that even phen‐based stacking interactions are present between the two helical strands. In complex 4 , the dinuclear [Cu 2 I 4 ] 2– dianion is involved in intermolecular interactions, which joins two cationic units in a linear fashion, whereas the monoanions in complexes 1 – 3 (i.e., PF 6 – , BF 4 – , and CuCl 2 – ) are only involved in intramolecular interactions or connect the cations laterally. The anion‐dependent topology serves as a reminder that the helical topology of a cation can be altered by changing the nature of the anion.