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Thiodiacetate–Manganese Chemistry with N ligands: Unique Control of the Supramolecular Arrangement over the Metal Coordination Mode
Author(s) -
Grirrane Abdessamad,
Pastor Antonio,
Galindo Agustín,
Álvarez Eleuterio,
Mealli Carlo,
Ienco Andrea,
Orlandini Annabella,
Rosa Patrick,
Caneschi Andrea,
Barra AnneLaure,
Sanz Javier Fernández
Publication year - 2011
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201100988
Subject(s) - supramolecular chemistry , chemistry , stacking , crystallography , manganese , metal , octahedron , non covalent interactions , coordination complex , octahedral molecular geometry , trigonal prismatic molecular geometry , stereochemistry , copper , molecule , crystal structure , hydrogen bond , organic chemistry
Compounds based on the Mn–tda unit (tda=S(CH 2 COO) 2 −2 ) and N co‐ligands have been analyzed in terms of structural, spectroscopic, magnetic properties and DFT calculations. The precursors [Mn(tda)(H 2 O)] n ( 1 ) and [Mn(tda)(H 2 O) 3 ] ⋅ H 2 O ( 2 ) have been characterized by powder and X‐ray diffraction, respectively. Their derivatives with bipyridyl‐type ligands have formulas [Mn(tda)(bipy)] n ( 3 ), [{Mn(N‐N)} 2 (μ‐H 2 O)(μ‐tda) 2 ] n (N‐N=4,4′‐Me 2 bipy ( 4 ), 5,5′‐Me 2 bipy, ( 5 )) and [Mn(tda){(MeO) 2 bipy} ⋅ 2 H 2 O] n ( 6 ). Depending on the presence/position of substituents at bipy, the supramolecular arrangement can affect the metal coordination type. While all the complexes consist of 1D coordination polymers, only 3 has a copper–acetate core with local trigonal prismatic metal coordination. The presence of substituents in 4 – 6 , together with water co‐ligands, reduces the supramolecular interactions and typical octahedral Mn II ions are observed. The unicity of 3 is also supported by magnetic studies and by DFT calculations, which confirm that the unusual Mn coordination is a consequence of extended noncovalent interactions (π–π stacking) between bipy ligands. Moreover, 3 is an example of broken paradigm for supramolecular chemistry. In fact, the desired stereochemical properties are achieved by using rigid metal building blocks, whereas in 3 the accumulation of weak noncovalent interactions controls the metal geometry. Other N co‐ligands have also been reacted with 1 to give the compounds [Mn(tda)(phen)] 2 ⋅ 6 H 2 O ( 7 ) (phen=1,10‐phenanthroline), [Mn(tda)(terpy)] n ( 8 ) (terpy=2,2′:6,2′′‐terpyridine), [Mn(tda)(pyterpy)] n ( 9 ) (pyterpy=4′‐(4‐pyridyl)‐2,2′:6,2′′‐terpyridine), [Mn(tda)(tpt)(H 2 O)] ⋅ 2 H 2 O ( 10 ) and [Mn(tda)(tpt)(H 2 O)] 2 ⋅ 2 H 2 O ( 11 ) (tpt=2,4,6‐tris(2‐pyridyl)‐1,3,5‐triazine). Their identified mono‐, bi‐ or polynuclear structures clearly indicate that hydrogen bonding is variously competitive with π–π stacking.