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A Zig‐Zag [Mn II 4 ] Cluster from a Novel Bis(β‐diketonate) Ligand
Author(s) -
Aromí Guillem,
Gamez Patrick,
Boldron Christophe,
Kooijman Huub,
Spek Anthony L.,
Reedijk Jan
Publication year - 2006
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.200600105
Subject(s) - chemistry , ligand (biochemistry) , crystallography , coupling constant , pyridine , cluster (spacecraft) , antiferromagnetism , molecule , yield (engineering) , hamiltonian (control theory) , phenol , stereochemistry , medicinal chemistry , organic chemistry , biochemistry , physics , receptor , materials science , particle physics , computer science , metallurgy , programming language , condensed matter physics , mathematical optimization , mathematics
Abstract A new ligand, H 5 L3, has been synthesized featuring seven linearly arranged oxygen donors in form of two 1,3‐diketone and three phenol groups. The X‐ray structure of H 5 L3 unveils a rare case where one of the diketones is in the enolic form and the other one in the bis(carbonyl) form. This structure is shown by 1 H NMR to persist in solution. Reaction of H 5 L3 with Mn(AcO) 2 in pyridine leads to the novel tetranuclear cluster [Mn 4 (H 2 L3) 2 (OAc) 2 (py) 5 ] ( 1 ), which displays an unusual core in form of a zig‐zag chain. Bulk magnetic measurements revealed the existence of weak antiferromagnetic coupling within the molecule. Numerical fits to a model described by the Hamiltonian H = –2 J 1 ( S 1 S 2 + S 3 S 4 ) – 2 J 2 ( S 2 S 3 ) yield coupling constants of J 1 = –2.23 cm –1 , J 2 = –0.85 cm –1 and g = 2.08. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)