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RESEARCH PRODUCT

Synthesis, Crystal Structure and Magnetic Properties of Heteropolynuclear Re IV M II Complexes Based on the Robust [ReCl 5 (pyzCOO)] 2– Unit (pyzCOO = 2‐pyrazinecarboxylate)

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The syntheses, crystal structures and magnetic properties of four rhenium(IV) compounds of formulae NBu4[ReCl5(pyzCOOH)]·H2O (1), [ReCl5(µ-pyzCOO)M(dmphen)2]·2CH3CN [M = Ni (2) and Co (3)] and {[ReCl5(µ3-pyzCOO)]2Mn2(dmphen)3}n (4) (NBu4 = tetra-n-butylammonium cation, pyzCOOH = 2-pyrazinecarboxylic acid, dmphen = 2,9-dimethyl-1,10-phenanthroline) are reported herein. Compound 1 was obtained by the reaction of NBu4[ReCl5(dmf)] (dmf = dimethylformamide) with pyzCOOH in acetone, whereas the other complexes were obtained by the reaction of 1 with M(ClO4)2·6H2O [M = Ni (2), Co (3), Mn (4)] and dmphen in acetonitrile. Complex 1 is a mononuclear compound, 2 and 3 are neutral heterodinuclear complexes and 4 is a neutral chain in which each pyzCOO– bridges one ReIV and two MnII in a very unusual µ3-binding mode. Compounds 2 and 3 behave as magnetically isolated species with intramolecular ferromagnetic coupling between ReIV and NiII or ReIV and CoII ions, respectively. In turn, weak antiferromagnetic coupling between the MnII ions through anti-syn-carboxylate bridges together with weak ferromagnetism below 3.1 K due to small spin canting is observed in 4.