Rational Self‐Assembly of Tricobalt Extended Metal Atom Chains and [MF6]2– Building Blocks into One‐Dimensional Coordination Polymers.

Following our recent work on the first crystallographically characterized coordination polymers based on tricobalt extended metal atom chains (EMACs), namely, [Co3(dpa)4MF6]<bold>·</bold>2DMF [M = ZrIV (<bold>1</bold>), SnIV (<bold>2</bold>), and ReIV (<bold>3</bold>); Hdpa = 2,2′‐dipyridylamine; DMF = <italic>N</italic>,<italic>N′</italic>‐dimethylformamide], we have generalized our synthetic approach based on robust fluoride complexes to prepare new self‐assembled one‐dimensional (1D) polymers formed by [Co3(dpa)4]2+ and 5d [MF6]2– [M = IrIV (<bold>4</bold>) and OsIV (<bold>5</bold>)] building blocks. These 1D complexes are isostructural and crystallize in the <italic>P</italic>4/<italic>ncc</italic> space group such that the fourfold axis is coincident with the metal axes of the rigorously linear chains. Magnetic studies reveal ferromagnetic coupling between the <italic>S</italic> = 1/2 {Co3} and [MF6]2– units in <bold>3</bold> and <bold>4</bold>, whereas the nonmagnetic [MF6]2– linkers of <bold>1</bold> and <bold>5</bold> mediate antiferromagnetic coupling between the {Co3} spins. For <bold>2</bold>, no significant exchange coupling was observed. Spin‐crossover behavior, which was observed for the parent [Co3(dpa)4Cl2] complex, was not detected for <bold>1</bold>–<bold>5</bold> up to 300 K. This work demonstrates that EMACs and [MF6]2– complexes can be considered as appealing building blocks for the design of new functional coordination networks. [ABSTRACT FROM AUTHOR]