Linking Chiral Clusters with Molybdate Building Blocks: From Homochiral Helical Supramolecular Arrays to Coordination Helices

The synthesis of four new oxo‐centered Fe clusters ( 1 a – c , 2 ) of the form [Fe III 3 (μ 3 ‐O)(CH 2 =CHCOO) 6 ] with acrylate as the bridging ligand gives rise to potentially intrinsically chiral oxo‐centered {M 3 } trimers that show a tendency to spontaneously resolve upon crystallization. For instance, 1 a , [Fe III 3 (μ 3 ‐O)(CH 2 =CHCOO) 6 ‐(H 2 O) 3 ] + , crystallizes in the chiral space group P 3 1 as a chloride salt. Crystallization of 1 b , [Fe 3 (μ 3 ‐O)(C 2 H 3 CO 2 ) 6 (H 2 O) 3 ]NO 3 ⋅4.5H 2 O, from aqueous solution followed by recrystallization from acetonitrile also gives rise to spontaneous resolution to yield the homochiral salt [Fe 3 (μ 3 ‐O)(C 2 H 3 CO 2 ) 6 ‐(H 2 O) 3 ]NO 3 ⋅CH 3 CN of 1 c (space group P 2 1 2 1 2 1 ). Furthermore, the reaction of 1 a with hexamolybdate in acetonitrile gives the helical coordination polymer {[(Fe 3 (μ 3 ‐O)L 6 (H 2 O))(MoO 4 )‐(Fe 3 (μ 3 ‐O)L 6 (H 2 O) 2 )]⋅2CH 3 CN⋅H 2 O} ∞ 2 (L: H 2 CCHCOO), which crystallizes in the space group P 2 1 . The nature of the ligand geometry allows the formation of atropisomers in both the discrete ( 1 a – c ) and linked {Fe 3 } clusters ( 2 ), which is described along with a magnetic analysis of 1 a and 2 .