Reaction of Copper Halides with Dafone and Halogens – Magnetic Exchange in Dibromine Linked Chains of Cu(dafone) 2 X 2

The reaction of Cu II halides with 4,5‐diazaflouren‐9‐one (dafone) in acetonitrile and in the presence of halogens gave four novel compounds: [Cu(dafone) 2 Cl 2 ]Br 2 ( 1 ), [Cu(dafone) 2 Br 2 ]Br 2 ( 2 ), [Cu(dafone) 2 (CH 3 CN) 2 ](IBr 2 ) 2 ( 3 ), and [Cu(dafone) 2 (CH 3 CN) 2 ](Br 3 ) 2 (Br 2 ) 2 ( 4 ). The well‐known preference of dafone to form an unsymmetrical chelate with Cu 2+ directs the halide ion and acetonitrile to the equatorial plane of the octahedral complex. In 1 and 2 , dibromine links the neutral halo complex molecules to form infinite chains of the previously known neutral molecules. The acetonitrile complex in 3 has the symmetrical mixed trihalide (IBr 2 – ) as a counterion, while in 4 the cation is surrounded by a tribromide‐dibromine network. Raman, EPR, optical absorption, and luminescence characteristics are discussed. The dibromine molecules in 1 and 2 provide a pathway for weak magnetic coupling along the chain polymer.