Features of Magnetic Behavior in the Row of Pentacoordinated Bis‐ o ‐Iminobenzosemiquinonato Metal (Al, Ga, In) Complexes

The series of pentacoordinated bis‐ o ‐iminobenzosemiquinonato complexes with general formula (imSQ) 2 MR where imSQ – is a radical anion of 4,6‐di‐ tert ‐butyl‐ N ‐(2,6‐di‐isopropylphenyl)‐ o ‐iminobenzoquinone (M = Al, Ga, In; R = Akl, Hal, N 3 , NCS) has been expanded through synthesis of six new (imSQ) 2 MR complexes [M = In, R = Me ( 1 ), Br ( 5 ), Cl ( 6 ); M = Ga, R = OPh ( 16 ), NCO ( 17 ); M = Al, R = NCO ( 23 )]. In all complexes (imSQ) 2 MR except for R = Alk the strong antiferromagnetic exchange coupling between organic radicals, conditioned by the presence of the pathway for superexchange, takes place. In the (imSQ) 2 GaR complexes the value of magnetic exchange interaction ( J ) was found to depend linearly on the distance between metal center and inorganic apical substituent: the shortening of Ga–R distance in the row Ga–I > Ga–Br > Ga–Cl > Ga–NCS > Ga–OPh is accompanied by the increasing of J value from –68.6 to –139.3 cm –1 . For Al and In analogues complexes such dependence has not been observed. The pathway for superexchange in pentacoordinated (imSQ) 2 MR complexes was found to be broken after complex coordination geometry changeover to hexacoordinated one, which was clearly demonstrated by the example of pyridine molecule coordination to the (imSQ) 2 InI ( 4 ).