A one-dimensional mixed-valence MnII/MnIII chain has been synthesized using N-salicylidene-l-alanine and 2,2′-bipyridine. The complex shows moderate catecholase and phenoxazinone synthase-like activity.

Three new one-dimensional CoII/CoIII chains have been synthesized using N-salicylidene-l-alanine/N-salicylidene-l-phenylalanine and 2,2′-bipyridine/1,10-phenanthroline. All three complexes exhibit phenoxazinone synthase-like activity.

Three new hetero-metallic copper(II)-manganese(II) complexes, [(CuL) 2 Mn 3 (C 6 H 5 CO 2) 6 ] (1), [(CuL) 2 Mn(CH 3 CO 2) 2 ] (2), and {[(CuL) 2 Mn(C 6 H 5 CH 2 CO 2) 2 ] • 2CH 3 CN} (3), have been synthesized using [CuL] as ''metalloligand'' (where H 2 L=N,N'-bis (2-hydroxynaphthyl-methylidene)-1,3-propanediamine). Single-crystal structural analyses show an almost linear pentanuclear structure for complex 1 where a square planar [CuL] unit is connected to each of the two terminal Mn II ions of a linear, centrosymmetric [Mn 3 (benzoate) 6 ] unit through the double phenoxido bridges. Both complexes 2 and 3 possess a linear tri-nuclear structure where two terminal squarepyramidal [CuL] units are bonded to the central Mn II ion through double phenoxido oxygen atoms along with a synsyn bridging acetate (for 2)/phenyl acetate (for 3). All three complexes exhibit catecholase, and phenoxazinone synthaselike activities under aerial conditions. For catecholase like activity, the turnover numbers (k cat) are 595, 40, and 205 h À 1 whereas, for phenoxazinone synthase like activity, the turnover numbers are 25, 4, and 11 h À 1 for complexes 1-3, respectively. The mechanism of both catalytic oxidase activities is proposed on the basis of mass spectral evidences. Variable-temperature (2-300 K) dc molar magnetic susceptibility measurements of 1 reveal antiferromagnetic interactions between the CuÀ Mn centres (J 1 = À 29.3 cm À 1), and also between the MnÀ Mn centres of the [Mn 3 (benzoate) 6 ] unit (J 2 = À 0.68 cm À 1). On increasing the magnetic field at 2 K, its ground spin state changes from S = 3/2 to S = 5/2 at 4 T, attributable to the low value of J 2 which makes the excited spin states close in energy with the ground spin state. Complexes 2 and 3 show antiferromagnetic coupling interactions between the CuÀ Mn pairs with J values of À 9.51, and À 5.32 cm À 1 , respectively.

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One new heterometallic nickel(II)-manganese(II) complex [(NiL1)2Mn3(C6H5CO2)6] (1) and two new copper(II)-manganese(II) complexes,[(CuL1)2Mn3(m-(NO2)C6H4CO2)6] (2) and [{CuL2(H2O)}2Mn3(m-(NO2)C6H4CO2)6] (3) have been synthesized and structurally characterized using [NiL1]/[CuL1]/[CuL2] as metalloligand (where H2L1 = N,N′-bis(2-hydroxynaphthyl-methylidene)-1,3-propanediamine,...