A solid material obtainable by a method of synthesising a dinuclear Mn and/or Mn catalyst salt from a ligand of formula: wherein: p is 3; R is independently selected from: hydrogen, C 1 -C 6 -alkyl, CH 2 CH 2 OH, and CH 2 COOH, or one of R is linked to the N of another Q via an ethylene bridge; R 1, R 2, R 3, and R 4 are independently selected from: H, C 1 -C 4 -alkyl, and C 1 -C 4 -alkylhydroxy, the salt comprising a non-coordinating anion selected from the group consisting of chloride, nitrate, benzoate, sulfate and acetate, the method comprising the following steps: (i) treating a 0.03 mmol/ml to 4 mmol/ml solution of the ligand in a non-aqueous solvent, with a manganese salt to form a complexation mixture, wherein the ratio of three nitrogen ring per ligand to a manganese salt is from 0.8:2 and the complexation mixture contains from 0 to 6 wt% of water; (ii) treating the solution of step (i) with hydrogen peroxide or a source of hydrogen peroxide to provide from 1 to 10 mole H 2 O 2 per mole of the manganese salt; (iii) treating the solution of step (ii) with base to provide a solution having a pH of from 8 to 13; (iv) treating the solution of step (iii) with acid to provide a solution having a pH of from 4 to 9; and (v) removing solvent via spray drying or via freeze drying from the solution resultant from step (iv) to provide the solid material. wherein: p is 3; R is independently selected from: hydrogen, C 1 -C 6 -alkyl, CH 2 CH 2 OH, and CH 2 COOH, or one of R is linked to the N of another Q via an ethylene bridge; R 1, R 2, R 3, and R 4 are independently selected from: H, C 1 -C 4 -alkyl, and C 1 -C 4 -alkylhydroxy, the salt comprising a non-coordinating anion selected from the group consisting of chloride, nitrate, benzoate, sulfate and acetate, the method comprising the following steps: (i) treating a 0.03 mmol/ml to 4 mmol/ml solution of the ligand in a non-aqueous solvent, with a manganese salt to form a complexation mixture, wherein the ratio of three nitrogen ring per ligand to a manganese salt is from 0.8:2 and the complexation mixture contains from 0 to 6 wt% of water; (ii) treating the solution of step (i) with hydrogen peroxide or a source of hydrogen peroxide to provide from 1 to 10 mole H 2 O 2 per mole of the manganese salt; (iii) treating the solution of step (ii) with base to provide a solution having a pH of from 8 to 13; (iv) treating the solution of step (iii) with acid to provide a solution having a pH of from 4 to 9; and (v) removing solvent via spray drying or via freeze drying from the solution resultant from step (iv) to provide the solid material. (i) treating a 0.03 mmol/ml to 4 mmol/ml solution of the ligand in a non-aqueous solvent, with a manganese salt to form a complexation mixture, wherein the ratio of three nitrogen ring per ligand to a manganese salt is from 0.8:2 and the complexation mixture contains from 0 to 6 wt% of water; (ii) treating the solution of step (i) with hydrogen peroxide or a source of hydrogen peroxide to provide from 1 to 10 mole H 2 O 2 per mole of the manganese salt; (iii) treating the solution of step (ii) with base to provide a solution having a pH of from 8 to 13; (iv) treating the solution of step (iii) with acid to provide a solution having a pH of from 4 to 9; and (v) removing solvent via spray drying or via freeze drying from the solution resultant from step (iv) to provide the solid material.