Manganese(II) acetylacetonate (Mn(acac)2) is a transition metal acetylacetonate that is trimeric in hydrocarbon solvents. It is monomeric and tetrahedral in its vapor state. It shows Mn-O bond energy of 65 kcal mol-1. It can be used with potassium permanganate in preparation of manganese triad (Mn(acac)3).
Purify it by stirring 16g of reagent for a few minutes with 100mL absolute EtOH and filter by suction as rapidly as possible through coarse filter paper. Sufficient EtOH is added to the filtrate, to make up for the loss of EtOH and to redissolve any solid that separates. Water (15mL) is added to the filtrate, and the solution is evaporated with a stream of N2 until reduced to half its volume. Cool for a few minutes and filter off the yellow crystals, dry them under a stream of N2, then in a vacuum at room temperature for 6-8hours. These conditions are important for obtaining the dihydrate. A vacuum to several mm of Hg or much lower pressure for several days produces the anhydrous complex. The degree of hydration can be established by determining the loss in weight of 100g of sample after heating for 4hours at 100o and <20mmHg. The theoretical loss in weight for 2H2O is 12.5%. The material sublimes at 200o/2mm. It is soluble in heptane, MeOH, EtOH or *C6H6 at 30o. [Charles Inorg Synth VI 164 1960, Fernelius & Biswas Inorg Synth V 105 1957, Beilstein 3 II 3122.]
