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Bis(benzoylacetonato)bis(morpholine-κ N)manganese(II) morpholine solvate

As a part of our ongoing study of bis(benzoylacetonato)manganese(II) adducts with various N and O donors, a morpholine adduct, bis(benzoylacetonato)bis(morpholine-&#954; N)manganese(II) was prepared. The compound was obtained as large (mostly single) crystals by overlayering a saturated solution of bis(benzoylacetonato)manganese(II) in morpholine with propan-2-ol. It was shown that the adduct crystallised as a morpholine solvate with two morpholine molecules per a [Mn(bzac)_2(morph)_2] unit. The title compound crystallises in the space group P2_1/n, with two formula units per unit cell. Manganese atoms are located at inversion centres (2c special position of the space group) and are coordinated by two benzoylacetonate anions and two molecules of morpholine, in a distorted octahedral geometry. This coordination moiety is hydrogen bonded to two morpholine molecules by a N&#8211; H...N bond of 3.146 A, and a N&#8211; H...O bond of 3.270 A. The shortest intermolecular contacts between these molecular aggregates is a C&#8211; H...&#960; contact of 3.715 A between a solvent morpholine carbon atom and a phenyl ring of the neighbouring coordination moiety. These interactions interconnect the molecular aggregates to form long chains along the a axis. When the structure is viewed along the <101> direction, the solvate morpholine molecules appear to be placed in channels protruding in that direction, surrounded by molecules of complex. However, the structure cannot be described as one of host-guest type since there are no significant interactions between molecules of complex which would hold them in such loose array. In fact, hydrogen bonding with solvate morpholine molecules is the main reason of the formation of channels in the crystal structure. When removed from the solution, or replaced into another solvent (other than morpholine), the crystals immediately start losing the solvent morpholine, upon which they crumble. The rate of the loss of morpholine was studied at several temperatures by measuring the isothermal weight loss on a thermogravimetric balance.

diketonate complexes; solvates; crystal structure; thermal decomposition

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