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metal-organic compounds
The title complex, trans-bis(dimethylformamide-κO)bis{N,N′-N′′,N′′′-tetra-tert-butyl[oxybis(phosphonic diamide-κO)]}manganese(II) dichloride dihydrate, [Mn(C16H40N4O3P2)2(C3H7NO)2]Cl2·2H2O, is the first example of a bis-chelate amido–pyrophosphate (pyrophosphoramide) complex containing an O[P(O)(NH)2]2 fragment. Its asymmetric unit contains half of the complex dication, one chloride anion and one water molecule. The MnII atom, located on an inversion centre, is octahedrally coordinated, with a slight elongation towards the monodentate dimethylformamide ligand. Structural features of the title complex, such as the P=O bond lengths and the planarity of the chelate ring, are compared with those of previously reported complexes with six-membered chelates involving the fragments C(O)NHP(O), (X)NP(O) [X = C(O), C(S), S(O)2 and P(O)] and O[P(O)(N)2]2. This analysis shows that the six-membered chelate rings are less puckered in pyrophosphoramide complexes containing a P(O)OP(O) skeleton, such as the title compound. The extended structure of the title complex involves a linear aggregate mediated by N—H
O and N—HCl hydrogen bonds, in which the chloride anion is an acceptor in two additional O—HCl hydrogen bonds.
O and N—HCl hydrogen bonds, in which the chloride anion is an acceptor in two additional O—HCl hydrogen bonds.addenda and errata
organic compounds
The crystal structures of three new racemic mixed-amide phosphinates are discussed. The compounds crystallize in centrosymmetric space groups and the racemic character is reflected by the symmetry.
