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—HO 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.
metal-organic compounds
Double nitrileπ interactions are relevant for the crystal packing of charge-diffuse conjugated tetracyanopropenide anions when combined with common heteroaromatic tris-chelate octahedral complexes, [Fe(phen)3]2−.
metal-organic compounds
The Cu atoms in the title complexes are five-coordinated in distorted trigonal bipyramidal environments by four N atoms of two 5,5′-dimethyl-2,2′-bipyridine ligands and one N atom of a dicyanamide anion, which is coordinated in a monodentate manner in the equatorial plane. The structures are stabilized by C—HN and C—HX hydrogen bonds (X = F and O) and π–π interactions between pyridine rings.