The title compound, C(8)H(16)N(2)O(4), is a Weinreb amide that is also an important inter-mediate for the preparation of ketones and aldehydes. The molecule possesses a centre of symmetry.

The P atom in the title mol-ecule, C(12)H(26)N(3)OP, has a distorted tetra-hedral configuration: its bond angles lie in the range 101.1 (2)-119.1 (2)°. The P-N bonds to the two cyclo-pentyl-amido moieties are significantly different [1.619 (4) and 1.643 (4) Å], with the shorter bond related to an anti orientation of the lone electron pair of the corresponding N atom relative to the P=O bond. Th...

In the title compound, C(14)H(18)N(3)OP, a crystallographic mirror plane bis-ects the mol-ecule (the C,N,C atoms of the dimethyl-amido moiety and the P=O unit lie on the mirror plane). The P atom has a distorted tetra-hedral geometry; the bond angles at P are in the range 98.98 (11)-115.28 (7)°. In the crystal, the O atom of the P=O group acts as a double hydrogen-bond acceptor for two symmetry...

The asymmetric unit of the title compound, [(CH(3))(2)NH(CH(2))(2)NH(CH(3))(2)][CoCl(4)], contains a tetra-chlorido-cobalt-ate(II) dianion and two halves of two centrosymmetric, crystallographically-independent, dications. One independent dication is disordered between two conformations in a 0.784 (13):0.216 (13) ratio. In the crystal, inter-molecular N-H⋯Cl hydrogen bonds link cations and anio...

In the title compound, C(23)H(39)N(3)O(2), the amide O atoms are displaced by 1.020 (1) and 1.211 (1) Å from the mean plane of the central pyridine ring. In the crystal, mol-ecules are connected by weak C-H⋯O hydrogen bonds between methyl-ene groups in the isobutyl substituents and the amide O atoms.

The asymmetric unit of the title compound, (C6H18N2)[ZnCl4], consists of one tetra-chlorido-zincate anion and two half-N,N,N'N'-tetra-methyl-ethylenedi-ammonium cations. Each of the two di-ammonium cations is located about an inversion center and one of them is disordered over two sets of sites in a 0.780 (17):0.220 (17) ratio. The Zn(II) atom has a slightly distorted tetra-hedral coordination ...