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 ...

In the title compound, C(14)H(30)N(3)OP, both cyclo-hexyl groups adopt chair conformations with the NH unit in an equatorial position. The P atom adopts a slightly distorted tetra-hedral environment. In the (CH(3))(2)NP(O) unit, the O-P-N-C torsion angles, showing the orientations of the methyl groups with respect to the phosphoryl group, are -166.6 (3) and 34.6 (4)°. The O atom of the P=O grou...

The title compound, C(15)H(23)N(3)O(2), crystallizes with two mol-ecules in the asymmetric unit which are linked by a C-H⋯N hydrogen bond. In the crystal, mol-ecules are connected via weak C-H⋯O and C-H⋯N hydrogen bonds between the amide O atoms and ethyl chains and between pyridine N atoms and aromatic H atoms in para positions. C-H⋯π inter-actions also occur.

In the title salt, C5H14N3(+)·C24H20B(-), the C-N bond lengths in the central CN3 unit are 1.3322 (11), 1.3385 (12) and 1.3422 (12) Å, indicating partial double-bond character. The central C atom is bonded to the three N atoms in a nearly ideal trigonal-planar geometry [N-C-N angles = 119.51 (8), 119.81 (9) and 120.69 (8)°] and the positive charge is delocalized in the CN3 plane. The bond lengt...

we investigate the long-term behavior of solutions of the difference equation[ x_{n+1}=x_{n}x_{n-3}-1 ,, n=0 ,, 1 ,, ldots ,, ]noindent where the initial conditions $x_{-3} ,, x_{-2} ,, x_{-1} ,, x_{0}$ are real numbers.  in particular, we look at the periodicity and asymptotic periodicity of solutions, as well as the existence of unbounded solutions.

in this article, the notion of $n-$derivation is introduced for all integers $ngeq 2$. although all derivations are $n-$derivations,  in general these notions are not equivalent. some properties of ordinary derivations are  investigated for $n-$derivations. also, we show that under certain mild condition  $n-$derivations are derivations.