Diaqua(1,4,8,11-tetraazacyclotetradecane-κ4 N 1,N 4,N 8,N 11)copper(II) diheptanoate dihydrate

The CuII atom in the title salt, [Cu(C10H24N4)(H2O)2][CH3(CH2)5CO2]2·2H2O, is chelated by the four N atoms of the 1,4,8,11-tetraazacyclotetradecane (cyclam) ligand and is coordinated by two water molecules in a tetragonally Jahn–Teller-distorted octahedral geometry. The CuII atom lies on a center of inversion. The cations, anions and uncoordinated water molecules are linked by N—H⋯O and O—H⋯O hydrogen bonds, forming a layer structure parallel to (100). The alkyl chain of the anion is disordered over two positions in a 0.82 (1):0.18 (1) ratio.

The Cu II atom in the title salt, [Cu(C 10 H 24 N 4 )(H 2 O) 2 ]-[CH 3 (CH 2 ) 5 CO 2 ] 2 Á2H 2 O, is chelated by the four N atoms of the 1,4,8,11-tetraazacyclotetradecane (cyclam) ligand and is coordinated by two water molecules in a tetragonally Jahn-Teller-distorted octahedral geometry. The Cu II atom lies on a center of inversion. The cations, anions and uncoordinated water molecules are linked by N-HÁ Á ÁO and O-HÁ Á ÁO hydrogen bonds, forming a layer structure parallel to (100). The alkyl chain of the anion is disordered over two positions in a 0.82 (1):0.18 (1) ratio.

Comment
The copper(II) ion forms a number of complexes with 1,4,8,11-tetraazacyclotetradecane in which the metal atom is coordinated by the four amino donor-atoms of the cyclic ligand. Among the carboxylate derivatives, neither the acetate nor the benzoate ions bind directly with the copper atom. The copper atom is coordinated instead by water molecules so that the carboxylate group interacts indirectly with the metal atom through the coordinated water molecules (Hunter et al., 2005;Lindoy et al., 2003). The copper(II) atom in the salt, [Cu(H 2 O) 2 (C 10 H 24 N 4 )] 2+ 2[CH 3 (CH 2 ) 5 CO 2 ] -. 2H 2 O (Scheme I), is chelated by the four nitrogen atoms of the cyclam ligand and is coordinated by two water molecules in a Jahn-Teller type of tetragonally distorted octahedral geometry. The copper atom lies on a center of inversion ( Fig. 1). The cations, anions and lattice water molecules are linked by N-H···O and O-H···O hydrogen bonds to form a layer structure.
Experimental 1,4,8,11-Tetraazacyclotetradecane (0.50 g, 2.50 mmol) dissolved in ethanol (25 ml) was mixed with a suspension of copper heptanoate (0.80 g, 2.5 mmol) in ethanol (50 ml) to give a purple solution. The solution was heated for an hour and then filtered. Prismatic crystals separated from the solution when it was left to cool slowly.

Refinement
Carbon-bound H-atoms were placed in calculated positions (C-H 0.95 to 0.99 Å) and were included in the refinement in the riding model approximation, with U(H) set to 1.2 to 1.5U(C).
The amino and water H-atoms were located in a difference Fourier map, and were refined with distance restraints of N-H···O 0.86±0.01, O-H 0.84±0.01 Å; their isotropic displacement parameters were freely refined.
The alkyl chain of the carboxylate ion is disordered over two positions; the disorder refined to an 82 (1):18 (1) ratio.
Bond distances for each pair of bonds were restrained to within 0.01Å of each other. The displacement parameters of the primed atoms were constrained to be equal of those of the unprimed ones. Fig. 1