μ-Adipato-bis[chlorido(2,2′:6′,2′′-terpyridine)copper(II)] tetrahydrate

In the title compound, [Cu2(C6H8O4)Cl2(C15H11N3)2]·4H2O, the dinuclear copper complex is located on a crystallographic inversion centre. Each Cu atom is in a distorted square-pyramidal coordination environment, with one O atom of an adipate dianion and three N atoms from the 2,2′:6′,2′′-terpyridine ligand occupying the basal plane, and one chlorine in the apical site. In addition, there is weak Cu—O interaction opposite of the chlorine with a distance of 2.768 (1) Å. The adipate ligand adopts a gauche–anti–gauche conformation. The interstitial water molecules form hydrogen-bonded tertramers that are connected to the complexes via O—H⋯O and O—H⋯Cl hydrogen bonds, thus leading to the formation of tightly hydrogen-bonded layers extending perpendicular to the b-axis direction.

In the title compound, [Cu 2 (C 6 H 8 O 4 )Cl 2 (C 15 H 11 N 3 ) 2 ]Á4H 2 O, the dinuclear copper complex is located on a crystallographic inversion centre. Each Cu atom is in a distorted squarepyramidal coordination environment, with one O atom of an adipate dianion and three N atoms from the 2,2 0 :6 0 ,2 00terpyridine ligand occupying the basal plane, and one chlorine in the apical site. In addition, there is weak Cu-O interaction opposite of the chlorine with a distance of 2.768 (1) Å . The adipate ligand adopts a gauche-anti-gauche conformation. The interstitial water molecules form hydrogen-bonded tertramers that are connected to the complexes via O-HÁ Á ÁO and O-HÁ Á ÁCl hydrogen bonds, thus leading to the formation of tightly hydrogen-bonded layers extending perpendicular to the b-axis direction.
In the centrosymmetric dinuclear copper complex, two [Cu 2 (C 15 H 11 N 3 ) 2 (C 6 H 8 O 4 )Cl 2 ] moieties are bridged by an adipate ligand with a Cu···Cu separation in the dimer of 9.715 (2) Å ( Fig. 1). The adipate ligand adopts a gauche-anti-gauche conformation. Each Cu atom is in a distorted square pyramidal coordination environment, with one O atom of an adipate dianion and three N atoms from the 2,2':6',2''-terpyridine ligand occupying the basal plane, and one chlorine in the apical site. In addition, there is a weak Cu-O interaction opposite of the chlorine with a distance of 2.768 (1) Å.
The interstitial water molecules are interacting with the metal complexes via hydrogen bonding interactions (Table 1).
There are three kinds of hydrogen bonds: From one of the lattice water molecule to the coordinated oxygen atom of the carboxylate group, from the other water molecule towards a chlorine atom of one of the ligands, and between the water molecules themselves, which are arranged as tetramers in planar squares. In this way each of the water tetramers ties together four different complexes via H bonds to each two chlorines and two carboxylate oxygen atoms. The complexes in turn are hydrogen bonded to four of the water tetramers, thus leading to the formation of hydrogen bonded layers that extend perpendicular to the b-direction of the unit cell. (Fig.2).

Experimental
Dropwise addition of 1 M aqueous Na 2 CO 3 (3.0 ml) to a stirred aqueous solution of CuCl 2 .6H 2 O (0.1215 g, 0.50 mmol) in H 2 O (5.0 ml) produced a blue CuCO 3 precipitate, which was centrifuged and washed with water until no Clwas detected in the supernatant. The resulting solid was added to a solution of adipic acid (0.0731, 0.50 mmol) and 2,2':6',2''-terpyridine (0.1166 g, 0.50 mmol) in 20 ml mixed solvent of H 2 O and CH 3 OH (v:v = 1:1). The mixture was stirred for half an hour and filtered, and the dark green filtrate (pH = 5.01) was left standing at room temperature. Green plate-like crystals were obtained several days later (Yield: ca. 23% based on Cu).
supplementary materials sup-2 Refinement H atoms bonded to C atoms were placed in geometrically calculated positions and refined using a riding moldel with C-H = 0.93-0.97 Å and U iso (H) = 1.2 Ueq(C). H atoms of water were found in difference Fourier syntheses and fixed as initially found. Fig. 1. ORTEP view of complex molecule of the title compound. Displacement ellipsoids are drawn at the 45% probability level (i = -x + 1, -y + 1, -z + 1). H atoms and lattice water molecules are omitted for clarity.