Tetrakis(μ2-phenylacetato-κ2 O:O′)bis[(isoquinoline-κN)copper(II)]

In the title centrosymmetric binuclear CuII complex, [Cu2(C8H7O2)4(C9H7N)2], the two Cu cations are bridged by four carboxylate groups of the phenylacetate anions; each Cu cation is further coordinated by an isoquinoline ligand to complete the distorted CuO4N square-pyramidal geometry. The Cu cation is displaced by 0.2092 (8) Å from the basal plane formed by the four O atoms. Within the dinuclear molecule, the Cu⋯Cu separation is 2.6453 (6) Å. Although a parallel, overlapped arrangement of isoquinoline ligands exists in the crystal structure; the longer face-to-face distance of 3.667 (5) Å suggests there is no π–π stacking between isoquinoline ring systems.

The molecular structure is shown in Fig. 1. Four phenylacetate anions bridge two Cu II cations to form the centrosymmetric complex. Within the dinuclear molecule the Cu···Cu separation of 2.6453 (6) Å is consistent with 2.646 Å found in a related binucealr Cu II complex bridged by acetate anions (Li et al., 2009) and 2.642 Å found in a polymeric Cu II complex bridged by thiourea (Li et al. 2007). The Cu II cation is coordinated by four carboxyl-O atoms from phenylacetate anions in the basal plane, an isoquinoline molecule further coordinates to the Cu II cation in the apical position to complete the distorted square-pyramidal coordination geometry; the Cu II cation is 0.2092 (8) Å deviated from the basal coordination plane.
The parallel, overlaped arrangement of isoquinoline ligands of adjacent complexes is observed in the crystal structure ( Fig. 2). The face-to-face distance of 3.667 (5) Å suggests no π-π stacking between isoquinoline ring systems in the crystal structure.

S3. Refinement
H atoms were placed in calculated positions with C-H = 0.93 (aromatic) and 0.97 Å (methylene) and refined in riding mode with U iso (H) = 1.2U eq (C).  The molecular structure of the title compound with 30% probability displacement ellipsoids (arbitrary spheres for H atoms) [symmetry code:

Figure 2
The unit cell packing diagram showing the parallel arrangement of isoquinoline ligands. H atoms have been omitted for clarity.

Data collection
Rigaku R-AXIS RAPID IP diffractometer Radiation source: fine-focus sealed tube Graphite monochromator Detector resolution: 10.0 pixels mm -1 ω scans Absorption correction: multi-scan (ABSCOR; Higashi, 1995) T min = 0.835, T max = 0.920 11731 measured reflections 3837 independent reflections 3409 reflections with I > 2σ(I) Special details Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes. Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq Cu 0.44020 (3)