Crystal structure of catena-poly[[[bis(3-oxo-1,3-diphenylprop-1-enolato-κ2 O,O′)zinc(II)]-μ2-tris[4-(pyridin-3-yl)phenyl]amine-κ2 N:N′] tetrahydrofuran monosolvate]

The synthesis and crystal structure of a coordination polymer composed of β-diketonato zinc(II) [Zn(dbm)2] and triarylamine-based bridging ligands (T3PyA) is reported. The asymmetric unit in the crystal consists of two independent halves of Zn(dbm)2, one T3PyA and one solvate THF. Each ZnII atom is located on an inversion centre and adopts an elongated octahedral coordination geometry. In the crystal, the coordination polymer chains are linked via C—H⋯π interactions into a three-dimensional framework.

The reaction of bis(3-oxo-1,3-diphenylprop-1-enolato-2 O,O 0 )zinc(II), [Zn(dbm) 2 ], with tris[4-(pyridin-3-yl)phenyl]amine (T3PyA) in tetrahydrofuran (THF) afforded the title crystalline coordination polymer, {[Zn(C 15 H 11 O 2 ) 2 (C 33 H 24 N 4 )]ÁC 4 H 8 O} n . The asymmetric unit contains two independent halves of Zn(dbm) 2 , one T3PyA and one THF. Each Zn II atom is located on an inversion centre and adopts an elongated octahedral coordination geometry, ligated by four O atoms of two dbm ligands in equatorial positions and by two N atoms of pyridine moieties from two different bridging T3PyA ligands in axial positions. The crystal packing shows a onedimensional polymer chain in which the two pyridyl groups of the T3PyA ligand bridge two independent Zn atoms of Zn(dbm) 2 . In the crystal, the coordination polymer chains are linked via C-HÁ Á Á interactions into a sheet structure parallel to (010). The sheets are cross-linked via further C-HÁ Á Á interactions into a three-dimensional network. The solvate THF molecule shows disorder over two sets of atomic sites having occupancies of 0.631 (7) and 0.369 (7).

Chemical context
The structure of coordination polymers generated from the self-assembly of metal ions and bridging organic ligands depends on the molecular structures of the ligands and the coordination geometries of the metal ions. The pyridyl-groupterminated spacer ligands with coordinating ability and optical or electronic functionalities have been widely used to construct a variety of coordination polymers with designable structures and attractive potential applications in material science (Robin & Fromm, 2006;Allendorf et al., 2009;Stavila et al., 2014). Triphenylamine-based structures are some of the most important moieties and electron-donating groups in organic electronic materials, e.g. organic or organic-inorganic hybrid light-emitting diodes and solar cells, because of their electroactivity, photoactivity and chemical stability (Shirota & Kageyama, 2007;Mahmood, 2016;Agarwala & Kabra, 2017). One of the pyridyl-group-terminated triphenylamine derivatives, tris [4-(pyridin-3-yl)phenyl]amine (T3PyA), was firstly synthesized by Hu et al. (2013) as a pH-sensitive fluorophore. Recently, its Pd II complex was also reported (Wang et al., 2016). We report herein on the crystal structure of the title coordination polymer composed of an exo-tridentate tripyridyl-type ligand, a -diketonato ligand and a closed-shell Zn II atom as the building blocks. ISSN 2056-9890

Structural commentary
The asymmetric unit of the title coordination polymer is composed of two unique halves of the bis(3-oxo-1,3-diphenylprop-1-enolato-2 O,O 0 )zinc(II) [Zn(dbm) 2 ] moiety, one T3PyA ligand bridging the Zn atoms in a 2 -2 mode and one tetrahydrofuran (THF) solvate molecule (Fig. 1). Each Zn atom is located on an inversion centre and adopts an elongated octahedral coordination geometry, ligated by four O atoms of bidentate -diketonato dbm ligands in equatorial positions and by two N atoms of pyridine moieties from two different bridging T3PyA ligands in axial positions. The equatorial Zn-O bond lengths [2.0440 (17)-2.0629 (18) Å ] are shorter than the axial Zn-N bond lengths [Zn1-N9 = 2.199 (2) Å and Zn2-N10 = 2.238 (2) Å ]. In the two inde-pendent Zn(dbm) 2 moieties, the bond lengths and angles are similar, but a difference in the dihedral angles between the mean planes of the benzene rings in dbm is observed [56.19 (16) between the C12-C17 and C21-C26 rings in the moiety containing Zn1,and 30.68 (14) between the C27-C32 and C36-C41 rings in the moiety containing Zn2]. The bridging T3PyA ligand has three pyridyl N atoms (N9, N10 and N11). Atoms N9 and N10 each coordinate to two different Zn atoms, while atom N11 does not interact with the surrounding atoms. The central N atom (N8) of T3PyA shows no pyramidalization, with a displacement of 0.052 (2) Å from the plane of the bonded C atoms (C42, C48 and C54) in the benzene rings. The dihedral angles between the mean planes of the benzene and pyridine rings in T3PyA are 47.56 (13), 33.60 (13) and 26.35 (15) , respectively, between the C42-C47 and N9/ C60-C64 rings, the C48-C53 and N10/C65-C69 rings, and the C54-C59 and N11/C70-C74 rings.

Figure 1
The molecular structure of the title compound, with the atom labelling.  hydrogen bond between the coordination polymer and the  major disorder component of the solvate THF molecule  (C13-H13Á Á ÁO7A, Table 1), while a C-HÁ Á Á interaction is observed between the minor disorder component of the solvate THF molecule and the coordination polymer (C75B-H75CÁ Á ÁCg4 ii ; Cg4 is the centroid of the N11/C70-C74 ring; symmetry code as in Table 1). The coordination polymer chains related by translation along the c axis are linked via a C-HÁ Á Á interaction (C40-H40Á Á ÁCg1 i ; Cg1 is the centroid of the N10/C65-C69 ring; symmetry code as in Table 1) into a network sheet parallel to (010) (Fig. 3). In addition, the coordination polymer chains related by a c-glide plane are linked via C-HÁ Á Á interactions (C43-H43Á Á ÁCg2 ii and C68-H68Á Á ÁCg3 iii ; Cg2 and Cg3 are the centroids of the C54-C59 and C36-C41 rings, respectively; symmetry codes as in Table 1) (Fig. 4). The sheets parallel to (010) are cross-linked via these C-HÁ Á Á interactions into a three-dimensional network.  Soldatov et al., 2003). In this complex, the Zn II atom is ligated by the two N atoms of the 4,4 0 -bipyridyl ligand and the four O atoms of two -diketonate anions, hence the Zn II atom is trans-N 2 O 4 six-coordinate, similar to that in the title compound.

Refinement
Crystal data, data collection and structure refinement details are summarized in Table 2. Hydrogen atoms were placed in geometrically calculated positions (C-H = 0.93-0.99 Å ) and refined as part of a riding model with U iso (H) = 1.2U eq (C). The solvate THF molecule is disordered over two sets of sites with refined occupancies of 0.631 (7) and 0.369 (7). EADP constraints and SAME restraints were used to model this disordered molecule. A small number of reflections affected by the beam stop and one outlier (311) were omitted from the refinement.  Data collection: RAPID-AUTO (Rigaku, 2006); cell refinement: RAPID-AUTO (Rigaku, 2006); data reduction: RAPID-AUTO (Rigaku, 2006); program(s) used to solve structure: SIR92 (Altomare et al., 1993); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015); molecular graphics: PLATON (Spek, 2009); software used to prepare material for publication: CrystalStructure (Rigaku, 2016).