Related literature {#sec1}
==================

For related structures, see: Hou *et al.* (2005[@bb2]); Zhang *et al.* (2007[@bb5])

Experimental {#sec2}
============

 {#sec2.1}

### Crystal data {#sec2.1.1}

\[Cu~2~Cl~3~(C~20~H~14~N~4~)\]*M* *~r~* = 543.78Triclinic,*a* = 8.1389 (8) Å*b* = 9.8161 (10) Å*c* = 12.4823 (13) Åα = 79.512 (2)°β = 85.036 (2)°γ = 88.202 (2)°*V* = 976.78 (17) Å^3^*Z* = 2Mo *K*α radiationμ = 2.60 mm^−1^*T* = 294 K0.15 × 0.12 × 0.10 mm

### Data collection {#sec2.1.2}

Bruker SMART diffractometerAbsorption correction: multi-scan (*SADABS*; Sheldrick, 1996[@bb3]) *T* ~min~ = 0.694, *T* ~max~ = 0.7717840 measured reflections3778 independent reflections3391 reflections with *I* \> 2σ(*I*)*R* ~int~ = 0.014

### Refinement {#sec2.1.3}

*R*\[*F* ^2^ \> 2σ(*F* ^2^)\] = 0.027*wR*(*F* ^2^) = 0.072*S* = 1.063778 reflections262 parametersH-atom parameters constrainedΔρ~max~ = 0.40 e Å^−3^Δρ~min~ = −0.34 e Å^−3^

 {#d5e369}

Data collection: *SMART* (Bruker, 1998[@bb1]); cell refinement: *SAINT* (Bruker, 1998[@bb1]); data reduction: *SAINT*; program(s) used to solve structure: *SHELXS97* (Sheldrick, 2008[@bb4]); program(s) used to refine structure: *SHELXL97* (Sheldrick, 2008[@bb4]); molecular graphics: *SHELXTL* (Sheldrick, 2008[@bb4]); software used to prepare material for publication: *SHELXTL*.

Supplementary Material
======================

Crystal structure: contains datablocks I, global. DOI: [10.1107/S1600536811014759/ng5143sup1.cif](http://dx.doi.org/10.1107/S1600536811014759/ng5143sup1.cif)

Structure factors: contains datablocks I. DOI: [10.1107/S1600536811014759/ng5143Isup2.hkl](http://dx.doi.org/10.1107/S1600536811014759/ng5143Isup2.hkl)

Additional supplementary materials: [crystallographic information](http://scripts.iucr.org/cgi-bin/sendsupfiles?ng5143&file=ng5143sup0.html&mime=text/html); [3D view](http://scripts.iucr.org/cgi-bin/sendcif?ng5143sup1&Qmime=cif); [checkCIF report](http://scripts.iucr.org/cgi-bin/paper?ng5143&checkcif=yes)

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: [NG5143](http://scripts.iucr.org/cgi-bin/sendsup?ng5143)).

Comment
=======

Terpyridine and its derivatives have been receiving rapidly increasing attention recently not only because of their versatility as building blocks in supramolecular assembles, but also due to the interesting electronic, photonic and magnetic properties of their transition metal complexes.

4\'-(4-Pyridyl)-2,2\':6\'2\'\'-terpyridine(pyterpy) belongs to this group of ligands and has usually been used to construct a great variety of structurally interesting entities, such as ribbon-type coordination polymers (Hou *et al.*, 2005) and self-catenated networks (Zhang *et al.*, 2007).

The structure of the title compound (I) is shown in Fig. 1. Single-crystal X-ray diffraction shows that the asymmetric unit contains two Cu crystallographically nonequivalent atoms. The Cu1 atom has a distorted square-pyramidal coordination formed by three N atoms of tridentate 4\'-(4-pyridyl)-2,2\':6\'2\'\'-terpyridine (pyterpy) ligand and two Cl atoms. The Cu2 atom is coordinated by one N atom from the pendent monodentate pyridine of pyterpy as well as by three Cl atoms, conferring a tetrahedral coordination geometry. The two terpy ligands in a *transoid* arrangement link Cu1 and Cu2 atoms, to form a mixed-valence tetrameric *M*~4~*L*~4~ rectangular unit with a separation of 11.017 Å, which is smaller than those in reported ribbon-type compounds, and then linked by a Cu~2~Cl~2~ cluster, leading to the formation of an infinite 1-D coordination polymer (Fig. 2).

Experimental {#experimental}
============

The mixture of CuCl (0.020 g, 0.2 mmol), 4\'-(4-pyridyl)-2,2\':6\'2\'\'-terpyridine (pyterpy) (0.062 g, 0.1 mmol), and acetonitrile (6 ml) were placed and sealed in a 15 ml Teflon-lined stainless steel reactor and heated to 180 °C for 72 h, then cooled down to room temperature at a rate of 2 °C/ 20 min. Single crystals suitable for X-ray diffraction were obtained in the form of black bars in *ca* 20% yield.

Refinement {#refinement}
==========

H atoms were positioned geometrically and refined using a riding model, with C---H = 0.93 Å (aromatic) and *U*~iso~(H) = 1.2*U*~eq~(C)

Figures
=======

![The asymmetric unit of the title compound.](e-67-0m639-fig1){#Fap1}

![The 1-D zigzag chain structure of the title compoud.](e-67-0m639-fig2){#Fap2}

Crystal data {#tablewrapcrystaldatalong}
============

  -------------------------------- ---------------------------------------
  \[Cu~2~Cl~3~(C~20~H~14~N~4~)\]   *Z* = 2
  *M~r~* = 543.78                  *F*(000) = 542
  Triclinic, *P*1                  *D*~x~ = 1.849 Mg m^−3^
  Hall symbol: -P 1                Mo *K*α radiation, λ = 0.71073 Å
  *a* = 8.1389 (8) Å               Cell parameters from 1056 reflections
  *b* = 9.8161 (10) Å              θ = 2.4--26.0°
  *c* = 12.4823 (13) Å             µ = 2.60 mm^−1^
  α = 79.512 (2)°                  *T* = 294 K
  β = 85.036 (2)°                  Block, black
  γ = 88.202 (2)°                  0.15 × 0.12 × 0.10 mm
  *V* = 976.78 (17) Å^3^           
  -------------------------------- ---------------------------------------

Data collection {#tablewrapdatacollectionlong}
===============

  --------------------------------------------------------------- --------------------------------------
  Bruker SMART diffractometer                                     3778 independent reflections
  Radiation source: fine-focus sealed tube                        3391 reflections with *I* \> 2σ(*I*)
  graphite                                                        *R*~int~ = 0.014
  φ and ω scans                                                   θ~max~ = 26.0°, θ~min~ = 2.1°
  Absorption correction: multi-scan (*SADABS*; Sheldrick, 1996)   *h* = −10→9
  *T*~min~ = 0.694, *T*~max~ = 0.771                              *k* = −12→12
  7840 measured reflections                                       *l* = −15→15
  --------------------------------------------------------------- --------------------------------------

Refinement {#tablewraprefinementdatalong}
==========

  ------------------------------------- -------------------------------------------------------------------------------------------------
  Refinement on *F*^2^                  Primary atom site location: structure-invariant direct methods
  Least-squares matrix: full            Secondary atom site location: difference Fourier map
  *R*\[*F*^2^ \> 2σ(*F*^2^)\] = 0.027   Hydrogen site location: inferred from neighbouring sites
  *wR*(*F*^2^) = 0.072                  H-atom parameters constrained
  *S* = 1.06                            *w* = 1/\[σ^2^(*F*~o~^2^) + (0.0383*P*)^2^ + 0.3983*P*\] where *P* = (*F*~o~^2^ + 2*F*~c~^2^)/3
  3778 reflections                      (Δ/σ)~max~ = 0.002
  262 parameters                        Δρ~max~ = 0.40 e Å^−3^
  0 restraints                          Δρ~min~ = −0.34 e Å^−3^
  ------------------------------------- -------------------------------------------------------------------------------------------------

Special details {#specialdetails}
===============

  ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
  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^) {#tablewrapcoords}
==================================================================================================

  ----- ------------- -------------- -------------- -------------------- --
        *x*           *y*            *z*            *U*~iso~\*/*U*~eq~   
  Cu1   1.55686 (3)   0.36696 (3)    −0.35707 (2)   0.02849 (9)          
  Cu2   1.49349 (3)   0.14312 (3)    −0.05428 (3)   0.04087 (10)         
  Cl1   1.36557 (7)   −0.05058 (6)   −0.10452 (5)   0.03600 (14)         
  Cl3   1.68201 (7)   0.25884 (6)    −0.18347 (5)   0.03968 (15)         
  Cl2   1.73952 (7)   0.30031 (7)    −0.48213 (5)   0.04485 (16)         
  C16   0.4539 (2)    0.3584 (2)     0.30399 (17)   0.0271 (4)           
  N2    0.6324 (2)    0.54582 (18)   0.28869 (14)   0.0266 (4)           
  N4    1.2937 (2)    0.24557 (19)   0.00438 (16)   0.0332 (4)           
  N3    0.3521 (2)    0.43980 (19)   0.35802 (14)   0.0299 (4)           
  N1    0.6210 (2)    0.77686 (18)   0.35354 (14)   0.0288 (4)           
  C11   1.3087 (3)    0.3651 (2)     0.03817 (19)   0.0333 (5)           
  H11   1.4103        0.4084         0.0239         0.040\*              
  C15   0.6150 (2)    0.4212 (2)     0.26284 (17)   0.0265 (4)           
  C14   0.7417 (2)    0.3610 (2)     0.20518 (17)   0.0282 (4)           
  H14   0.7274        0.2755         0.1854         0.034\*              
  C9    1.0297 (2)    0.3681 (2)     0.11560 (17)   0.0273 (4)           
  C8    0.8918 (2)    0.4302 (2)     0.17696 (17)   0.0260 (4)           
  C6    0.7742 (2)    0.6135 (2)     0.26509 (17)   0.0270 (4)           
  C7    0.9077 (2)    0.5576 (2)     0.20962 (17)   0.0286 (4)           
  H7    1.0068        0.6047         0.1944         0.034\*              
  C10   1.1832 (3)    0.4291 (2)     0.09312 (19)   0.0324 (5)           
  H10   1.2014        0.5126         0.1150         0.039\*              
  C1    0.6025 (3)    0.8956 (2)     0.39099 (19)   0.0355 (5)           
  H1    0.5002        0.9170         0.4237         0.043\*              
  C3    0.8787 (3)    0.9570 (3)     0.3336 (2)     0.0464 (6)           
  H3    0.9655        1.0182         0.3272         0.056\*              
  C18   0.2576 (3)    0.1787 (3)     0.3369 (2)     0.0415 (6)           
  H18   0.2260        0.0904         0.3308         0.050\*              
  C4    0.9006 (3)    0.8347 (2)     0.2933 (2)     0.0404 (6)           
  H4    1.0018        0.8122         0.2598         0.049\*              
  C5    0.7688 (3)    0.7472 (2)     0.30392 (17)   0.0286 (4)           
  C17   0.4102 (3)    0.2284 (2)     0.29147 (19)   0.0335 (5)           
  H17   0.4816        0.1749         0.2532         0.040\*              
  C2    0.7283 (3)    0.9875 (3)     0.3832 (2)     0.0411 (6)           
  H2    0.7120        1.0691         0.4109         0.049\*              
  C13   1.0125 (3)    0.2455 (3)     0.0776 (2)     0.0465 (7)           
  H13   0.9113        0.2014         0.0886         0.056\*              
  C20   0.2040 (3)    0.3911 (3)     0.40001 (19)   0.0368 (5)           
  H20   0.1330        0.4468         0.4364         0.044\*              
  C19   0.1529 (3)    0.2610 (3)     0.3913 (2)     0.0420 (6)           
  H19   0.0496        0.2296         0.4216         0.050\*              
  C12   1.1452 (3)    0.1887 (3)     0.0232 (2)     0.0480 (7)           
  H12   1.1300        0.1065         −0.0014        0.058\*              
  ----- ------------- -------------- -------------- -------------------- --

Atomic displacement parameters (Å^2^) {#tablewrapadps}
=====================================

  ----- -------------- -------------- -------------- -------------- -------------- ---------------
        *U*^11^        *U*^22^        *U*^33^        *U*^12^        *U*^13^        *U*^23^
  Cu1   0.02035 (14)   0.03193 (16)   0.03487 (16)   0.00211 (10)   0.00583 (10)   −0.01466 (11)
  Cu2   0.02869 (16)   0.04265 (18)   0.0509 (2)     0.00035 (12)   0.01106 (13)   −0.01440 (14)
  Cl1   0.0362 (3)     0.0355 (3)     0.0399 (3)     −0.0021 (2)    −0.0025 (2)    −0.0165 (2)
  Cl3   0.0261 (3)     0.0494 (3)     0.0401 (3)     −0.0083 (2)    0.0011 (2)     0.0003 (3)
  Cl2   0.0350 (3)     0.0568 (4)     0.0461 (3)     0.0020 (3)     0.0134 (2)     −0.0265 (3)
  C16   0.0199 (10)    0.0300 (11)    0.0308 (11)    0.0016 (8)     0.0031 (8)     −0.0069 (9)
  N2    0.0191 (8)     0.0270 (9)     0.0340 (9)     0.0018 (7)     0.0035 (7)     −0.0092 (7)
  N4    0.0229 (9)     0.0345 (10)    0.0428 (11)    0.0016 (7)     0.0081 (8)     −0.0140 (8)
  N3    0.0234 (9)     0.0323 (10)    0.0334 (10)    0.0012 (7)     0.0061 (7)     −0.0085 (8)
  N1    0.0244 (9)     0.0311 (9)     0.0335 (9)     0.0033 (7)     −0.0003 (7)    −0.0143 (8)
  C11   0.0208 (10)    0.0339 (12)    0.0455 (13)    −0.0020 (9)    0.0067 (9)     −0.0120 (10)
  C15   0.0211 (10)    0.0263 (10)    0.0319 (11)    0.0001 (8)     0.0028 (8)     −0.0073 (8)
  C14   0.0228 (10)    0.0270 (10)    0.0359 (11)    −0.0002 (8)    0.0051 (8)     −0.0121 (9)
  C9    0.0217 (10)    0.0289 (11)    0.0315 (11)    0.0030 (8)     0.0033 (8)     −0.0092 (9)
  C8    0.0211 (10)    0.0285 (11)    0.0291 (10)    0.0023 (8)     0.0016 (8)     −0.0094 (8)
  C6    0.0203 (10)    0.0284 (11)    0.0331 (11)    0.0024 (8)     0.0015 (8)     −0.0099 (9)
  C7    0.0199 (10)    0.0309 (11)    0.0365 (12)    −0.0011 (8)    0.0035 (8)     −0.0125 (9)
  C10   0.0235 (11)    0.0306 (11)    0.0452 (13)    −0.0013 (9)    0.0034 (9)     −0.0149 (10)
  C1    0.0316 (12)    0.0363 (12)    0.0416 (13)    0.0062 (10)    0.0012 (10)    −0.0184 (10)
  C3    0.0365 (13)    0.0401 (14)    0.0682 (18)    −0.0090 (11)   −0.0012 (12)   −0.0244 (13)
  C18   0.0294 (12)    0.0366 (13)    0.0583 (16)    −0.0068 (10)   0.0024 (11)    −0.0096 (11)
  C4    0.0261 (11)    0.0393 (13)    0.0595 (15)    −0.0017 (10)   0.0031 (10)    −0.0213 (12)
  C5    0.0238 (10)    0.0294 (11)    0.0342 (11)    0.0038 (8)     −0.0005 (8)    −0.0117 (9)
  C17   0.0232 (11)    0.0334 (12)    0.0444 (13)    −0.0002 (9)    0.0043 (9)     −0.0115 (10)
  C2    0.0433 (14)    0.0348 (13)    0.0504 (14)    0.0015 (10)    −0.0019 (11)   −0.0231 (11)
  C13   0.0246 (11)    0.0452 (14)    0.0749 (18)    −0.0108 (10)   0.0186 (11)    −0.0334 (13)
  C20   0.0240 (11)    0.0434 (13)    0.0411 (13)    0.0019 (10)    0.0092 (9)     −0.0087 (10)
  C19   0.0225 (11)    0.0462 (14)    0.0538 (15)    −0.0075 (10)   0.0082 (10)    −0.0044 (12)
  C12   0.0326 (13)    0.0413 (14)    0.0762 (19)    −0.0075 (11)   0.0179 (12)    −0.0361 (13)
  ----- -------------- -------------- -------------- -------------- -------------- ---------------

Geometric parameters (Å, °) {#tablewrapgeomlong}
===========================

  ------------------------- ------------- ----------------- -------------
  Cu1---N2^i^               1.9466 (16)   C14---H14         0.9300
  Cu1---N1^i^               2.0455 (18)   C9---C10          1.387 (3)
  Cu1---N3^i^               2.0557 (18)   C9---C13          1.387 (3)
  Cu1---Cl2                 2.2325 (6)    C9---C8           1.483 (3)
  Cu1---Cl3                 2.5172 (6)    C8---C7           1.397 (3)
  Cu2---N4                  2.0374 (18)   C6---C7           1.390 (3)
  Cu2---Cl3                 2.2933 (6)    C6---C5           1.478 (3)
  Cu2---Cl1^ii^             2.3964 (7)    C7---H7           0.9300
  Cu2---Cl1                 2.4007 (6)    C10---H10         0.9300
  Cu2---Cu2^ii^             2.8917 (7)    C1---C2           1.371 (3)
  Cl1---Cu2^ii^             2.3964 (7)    C1---H1           0.9300
  C16---N3                  1.355 (3)     C3---C2           1.373 (3)
  C16---C17                 1.375 (3)     C3---C4           1.385 (3)
  C16---C15                 1.477 (3)     C3---H3           0.9300
  N2---C6                   1.333 (3)     C18---C19         1.377 (3)
  N2---C15                  1.335 (3)     C18---C17         1.385 (3)
  N2---Cu1^i^               1.9466 (16)   C18---H18         0.9300
  N4---C11                  1.330 (3)     C4---C5           1.377 (3)
  N4---C12                  1.332 (3)     C4---H4           0.9300
  N3---C20                  1.339 (3)     C17---H17         0.9300
  N3---Cu1^i^               2.0557 (18)   C2---H2           0.9300
  N1---C1                   1.332 (3)     C13---C12         1.382 (3)
  N1---C5                   1.353 (3)     C13---H13         0.9300
  N1---Cu1^i^               2.0455 (18)   C20---C19         1.381 (3)
  C11---C10                 1.380 (3)     C20---H20         0.9300
  C11---H11                 0.9300        C19---H19         0.9300
  C15---C14                 1.385 (3)     C12---H12         0.9300
  C14---C8                  1.403 (3)                       
                                                            
  N2^i^---Cu1---N1^i^       78.97 (7)     C10---C9---C8     121.92 (19)
  N2^i^---Cu1---N3^i^       79.19 (7)     C13---C9---C8     121.8 (2)
  N1^i^---Cu1---N3^i^       156.19 (7)    C7---C8---C14     118.17 (18)
  N2^i^---Cu1---Cl2         162.20 (6)    C7---C8---C9      121.33 (19)
  N1^i^---Cu1---Cl2         99.27 (5)     C14---C8---C9     120.49 (19)
  N3^i^---Cu1---Cl2         98.61 (5)     N2---C6---C7      120.70 (19)
  N2^i^---Cu1---Cl3         96.91 (5)     N2---C6---C5      112.78 (17)
  N1^i^---Cu1---Cl3         97.93 (5)     C7---C6---C5      126.51 (19)
  N3^i^---Cu1---Cl3         93.99 (5)     C6---C7---C8      119.42 (19)
  Cl2---Cu1---Cl3           100.87 (2)    C6---C7---H7      120.3
  N4---Cu2---Cl3            120.37 (6)    C8---C7---H7      120.3
  N4---Cu2---Cl1^ii^        104.34 (6)    C11---C10---C9    119.6 (2)
  Cl3---Cu2---Cl1^ii^       107.93 (2)    C11---C10---H10   120.2
  N4---Cu2---Cl1            101.32 (6)    C9---C10---H10    120.2
  Cl3---Cu2---Cl1           115.66 (2)    N1---C1---C2      122.6 (2)
  Cl1^ii^---Cu2---Cl1       105.86 (2)    N1---C1---H1      118.7
  N4---Cu2---Cu2^ii^        111.61 (6)    C2---C1---H1      118.7
  Cl3---Cu2---Cu2^ii^       127.92 (2)    C2---C3---C4      119.6 (2)
  Cl1^ii^---Cu2---Cu2^ii^   52.998 (16)   C2---C3---H3      120.2
  Cl1---Cu2---Cu2^ii^       52.861 (18)   C4---C3---H3      120.2
  Cu2^ii^---Cl1---Cu2       74.14 (2)     C19---C18---C17   119.5 (2)
  Cu2---Cl3---Cu1           112.90 (2)    C19---C18---H18   120.2
  N3---C16---C17            122.26 (19)   C17---C18---H18   120.2
  N3---C16---C15            113.85 (18)   C5---C4---C3      118.4 (2)
  C17---C16---C15           123.88 (18)   C5---C4---H4      120.8
  C6---N2---C15             121.47 (17)   C3---C4---H4      120.8
  C6---N2---Cu1^i^          119.54 (14)   N1---C5---C4      121.9 (2)
  C15---N2---Cu1^i^         118.95 (14)   N1---C5---C6      113.76 (18)
  C11---N4---C12            116.29 (19)   C4---C5---C6      124.37 (19)
  C11---N4---Cu2            121.51 (15)   C16---C17---C18   118.6 (2)
  C12---N4---Cu2            121.71 (15)   C16---C17---H17   120.7
  C20---N3---C16            118.36 (19)   C18---C17---H17   120.7
  C20---N3---Cu1^i^         127.42 (15)   C1---C2---C3      118.8 (2)
  C16---N3---Cu1^i^         114.11 (14)   C1---C2---H2      120.6
  C1---N1---C5              118.65 (19)   C3---C2---H2      120.6
  C1---N1---Cu1^i^          126.56 (15)   C12---C13---C9    120.2 (2)
  C5---N1---Cu1^i^          114.75 (14)   C12---C13---H13   119.9
  N4---C11---C10            124.2 (2)     C9---C13---H13    119.9
  N4---C11---H11            117.9         N3---C20---C19    122.4 (2)
  C10---C11---H11           117.9         N3---C20---H20    118.8
  N2---C15---C14            120.84 (19)   C19---C20---H20   118.8
  N2---C15---C16            113.24 (17)   C18---C19---C20   118.9 (2)
  C14---C15---C16           125.90 (19)   C18---C19---H19   120.6
  C15---C14---C8            119.30 (19)   C20---C19---H19   120.6
  C15---C14---H14           120.4         N4---C12---C13    123.4 (2)
  C8---C14---H14            120.4         N4---C12---H12    118.3
  C10---C9---C13            116.26 (19)   C13---C12---H12   118.3
  ------------------------- ------------- ----------------- -------------

Symmetry codes: (i) −*x*+2, −*y*+1, −*z*; (ii) −*x*+3, −*y*, −*z*.
