metal-organic compounds
catena-Poly[[bis(pyridine-κN)zinc]-μ-5-carboxybenzene-1,3-dicarboxylato-κ2O1:O3]
aDivision of Chemistry, School of Science, University of Phayao, Phayao 56000, Thailand, and bDepartment of Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand
*Correspondence e-mail: apinpus@chiangmai.ac.th
The title one-dimensional coordination polymer, [Zn(C9H4O6)(C5H5N)2]n or [Zn(HBTC)(py)2]n, (I), where BTC is benzene-1,3,5-tricarboxylate and py is pyridine, is a solvent-free polymorph of [Zn(HBTC)(py)2]·2C2H5OH [Yaghi et al. (1997). Chem. Mater. 9, 1074–1076]. Differences in the spatial arrangements and supramolecular packing of the [Zn(HBTC)(py)2]n chains in the two structures are described. The chain in (I) extends parallel to [100] and is severely puckered, with a Zn⋯Zn distance of 8.3599 (3) Å and a Zn⋯Zn⋯Zn angle of 107.516 (3)°, as a result of hydrogen-bonding interactions of the types O—H⋯O and C—H⋯O. There is no evidence for π–π interactions in (I). The differences between the solvent-free and solvent-containing structures can be accounted for by the absence of the ethanol solvent molecule and the use of the converging pair of O atoms in the bis-monodentate bridging HBTC2− ligand in (I).
Related literature
For the ethanol monosolvate of (I), see: Yaghi et al. (1997). For a review on supramolecular in coordination compounds, see: Zhang et al. (2009).
Experimental
Crystal data
|
Data collection: APEX2 (Bruker, 2007); cell SAINT (Bruker, 2007); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008) and WinGX (Farrugia, 2012); program(s) used to refine structure: SHELXL2013 (Sheldrick, 2008) and WinGX; molecular graphics: DIAMOND (Brandenburg, 1999); software used to prepare material for publication: publCIF (Westrip, 2010).
Supporting information
10.1107/S1600536813014347/cq2004sup1.cif
contains datablocks I, global. DOI:Structure factors: contains datablock I. DOI: 10.1107/S1600536813014347/cq2004Isup2.hkl
A small fraction of pyridine (0.50 ml, 6.18 mmol; 99.8% Sigma-Aldrich) was gradually added to a 2.50 ml of a 0.204 molL-1 aqueous solution of 1,3,5-benzenetricarboxylic acid (H3BTC; 0.509 mmol; 95% Sigma-Aldrich) with stirring until the acid was completely dissolved. Then 2.50 ml of 0.296 molL-1 ZnSO4.7H2O (aq) solution (0.741 mmol; 99% Sigma-Aldrich) was added, giving a clear solution. The solution was left at ambient temperature for 2 days before the colourless crystals of I started to crystallize.
Atom H5W atom was located in a difference Fourier map. The aromatic H-atoms were treated as riding groups on the bonded C-atoms using a C—H bond length of 0.93 Å.
Data collection: APEX2 (Bruker, 2007); cell
SAINT (Bruker, 2007); data reduction: SAINT (Bruker, 2007); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008) and WinGX (Farrugia, 2012); program(s) used to refine structure: SHELXL2013 (Sheldrick, 2008) and WinGX (Farrugia, 2012); molecular graphics: DIAMOND (Brandenburg, 1999); software used to prepare material for publication: publCIF (Westrip, 2010).Fig. 1. View of an extended unit of I with atom numbering scheme. Displacement ellipsoids are drawn at the 70% probability level. [Symmetry codes: (i) 1/2 + x, 0.5 - y, 1 - z; (ii) -1/2 + x, 0.5 - y, 1 - z] | |
Fig. 2. View of the one-dimensional chain of I. Hydrogen atoms are omitted for clarity. | |
Fig. 3. View of supramolecular packing in I, directed primarily by the O—H···O hydrogen bonding interactions (dotted lines). |
[Zn(C9H4O6)(C5H5N)2] | Dx = 1.613 Mg m−3 |
Mr = 431.69 | Mo Kα radiation, λ = 0.71073 Å |
Orthorhombic, Pbca | Cell parameters from 12396 reflections |
a = 13.4850 (4) Å | θ = 2.3–28.3° |
b = 15.7677 (4) Å | µ = 1.42 mm−1 |
c = 16.7252 (4) Å | T = 293 K |
V = 3556.24 (16) Å3 | Block, colorless |
Z = 8 | 0.40 × 0.32 × 0.20 mm |
F(000) = 1760 |
Bruker SMART CCD area-detector diffractometer | 3448 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.027 |
ω scan | θmax = 28.3°, θmin = 2.3° |
Absorption correction: multi-scan (SADABS; Bruker, 2001) | h = −17→16 |
Tmin = 0.638, Tmax = 0.746 | k = −18→21 |
18851 measured reflections | l = −22→18 |
4402 independent reflections |
Refinement on F2 | 0 restraints |
Least-squares matrix: full | Hydrogen site location: mixed |
R[F2 > 2σ(F2)] = 0.028 | H atoms treated by a mixture of independent and constrained refinement |
wR(F2) = 0.075 | w = 1/[σ2(Fo2) + (0.0343P)2 + 1.2882P] where P = (Fo2 + 2Fc2)/3 |
S = 1.03 | (Δ/σ)max = 0.001 |
4402 reflections | Δρmax = 0.32 e Å−3 |
257 parameters | Δρmin = −0.27 e Å−3 |
[Zn(C9H4O6)(C5H5N)2] | V = 3556.24 (16) Å3 |
Mr = 431.69 | Z = 8 |
Orthorhombic, Pbca | Mo Kα radiation |
a = 13.4850 (4) Å | µ = 1.42 mm−1 |
b = 15.7677 (4) Å | T = 293 K |
c = 16.7252 (4) Å | 0.40 × 0.32 × 0.20 mm |
Bruker SMART CCD area-detector diffractometer | 4402 independent reflections |
Absorption correction: multi-scan (SADABS; Bruker, 2001) | 3448 reflections with I > 2σ(I) |
Tmin = 0.638, Tmax = 0.746 | Rint = 0.027 |
18851 measured reflections |
R[F2 > 2σ(F2)] = 0.028 | 0 restraints |
wR(F2) = 0.075 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.03 | Δρmax = 0.32 e Å−3 |
4402 reflections | Δρmin = −0.27 e Å−3 |
257 parameters |
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. |
x | y | z | Uiso*/Ueq | ||
Zn1 | 0.13687 (2) | 0.15689 (2) | 0.38115 (2) | 0.02934 (7) | |
O1 | 0.22574 (9) | 0.24099 (8) | 0.43444 (8) | 0.0387 (3) | |
O2 | 0.02076 (9) | 0.12804 (8) | 0.44224 (8) | 0.0380 (3) | |
O3 | 0.08532 (9) | 0.31056 (8) | 0.42911 (9) | 0.0403 (3) | |
O4 | 0.17223 (13) | 0.64303 (10) | 0.62643 (11) | 0.0636 (5) | |
O5 | 0.06430 (11) | 0.59328 (10) | 0.53854 (11) | 0.0610 (5) | |
O6 | 0.50499 (11) | 0.48839 (11) | 0.63064 (10) | 0.0572 (4) | |
N1 | 0.24456 (11) | 0.07341 (9) | 0.34795 (9) | 0.0344 (3) | |
N2 | 0.08742 (12) | 0.20600 (9) | 0.27386 (9) | 0.0351 (3) | |
C1 | 0.34018 (14) | 0.09488 (13) | 0.35799 (13) | 0.0403 (4) | |
H1 | 0.3551 | 0.1456 | 0.3837 | 0.048* | |
C2 | 0.41665 (16) | 0.04472 (14) | 0.33178 (15) | 0.0526 (6) | |
H2 | 0.4821 | 0.0612 | 0.3398 | 0.063* | |
C3 | 0.39544 (18) | −0.02992 (14) | 0.29374 (14) | 0.0554 (6) | |
H3 | 0.4463 | −0.0645 | 0.2749 | 0.066* | |
C4 | 0.29877 (19) | −0.05299 (13) | 0.28377 (14) | 0.0554 (6) | |
H4 | 0.2829 | −0.1038 | 0.2586 | 0.066* | |
C5 | 0.22515 (16) | −0.00031 (13) | 0.31132 (12) | 0.0451 (5) | |
H5 | 0.1594 | −0.0164 | 0.3043 | 0.054* | |
C6 | 0.14604 (16) | 0.21440 (13) | 0.21013 (12) | 0.0455 (5) | |
H6 | 0.2091 | 0.1906 | 0.2119 | 0.055* | |
C7 | 0.1175 (2) | 0.25651 (16) | 0.14217 (13) | 0.0581 (6) | |
H7 | 0.1607 | 0.2614 | 0.0991 | 0.070* | |
C8 | 0.0245 (2) | 0.29120 (16) | 0.13863 (15) | 0.0639 (7) | |
H8 | 0.0034 | 0.3200 | 0.0932 | 0.077* | |
C9 | −0.03721 (19) | 0.28258 (14) | 0.20360 (15) | 0.0570 (6) | |
H9 | −0.1010 | 0.3050 | 0.2025 | 0.068* | |
C10 | −0.00334 (15) | 0.24024 (12) | 0.27043 (12) | 0.0424 (5) | |
H10 | −0.0449 | 0.2353 | 0.3145 | 0.051* | |
C11 | 0.17367 (13) | 0.30629 (11) | 0.44909 (10) | 0.0290 (3) | |
C12 | 0.22248 (12) | 0.37837 (10) | 0.49276 (10) | 0.0274 (3) | |
C13 | 0.32159 (13) | 0.37427 (11) | 0.51554 (10) | 0.0290 (4) | |
H13 | 0.3589 | 0.3265 | 0.5029 | 0.035* | |
C14 | 0.36539 (12) | 0.44093 (11) | 0.55706 (10) | 0.0296 (4) | |
C15 | 0.30929 (13) | 0.51149 (11) | 0.57672 (11) | 0.0325 (4) | |
H15 | 0.3381 | 0.5560 | 0.6048 | 0.039* | |
C16 | 0.20993 (12) | 0.51606 (11) | 0.55457 (11) | 0.0311 (4) | |
C17 | 0.16744 (13) | 0.44966 (11) | 0.51237 (11) | 0.0306 (4) | |
H17 | 0.1013 | 0.4530 | 0.4970 | 0.037* | |
C18 | 0.14864 (13) | 0.59105 (12) | 0.57802 (13) | 0.0377 (4) | |
C19 | 0.47177 (13) | 0.43569 (11) | 0.58439 (11) | 0.0322 (4) | |
H5W | 0.022 (2) | 0.6310 (19) | 0.5540 (18) | 0.096 (10)* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Zn1 | 0.02247 (11) | 0.02948 (11) | 0.03608 (12) | −0.00104 (8) | 0.00170 (8) | −0.00546 (8) |
O1 | 0.0273 (7) | 0.0301 (6) | 0.0587 (8) | 0.0041 (5) | −0.0047 (6) | −0.0160 (6) |
O2 | 0.0269 (7) | 0.0399 (7) | 0.0472 (7) | −0.0100 (5) | 0.0077 (6) | −0.0080 (6) |
O3 | 0.0262 (7) | 0.0345 (7) | 0.0604 (9) | 0.0031 (5) | −0.0077 (6) | −0.0175 (6) |
O4 | 0.0489 (9) | 0.0533 (10) | 0.0887 (13) | 0.0178 (8) | −0.0231 (9) | −0.0421 (9) |
O5 | 0.0303 (8) | 0.0560 (10) | 0.0967 (13) | 0.0175 (7) | −0.0177 (8) | −0.0409 (9) |
O6 | 0.0325 (8) | 0.0634 (10) | 0.0759 (11) | 0.0070 (7) | −0.0159 (7) | −0.0354 (8) |
N1 | 0.0317 (8) | 0.0309 (8) | 0.0407 (8) | 0.0036 (6) | 0.0055 (7) | −0.0024 (7) |
N2 | 0.0352 (9) | 0.0350 (8) | 0.0352 (8) | 0.0005 (7) | −0.0019 (7) | −0.0053 (7) |
C1 | 0.0338 (10) | 0.0344 (10) | 0.0526 (11) | 0.0012 (8) | 0.0058 (9) | −0.0005 (9) |
C2 | 0.0342 (11) | 0.0496 (12) | 0.0740 (16) | 0.0100 (9) | 0.0150 (10) | 0.0077 (11) |
C3 | 0.0593 (15) | 0.0445 (12) | 0.0625 (14) | 0.0220 (11) | 0.0265 (12) | 0.0054 (11) |
C4 | 0.0711 (16) | 0.0364 (11) | 0.0587 (14) | 0.0090 (11) | 0.0144 (12) | −0.0115 (10) |
C5 | 0.0442 (12) | 0.0368 (10) | 0.0544 (12) | 0.0002 (9) | 0.0051 (10) | −0.0112 (9) |
C6 | 0.0488 (13) | 0.0469 (11) | 0.0408 (11) | −0.0019 (10) | 0.0059 (9) | −0.0068 (9) |
C7 | 0.0817 (18) | 0.0554 (14) | 0.0373 (11) | −0.0166 (13) | 0.0046 (11) | −0.0009 (11) |
C8 | 0.094 (2) | 0.0476 (13) | 0.0500 (14) | −0.0149 (14) | −0.0259 (14) | 0.0094 (11) |
C9 | 0.0558 (15) | 0.0443 (12) | 0.0710 (16) | 0.0029 (11) | −0.0223 (12) | 0.0006 (11) |
C10 | 0.0403 (11) | 0.0397 (10) | 0.0472 (11) | 0.0016 (9) | −0.0036 (9) | −0.0043 (9) |
C11 | 0.0273 (8) | 0.0256 (8) | 0.0342 (9) | −0.0003 (7) | 0.0012 (7) | −0.0049 (7) |
C12 | 0.0239 (8) | 0.0256 (8) | 0.0328 (8) | −0.0012 (6) | 0.0005 (7) | −0.0037 (7) |
C13 | 0.0239 (8) | 0.0272 (8) | 0.0358 (9) | 0.0041 (7) | 0.0006 (7) | −0.0042 (7) |
C14 | 0.0224 (8) | 0.0321 (9) | 0.0342 (9) | 0.0018 (7) | −0.0015 (7) | −0.0028 (7) |
C15 | 0.0258 (9) | 0.0304 (9) | 0.0414 (10) | −0.0007 (7) | −0.0038 (7) | −0.0100 (8) |
C16 | 0.0242 (8) | 0.0287 (8) | 0.0404 (9) | 0.0023 (7) | −0.0015 (7) | −0.0080 (7) |
C17 | 0.0215 (8) | 0.0300 (9) | 0.0404 (10) | 0.0008 (7) | −0.0027 (7) | −0.0057 (7) |
C18 | 0.0256 (9) | 0.0338 (9) | 0.0536 (12) | 0.0040 (7) | −0.0019 (8) | −0.0114 (9) |
C19 | 0.0246 (8) | 0.0359 (9) | 0.0361 (9) | 0.0021 (7) | −0.0013 (7) | −0.0018 (8) |
Zn1—O2 | 1.9241 (12) | C5—H5 | 0.9300 |
Zn1—O1 | 1.9973 (12) | C6—C7 | 1.371 (3) |
Zn1—N1 | 2.0371 (14) | C6—H6 | 0.9300 |
Zn1—N2 | 2.0650 (15) | C7—C8 | 1.370 (4) |
O1—C11 | 1.270 (2) | C7—H7 | 0.9300 |
O2—C19i | 1.283 (2) | C8—C9 | 1.375 (4) |
O3—C11 | 1.239 (2) | C8—H8 | 0.9300 |
O4—C18 | 1.195 (2) | C9—C10 | 1.380 (3) |
O5—C18 | 1.315 (2) | C9—H9 | 0.9300 |
O5—H5W | 0.86 (3) | C10—H10 | 0.9300 |
O6—C19 | 1.220 (2) | C11—C12 | 1.503 (2) |
N1—C5 | 1.340 (2) | C12—C17 | 1.386 (2) |
N1—C1 | 1.344 (2) | C12—C13 | 1.391 (2) |
N2—C6 | 1.334 (3) | C13—C14 | 1.391 (2) |
N2—C10 | 1.339 (2) | C13—H13 | 0.9300 |
C1—C2 | 1.372 (3) | C14—C15 | 1.385 (2) |
C1—H1 | 0.9300 | C14—C19 | 1.508 (2) |
C2—C3 | 1.368 (3) | C15—C16 | 1.392 (2) |
C2—H2 | 0.9300 | C15—H15 | 0.9300 |
C3—C4 | 1.364 (3) | C16—C17 | 1.387 (2) |
C3—H3 | 0.9300 | C16—C18 | 1.495 (2) |
C4—C5 | 1.374 (3) | C17—H17 | 0.9300 |
C4—H4 | 0.9300 | C19—O2ii | 1.283 (2) |
O2—Zn1—O1 | 114.10 (5) | C7—C8—C9 | 118.7 (2) |
O2—Zn1—N1 | 124.90 (6) | C7—C8—H8 | 120.6 |
O1—Zn1—N1 | 97.06 (6) | C9—C8—H8 | 120.6 |
O2—Zn1—N2 | 106.70 (6) | C8—C9—C10 | 119.2 (2) |
O1—Zn1—N2 | 109.43 (6) | C8—C9—H9 | 120.4 |
N1—Zn1—N2 | 103.63 (6) | C10—C9—H9 | 120.4 |
C11—O1—Zn1 | 107.01 (11) | N2—C10—C9 | 122.2 (2) |
C19i—O2—Zn1 | 114.84 (11) | N2—C10—H10 | 118.9 |
C18—O5—H5W | 116 (2) | C9—C10—H10 | 118.9 |
C5—N1—C1 | 117.60 (17) | O3—C11—O1 | 121.57 (15) |
C5—N1—Zn1 | 123.09 (13) | O3—C11—C12 | 120.73 (15) |
C1—N1—Zn1 | 119.16 (13) | O1—C11—C12 | 117.69 (15) |
C6—N2—C10 | 117.87 (18) | C17—C12—C13 | 119.16 (15) |
C6—N2—Zn1 | 122.71 (14) | C17—C12—C11 | 119.58 (15) |
C10—N2—Zn1 | 118.92 (13) | C13—C12—C11 | 121.25 (15) |
N1—C1—C2 | 122.4 (2) | C12—C13—C14 | 120.63 (15) |
N1—C1—H1 | 118.8 | C12—C13—H13 | 119.7 |
C2—C1—H1 | 118.8 | C14—C13—H13 | 119.7 |
C3—C2—C1 | 119.2 (2) | C15—C14—C13 | 119.57 (15) |
C3—C2—H2 | 120.4 | C15—C14—C19 | 119.45 (15) |
C1—C2—H2 | 120.4 | C13—C14—C19 | 120.92 (15) |
C4—C3—C2 | 119.09 (19) | C14—C15—C16 | 120.28 (16) |
C4—C3—H3 | 120.5 | C14—C15—H15 | 119.9 |
C2—C3—H3 | 120.5 | C16—C15—H15 | 119.9 |
C3—C4—C5 | 119.2 (2) | C17—C16—C15 | 119.61 (15) |
C3—C4—H4 | 120.4 | C17—C16—C18 | 120.15 (15) |
C5—C4—H4 | 120.4 | C15—C16—C18 | 120.22 (15) |
N1—C5—C4 | 122.5 (2) | C12—C17—C16 | 120.75 (16) |
N1—C5—H5 | 118.8 | C12—C17—H17 | 119.6 |
C4—C5—H5 | 118.8 | C16—C17—H17 | 119.6 |
N2—C6—C7 | 123.0 (2) | O4—C18—O5 | 123.49 (18) |
N2—C6—H6 | 118.5 | O4—C18—C16 | 124.95 (17) |
C7—C6—H6 | 118.5 | O5—C18—C16 | 111.55 (16) |
C8—C7—C6 | 119.1 (2) | O6—C19—O2ii | 124.36 (17) |
C8—C7—H7 | 120.5 | O6—C19—C14 | 120.27 (16) |
C6—C7—H7 | 120.5 | O2ii—C19—C14 | 115.32 (15) |
Symmetry codes: (i) x−1/2, −y+1/2, −z+1; (ii) x+1/2, −y+1/2, −z+1. |
D—H···A | D—H | H···A | D···A | D—H···A |
O5—H5W···O3iii | 0.86 (3) | 1.74 (3) | 2.5813 (19) | 164 (3) |
C1—H1···O1 | 0.93 | 2.45 | 3.053 (2) | 122 |
C5—H5···O6i | 0.93 | 2.39 | 3.129 (3) | 136 |
C17—H17···O5 | 0.93 | 2.37 | 2.693 (2) | 100 |
C17—H17···O5iii | 0.93 | 2.42 | 3.309 (2) | 159 |
Symmetry codes: (i) x−1/2, −y+1/2, −z+1; (iii) −x, −y+1, −z+1. |
Experimental details
Crystal data | |
Chemical formula | [Zn(C9H4O6)(C5H5N)2] |
Mr | 431.69 |
Crystal system, space group | Orthorhombic, Pbca |
Temperature (K) | 293 |
a, b, c (Å) | 13.4850 (4), 15.7677 (4), 16.7252 (4) |
V (Å3) | 3556.24 (16) |
Z | 8 |
Radiation type | Mo Kα |
µ (mm−1) | 1.42 |
Crystal size (mm) | 0.40 × 0.32 × 0.20 |
Data collection | |
Diffractometer | Bruker SMART CCD area-detector diffractometer |
Absorption correction | Multi-scan (SADABS; Bruker, 2001) |
Tmin, Tmax | 0.638, 0.746 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 18851, 4402, 3448 |
Rint | 0.027 |
(sin θ/λ)max (Å−1) | 0.667 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.028, 0.075, 1.03 |
No. of reflections | 4402 |
No. of parameters | 257 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.32, −0.27 |
Computer programs: APEX2 (Bruker, 2007), SAINT (Bruker, 2007), SHELXS97 (Sheldrick, 2008) and WinGX (Farrugia, 2012), SHELXL2013 (Sheldrick, 2008) and WinGX (Farrugia, 2012), DIAMOND (Brandenburg, 1999), publCIF (Westrip, 2010).
D—H···A | D—H | H···A | D···A | D—H···A |
O5—H5W···O3i | 0.86 (3) | 1.74 (3) | 2.5813 (19) | 164 (3) |
C1—H1···O1 | 0.93 | 2.45 | 3.053 (2) | 122.2 |
C5—H5···O6ii | 0.93 | 2.39 | 3.129 (3) | 136.2 |
C17—H17···O5 | 0.93 | 2.37 | 2.693 (2) | 100.0 |
C17—H17···O5i | 0.93 | 2.42 | 3.309 (2) | 159.2 |
Symmetry codes: (i) −x, −y+1, −z+1; (ii) x−1/2, −y+1/2, −z+1. |
Acknowledgements
This work was financially supported by the Thailand Research Fund and the National Research University Project.
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The reported complex [Zn(HBTC)(py)2]n (I), where BTC = 1,3,5-benzenetricarboxylate and pyr = pyridine (C5H5N), is a supramolecular isomer of the previously reported [Zn(HBTC)(py)2].2C2H5OH (Yaghi et al., 1997). It is clear that the two isomers result from differences in the synthesis method. In order to synthesize I, a simple solution route was adopted, whereas the crystals of [Zn(HBTC)(py)2].2C2H5OH have only been synthesized when poly(ethyleneoxide) (PEO) gel is used as the reaction medium in the presence of C2H5OH as solvent (Yaghi et al., 1997). The absence or presence of the C2H5OH solvent molecules results in different spatial arrangements and supramolecular packing in the two isomers.
While the two supramolecular isomers are built up of the same structural building motifs, i.e. a tetrahedral Zn(II) ion, two monodentate pyr molecules and a bridging HBTC2- anion, the architecture of the one-dimensional chains of the two isomers notably differs. In the case of I, an asymmetric unit comprises a tetrahedral Zn(II) ion (Fig. 1), coordinated by two N atoms (N1 and N2) from two crystallographically independent pyr molecules and two O atoms (O1 and O2) from two distinct carboxylato groups of the HBTC2- anion. The HBTC2- ligand in structure I adopts a bis-monodentate bridging mode (µ2-η1:η1:η0:η0:η0:η0) (Fig. 2), linking two adjacent Zn(II) ions to form a one-dimensional chain of chemical composition [Zn(HBTC)(py)2]n, extending in the [1 0 0] direction. Because of the converging positions of the coordinating O1 and O2 atoms, the derived chain is severely puckered with a Zn···Zn distance of 8.3599 (3) Å and a Zn···Zn···Zn angle of 107.516 (3)°. In comparison, the one-dimensional chain of the previously reported [Zn(HBTC)(py)2].2C2H5OH isomer is almost linear with corresponding distance and angle values of 10.162 (2) Å and 180°, respectively. The presence of the C2H5OH solvent molecule in the vicinity of the two coordinating carboxylato groups in the [Zn(HBTC)(py)2].2C2H5OH isomer ostensibly forces the coordinating atoms to be the diverging pair of O atoms (equivalent to O3 and O6 in I), rather than the converging pair as in I.
A larger degree of puckering in I compared to that of the previously reported isomer imparts an immense influence on the corresponding supramolecular interactions and packing. While there are no π–π interactions in I, which is in contrast to the [Zn(HBTC)(py)2].2C2H5OH case, an acidic proton of the bridging HBTC2- anion is involved in the hydrogen bonding interactions with the O atom of the HBTC2- anion from the adjacent chain (Fig. 3). Weak C—H···O hydrogen bonding interactions further link these one-dimensional chains into a dense, three-dimensional supramolecular structure.