In the crystal structure of the title compound, the central zinc(II) metal atom is surrounded by two N atoms of a bidentate 4,7-methoxy-1,10-phenanthroline ligand and two chlorido ligands in a distorted tetrahedral coordination environment.
Keywords: crystal structure; zinc; 4,7-dimethoxy-1,10-phenanthroline; coordinating chloride ions; distorted tetrahedral coordination environment; metal complex; τ4 descriptor
Abstract
In the title complex, [ZnCl2(C14H12N2O2)], the ZnII atom is located on a twofold rotation axis and is fourfold coordinated by two chlorido ligands and a bidentate 4,7-methoxy-1,10-phenanthroline ligand in a distorted tetrahedral environment. Weak π–π stacking interactions between adjacent 4,7-dimethoxy-1,10-phenanthroline rings [centroid-to-centroid distances = 3.5969 (11) and 3.7738 (11) Å] contribute to the alignment of the complexes in layers parallel to (
01).
Structure description
Over the last five years, metal complexes containing 4,7-dimethoxy-1,10-phenanthroline have garnered significant attention due to their catalytic activity (EL-Atawy et al., 2018 ▸; Liu et al., 2020 ▸) and potential as antitumor agents (Khoury et al., 2022 ▸). Likewise, oxidovanadium(IV) complexes incorporating 4,7-dimethoxy-1,10-phenanthroline have been found to be effective against several cancer cell lines, including A2780 human ovarian adenocarcinoma and HCT116 human colorectal carcinoma (Choroba et al., 2023 ▸). Currently, our research group focuses on creating metal complexes that have uses in biological systems. As part of this work, herein we present the synthesis and crystal structure of the title complex, which shows promise as a valuable precursor for the synthesis of novel zinc(II) complexes.
In the centrosymmetric crystal structure of the title complex, the zinc(II) atom is located on a twofold rotation axis (multiplicity 4, Wyckoff letter e) of space group C2/c. The coordination environment is that of a distorted tetrahedron defined by two pyridine nitrogen atoms from the 4,7-methoxy-1,10-phenanthroline ligand and two chlorido ligands (Fig. 1 ▸). The Zn—N bond lengths are in good agreement with comparable tetrahedral 1,10-phenanthroline complexes currently available in the Cambridge Structure Database (CSD, version 5.45, Nov 2023; Groom et al., 2016 ▸): refcodes DUCBOT (Niu et al., 2009 ▸); TOBGOH (Li et al., 2008 ▸); GODCOU (Luo et al., 2019 ▸); QEVLIQ (Cetin et al., 2020 ▸); ZNPHAT (Reimann et al., 1966 ▸). At this time no 4,7-dimethoxy-1,10-phenanthroline zinc metal complexes have been deposited in the database. Similar behavior is observed for the Zn—Cl bond lengths. The τ4 descriptor value (Yang et al., 2007 ▸) of 0.87 reflects the distortion from the perfect tetrahedral coordination (τ4 = 1.0). Numerical data of relevant bond lengths and angles are presented in Table 1 ▸.
Figure 1.
The molecular structure of the title compound with displacement ellipsoids drawn at the 50% probability level; H atoms are omitted for clarity. Symmetry code: (i) −x + 1, y, −z +
.
Table 1. Selected geometric parameters (Å, °).
| Zn1—Cl1 | 2.2186 (5) | Zn1—N1i | 2.0744 (18) |
| Zn1—Cl1i | 2.2186 (5) | Zn1—N1 | 2.0744 (18) |
| Cl1—Zn1—Cl1i | 120.75 (3) | N1i—Zn1—Cl1 | 107.88 (4) |
| N1i—Zn1—Cl1i | 116.53 (4) | N1—Zn1—Cl1i | 107.88 (4) |
| N1—Zn1—Cl1 | 116.53 (4) | N1i—Zn1—N1 | 80.66 (9) |
Symmetry code: (i)
.
The title complex packs into layers parallel to (
01) (Fig. 2 ▸). Contiguous pyridine rings show weak π–π stacking interactions, with centroid-to-centroid distances (Cg⋯Cg) alternating between 3.5969 (11) and 3.7738 (11) Å, and offset distances of 1.370 and 1.822 Å, respectively. No other significant supramolecular interactions are present in the crystal packing of the title compound.
Figure 2.
Perspective view of the crystal packing of the title complex approximately along the b axis; H atoms are omitted for clarity.
Synthesis and crystallization
The title complex was synthesized by the addition of 4,7-dimethoxy-1,10-phenanthroline (0.176 g, 0.733 mmol) to a 40.0 ml acetonitrile suspension of zinc(II) chloride (0.100 g, 0.733 mmol). After the ligand was added, the resulting solution was heated at 333 K and stirred for 2 h. The resulting solution was then filtrated using a PTFE syringe filter to obtain a clear solution. Crystal suitable for X-ray diffraction were grown by vapor diffusion of diethyl ether over a saturated acetonitrile solution of the title complex.
Refinement
Crystal data, data collection and structure refinement details are summarized in Table 2 ▸.
Table 2. Experimental details.
| Crystal data | |
| Chemical formula | [ZnCl2(C14H12N2O2)] |
| M r | 376.53 |
| Crystal system, space group | Monoclinic, C2/c |
| Temperature (K) | 100 |
| a, b, c (Å) | 14.7877 (6), 9.9287 (4), 9.5230 (3) |
| β (°) | 95.233 (4) |
| V (Å3) | 1392.36 (9) |
| Z | 4 |
| Radiation type | Cu Kα |
| μ (mm−1) | 6.03 |
| Crystal size (mm) | 0.10 × 0.05 × 0.03 |
| Data collection | |
| Diffractometer | XtaLAB Synergy, Dualflex, HyPix |
| Absorption correction | Gaussian (CrysAlis PRO; Rigaku OD, 2023 ▸) |
| T min, T max | 0.780, 1.000 |
| No. of measured, independent and observed [I > 2σ(I)] reflections | 6451, 1385, 1282 |
| R int | 0.044 |
| (sin θ/λ)max (Å−1) | 0.630 |
| Refinement | |
| R[F 2 > 2σ(F 2)], wR(F 2), S | 0.028, 0.078, 1.07 |
| No. of reflections | 1385 |
| No. of parameters | 97 |
| H-atom treatment | H-atom parameters constrained |
| Δρmax, Δρmin (e Å−3) | 0.36, −0.54 |
Supplementary Material
Crystal structure: contains datablock(s) I. DOI: 10.1107/S2414314624000373/wm4203sup1.cif
Structure factors: contains datablock(s) I. DOI: 10.1107/S2414314624000373/wm4203Isup2.hkl
Supporting information file. DOI: 10.1107/S2414314624000373/wm4203Isup3.mol
CCDC reference: 2324427
Additional supporting information: crystallographic information; 3D view; checkCIF report
Acknowledgments
We are thankful for the support of the Department of Chemistry and Biochemistry at the University of the Incarnate Word and the X-ray Diffraction Laboratory at the University of Texas at San Antonio.
full crystallographic data
Crystal data
| [ZnCl2(C14H12N2O2)] | F(000) = 760 |
| Mr = 376.53 | Dx = 1.796 Mg m−3 |
| Monoclinic, C2/c | Cu Kα radiation, λ = 1.54184 Å |
| a = 14.7877 (6) Å | Cell parameters from 4164 reflections |
| b = 9.9287 (4) Å | θ = 4.6–76.0° |
| c = 9.5230 (3) Å | µ = 6.03 mm−1 |
| β = 95.233 (4)° | T = 100 K |
| V = 1392.36 (9) Å3 | Block, clear colourless |
| Z = 4 | 0.10 × 0.05 × 0.03 mm |
Data collection
| XtaLAB Synergy, Dualflex, HyPix diffractometer | 1385 independent reflections |
| Radiation source: micro-focus sealed X-ray tube, PhotonJet (Cu) X-ray Source | 1282 reflections with I > 2σ(I) |
| Mirror monochromator | Rint = 0.044 |
| Detector resolution: 10.0000 pixels mm-1 | θmax = 76.1°, θmin = 5.4° |
| ω scans | h = −18→17 |
| Absorption correction: gaussian (CrysAlisPro; Rigaku OD, 2023) | k = −10→12 |
| Tmin = 0.780, Tmax = 1.000 | l = −7→11 |
| 6451 measured reflections |
Refinement
| Refinement on F2 | Primary atom site location: dual |
| Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
| R[F2 > 2σ(F2)] = 0.028 | H-atom parameters constrained |
| wR(F2) = 0.078 | w = 1/[σ2(Fo2) + (0.0424P)2 + 1.5215P] where P = (Fo2 + 2Fc2)/3 |
| S = 1.07 | (Δ/σ)max < 0.001 |
| 1385 reflections | Δρmax = 0.36 e Å−3 |
| 97 parameters | Δρmin = −0.54 e Å−3 |
| 0 restraints |
Special details
| Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes. |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2)
| x | y | z | Uiso*/Ueq | ||
| Zn1 | 0.500000 | 0.13609 (4) | 0.250000 | 0.02301 (15) | |
| Cl1 | 0.39338 (4) | 0.02563 (5) | 0.35249 (5) | 0.03050 (17) | |
| O1 | 0.66212 (10) | 0.65250 (14) | 0.53657 (14) | 0.0218 (3) | |
| N1 | 0.56174 (11) | 0.29536 (17) | 0.36247 (16) | 0.0199 (3) | |
| C5 | 0.53355 (13) | 0.4178 (2) | 0.30988 (19) | 0.0182 (4) | |
| C4 | 0.56632 (13) | 0.5410 (2) | 0.36602 (19) | 0.0183 (4) | |
| C6 | 0.53195 (13) | 0.6646 (2) | 0.30625 (19) | 0.0189 (4) | |
| H6 | 0.553852 | 0.747773 | 0.345289 | 0.023* | |
| C2 | 0.66450 (14) | 0.4095 (2) | 0.5321 (2) | 0.0218 (4) | |
| H2 | 0.711381 | 0.402937 | 0.606948 | 0.026* | |
| C3 | 0.63399 (13) | 0.5341 (2) | 0.48287 (19) | 0.0194 (4) | |
| C1 | 0.62520 (13) | 0.2938 (2) | 0.4699 (2) | 0.0214 (4) | |
| H1 | 0.645131 | 0.208835 | 0.506840 | 0.026* | |
| C7 | 0.73512 (14) | 0.6509 (2) | 0.6477 (2) | 0.0239 (4) | |
| H7A | 0.789459 | 0.611872 | 0.612157 | 0.036* | |
| H7B | 0.717317 | 0.596632 | 0.726610 | 0.036* | |
| H7C | 0.748220 | 0.743207 | 0.679964 | 0.036* |
Atomic displacement parameters (Å2)
| U11 | U22 | U33 | U12 | U13 | U23 | |
| Zn1 | 0.0248 (2) | 0.0126 (2) | 0.0319 (2) | 0.000 | 0.00398 (15) | 0.000 |
| Cl1 | 0.0338 (3) | 0.0212 (3) | 0.0364 (3) | −0.0083 (2) | 0.0030 (2) | 0.0048 (2) |
| O1 | 0.0250 (7) | 0.0181 (7) | 0.0219 (7) | −0.0025 (6) | −0.0002 (5) | −0.0008 (5) |
| N1 | 0.0218 (7) | 0.0143 (8) | 0.0243 (8) | 0.0015 (7) | 0.0068 (6) | 0.0027 (6) |
| C5 | 0.0202 (9) | 0.0141 (10) | 0.0211 (8) | 0.0012 (8) | 0.0075 (7) | 0.0012 (7) |
| C4 | 0.0196 (8) | 0.0168 (10) | 0.0192 (8) | −0.0011 (7) | 0.0063 (7) | −0.0004 (7) |
| C6 | 0.0208 (9) | 0.0147 (9) | 0.0220 (9) | −0.0008 (8) | 0.0058 (7) | −0.0009 (7) |
| C2 | 0.0221 (9) | 0.0235 (11) | 0.0206 (8) | 0.0013 (8) | 0.0050 (7) | 0.0021 (8) |
| C3 | 0.0213 (9) | 0.0185 (10) | 0.0196 (9) | −0.0016 (8) | 0.0076 (7) | 0.0013 (7) |
| C1 | 0.0234 (9) | 0.0174 (10) | 0.0241 (9) | 0.0032 (8) | 0.0059 (7) | 0.0052 (8) |
| C7 | 0.0239 (9) | 0.0263 (11) | 0.0210 (9) | −0.0028 (9) | −0.0005 (7) | 0.0004 (8) |
Geometric parameters (Å, º)
| Zn1—Cl1 | 2.2186 (5) | C4—C3 | 1.429 (3) |
| Zn1—Cl1i | 2.2186 (5) | C6—C6i | 1.362 (4) |
| Zn1—N1i | 2.0744 (18) | C6—H6 | 0.9500 |
| Zn1—N1 | 2.0744 (18) | C2—H2 | 0.9500 |
| O1—C3 | 1.334 (2) | C2—C3 | 1.383 (3) |
| O1—C7 | 1.441 (2) | C2—C1 | 1.395 (3) |
| N1—C5 | 1.365 (3) | C1—H1 | 0.9500 |
| N1—C1 | 1.324 (3) | C7—H7A | 0.9800 |
| C5—C5i | 1.442 (4) | C7—H7B | 0.9800 |
| C5—C4 | 1.404 (3) | C7—H7C | 0.9800 |
| C4—C6 | 1.427 (3) | ||
| Cl1—Zn1—Cl1i | 120.75 (3) | C6i—C6—C4 | 120.66 (11) |
| N1i—Zn1—Cl1i | 116.53 (4) | C6i—C6—H6 | 119.7 |
| N1—Zn1—Cl1 | 116.53 (4) | C3—C2—H2 | 120.6 |
| N1i—Zn1—Cl1 | 107.88 (4) | C3—C2—C1 | 118.81 (19) |
| N1—Zn1—Cl1i | 107.88 (4) | C1—C2—H2 | 120.6 |
| N1i—Zn1—N1 | 80.66 (9) | O1—C3—C4 | 115.33 (18) |
| C3—O1—C7 | 117.29 (16) | O1—C3—C2 | 125.27 (18) |
| C5—N1—Zn1 | 112.59 (13) | C2—C3—C4 | 119.40 (19) |
| C1—N1—Zn1 | 129.60 (15) | N1—C1—C2 | 123.82 (19) |
| C1—N1—C5 | 117.74 (18) | N1—C1—H1 | 118.1 |
| N1—C5—C5i | 117.08 (11) | C2—C1—H1 | 118.1 |
| N1—C5—C4 | 123.58 (18) | O1—C7—H7A | 109.5 |
| C4—C5—C5i | 119.34 (11) | O1—C7—H7B | 109.5 |
| C5—C4—C6 | 119.99 (18) | O1—C7—H7C | 109.5 |
| C5—C4—C3 | 116.58 (18) | H7A—C7—H7B | 109.5 |
| C6—C4—C3 | 123.43 (18) | H7A—C7—H7C | 109.5 |
| C4—C6—H6 | 119.7 | H7B—C7—H7C | 109.5 |
| Zn1—N1—C5—C5i | 1.0 (2) | C6—C4—C3—O1 | 1.8 (2) |
| Zn1—N1—C5—C4 | −178.96 (14) | C6—C4—C3—C2 | −178.77 (17) |
| Zn1—N1—C1—C2 | 176.64 (13) | C3—C4—C6—C6i | 179.3 (2) |
| N1—C5—C4—C6 | −178.83 (16) | C3—C2—C1—N1 | 2.2 (3) |
| N1—C5—C4—C3 | 1.2 (3) | C1—N1—C5—C5i | 178.14 (19) |
| C5—N1—C1—C2 | 0.1 (3) | C1—N1—C5—C4 | −1.8 (3) |
| C5i—C5—C4—C6 | 1.2 (3) | C1—C2—C3—O1 | 176.58 (17) |
| C5i—C5—C4—C3 | −178.81 (19) | C1—C2—C3—C4 | −2.8 (3) |
| C5—C4—C6—C6i | −0.7 (3) | C7—O1—C3—C4 | −175.50 (15) |
| C5—C4—C3—O1 | −178.24 (15) | C7—O1—C3—C2 | 5.1 (3) |
| C5—C4—C3—C2 | 1.2 (2) |
Symmetry code: (i) −x+1, y, −z+1/2.
Funding Statement
Funding for this research was provided by: National Science Foundation (award No. 1920059); Welch Foundation (award No. BN0032); The University of the Incarnate Word Faculty Endowed Research Award; Constance and Miriam Jauchler Jones Endowed Chair.
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Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Supplementary Materials
Crystal structure: contains datablock(s) I. DOI: 10.1107/S2414314624000373/wm4203sup1.cif
Structure factors: contains datablock(s) I. DOI: 10.1107/S2414314624000373/wm4203Isup2.hkl
Supporting information file. DOI: 10.1107/S2414314624000373/wm4203Isup3.mol
CCDC reference: 2324427
Additional supporting information: crystallographic information; 3D view; checkCIF report