Di­chlorido­(4,7-dimeth­oxy-1,10-phenanthroline-κ2N,N′)zinc(II)

Rose, N.P.; Arman, H.D.; Adrian, R.A.

doi:10.1107/S2414314624000373

metal-organic compounds

IUCrDATA

ISSN: 2414-3146

Volume 9| Part 1| January 2024| x240037

https://doi.org/10.1107/S2414314624000373

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Dichlorido(4,7-dimethoxy-1,10-phenanthroline-κ²N,N′)zinc(II)

Nalani P. Rose,^a Hadi D. Arman ^b and Rafael A. Adrian ^a ^*

^aDepartment of Chemistry and Biochemistry, University of the Incarnate Word, San Antonio, Texas 78209, USA, and ^bDepartment of Chemistry, The University of Texas at San Antonio, San Antonio, Texas 78249, USA
^*Correspondence e-mail: adrian@uiwtx.edu

Edited by M. Weil, Vienna University of Technology, Austria (Received 18 December 2023; accepted 9 January 2024; online 12 January 2024)

In the title complex, [ZnCl₂(C₁₄H₁₂N₂O₂)], the Zn^II 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 ( $[\overline{2}]$ 01).

Keywords: crystal structure; zinc; 4,7-dimethoxy-1,10-phenanthroline; coordinating chloride ions; distorted tetrahedral coordination environment; metal complex; τ₄ descriptor.

CCDC reference: 2324427

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.

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) $[-x+1, y, -z+{\script{1\over 2}}]$ .

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 + $[{1\over 2}]$ .

The title complex packs into layers parallel to ( $[\overline{2}]$ 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 $[Rigaku OD (2023). CrysAlis PRO. Rigaku Oxford Diffraction, Yarnton, England.]$ )
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[F² > 2σ(F²)], wR(F²), S	0.028, 0.078, 1.07
No. of reflections	1385
No. of parameters	97
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.36, −0.54
Computer programs: CrysAlis PRO (Rigaku OD, 2023 $[Rigaku OD (2023). CrysAlis PRO. Rigaku Oxford Diffraction, Yarnton, England.]$ ), SHELXT (Sheldrick, 2015a ), SHELXL (Sheldrick, 2015b ), and OLEX2 (Dolomanov et al., 2009 ).

Structural data

CCDC reference: 2324427

Crystal structure: contains datablock I. DOI: https://doi.org/10.1107/S2414314624000373/wm4203sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2414314624000373/wm4203Isup2.hkl

Supporting information file. DOI: https://doi.org/10.1107/S2414314624000373/wm4203Isup3.mol

checkCIF report

Computing details top

Dichlorido(4,7-dimethoxy-1,10-phenanthroline-κ²N,N')zinc(II) top

Crystal data top

[ZnCl₂(C₁₄H₁₂N₂O₂)]	F(000) = 760
M_r = 376.53	D_x = 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 top

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	R_int = 0.044
Detector resolution: 10.0000 pixels mm^-1	θ_max = 76.1°, θ_min = 5.4°
ω scans	h = −18→17
Absorption correction: gaussian (CrysAlisPro; Rigaku OD, 2023)	k = −10→12
T_min = 0.780, T_max = 1.000	l = −7→11
6451 measured reflections

Refinement top

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(F_o²) + (0.0424P)² + 1.5215P] where P = (F_o² + 2F_c²)/3
S = 1.07	(Δ/σ)_max < 0.001
1385 reflections	Δρ_max = 0.36 e Å⁻³
97 parameters	Δρ_min = −0.54 e Å⁻³
0 restraints

Special details top

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) top

	x	y	z	U_iso*/U_eq
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) top

	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) top

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.

Acknowledgements

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.

Funding information

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.

References

Cetin, M. M., Shafiei–Haghighi, S., Chen, J., Zhang, S., Miller, A. C., Unruh, D. K., Casadonte, D. J. Jr, Lohr, T. L., Marks, T. J., Mayer, M. F., Stoddart, J. F. & Findlater, M. (2020). J. Polym. Sci. 58, 1130–1143. Web of Science CSD CrossRef CAS Google Scholar
Choroba, K., Filipe, B., Świtlicka, A., Penkala, M., Machura, B., Bieńko, A., Cordeiro, S., Baptista, P. V. & Fernandes, A. R. (2023). J. Med. Chem. 66, 8580–8599. Web of Science CSD CrossRef CAS PubMed Google Scholar
Dolomanov, O. V., Bourhis, L. J., Gildea, R. J., Howard, J. A. K. & Puschmann, H. (2009). J. Appl. Cryst. 42, 339–341. Web of Science CrossRef CAS IUCr Journals Google Scholar
EL-Atawy, M. A., Ferretti, F. & Ragaini, F. (2018). Eur. J. Org. Chem. pp. 4818–4825. Google Scholar
Groom, C. R., Bruno, I. J., Lightfoot, M. P. & Ward, S. C. (2016). Acta Cryst. B72, 171–179. Web of Science CrossRef IUCr Journals Google Scholar
Khoury, A., Elias, E., Mehanna, S., Shebaby, W., Deo, K. M., Mansour, N., Khalil, C., Sayyed, K., Sakoff, J. A., Gilbert, J., Daher, C. F., Gordon, C. P., Taleb, R. I. & Aldrich-Wright, J. R. (2022). J. Med. Chem. 65, 16481–16493. Web of Science CrossRef CAS PubMed Google Scholar
Li, H., Hu, T. Q. & Zhang, S. G. (2008). Acta Cryst. E64, m771. Web of Science CSD CrossRef IUCr Journals Google Scholar
Liu, M., Zhang, Z., Yan, J., Liu, S., Liu, H., Liu, Z., Wang, W., He, Z. & Han, B. (2020). Chem, 6, 3288–3296. Web of Science CrossRef CAS Google Scholar
Luo, Q., Peng, K., Zhang, J. & Xia, J. (2019). Organometallics, 38, 647–653. Web of Science CSD CrossRef CAS Google Scholar
Niu, C.-Y., Dang, Y.-L., Wan, X.-S. & Kou, C.-H. (2009). Acta Cryst. E65, m860. Web of Science CSD CrossRef IUCr Journals Google Scholar
Reimann, C. W., Block, S. & Perloff, A. (1966). Inorg. Chem. 5, 1185–1189. CSD CrossRef CAS Web of Science Google Scholar
Rigaku OD (2023). CrysAlis PRO. Rigaku Oxford Diffraction, Yarnton, England. Google Scholar
Sheldrick, G. M. (2015a). Acta Cryst. A71, 3–8. Web of Science CrossRef IUCr Journals Google Scholar
Sheldrick, G. M. (2015b). Acta Cryst. C71, 3–8. Web of Science CrossRef IUCr Journals Google Scholar
Yang, L., Powell, D. R. & Houser, R. P. (2007). Dalton Trans. pp. 955–964. Web of Science CSD CrossRef PubMed CAS Google Scholar