Crystal structure of a copper complex containing the 4-bromo-2-{[(2-hy­droxy­eth­yl)imino]­meth­yl}phenol base Schiff ligand

Niang, A.; Mane, E.S.; Mazzeo, P.P.; Ka, D.; Diouf, O.; Gaye, M.L.; Thiam, I.E.; Bacchi, A.

doi:10.1107/S2056989026009746

research communications

CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 82| Part 10| October 2026| Pages 1213-1216

https://doi.org/10.1107/S2056989026009746

Open

access

Crystal structure of a copper complex containing the 4-bromo-2-{[(2-hydroxyethyl)imino]methyl}phenol base Schiff ligand

Adama Niang,^a Elhadji Sékou Mane,^a Paolo Pio Mazzeo,^b,^c Diéwo Ka,^a Ousmane Diouf,^a Mohamed Lamine Gaye,^a Ibrahima Elhadji Thiam ^a and Alessia Bacchi ^b,^c ^*

^aDépartement de Chimie, Faculté des Sciences et Techniques, Université Cheik Anta Diop, Dakar, Senegal, ^bDepartment of Chemical Sciences, Life Science and Environmental Sustainability, University of Parma, Parco Area delle Scienze 17/A, 43124 Parma, Italy, and ^cBiopharmanet-TEC, University of Parma, Parco Area Delle Scienze 27/A, Parma 43124, Italy
^*Correspondence e-mail: [email protected]

Edited by J. Ellena, Universidade de Sâo Paulo, Brazil (Received 22 June 2026; accepted 17 September 2026; online 30 September 2026)

The coordination co-crystal (4-bromo-2-{[(2-hydroxyethyl)imino]methyl}phenololato-κ³O,N,O′)(thiocyanato-κN)copper(II)–5-bromo-2-hydroxybenzaldehyde–water (2/1/1), [Cu(C₉H₉BrNO₂)(NCS)]·0.5C₇H₅BrO₂·0.5H₂O or [Cu(HL)(SCN)]₂·C₇H₅BrO₂·H₂O, crystallizes in the monoclinic space group P2₁/c. The asymmetric unit contains two mononuclear units of the complex, each consisting of one deprotonated ligand, one thiocyanate anion (SCN⁻) coordinated through its nitrogen atom, one free water molecule, and one free 5-bromosalicylaldehyde molecule, forming a co-crystal. The copper atom is four-coordinate, adopting a slightly distorted square-planar geometry defined by the tridentate ligand and the nitrogen atom of the thiocyanate anion. Bond length values show that the thiocyanate ion has a linear S—C≡N arrangement, typical of a terminal, N-bound isothiocyanate group. The water molecule plays a key role in linking the two complex units through O—H⋯O hydrogen bonds. In the crystal, C—H⋯O and C—H⋯Br hydrogen bonds allow the free 5-bromosalicylaldehyde molecule to form a bridge between two adjacent layers. Additional O—H⋯O, C—H⋯S, O—H⋯S, and C—H⋯N interactions further consolidate the overall structure.

Keywords: crystal structure; co-crystal; coordination polymer complex; copper(II).

CCDC reference: 2588876

1. Chemical context

The use of salicylaldehyde-derived ligands in the synthesis of coordination complexes has become increasingly important and represents a frequent research topic, particularly in copper-catalysed reactions (Juyal et al., 2023 ). Indeed, these ligands contain donor sites such as the phenolic oxygen atom and the imine nitrogen atom, enabling the formation of stable complexes with various geometries, notably polynuclear copper(II) complexes.

Numerous applications have been reported, including in catalysis (Shelar et al., 2021 ), materials science (Abu-Dief & Mohamed, 2015 ), and medicine (More et al., 2019 ). The formation of a co-crystal associated with a polynuclear copper complex represents an important aspect of supramolecular chemistry, as such systems are stabilized by networks of non-covalent interactions, including hydrogen bonds (Benito et al., 2025 ).

In the field of crystal engineering, co-crystals defined as single-phase crystalline materials comprising two or more neutral molecular species have long been exploited to tune physicochemical attributes while preserving the molecular identity of active components (Taylor & Day, 2018 ). We have synthesized a tridentate Schiff base ligand, (E)-4-bromo-2-{[(2-hydroxyethyl)imino]methyl}phenol, derived from salicylaldehyde, which forms a polynuclear complex with copper(II) chloride and potassium thiocyanate.

2. Structural commentary

The title compound (Fig. 1) crystallizes in the monoclinic system, space group P2₁/c. The asymmetric unit, [Cu(HL)(SCN)]₂(C₇H₅BrO₂)·H₂O, contains two monodeprotonated ligand molecules, two independent copper(II) ions, two monodentate thiocyanate anions, one co-crystallized bromo-hydroxybenzaldehyde molecule and one free water molecule.

Figure 1
The molecular structure of the title compound showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level.

The Schiff base ligand acts in a tridentate fashion through the phenolate oxygen atom, the azomethine nitrogen atom, and the alcoholic oxygen atom, resulting in one five-membered (CuOCCN) and one six-membered (CuOCCCN) chelate ring around each Cu^II ion.

Each copper atom is four-coordinate, bound by an N₂O₂ donor set comprising one azomethine (imine) nitrogen and two oxygen atoms (one phenolate, one alcoholic) from the Schiff base ligand, together with one nitrogen atom from its own thiocyanate group, forming an essentially square-planar, moderately distorted coordination plane. The bond lengths within this square plane are Cu1—O1 = 1.911 (2) Å, Cu1—N1 = 1.928 (3) Å, Cu1—N3 = 1.952 (3) Å, and Cu1—O2 = 2.038 (2) Å. For the corresponding values for Cu2, see Table 1).

Table 1
Selected geometric parameters (Å, °)

Cu1—O1	1.911 (2)	Cu2—O3	1.923 (2)
Cu1—O2	2.038 (2)	Cu2—O4	2.005 (2)
Cu1—N1	1.928 (3)	Cu2—N4	1.995 (3)
Cu1—N3	1.952 (3)	Cu2—N2	1.927 (3)

O1—Cu1—O2	166.82 (10)	O3—Cu2—O4	166.23 (10)
N3—Cu1—O2	89.45 (11)	O3—Cu2—N4	91.49 (10)
O1—Cu1—N1	93.58 (10)	O3—Cu2—N2	93.35 (11)
O1—Cu1—N3	94.69 (11)	N4—Cu2—O4	92.01 (10)
N1—Cu1—O2	82.51 (10)	N2—Cu2—O4	82.24 (11)
N1—Cu1—N3	171.73 (12)	N2—Cu2—N4	173.38 (11)

A single, additional axial contact to the nitrogen atom of the thiocyanate group of the neighbouring mononuclear unit is present at each copper centre, but this contact is long and markedly asymmetric between the two independent centres [2.961 (3) Å for Cu1 versus 3.100 (3) Å for Cu2]. The latter value exceeds the sum of the van der Waals radii for Cu⋯N and cannot reasonably be described as a coordination bond. The geometry is therefore described as distorted square-planar (four-coordinate, N₂O₂), with a weak, asymmetric secondary axial contact of semi-coordinate character, rather than as distorted square-planar.

It is this weak, asymmetric N⋯Cu axial contact, not a Cu—S bond, that links each mononuclear [Cu(HL)(SCN)] unit to its neighbour and propagates the one-dimensional polymeric chain.

The deviations of the angles from the ideal value of 90° [O1—Cu1—N1 = 93.58 (10)°, O2—Cu1—N3 = 89.45 (11)°, N1—Cu1—O2 = 82.51 (10)°, and O1—Cu1—N3 = 94.69 (11)°] confirm the distortion of the coordination geometry.

The Cu1> ion is displaced from the least-squares plane defined by O1, N1, O2 and N3 (r.m.s. deviation 0.117 Å) by 0.006 (12) Å, indicating that the metal centre lies essentially within the equatorial plane. The dihedral angle of 175.63 (17)° between the phenolate ring plane (O1/C1–C6) and the plane of the open-chain fragment (C7/N1/C8/C9/O2) reveals a slight but measurable deviation from planarity, indicative of a twist in the ligand backbone.

The Cu1⋯Cu2 separation between two adjacent units is 3.7765 (5) Å, a distance too long to invoke any meaningful metal–metal interaction. The cis angles span the range 82.51 (10)–94.69 (11)°, in good agreement with values reported for related complexes. The trans angles O1—Cu1—O2 = 166.82 (10)° and N3—Cu1—N1 = 171.73 (12)° deviate significantly from the ideal value of 180°, further confirming that Cu1 resides in a severely distorted square-planar coordination environment. The environment about Cu2 is similar, see Table 1).

The bond lengths within the two thiocyanate groups are S1—C19 = 1.629 (3) Å, C19—N3 = 1.153 (4) Å, and S2—C20 = 1.643 (4) Å, C20—N4 = 1.106 (4) Å. These values are consistent with the linear S—C≡N arrangement typical of a terminal, N-bound isothiocyanate group.

The sulfur atoms S1 and S2 are not bonded to any copper atom. The bridging mode is therefore not the classical μ-1,3 (S,N) mode frequently found in Cu–SCN polymers, but an asymmetric end-on μ-1,1 (N,N′) bridge, in which each thiocyanate nitrogen atom is strongly bonded to its own copper centre and forms a second, much weaker, semi-coordinate contact with the neighbouring copper centre, as summarized below.

3. Supramolecular features

We note four strong interactions of the O—H—O type (Table 2). The water molecule connects unit Cu2 via O4—H4⋯O7 to unit Cu1 via O7—H7A··O1. The O2—H2⋯O3 hydrogen bond similarly connects the two units. The O5—H5A⋯O6 interaction corresponds to the classical intramolecular hydrogen bond within the co-crystallized aldehyde fragment, confirming its nature as an isolated unit maintained in the network mainly by the weak C—H⋯·Br, C—H⋯S, C—H⋯N and C—H⋯O contacts and extending the three-dimensional network and further enhances the cohesion of the structure. The packing is shown in Fig. 2.

Table 2
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O4—H4⋯O7	0.82	1.75	2.562 (4)	174
O2—H2⋯O3	0.82	1.84	2.647 (3)	169
O7—H7A⋯O1	0.85	1.88	2.709 (4)	163
O7—H7B⋯S2ⁱ	0.85	2.64	3.290 (3)	135
O5—H5A⋯O6	0.82	1.94	2.655 (6)	146
C18—H18A⋯Br3ⁱⁱ	0.97	3.32	3.856 (4)	117
C18—H18A⋯S1	0.97	2.98	3.801 (4)	143
C18—H18A⋯N3	0.97	3.22	3.785 (5)	119
C17—H17A⋯O5	0.97	2.73	3.368 (5)	124
C16—H16⋯O6ⁱⁱⁱ	0.93	2.52	3.376 (5)	153
C2—H2A⋯O2^iv	0.93	2.92	3.726 (4)	146
C2—H2A⋯O7	0.93	3.08	3.548 (5)	113
C9—H9A⋯N4^v	0.97	3.20	3.851 (4)	126
C9—H9B⋯O3^v	0.97	3.03	3.613 (5)	120
C9—H9B⋯N4	0.97	3.20	3.700 (5)	114
C11—H11⋯S2^v	0.93	3.11	3.709 (4)	124
C8—H8A⋯S1^vi	0.97	3.29	3.881 (3)	121
C8—H8A⋯O3^v	0.97	3.07	3.773 (5)	130
C8—H8B⋯S2ⁱⁱⁱ	0.97	3.30	3.784 (4)	113
C8—H8B⋯O7^vi	0.97	2.96	3.739 (6)	138
C14—H14⋯O6ⁱⁱⁱ	0.93	3.12	3.827 (6)	134
C12—H12⋯S2^v	0.93	2.93	3.616 (5)	131
C22—H22⋯O6ⁱⁱⁱ	0.93	2.97	3.847 (6)	158
C27—H27⋯Br2^vii	0.93	3.04	3.949 (6)	166
Symmetry codes: (i) ; (ii) $[-x, y+{\script{1\over 2}}, -z+{\script{1\over 2}}]$ ; (iii) $[x, -y+{\script{3\over 2}}, z-{\script{1\over 2}}]$ ; (iv) $[-x+1, y+{\script{1\over 2}}, -z+{\script{1\over 2}}]$ ; (v) ; (vi) $[-x+1, y-{\script{1\over 2}}, -z+{\script{1\over 2}}]$ ; (vii) .

Figure 2
Partial packing diagram for the title compound along [001].

4. Database survey

A search of the Cambridge Structural Database (CSD version 5.46, updates of November 2024 and February 2025; Groom et al., 2016) yielded 25 hits containing crystal structures of coordination complexes bearing the 4-bromo-2-{[(2-hydroxyethyl)imino]methyl}phenol ligand. The first result corresponds to the structure of the free ligand reported by Thakur et al. 2024 (refcode YAWNOB01). 23 of the remaining hits correspond to coordination complexes of first-row transition metals. Only one second-row transition metal complex is noted, namely a cadmium complex (AWOHIE; Yu et al., 2011 ). Half of the hits correspond to mononuclear complexes in which two molecules of the tridentate ligand chelate the metal ion including refcodes BAVGUD, BAVROI (Abbasi et al., 2017 ); HEDKUX (Liang et al., 2006 ); HEDKUX01 (Chumakov et al., 2007 ); HEDKUX02 (Zabierowski et al., 2013 ); MIWSEQ (De et al., 2001 ), among others. Polynuclear complexes are also reported, including a dinuclear copper complex (FOQKAY; Thakurta et al., 2009a ,b ), a tetranuclear copper complex (LICWAW; Yoshida et al.), and a tetranuclear iron complex (EBUWII; Oshio et al., 2004 ).

5. Synthesis and crystallization

The Schiff base ligand HL was prepared by adding 2.5 g (13.5 mmol) of 5-bromosalicylaldehyde and 0.8 g (13.5 mmol) of 2-aminoethanol, along with a few drops of glacial acetic acid, to 20 mL of ethanol in a flask. The mixture was refluxed, then evaporated to dryness using a rotary evaporator, giving a light-brown oil in 80% yield. This oil was dissolved in ethanol (100 mL) to give a 0.108 mol l⁻¹ ligand solution.

For the complex synthesis, 0.17 g (1 mmol) of copper(II) chloride dihydrate and 0.19 g (2 mmol) of potassium thiocyanate were dissolved in 10 mL of methanol and stirred under reflux for 30 minutes, giving a brown solution. Then, 9.2 mL of the ligand solution was added dropwise to the metal solution. After refluxing for 1 h, a green precipitate formed, which was filtered, washed with methanol, and dried, giving 0.14 g of product. Green single crystals suitable for X-ray diffraction were obtained after two weeks.

6. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 3. H atoms were positioned geometrically and refined as riding with U_iso(H) = 1.2U_eq(C).

Table 3
Experimental details

Crystal data
Chemical formula	[Cu(C₉H₉BrNO₂)(NCS)]·0.5C₇H₅BrO₂·0.5H₂O
M_r	948.44
Crystal system, space group	Monoclinic, P2₁/c
Temperature (K)	296
a, b, c (Å)	18.4400 (5), 13.7346 (3), 13.6402 (3)
β (°)	103.136 (1)
V (Å³)	3364.20 (14)
Z	4
Radiation type	Mo Kα
μ (mm⁻¹)	5.00
Crystal size (mm)	0.2 × 0.2 × 0.2

Data collection
Diffractometer	Bruker D8 Venture Equipped with PhotonII Detector
Absorption correction	Multi-scan (SADABS; Krause et al., 2015 )
No. of measured, independent and observed [I > 2σ(I)] reflections	60122, 6909, 5316
R_int	0.070
(sin θ/λ)_max (Å⁻¹)	0.626

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.034, 0.081, 1.01
No. of reflections	6909
No. of parameters	412
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.62, −0.61
Computer programs: APEX and SAINT (Bruker, 2014 ), OLEX2.solve (Bourhis et al., 2015), SHELXL2018/3 (Sheldrick, 2015 ) and OLEX2 (Dolomanov et al., 2009 ).

Supporting information

CCDC reference: 2588876

Crystal structure: contains datablock I. DOI: https://doi.org/10.1107/S2056989026009746/ex2102sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2056989026009746/ex2102Isup2.hkl

checkCIF report

Computing details top

(4-Bromo-2-{[(2-hydroxyethyl)imino]methyl}phenololato-κ³O,N,O')(thiocyanato-κN)copper(II)–5-bromo-2-hydroxybenzaldehyde–water (2/1/1) top

Crystal data top

[Cu(C₉H₉BrNO₂)(NCS)]·0.5C₇H₅BrO₂·0.5H₂O	F(000) = 1864
M_r = 948.44	D_x = 1.873 Mg m⁻³
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71073 Å
a = 18.4400 (5) Å	Cell parameters from 60122 reflections
b = 13.7346 (3) Å	θ = 1.9–26.4°
c = 13.6402 (3) Å	µ = 5.00 mm⁻¹
β = 103.136 (1)°	T = 296 K
V = 3364.20 (14) Å³	Prism, green
Z = 4	0.2 × 0.2 × 0.2 mm

Data collection top

Bruker D8 Venture Equipped with PhotonII Detector diffractometer	5316 reflections with I > 2σ(I)
profile data from ω–scans	R_int = 0.070
Absorption correction: multi-scan (SADABS; Krause et al., 2015)	θ_max = 26.4°, θ_min = 1.9°
	h = −23→23
60122 measured reflections	k = −17→17
6909 independent reflections	l = −17→15

Refinement top

Refinement on F²	0 restraints
Least-squares matrix: full	Hydrogen site location: mixed
R[F² > 2σ(F²)] = 0.034	H-atom parameters constrained
wR(F²) = 0.081	w = 1/[σ²(F_o²) + (0.0255P)² + 4.7568P] where P = (F_o² + 2F_c²)/3
S = 1.01	(Δ/σ)_max = 0.001
6909 reflections	Δρ_max = 0.62 e Å⁻³
412 parameters	Δρ_min = −0.61 e Å⁻³

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
Cu2	0.35837 (2)	0.72579 (3)	0.41858 (3)	0.03257 (10)
Cu1	0.52874 (2)	0.71541 (3)	0.30893 (3)	0.03342 (10)
Br3	−0.17062 (2)	0.47243 (3)	0.42161 (4)	0.06458 (14)
Br1	0.88193 (3)	0.96575 (4)	0.53387 (5)	0.07697 (16)
Br2	0.11977 (3)	0.30742 (4)	0.22273 (4)	0.08438 (19)
S1	0.29927 (5)	0.78586 (7)	0.09224 (7)	0.0424 (2)
S2	0.58322 (6)	0.80940 (7)	0.62694 (8)	0.0485 (2)
O3	0.36588 (12)	0.59043 (15)	0.38633 (18)	0.0365 (5)
O4	0.35052 (13)	0.87140 (16)	0.41724 (18)	0.0386 (5)
H4	0.388208	0.901725	0.414008	0.058*
O1	0.56911 (13)	0.84305 (15)	0.33838 (18)	0.0376 (5)
O2	0.48631 (13)	0.57876 (16)	0.31199 (19)	0.0399 (6)
H2	0.446357	0.578002	0.328833	0.060*
N4	0.46559 (16)	0.73030 (19)	0.4895 (2)	0.0353 (6)
N1	0.61991 (15)	0.65156 (18)	0.3749 (2)	0.0340 (6)
N2	0.25666 (15)	0.7357 (2)	0.3433 (2)	0.0338 (6)
N3	0.43073 (16)	0.7612 (2)	0.2376 (2)	0.0397 (7)
O7	0.46760 (17)	0.96055 (19)	0.3943 (3)	0.0702 (10)
H7A	0.502551	0.934333	0.372361	0.105*
H7B	0.481742	1.019032	0.407084	0.105*
O5	0.0839 (2)	0.7473 (3)	0.4295 (3)	0.0837 (11)
H5A	0.093367	0.779032	0.481825	0.126*
C19	0.37653 (18)	0.7704 (2)	0.1765 (2)	0.0305 (7)
C1	0.63814 (19)	0.8652 (2)	0.3819 (2)	0.0336 (7)
C6	0.69389 (18)	0.7959 (2)	0.4217 (2)	0.0339 (7)
C7	0.68112 (18)	0.6930 (2)	0.4166 (3)	0.0354 (7)
H7	0.720737	0.653006	0.446251	0.042*
C10	0.30904 (19)	0.5317 (2)	0.3505 (2)	0.0345 (7)
C18	0.2894 (2)	0.9050 (2)	0.3404 (3)	0.0412 (8)
H18A	0.302755	0.905842	0.275613	0.049*
H18B	0.275062	0.970303	0.355478	0.049*
C17	0.2264 (2)	0.8346 (2)	0.3389 (3)	0.0424 (8)
H17A	0.204564	0.846199	0.396192	0.051*
H17B	0.188028	0.843103	0.277853	0.051*
O6	0.0669 (2)	0.8034 (3)	0.6092 (3)	0.0965 (12)
C15	0.23619 (19)	0.5640 (3)	0.3092 (3)	0.0376 (8)
C16	0.21500 (19)	0.6653 (3)	0.3038 (3)	0.0385 (8)
H16	0.166982	0.680496	0.268639	0.046*
C2	0.6592 (2)	0.9643 (2)	0.3897 (3)	0.0399 (8)
H2A	0.623644	1.011294	0.363949	0.048*
C20	0.5114 (2)	0.7642 (2)	0.5457 (3)	0.0385 (8)
C5	0.7662 (2)	0.8277 (3)	0.4681 (3)	0.0426 (8)
H5	0.802604	0.782312	0.495451	0.051*
C9	0.5384 (2)	0.5164 (3)	0.3777 (3)	0.0470 (9)
H9A	0.528637	0.448840	0.358511	0.056*
H9B	0.533871	0.524355	0.446689	0.056*
C11	0.3229 (2)	0.4310 (3)	0.3530 (3)	0.0450 (9)
H11	0.370795	0.408127	0.379841	0.054*
C8	0.6145 (2)	0.5446 (2)	0.3682 (3)	0.0452 (9)
H8A	0.651666	0.515002	0.421687	0.054*
H8B	0.622919	0.522553	0.304106	0.054*
C3	0.7297 (2)	0.9935 (3)	0.4337 (3)	0.0446 (9)
H3	0.741978	1.059317	0.437188	0.054*
C4	0.7831 (2)	0.9240 (3)	0.4734 (3)	0.0461 (9)
C14	0.1799 (2)	0.4965 (3)	0.2705 (3)	0.0495 (10)
H14	0.131914	0.517809	0.241540	0.059*
C24	−0.0898 (2)	0.5597 (3)	0.4264 (3)	0.0462 (9)
C13	0.1959 (2)	0.3992 (3)	0.2754 (3)	0.0521 (10)
C12	0.2665 (2)	0.3655 (3)	0.3162 (3)	0.0518 (10)
H12	0.276256	0.299005	0.319076	0.062*
C25	−0.0669 (2)	0.6183 (3)	0.5070 (3)	0.0488 (9)
H25	−0.090676	0.615755	0.560213	0.059*
C26	−0.0078 (2)	0.6828 (3)	0.5107 (3)	0.0511 (10)
C21	0.0275 (2)	0.6859 (3)	0.4308 (4)	0.0555 (11)
C23	−0.0552 (2)	0.5622 (3)	0.3469 (3)	0.0559 (11)
H23	−0.071640	0.521800	0.291633	0.067*
C22	0.0035 (2)	0.6245 (3)	0.3492 (4)	0.0611 (12)
H22	0.027240	0.625415	0.295851	0.073*
C27	0.0160 (3)	0.7449 (4)	0.5975 (4)	0.0801 (15)
H27	−0.009566	0.739894	0.648683	0.096*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Cu2	0.0329 (2)	0.0294 (2)	0.0334 (2)	−0.00098 (16)	0.00347 (17)	−0.00299 (17)
Cu1	0.0343 (2)	0.0288 (2)	0.0348 (2)	0.00313 (16)	0.00299 (17)	0.00019 (17)
Br3	0.0459 (2)	0.0590 (3)	0.0845 (3)	−0.0085 (2)	0.0057 (2)	−0.0066 (2)
Br1	0.0490 (3)	0.0770 (3)	0.0974 (4)	−0.0180 (2)	0.0010 (2)	−0.0192 (3)
Br2	0.0856 (4)	0.0834 (3)	0.0933 (4)	−0.0563 (3)	0.0395 (3)	−0.0404 (3)
S1	0.0369 (5)	0.0564 (6)	0.0320 (5)	0.0095 (4)	0.0035 (4)	−0.0040 (4)
S2	0.0446 (5)	0.0535 (6)	0.0441 (5)	−0.0064 (4)	0.0029 (4)	−0.0037 (4)
O3	0.0330 (12)	0.0300 (11)	0.0454 (14)	−0.0018 (9)	0.0066 (10)	−0.0056 (10)
O4	0.0419 (14)	0.0305 (12)	0.0446 (14)	−0.0008 (10)	0.0124 (11)	−0.0016 (11)
O1	0.0366 (13)	0.0297 (11)	0.0434 (14)	0.0029 (10)	0.0026 (11)	−0.0007 (10)
O2	0.0391 (14)	0.0338 (12)	0.0475 (15)	−0.0012 (11)	0.0111 (11)	−0.0019 (11)
N4	0.0459 (17)	0.0333 (15)	0.0233 (14)	−0.0138 (13)	0.0007 (13)	−0.0050 (12)
N1	0.0369 (16)	0.0277 (13)	0.0372 (16)	0.0042 (11)	0.0075 (12)	0.0027 (12)
N2	0.0313 (15)	0.0385 (15)	0.0319 (15)	0.0023 (12)	0.0078 (12)	−0.0005 (12)
N3	0.0369 (16)	0.0424 (16)	0.0379 (17)	0.0038 (13)	0.0044 (14)	0.0008 (13)
O7	0.0595 (19)	0.0332 (14)	0.131 (3)	0.0022 (13)	0.048 (2)	0.0022 (17)
O5	0.063 (2)	0.084 (3)	0.112 (3)	−0.0221 (18)	0.038 (2)	0.012 (2)
C19	0.0388 (19)	0.0279 (15)	0.0267 (16)	0.0020 (13)	0.0114 (15)	−0.0019 (13)
C1	0.0390 (19)	0.0350 (17)	0.0289 (17)	0.0013 (14)	0.0123 (15)	0.0002 (14)
C6	0.0345 (18)	0.0370 (17)	0.0307 (17)	0.0011 (14)	0.0086 (14)	−0.0002 (14)
C7	0.0327 (18)	0.0366 (17)	0.0365 (19)	0.0083 (14)	0.0069 (15)	0.0067 (15)
C10	0.0414 (19)	0.0331 (17)	0.0327 (18)	−0.0085 (14)	0.0161 (15)	−0.0065 (14)
C18	0.051 (2)	0.0343 (18)	0.041 (2)	0.0109 (16)	0.0169 (17)	0.0069 (16)
C17	0.037 (2)	0.0419 (19)	0.048 (2)	0.0089 (15)	0.0089 (16)	0.0030 (17)
O6	0.078 (3)	0.102 (3)	0.099 (3)	−0.041 (2)	−0.001 (2)	−0.012 (2)
C15	0.0362 (19)	0.0426 (19)	0.0358 (19)	−0.0062 (15)	0.0117 (15)	−0.0088 (15)
C16	0.0281 (17)	0.050 (2)	0.0364 (19)	−0.0015 (15)	0.0051 (14)	−0.0060 (16)
C2	0.049 (2)	0.0314 (17)	0.041 (2)	0.0011 (15)	0.0136 (17)	−0.0020 (15)
C20	0.044 (2)	0.0340 (17)	0.043 (2)	0.0084 (16)	0.0222 (18)	0.0087 (16)
C5	0.0369 (19)	0.047 (2)	0.044 (2)	0.0020 (16)	0.0080 (16)	−0.0002 (17)
C9	0.048 (2)	0.0324 (18)	0.063 (3)	0.0054 (16)	0.0182 (19)	0.0097 (18)
C11	0.052 (2)	0.0371 (19)	0.046 (2)	−0.0023 (16)	0.0118 (18)	−0.0015 (16)
C8	0.046 (2)	0.0290 (17)	0.061 (3)	0.0065 (15)	0.0132 (18)	0.0037 (17)
C3	0.057 (2)	0.0362 (19)	0.042 (2)	−0.0074 (17)	0.0153 (18)	−0.0066 (16)
C4	0.040 (2)	0.053 (2)	0.044 (2)	−0.0118 (17)	0.0093 (17)	−0.0111 (18)
C14	0.037 (2)	0.060 (2)	0.053 (2)	−0.0152 (18)	0.0127 (18)	−0.018 (2)
C24	0.037 (2)	0.046 (2)	0.053 (2)	0.0041 (16)	0.0040 (18)	0.0042 (18)
C13	0.060 (3)	0.052 (2)	0.051 (2)	−0.027 (2)	0.025 (2)	−0.0200 (19)
C12	0.073 (3)	0.0360 (19)	0.052 (2)	−0.0137 (19)	0.024 (2)	−0.0082 (18)
C25	0.040 (2)	0.058 (2)	0.047 (2)	−0.0010 (18)	0.0089 (17)	0.0069 (19)
C26	0.041 (2)	0.057 (2)	0.053 (2)	−0.0026 (18)	0.0039 (18)	0.005 (2)
C21	0.041 (2)	0.056 (2)	0.070 (3)	0.0054 (19)	0.013 (2)	0.017 (2)
C23	0.060 (3)	0.052 (2)	0.054 (3)	0.012 (2)	0.009 (2)	0.001 (2)
C22	0.060 (3)	0.065 (3)	0.066 (3)	0.019 (2)	0.031 (2)	0.019 (2)
C27	0.069 (3)	0.093 (4)	0.074 (4)	−0.030 (3)	0.008 (3)	−0.006 (3)

Geometric parameters (Å, º) top

Cu1—O1	1.911 (2)	C18—H18B	0.9700
Cu1—O2	2.038 (2)	C18—C17	1.508 (5)
Cu1—N1	1.928 (3)	C17—H17A	0.9700
Cu1—N3	1.952 (3)	C17—H17B	0.9700
Cu2—O3	1.923 (2)	O6—C27	1.217 (5)
Cu2—O4	2.005 (2)	C15—C16	1.442 (5)
Cu2—N4	1.995 (3)	C15—C14	1.403 (5)
Cu2—N2	1.927 (3)	C16—H16	0.9300
Br3—C24	1.903 (4)	C2—H2A	0.9300
Br1—C4	1.910 (4)	C2—C3	1.363 (5)
Br2—C13	1.902 (4)	C5—H5	0.9300
S1—C19	1.629 (3)	C5—C4	1.358 (5)
S2—C20	1.643 (4)	C9—H9A	0.9700
O3—C10	1.325 (4)	C9—H9B	0.9700
O4—H4	0.8200	C9—C8	1.490 (5)
O4—C18	1.430 (4)	C11—H11	0.9300
O1—C1	1.312 (4)	C11—C12	1.380 (5)
O2—H2	0.8200	C8—H8A	0.9700
O2—C9	1.437 (4)	C8—H8B	0.9700
N4—C20	1.106 (4)	C3—H3	0.9300
N1—C7	1.277 (4)	C3—C4	1.390 (5)
N1—C8	1.474 (4)	C14—H14	0.9300
N2—C17	1.464 (4)	C14—C13	1.367 (6)
N2—C16	1.276 (4)	C24—C25	1.350 (5)
N3—C19	1.153 (4)	C24—C23	1.378 (6)
O7—H7A	0.8502	C13—C12	1.375 (6)
O7—H7B	0.8501	C12—H12	0.9300
O5—H5A	0.8200	C25—H25	0.9300
O5—C21	1.343 (5)	C25—C26	1.396 (5)
C1—C6	1.416 (5)	C26—C21	1.391 (6)
C1—C2	1.412 (5)	C26—C27	1.445 (7)
C6—C7	1.431 (5)	C21—C22	1.387 (6)
C6—C5	1.409 (5)	C23—H23	0.9300
C7—H7	0.9300	C23—C22	1.375 (6)
C10—C15	1.405 (5)	C22—H22	0.9300
C10—C11	1.406 (5)	C27—H27	0.9300
C18—H18A	0.9700

O1—Cu1—O2	166.82 (10)	C15—C16—H16	117.3
N3—Cu1—O2	89.45 (11)	C1—C2—H2A	118.8
O1—Cu1—N1	93.58 (10)	C3—C2—C1	122.4 (3)
O1—Cu1—N3	94.69 (11)	C3—C2—H2A	118.8
N1—Cu1—O2	82.51 (10)	N4—C20—S2	176.2 (3)
N1—Cu1—N3	171.73 (12)	C6—C5—H5	119.7
O3—Cu2—O4	166.23 (10)	C4—C5—C6	120.6 (3)
O3—Cu2—N4	91.49 (10)	C4—C5—H5	119.7
O3—Cu2—N2	93.35 (11)	O2—C9—H9A	110.2
N4—Cu2—O4	92.01 (10)	O2—C9—H9B	110.2
N2—Cu2—O4	82.24 (11)	O2—C9—C8	107.5 (3)
N2—Cu2—N4	173.38 (11)	H9A—C9—H9B	108.5
C10—O3—Cu2	125.5 (2)	C8—C9—H9A	110.2
Cu2—O4—H4	116.5	C8—C9—H9B	110.2
C18—O4—Cu2	111.8 (2)	C10—C11—H11	119.5
C18—O4—H4	109.5	C12—C11—C10	121.0 (4)
C1—O1—Cu1	126.8 (2)	C12—C11—H11	119.5
Cu1—O2—H2	113.0	N1—C8—C9	107.8 (3)
C9—O2—Cu1	110.9 (2)	N1—C8—H8A	110.1
C9—O2—H2	109.5	N1—C8—H8B	110.1
C20—N4—Cu2	150.0 (3)	C9—C8—H8A	110.1
C7—N1—Cu1	126.4 (2)	C9—C8—H8B	110.1
C7—N1—C8	120.9 (3)	H8A—C8—H8B	108.5
C8—N1—Cu1	112.6 (2)	C2—C3—H3	120.3
C17—N2—Cu2	113.8 (2)	C2—C3—C4	119.3 (3)
C16—N2—Cu2	126.2 (2)	C4—C3—H3	120.3
C16—N2—C17	119.9 (3)	C5—C4—Br1	120.0 (3)
C19—N3—Cu1	161.4 (3)	C5—C4—C3	121.0 (3)
H7A—O7—H7B	104.5	C3—C4—Br1	119.0 (3)
C21—O5—H5A	109.5	C15—C14—H14	120.2
N3—C19—S1	178.3 (3)	C13—C14—C15	119.6 (4)
O1—C1—C6	124.2 (3)	C13—C14—H14	120.2
O1—C1—C2	118.7 (3)	C25—C24—Br3	120.1 (3)
C2—C1—C6	117.1 (3)	C25—C24—C23	120.7 (4)
C1—C6—C7	123.2 (3)	C23—C24—Br3	119.2 (3)
C5—C6—C1	119.6 (3)	C14—C13—Br2	119.8 (3)
C5—C6—C7	117.2 (3)	C14—C13—C12	121.5 (3)
N1—C7—C6	125.5 (3)	C12—C13—Br2	118.7 (3)
N1—C7—H7	117.2	C11—C12—H12	120.2
C6—C7—H7	117.2	C13—C12—C11	119.6 (4)
O3—C10—C15	124.0 (3)	C13—C12—H12	120.2
O3—C10—C11	117.7 (3)	C24—C25—H25	119.9
C15—C10—C11	118.2 (3)	C24—C25—C26	120.3 (4)
O4—C18—H18A	110.5	C26—C25—H25	119.9
O4—C18—H18B	110.5	C25—C26—C27	119.6 (4)
O4—C18—C17	106.2 (3)	C21—C26—C25	119.4 (4)
H18A—C18—H18B	108.7	C21—C26—C27	120.9 (4)
C17—C18—H18A	110.5	O5—C21—C26	122.1 (4)
C17—C18—H18B	110.5	O5—C21—C22	118.5 (4)
N2—C17—C18	108.0 (3)	C22—C21—C26	119.3 (4)
N2—C17—H17A	110.1	C24—C23—H23	120.0
N2—C17—H17B	110.1	C22—C23—C24	120.1 (4)
C18—C17—H17A	110.1	C22—C23—H23	120.0
C18—C17—H17B	110.1	C21—C22—H22	119.9
H17A—C17—H17B	108.4	C23—C22—C21	120.1 (4)
C10—C15—C16	123.3 (3)	C23—C22—H22	119.9
C14—C15—C10	120.0 (3)	O6—C27—C26	125.4 (5)
C14—C15—C16	116.7 (3)	O6—C27—H27	117.3
N2—C16—C15	125.4 (3)	C26—C27—H27	117.3
N2—C16—H16	117.3

Cu2—O3—C10—C15	15.2 (4)	C10—C15—C14—C13	1.7 (6)
Cu2—O3—C10—C11	−165.6 (2)	C10—C11—C12—C13	0.8 (6)
Cu2—O4—C18—C17	39.3 (3)	C17—N2—C16—C15	−175.2 (3)
Cu2—N2—C17—C18	31.8 (3)	C15—C10—C11—C12	−0.2 (5)
Cu2—N2—C16—C15	0.8 (5)	C15—C14—C13—Br2	−179.9 (3)
Cu1—O1—C1—C6	−5.0 (5)	C15—C14—C13—C12	−1.0 (6)
Cu1—O1—C1—C2	174.7 (2)	C16—N2—C17—C18	−151.7 (3)
Cu1—O2—C9—C8	−35.9 (3)	C16—C15—C14—C13	−178.5 (3)
Cu1—N1—C7—C6	−0.5 (5)	C2—C1—C6—C7	−178.3 (3)
Cu1—N1—C8—C9	−37.5 (4)	C2—C1—C6—C5	1.1 (5)
Br3—C24—C25—C26	−179.8 (3)	C2—C3—C4—Br1	179.5 (3)
Br3—C24—C23—C22	−179.7 (3)	C2—C3—C4—C5	0.5 (6)
Br2—C13—C12—C11	178.7 (3)	C5—C6—C7—N1	−177.9 (3)
O3—C10—C15—C16	−1.6 (5)	C11—C10—C15—C16	179.1 (3)
O3—C10—C15—C14	178.2 (3)	C11—C10—C15—C14	−1.1 (5)
O3—C10—C11—C12	−179.5 (3)	C8—N1—C7—C6	175.9 (3)
O4—C18—C17—N2	−45.1 (4)	C14—C15—C16—N2	173.2 (3)
O1—C1—C6—C7	1.5 (5)	C14—C13—C12—C11	−0.2 (6)
O1—C1—C6—C5	−179.2 (3)	C24—C25—C26—C21	−0.1 (6)
O1—C1—C2—C3	−180.0 (3)	C24—C25—C26—C27	−179.9 (4)
O2—C9—C8—N1	46.9 (4)	C24—C23—C22—C21	−0.9 (6)
O5—C21—C22—C23	−178.5 (4)	C25—C24—C23—C22	0.4 (6)
C1—C6—C7—N1	1.5 (5)	C25—C26—C21—O5	179.1 (4)
C1—C6—C5—C4	−1.2 (5)	C25—C26—C21—C22	−0.4 (6)
C1—C2—C3—C4	−0.6 (5)	C25—C26—C27—O6	179.7 (5)
C6—C1—C2—C3	−0.2 (5)	C26—C21—C22—C23	0.9 (6)
C6—C5—C4—Br1	−178.6 (3)	C21—C26—C27—O6	−0.1 (8)
C6—C5—C4—C3	0.4 (6)	C23—C24—C25—C26	0.2 (6)
C7—N1—C8—C9	145.7 (3)	C27—C26—C21—O5	−1.1 (7)
C7—C6—C5—C4	178.2 (3)	C27—C26—C21—C22	179.4 (4)
C10—C15—C16—N2	−7.0 (6)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O4—H4···O7	0.82	1.75	2.562 (4)	174
O2—H2···O3	0.82	1.84	2.647 (3)	169
O7—H7A···O1	0.85	1.88	2.709 (4)	163
O7—H7B···S2ⁱ	0.85	2.64	3.290 (3)	135
O5—H5A···O6	0.82	1.94	2.655 (6)	146
C18—H18A···Br3ⁱⁱ	0.97	3.32	3.856 (4)	117
C18—H18A···S1	0.97	2.98	3.801 (4)	143
C18—H18A···N3	0.97	3.22	3.785 (5)	119
C17—H17A···O5	0.97	2.73	3.368 (5)	124
C16—H16···O6ⁱⁱⁱ	0.93	2.52	3.376 (5)	153
C2—H2A···O2^iv	0.93	2.92	3.726 (4)	146
C2—H2A···O7	0.93	3.08	3.548 (5)	113
C9—H9A···N4^v	0.97	3.20	3.851 (4)	126
C9—H9B···O3^v	0.97	3.03	3.613 (5)	120
C9—H9B···N4	0.97	3.20	3.700 (5)	114
C11—H11···S2^v	0.93	3.11	3.709 (4)	124
C8—H8A···S1^vi	0.97	3.29	3.881 (3)	121
C8—H8A···O3^v	0.97	3.07	3.773 (5)	130
C8—H8B···S2ⁱⁱⁱ	0.97	3.30	3.784 (4)	113
C8—H8B···O7^vi	0.97	2.96	3.739 (6)	138
C14—H14···O6ⁱⁱⁱ	0.93	3.12	3.827 (6)	134
C12—H12···S2^v	0.93	2.93	3.616 (5)	131
C22—H22···O6ⁱⁱⁱ	0.93	2.97	3.847 (6)	158
C27—H27···Br2^vii	0.93	3.04	3.949 (6)	166

Symmetry codes: (i) −x+1, −y+2, −z+1; (ii) −x, y+1/2, −z+1/2; (iii) x, −y+3/2, z−1/2; (iv) −x+1, y+1/2, −z+1/2; (v) −x+1, −y+1, −z+1; (vi) −x+1, y−1/2, −z+1/2; (vii) −x, −y+1, −z+1.

Acknowledgements

IET gratefully acknowledges the support of Dr Eugenio Cavallo, Scientific Attaché, and the Italian Embassy in Dakar for their assistance in facilitating participation in the MAECI programme "Contributi per missioni di studio e ricerca 2025/ Contributions for study and research missions 2025", as well as for their continued commitment to fostering scientific collaboration between Senegal and Italy. The authors are grateful to the FAIRE programme provided by the Cambridge Crystallographic Data Centre (CCDC) for the opportunity to use the Cambridge Structural Database (CSD) and associated software.

References

Abbasi, Z., Salehi, M., Kubicki, M. & Khaleghian, A. (2017). J. Coord. Chem. 70, 3132–3146. CrossRef CAS Google Scholar
Abu-Dief, A. M. & Mohamed, I. M. A. (2015). Beni-Suef Univ. J. Basic Appl. Sci. 4, 119–133. Google Scholar
Benito, M., Mahmoudi, G., Molins, E., Zangrando, E., Servati Gargari, M., Gomila, R. M., Frontera, A. & Safin, D. A. (2025). CrystEngComm 27, 164–175. CrossRef CAS Google Scholar
Bruker (2014). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Chumakov, M. Yu., Tsapkov, I. V., Bocelli, G., Antosyak, Ya. B. & Gulya, P. (2007). Crystallogr. Rep. 52, 277. Google Scholar
De, L. R., Samanta, K., Maiti, K. & Keller, E. (2001). Inorg. Chim. Acta 316, 113–116. CrossRef CAS 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
Juyal, V. K., Pathak, A., Panwar, M., Thakuri, S. C., Prakash, O., Agrwal, A. & Nand, V. (2023). J. Organomet. Chem. 999, 122825. CrossRef Google Scholar
Krause, L., Herbst-Irmer, R., Sheldrick, G. M. & Stalke, D. (2015). J. Appl. Cryst. 48, 3–10. Web of Science CSD CrossRef ICSD CAS IUCr Journals Google Scholar
Liang, F.-Z., Ma, J.-P. & Zhu, J.-H. (2006). Chin. J. Inorg. Chem. 22, 115. Google Scholar
More, M. S., Joshi, P. G., Mishra, Y. K. & Khanna, P. K. (2019). Mater. Today Chem. 14, 100195. CrossRef PubMed Google Scholar
Oshio, H., Hoshino, N., Ito, T. & Nakano, M. (2004). J. Am. Chem. Soc. 126, 8805–8812. Web of Science CrossRef PubMed CAS Google Scholar
Shelar, D. S., Dhavan, P. P., Singh, P. R., Jadhav, B. L., Vaidya, S. P. & Manjare, S. T. (2021). J. Mol. Struct. 1244, 130914. CrossRef Google Scholar
Sheldrick, G. M. (2015). Acta Cryst. C71, 3–8. Web of Science CrossRef IUCr Journals Google Scholar
Taylor, C. R. & Day, G. M. (2018). Cryst. Growth Des. 18, 892–904. Web of Science CrossRef CAS PubMed Google Scholar
Thakur, S., Rohilla, J., Sharma, S., Singh, R., Kamboj, R. & Kaur, V. (2024). Dalton Trans. 53, 18283–18295. CrossRef CAS PubMed Google Scholar
Thakurta, S., Chakraborty, J., Rosair, G., Butcher, R. J. & Mitra, S. (2009a). Inorg. Chim. Acta 362, 2828–2836. CrossRef CAS Google Scholar
Thakurta, S., Roy, P., Rosair, G., Gómez-García, C. J., Garribba, E. & Mitra, S. (2009b). Polyhedron 28, 695–702. CrossRef CAS Google Scholar
Yu, J. (2011). Acta Cryst. E67, m1035. CrossRef IUCr Journals Google Scholar
Zabierowski, P., Szklarzewicz, J., Kurpiewska, K., Lewiński, K. & Nitek, W. (2013). Polyhedron 49, 74–83. CrossRef CAS Google Scholar

This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.