Synthesis, structure and selective luminescence sensing for iron(III) ions of a three-dimensional zinc(II) (4,6)-connected coordination network

Coordination polymers constructed from conjugated organic ligands and metal ions with a d¹⁰ electronic configuration exhibit intriguing properties for chemical sensing and photochemistry. A Zn^II-based coordination polymer, namely poly[aqua­(μ₆-biphenyl-3,3′,5,5′-tetra­carboxyl­ato)(μ₂-4,4′-bi­pyridine)­di­zinc(II)], [Zn₂(C₁₆H₆O₈)(C₁₀H₈N₂)(H₂O)₂]_n or [Zn₂(m,m-bpta)(4,4′-bipy)(H₂O)₂]_n, was syn­thesized from a mixture of biphenyl-3,3′,5,5′-tetra­carb­oxy­lic acid [H₄(m,m-bpta)], 4,4′-bi­pyridine (4,4′-bipy) and Zn(NO₃)₂·6H₂O under solvo­thermal conditions. The title complex has been structurally characterized by IR spectroscopy, elemental analysis, single-crystal X-ray diffraction and powder X-ray diffraction analysis, and features a μ₆-coordination mode. The Zn^II ions adopt square-pyramidal geometries and are bridged by two syn–syn carboxyl­ate groups to form [Zn₂(COO)₂] secondary buildding units (SBUs). The SBUs are crosslinked by (m,m-bpta)⁴⁻ ligands to produce a two-dimensional grid-like layer that exhibits a stair-like structure along the a axis. Adjacent layers are linked by 4,4′-bipy ligands to form a three-dimensional network with a {4⁴.6¹⁰.8}{4⁴.6²} topology. In the solid state, the complex displays a strong photoluminescence and an excellent solvent stability. In addition, the luminescence sensing results indicate a highly selective and sensitive sensing for Fe³⁺ ions.

Computing details

Data collection: APEX2 (Bruker, 2012); cell refinement: SAINT (Bruker, 2012); data reduction: SAINT (Bruker, 2012); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2018 (Sheldrick, 2015); molecular graphics: SHELXTL (Bruker, 2008), DIAMOND (Brandenburg, 2005) and Mercury (Macrae et al., 2008); software used to prepare material for publication: publCIF (Westrip, 2010).

Poly[aqua(µ₆-biphenyl-3,3',5,5'-tetracarboxylato)(µ₂-4,4'-bipyridine)dizinc(II)]

Crystal data

[Zn2(C16H6O8)(C10H8N2)(H2O)2]	Z = 1
Mr = 649.16	F(000) = 328
Triclinic, P1	Dx = 1.892 Mg m^−3
a = 7.7926 (5) Å	Mo Kα radiation, λ = 0.71073 Å
b = 8.2969 (5) Å	Cell parameters from 5744 reflections
c = 9.7964 (9) Å	θ = 2.7–27.7°
α = 73.953 (2)°	µ = 2.18 mm^−1
β = 76.973 (2)°	T = 296 K
γ = 71.184 (1)°	Block, colourless
V = 569.67 (7) Å^3	0.35 × 0.32 × 0.30 mm

Data collection

Bruker APEXII CCD diffractometer	2226 reflections with I > 2σ(I)
Radiation source: sealed tube	Rint = 0.044
φ and ω scans	θmax = 28.3°, θmin = 2.7°
Absorption correction: multi-scan (SADABS; Bruker, 2012)	h = −10→10
Tmin = 0.670, Tmax = 0.746	k = −11→11
12819 measured reflections	l = −12→13
2827 independent reflections

Refinement

Refinement on F^2	0 restraints
Least-squares matrix: full	Hydrogen site location: mixed
R[F^2 > 2σ(F^2)] = 0.037	H-atom parameters constrained
wR(F^2) = 0.076	w = 1/[σ^2(Fo^2) + (0.0301P)^2 + 0.4864P] where P = (Fo^2 + 2Fc^2)/3
S = 1.04	(Δ/σ)max < 0.001
2827 reflections	Δρmax = 0.46 e Å^−3
181 parameters	Δρmin = −0.39 e Å^−3

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 (Ų)

	x	y	z	Uiso*/Ueq
Zn1	0.49602 (4)	1.12378 (4)	0.11306 (3)	0.02067 (11)
O1	0.6404 (3)	0.8846 (2)	0.1782 (2)	0.0270 (5)
O2	0.6622 (3)	0.7200 (2)	0.02631 (19)	0.0243 (4)
O3	1.2633 (2)	0.0449 (2)	0.2484 (2)	0.0243 (4)
O4	1.0140 (3)	0.0814 (3)	0.1577 (2)	0.0367 (5)
O5	0.7460 (3)	1.1746 (2)	−0.0172 (2)	0.0284 (5)
H5A	0.805141	1.117378	−0.077048	0.043*
H5B	0.825267	1.169214	0.027872	0.043*
N1	0.5072 (3)	1.2651 (3)	0.2472 (2)	0.0195 (5)
C1	0.7033 (3)	0.7463 (3)	0.1336 (3)	0.0160 (5)
C2	0.8319 (3)	0.5988 (3)	0.2197 (3)	0.0143 (5)
C3	0.9027 (3)	0.4374 (3)	0.1828 (3)	0.0157 (5)
H3	0.873617	0.420509	0.101758	0.019*
C4	1.0173 (3)	0.3015 (3)	0.2678 (3)	0.0165 (5)
C5	1.1032 (4)	0.1292 (3)	0.2218 (3)	0.0198 (6)
C6	1.0551 (3)	0.3265 (3)	0.3909 (3)	0.0187 (6)
H6	1.131236	0.234325	0.447440	0.022*
C7	0.9818 (3)	0.4870 (3)	0.4326 (3)	0.0153 (5)
C8	0.8739 (3)	0.6225 (3)	0.3420 (3)	0.0172 (5)
H8	0.828482	0.732147	0.363902	0.021*
C9	0.4273 (4)	1.4377 (3)	0.2270 (3)	0.0214 (6)
H9	0.373843	1.495040	0.144488	0.026*
C10	0.4212 (4)	1.5329 (3)	0.3233 (3)	0.0190 (6)
H10	0.363880	1.652217	0.305744	0.023*
C11	0.5010 (3)	1.4505 (3)	0.4472 (3)	0.0166 (5)
C12	0.5827 (4)	1.2711 (3)	0.4677 (3)	0.0234 (6)
H12	0.636665	1.210181	0.549434	0.028*
C13	0.5831 (4)	1.1851 (3)	0.3669 (3)	0.0234 (6)
H13	0.638659	1.065519	0.382218	0.028*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Zn1	0.02881 (19)	0.01352 (14)	0.02106 (18)	0.00476 (12)	−0.01717 (13)	−0.00782 (11)
O1	0.0320 (11)	0.0155 (9)	0.0286 (11)	0.0093 (8)	−0.0154 (9)	−0.0070 (8)
O2	0.0307 (11)	0.0225 (9)	0.0188 (10)	0.0021 (8)	−0.0165 (8)	−0.0042 (8)
O3	0.0228 (10)	0.0180 (9)	0.0288 (11)	0.0029 (8)	−0.0100 (8)	−0.0054 (8)
O4	0.0361 (12)	0.0327 (11)	0.0512 (14)	0.0038 (9)	−0.0226 (11)	−0.0279 (10)
O5	0.0278 (11)	0.0282 (10)	0.0301 (11)	−0.0003 (8)	−0.0074 (9)	−0.0140 (9)
N1	0.0220 (12)	0.0211 (11)	0.0177 (11)	−0.0042 (9)	−0.0053 (9)	−0.0084 (9)
C1	0.0135 (13)	0.0155 (11)	0.0157 (13)	−0.0012 (10)	−0.0040 (10)	−0.0001 (10)
C2	0.0141 (12)	0.0157 (11)	0.0116 (12)	−0.0003 (10)	−0.0054 (10)	−0.0022 (9)
C3	0.0164 (13)	0.0183 (11)	0.0133 (12)	−0.0009 (10)	−0.0074 (10)	−0.0055 (10)
C4	0.0162 (13)	0.0163 (11)	0.0165 (13)	−0.0003 (10)	−0.0042 (10)	−0.0064 (10)
C5	0.0247 (14)	0.0172 (12)	0.0163 (13)	−0.0013 (11)	−0.0053 (11)	−0.0056 (10)
C6	0.0201 (14)	0.0160 (11)	0.0190 (14)	0.0013 (10)	−0.0107 (11)	−0.0037 (10)
C7	0.0136 (13)	0.0162 (11)	0.0151 (13)	0.0006 (10)	−0.0047 (10)	−0.0056 (10)
C8	0.0182 (13)	0.0144 (11)	0.0176 (13)	0.0008 (10)	−0.0059 (11)	−0.0052 (10)
C9	0.0260 (15)	0.0190 (12)	0.0196 (14)	−0.0034 (11)	−0.0092 (12)	−0.0035 (11)
C10	0.0229 (14)	0.0160 (11)	0.0193 (14)	−0.0028 (10)	−0.0042 (11)	−0.0077 (10)
C11	0.0175 (13)	0.0204 (12)	0.0129 (13)	−0.0059 (10)	0.0007 (10)	−0.0068 (10)
C12	0.0330 (16)	0.0193 (12)	0.0185 (14)	−0.0011 (11)	−0.0115 (12)	−0.0062 (11)
C13	0.0327 (16)	0.0169 (12)	0.0209 (14)	−0.0010 (11)	−0.0101 (12)	−0.0065 (11)

Geometric parameters (Å, º)

Zn1—O1	1.9479 (17)	C3—H3	0.9300
Zn1—O2^i	1.9531 (17)	C4—C6	1.386 (3)
Zn1—N1	2.020 (2)	C4—C5	1.516 (3)
Zn1—O3^ii	2.1622 (19)	C6—C7	1.404 (3)
Zn1—O5	2.171 (2)	C6—H6	0.9300
O1—C1	1.251 (3)	C7—C8	1.390 (3)
O2—C1	1.256 (3)	C7—C7^iii	1.496 (5)
O3—C5	1.263 (3)	C8—H8	0.9300
O4—C5	1.244 (3)	C9—C10	1.373 (3)
O5—H5A	0.8201	C9—H9	0.9300
O5—H5B	0.8202	C10—C11	1.391 (3)
N1—C13	1.340 (3)	C10—H10	0.9300
N1—C9	1.342 (3)	C11—C12	1.394 (3)
C1—C2	1.494 (3)	C11—C11^iv	1.482 (5)
C2—C3	1.389 (3)	C12—C13	1.367 (4)
C2—C8	1.389 (3)	C12—H12	0.9300
C3—C4	1.389 (3)	C13—H13	0.9300
O1—Zn1—O2^i	145.01 (8)	C3—C4—C5	119.2 (2)
O1—Zn1—N1	107.61 (8)	C6—C4—C5	121.0 (2)
O2^i—Zn1—N1	107.33 (8)	O4—C5—O3	124.1 (2)
O1—Zn1—O3^ii	86.45 (7)	O4—C5—C4	118.2 (2)
O2^i—Zn1—O3^ii	90.12 (7)	O3—C5—C4	117.7 (2)
N1—Zn1—O3^ii	92.70 (8)	C4—C6—C7	121.9 (2)
O1—Zn1—O5	87.59 (8)	C4—C6—H6	119.1
O2^i—Zn1—O5	94.44 (8)	C7—C6—H6	119.1
N1—Zn1—O5	89.65 (8)	C8—C7—C6	116.9 (2)
O3^ii—Zn1—O5	174.02 (7)	C8—C7—C7^iii	121.1 (3)
C1—O1—Zn1	138.22 (17)	C6—C7—C7^iii	122.0 (3)
C1—O2—Zn1^i	130.58 (16)	C7—C8—C2	121.9 (2)
C5—O3—Zn1^v	119.64 (16)	C7—C8—H8	119.1
Zn1—O5—H5A	121.1	C2—C8—H8	119.1
Zn1—O5—H5B	115.3	N1—C9—C10	122.6 (2)
H5A—O5—H5B	102.1	N1—C9—H9	118.7
C13—N1—C9	117.6 (2)	C10—C9—H9	118.7
C13—N1—Zn1	120.11 (17)	C9—C10—C11	119.9 (2)
C9—N1—Zn1	122.03 (17)	C9—C10—H10	120.1
O1—C1—O2	125.4 (2)	C11—C10—H10	120.1
O1—C1—C2	116.6 (2)	C12—C11—C10	117.1 (2)
O2—C1—C2	117.9 (2)	C12—C11—C11^iv	121.6 (3)
C3—C2—C8	119.9 (2)	C10—C11—C11^iv	121.4 (3)
C3—C2—C1	121.0 (2)	C13—C12—C11	119.7 (2)
C8—C2—C1	119.0 (2)	C13—C12—H12	120.2
C4—C3—C2	119.5 (2)	C11—C12—H12	120.2
C4—C3—H3	120.2	N1—C13—C12	123.1 (2)
C2—C3—H3	120.2	N1—C13—H13	118.5
C3—C4—C6	119.8 (2)	C12—C13—H13	118.5
Zn1—O1—C1—O2	−11.0 (4)	C3—C4—C6—C7	−0.5 (4)
Zn1—O1—C1—C2	171.65 (18)	C5—C4—C6—C7	177.8 (2)
Zn1^i—O2—C1—O1	3.4 (4)	C4—C6—C7—C8	−2.1 (4)
Zn1^i—O2—C1—C2	−179.26 (16)	C4—C6—C7—C7^iii	178.3 (3)
O1—C1—C2—C3	177.1 (2)	C6—C7—C8—C2	3.3 (4)
O2—C1—C2—C3	−0.4 (4)	C7^iii—C7—C8—C2	−177.1 (3)
O1—C1—C2—C8	0.0 (4)	C3—C2—C8—C7	−1.9 (4)
O2—C1—C2—C8	−177.5 (2)	C1—C2—C8—C7	175.3 (2)
C8—C2—C3—C4	−0.9 (4)	C13—N1—C9—C10	0.1 (4)
C1—C2—C3—C4	−178.0 (2)	Zn1—N1—C9—C10	174.7 (2)
C2—C3—C4—C6	2.0 (4)	N1—C9—C10—C11	0.4 (4)
C2—C3—C4—C5	−176.3 (2)	C9—C10—C11—C12	−0.7 (4)
Zn1^v—O3—C5—O4	100.0 (3)	C9—C10—C11—C11^iv	179.3 (3)
Zn1^v—O3—C5—C4	−78.3 (3)	C10—C11—C12—C13	0.7 (4)
C3—C4—C5—O4	−33.4 (4)	C11^iv—C11—C12—C13	−179.4 (3)
C6—C4—C5—O4	148.2 (3)	C9—N1—C13—C12	−0.1 (4)
C3—C4—C5—O3	145.0 (2)	Zn1—N1—C13—C12	−174.9 (2)
C6—C4—C5—O3	−33.3 (4)	C11—C12—C13—N1	−0.3 (4)

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

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C12—H12···O3^iii	0.93	2.51	3.390 (3)	157
C9—H9···O5^vi	0.93	2.63	3.345 (3)	134
O5—H5B···O4^vii	0.82	1.99	2.781 (3)	163
O5—H5A···O4^viii	0.82	2.01	2.793 (3)	159
O5—H5A···O3^viii	0.82	2.65	3.300 (3)	137

Symmetry codes: (iii) −x+2, −y+1, −z+1; (vi) −x+1, −y+3, −z; (vii) x, y+1, z; (viii) −x+2, −y+1, −z.