Crystal structure of bis-{μ2-3-(pyridin-2-yl)-5-[(1,2,4-triazol-1-yl)meth-yl]-1,2,4-triazolato}bis-[aqua-nitrato-copper(II)] dihydrate.

The structure of the dinuclear title complex, [Cu2(C10H8N7)2(NO3)2(H2O)2]·2H2O, consists of centrosymmetric dimeric units with a copper-copper separation of 4.0408 (3) Å. The Cu(II) ions in the dimer display a distorted octa-hedral coordination geometry and are bridged by two triazole rings, forming an approximately planar Cu2N4 core (r.m.s. deviation = 0.049 Å). In the crystal, O-H⋯O, O-H⋯N and C-H⋯O hydrogen bonds and π-π inter-actions link the mol-ecules into a three-dimensional network.

Chemical context

The presence in the triazole ring, three donor atoms and the possibility of introducing in the heterocycle substituents of a different nature creates the conditions for target synthesis of complexes with inter­esting structures and properties. The study of this type of coordination compound is promising since, as a result, a compound can be obtained with useful physical properties such as optical, magnetic or catalytic (Soghomonian et al., 1993 ▸; Blake et al., 1999 ▸). Another inter­esting aspect of these compounds is the possibility of their use as functional models of enzymes such as catechol oxidase (Moliner et al., 2001 ▸; Klingele et al., 2009 ▸; Selmeczi et al., 2003 ▸).

Structural commentary

The structure of the title complex mol­ecule (Fig. 1 ▸) has a crystallographically imposed centre of symmetry, and contains two copper(II) metal atoms doubly bridged by the triazole rings of two deprotonated ligands. Each copper(II) ion is coordinated in a distorted elongated octa­hedral geometry by one pyridine and three triazole nitro­gen atoms forming the equatorial plane, and by the O atoms of a water mol­ecule and a monodentate nitrate anion at the apices. The Cu—N bond lengths involving the bridging triazole ring [mean value 1.9722 (15) Å] are slightly, but significantly, shorter than those involving the pyridine and peripheral triazole rings [Cu1—N4 = 2.0386 (16) and Cu1—N7 = 2.0409 (17) Å]. The inner Cu2N4 core is approximately planar [r.m.s. deviation = 0.049 Å; maximum displacement 0.062 (2) Å for atom N2], with a Cu⋯Cu separation of 4.0408 (3) Å, in good agreement with the values usually observed in μ-triazolyl-bridged complexes (Haasnoot, 2000 ▸). The central triazole ring makes dihedral angles of 7.78 (8) and 49.30 (8)°, respectively, with the pyridine and peripheral triazole rings. The six-membered chelate ring Cu1/N5/C7/C8/N6/N7 assumes a boat conformation [puckering parameters: Q T = 0.619 (2) Å; θ2 = 88.62 (16)°], while the five-membered Cu1/N2/C1/C2/N4 chelate ring adopts a flattened envelope conformation with the Cu atom as flap [puckering parameters: Q = 0.127 (2) Å; φ = −156.8 (8)°].

Figure 1

The mol­ecular structure of the title compound with displacement ellipsoids drawn at the 40% probability level. Dashed lines indicate hydrogen bonds. Unlabelled atoms are related to labelled atoms by (−x, 1 − y, −z).

Supra­molecular features

In the crystal, the complex molecules and water mol­ecules of crystallization are linked through O—H⋯O, O—H⋯N and C—H⋯O hydrogen bonds (Table 1 ▸), forming a three-dimensional network (Fig. 2 ▸). The crystal structure is further stabilized by π–π stacking inter­actions with centroid–centroid separations Cg1⋯Cg2ii = 3.8296 (13) Å and Cg3⋯Cg3iii = 3.5372 (10), and perpendic­ular inter­planar distances Cg1⋯Cg2ii = 3.5584 (9) and Cg3⋯Cg3iii = 3.3234 (10) Å [Cg1, Cg2 and Cg3 are the centroids of the N1/C2/N3/C7i/N5i, N4/C2–C6 and N6/N7/C9/N8/C10 rings, respectively; symmetry codes: (i) −x, 1 − y, −z; (ii) −x, −y, −z; (iii) 1 − x, −y, 1 − z].

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O4—H41O⋯O5i	0.71 (3)	2.03 (3)	2.735 (2)	172 (3)
O4—H42O⋯O5ii	0.79 (3)	1.96 (3)	2.735 (2)	168 (3)
O5—H51O⋯O2iii	0.78 (3)	2.02 (3)	2.773 (2)	163 (3)
O5—H52O⋯N3iv	0.76 (3)	2.08 (3)	2.836 (2)	177 (3)
C5—H5⋯O1i	0.95	2.43	3.360 (3)	166
C8—H8A⋯O4	0.99	2.56	3.160 (3)	119
C8—H8B⋯O2iii	0.99	2.36	3.319 (3)	162
C9—H9⋯O3v	0.95	2.44	3.205 (3)	137

Symmetry codes: (i) ; (ii) ; (iii) ; (iv) ; (v) .

Figure 2

Packing diagram of the title compound, viewed along the b axis. Inter­molecular hydrogen bonds are shown as blue dotted lines.

Database survey

The Cambridge Structural Database (CSD Version 5.36 with three updates; Groom & Allen, 2014 ▸), returned 45 entries with the triazole bridging fragment Cu–(N–N)2–Cu. The most similar are: di­aqua­bis­(μ-3,5-bis­(2-pyrid­yl)-1,2,4-triazolato-N′,N 1,N 2,N′′)bis­(tri­fluoro­methane­sulfonato-O)dicopper(II) (Prins et al., 1985 ▸), bis­[μ-5-(pyridin-2-yl)-3-(1H-1,2,4-triazol-3-yl)-1,2,4-triazolato]di­aqua­dicopper diperchlorate (Zhou et al., 2014 ▸), bis­[μ3-(pyridin-2-yl)-5-([5-(pyridin-2-yl)-1,2,4-tria­zol-1-id-3-yl]meth­yl)-1,2,4-triazol-1-ide]tri­aqua­tricopper di­perchlorate dihydrate (Gusev et al., 2014 ▸) and bis­(μ-5-(2-eth­oxy-2-oxoeth­yl)-3-(pyridin-2-yl)-1H-1,2,4-triazol­yl)bis(acetonitrile)­bis­(perchlorato-O)dicopper (Khomenko et al., 2012 ▸). Only 10 compounds containing a pyridyl and a methyl­ene moiety, as substituents in the 3- and 5-positions of 1,2,4-triazole, were found (Lin et al., 2013 ▸; Gusev et al., 2014 ▸ and references therein).

Synthesis and crystallization

A water solution of Cu(NO3)2·3H2O (0.25 mmol, 0.0605 g) was added to a hot solution of 2-[5-(1,2,4,)-triazol-1-yl-methyl-1H-(1,2,4)-triazol-3­yl]pyridine (0.25 mmol, 0.059 g) in water (7 ml). The transparent blue solution was left to evaporate slowly in the air and after few hours, blue single crystals suitable for X-ray analysis were obtained (yield: 67%).

Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2 ▸. H atoms of water mol­ecules were located from a difference Fourier map and refined freely. All other H atoms were constrained to ride on their parent atoms, with C—H = 0.95–0.99 Å and with U iso(H) = 1.2U eq(C).

Table 2

Experimental details

Crystal data
Chemical formula	[Cu2(C10H8N7)2(NO3)2(H2O)2]·2H2O
M r	775.63
Crystal system, space group	Triclinic, P
Temperature (K)	173
a, b, c (Å)	8.8421 (2), 8.8636 (2), 10.5686 (2)
α, β, γ (°)	70.114 (1), 88.6311 (10), 66.765 (1)
V (Å3)	709.87 (3)
Z	1
Radiation type	Mo Kα
μ (mm−1)	1.58
Crystal size (mm)	0.50 × 0.50 × 0.45
Data collection
Diffractometer	Bruker APEXII CCD
Absorption correction	Multi-scan (SADABS; Bruker, 2003 ▸)
T min, T max	0.505, 0.536
No. of measured, independent and observed [I > 2σ(I)] reflections	8672, 2945, 2711
R int	0.025
(sin θ/λ)max (Å−1)	0.629
Refinement
R[F 2 > 2σ(F 2)], wR(F 2), S	0.027, 0.073, 1.07
No. of reflections	2945
No. of parameters	233
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å−3)	0.26, −0.57

Computer programs: APEX2 and SAINT (Bruker, 2003 ▸), SHELXS97 and SHELXTL (Sheldrick, 2008 ▸) and SHELXL2014 (Sheldrick, 2015 ▸).

Crystal structure: contains datablock(s) I. DOI: 10.1107/S2056989016003479/rz5185sup1.cif

Structure factors: contains datablock(s) I. DOI: 10.1107/S2056989016003479/rz5185Isup2.hkl

CCDC reference: 1456451

Additional supporting information: crystallographic information; 3D view; checkCIF report

[Cu2(C10H8N7)2(NO3)2(H2O)2]·2H2O	Z = 1
Mr = 775.63	F(000) = 394
Triclinic, P1	Dx = 1.814 Mg m−3
a = 8.8421 (2) Å	Mo Kα radiation, λ = 0.71073 Å
b = 8.8636 (2) Å	Cell parameters from 6116 reflections
c = 10.5686 (2) Å	θ = 2.5–26.5°
α = 70.114 (1)°	µ = 1.58 mm−1
β = 88.6311 (10)°	T = 173 K
γ = 66.765 (1)°	Prism, blue
V = 709.87 (3) Å3	0.50 × 0.50 × 0.45 mm

Bruker APEXII CCD diffractometer	2711 reflections with I > 2σ(I)
φ and ω scans	Rint = 0.025
Absorption correction: multi-scan (SADABS; Bruker, 2003)	θmax = 26.6°, θmin = 2.5°
Tmin = 0.505, Tmax = 0.536	h = −8→11
8672 measured reflections	k = −11→11
2945 independent reflections	l = −13→13

Refinement on F2	0 restraints
Least-squares matrix: full	Hydrogen site location: mixed
R[F2 > 2σ(F2)] = 0.027	H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.073	w = 1/[σ2(Fo2) + (0.0387P)2 + 0.4452P] where P = (Fo2 + 2Fc2)/3
S = 1.07	(Δ/σ)max < 0.001
2945 reflections	Δρmax = 0.26 e Å−3
233 parameters	Δρmin = −0.57 e Å−3

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
Cu1	0.11824 (3)	0.26915 (3)	0.15525 (2)	0.01617 (9)
N1	−0.2107 (2)	0.3725 (2)	0.34951 (17)	0.0208 (4)
N2	−0.0714 (2)	0.3636 (2)	0.01433 (17)	0.0166 (3)
N3	−0.3010 (2)	0.3463 (2)	−0.04965 (17)	0.0185 (3)
N4	0.0614 (2)	0.0562 (2)	0.20396 (16)	0.0169 (3)
N5	0.1657 (2)	0.4800 (2)	0.08348 (17)	0.0169 (3)
N6	0.3708 (2)	0.2657 (2)	0.34195 (17)	0.0184 (3)
N7	0.2554 (2)	0.2013 (2)	0.33410 (17)	0.0185 (3)
N8	0.3280 (2)	0.1530 (3)	0.55105 (19)	0.0291 (4)
O1	−0.1224 (2)	0.4373 (2)	0.27750 (19)	0.0352 (4)
O2	−0.34096 (19)	0.4721 (2)	0.38151 (16)	0.0281 (3)
O3	−0.1751 (2)	0.2133 (2)	0.38786 (18)	0.0361 (4)
O4	0.3491 (2)	0.1266 (2)	0.07991 (19)	0.0289 (4)
H41O	0.388 (3)	0.033 (4)	0.104 (3)	0.029 (8)*
H42O	0.376 (3)	0.168 (4)	0.010 (3)	0.032 (8)*
O5	0.5124 (2)	0.7700 (2)	0.15015 (19)	0.0254 (3)
H51O	0.563 (4)	0.698 (4)	0.219 (3)	0.042 (9)*
H52O	0.458 (4)	0.736 (4)	0.125 (3)	0.041 (9)*
C1	−0.1560 (2)	0.2649 (2)	0.03218 (19)	0.0165 (4)
C2	−0.0792 (2)	0.0862 (2)	0.13281 (19)	0.0172 (4)
C3	0.1479 (3)	−0.1054 (3)	0.2939 (2)	0.0207 (4)
H3	0.2474	−0.1283	0.3438	0.025*
C4	0.0969 (3)	−0.2412 (3)	0.3170 (2)	0.0237 (4)
H4	0.1614	−0.3551	0.3810	0.028*
C5	−0.0481 (3)	−0.2088 (3)	0.2461 (2)	0.0239 (4)
H5	−0.0858	−0.2994	0.2614	0.029*
C6	−0.1384 (3)	−0.0411 (3)	0.1517 (2)	0.0221 (4)
H6	−0.2389	−0.0149	0.1013	0.027*
C7	0.3006 (2)	0.4957 (2)	0.1186 (2)	0.0173 (4)
C8	0.4370 (2)	0.3469 (3)	0.2234 (2)	0.0204 (4)
H8A	0.5019	0.2577	0.1842	0.025*
H8B	0.5126	0.3913	0.2508	0.025*
C9	0.2342 (3)	0.1361 (3)	0.4624 (2)	0.0227 (4)
H9	0.1591	0.0820	0.4898	0.027*
C10	0.4109 (3)	0.2351 (3)	0.4713 (2)	0.0249 (4)
H10	0.4888	0.2679	0.5026	0.030*

	U11	U22	U33	U12	U13	U23
Cu1	0.01744 (14)	0.01210 (13)	0.01794 (14)	−0.00721 (9)	−0.00253 (9)	−0.00253 (10)
N1	0.0217 (9)	0.0206 (8)	0.0188 (8)	−0.0079 (7)	−0.0028 (7)	−0.0063 (7)
N2	0.0175 (8)	0.0123 (7)	0.0186 (8)	−0.0065 (6)	−0.0017 (6)	−0.0031 (6)
N3	0.0192 (8)	0.0183 (8)	0.0192 (8)	−0.0098 (7)	0.0007 (7)	−0.0052 (7)
N4	0.0192 (8)	0.0149 (7)	0.0165 (8)	−0.0071 (6)	0.0009 (6)	−0.0054 (6)
N5	0.0165 (8)	0.0132 (7)	0.0183 (8)	−0.0058 (6)	−0.0029 (6)	−0.0027 (6)
N6	0.0178 (8)	0.0149 (7)	0.0209 (9)	−0.0071 (6)	−0.0037 (6)	−0.0038 (7)
N7	0.0168 (8)	0.0169 (8)	0.0211 (9)	−0.0079 (6)	−0.0007 (6)	−0.0047 (7)
N8	0.0331 (10)	0.0328 (10)	0.0214 (9)	−0.0139 (8)	0.0005 (8)	−0.0090 (8)
O1	0.0337 (9)	0.0291 (8)	0.0463 (11)	−0.0184 (7)	0.0147 (8)	−0.0121 (8)
O2	0.0240 (8)	0.0294 (8)	0.0283 (8)	−0.0063 (6)	0.0038 (6)	−0.0128 (7)
O3	0.0486 (11)	0.0177 (8)	0.0398 (10)	−0.0139 (7)	0.0086 (8)	−0.0074 (7)
O4	0.0316 (9)	0.0164 (8)	0.0332 (10)	−0.0058 (7)	0.0129 (7)	−0.0079 (7)
O5	0.0245 (8)	0.0180 (7)	0.0312 (9)	−0.0098 (7)	−0.0023 (7)	−0.0045 (7)
C1	0.0187 (9)	0.0154 (9)	0.0170 (9)	−0.0089 (7)	0.0013 (7)	−0.0053 (7)
C2	0.0197 (9)	0.0165 (9)	0.0164 (9)	−0.0077 (7)	0.0031 (7)	−0.0067 (8)
C3	0.0219 (10)	0.0172 (9)	0.0195 (10)	−0.0059 (8)	0.0000 (8)	−0.0049 (8)
C4	0.0341 (12)	0.0143 (9)	0.0185 (10)	−0.0087 (8)	0.0023 (8)	−0.0025 (8)
C5	0.0361 (12)	0.0179 (9)	0.0226 (11)	−0.0162 (9)	0.0069 (9)	−0.0073 (8)
C6	0.0265 (11)	0.0212 (10)	0.0221 (10)	−0.0140 (8)	0.0015 (8)	−0.0069 (8)
C7	0.0167 (9)	0.0177 (9)	0.0179 (10)	−0.0082 (7)	0.0007 (7)	−0.0056 (8)
C8	0.0168 (9)	0.0196 (9)	0.0225 (10)	−0.0090 (8)	−0.0020 (8)	−0.0027 (8)
C9	0.0244 (10)	0.0204 (10)	0.0214 (10)	−0.0087 (8)	0.0019 (8)	−0.0058 (8)
C10	0.0281 (11)	0.0234 (10)	0.0226 (11)	−0.0101 (9)	−0.0038 (8)	−0.0079 (9)

Cu1—N5	1.9709 (15)	N8—C9	1.349 (3)
Cu1—N2	1.9732 (16)	O4—H41O	0.71 (3)
Cu1—N4	2.0386 (16)	O4—H42O	0.79 (3)
Cu1—N7	2.0409 (17)	O5—H51O	0.78 (3)
Cu1—O4	2.2293 (16)	O5—H52O	0.76 (3)
N1—O3	1.234 (2)	C1—C2	1.463 (3)
N1—O1	1.244 (2)	C2—C6	1.376 (3)
N1—O2	1.266 (2)	C3—C4	1.391 (3)
N2—C1	1.326 (2)	C3—H3	0.9500
N2—N5i	1.356 (2)	C4—C5	1.377 (3)
N3—C7i	1.342 (2)	C4—H4	0.9500
N3—C1	1.346 (3)	C5—C6	1.391 (3)
N4—C3	1.335 (3)	C5—H5	0.9500
N4—C2	1.352 (3)	C6—H6	0.9500
N5—C7	1.329 (2)	C7—N3i	1.342 (2)
N5—N2i	1.356 (2)	C7—C8	1.496 (3)
N6—C10	1.328 (3)	C8—H8A	0.9900
N6—N7	1.368 (2)	C8—H8B	0.9900
N6—C8	1.455 (3)	C9—H9	0.9500
N7—C9	1.321 (3)	C10—H10	0.9500
N8—C10	1.323 (3)
N5—Cu1—N2	93.75 (6)	N2—C1—N3	113.40 (17)
N5—Cu1—N4	172.58 (6)	N2—C1—C2	116.86 (17)
N2—Cu1—N4	80.29 (6)	N3—C1—C2	129.72 (17)
N5—Cu1—N7	88.59 (6)	N4—C2—C6	122.81 (18)
N2—Cu1—N7	161.96 (7)	N4—C2—C1	112.59 (16)
N4—Cu1—N7	98.45 (6)	C6—C2—C1	124.57 (18)
N5—Cu1—O4	87.79 (7)	N4—C3—C4	122.16 (19)
N2—Cu1—O4	108.72 (7)	N4—C3—H3	118.9
N4—Cu1—O4	89.95 (6)	C4—C3—H3	118.9
N7—Cu1—O4	89.23 (7)	C5—C4—C3	119.35 (19)
O3—N1—O1	120.96 (18)	C5—C4—H4	120.3
O3—N1—O2	119.57 (17)	C3—C4—H4	120.3
O1—N1—O2	119.45 (17)	C4—C5—C6	118.81 (18)
C1—N2—N5i	105.92 (15)	C4—C5—H5	120.6
C1—N2—Cu1	114.60 (13)	C6—C5—H5	120.6
N5i—N2—Cu1	137.73 (12)	C2—C6—C5	118.65 (19)
C7i—N3—C1	101.45 (15)	C2—C6—H6	120.7
C3—N4—C2	118.20 (16)	C5—C6—H6	120.7
C3—N4—Cu1	127.56 (14)	N5—C7—N3i	113.47 (17)
C2—N4—Cu1	114.23 (13)	N5—C7—C8	121.54 (17)
C7—N5—N2i	105.75 (15)	N3i—C7—C8	124.98 (17)
C7—N5—Cu1	126.66 (13)	N6—C8—C7	111.03 (16)
N2i—N5—Cu1	127.56 (12)	N6—C8—H8A	109.4
C10—N6—N7	108.72 (16)	C7—C8—H8A	109.4
C10—N6—C8	128.56 (17)	N6—C8—H8B	109.4
N7—N6—C8	122.68 (16)	C7—C8—H8B	109.4
C9—N7—N6	102.89 (16)	H8A—C8—H8B	108.0
C9—N7—Cu1	132.81 (14)	N7—C9—N8	114.40 (19)
N6—N7—Cu1	122.03 (12)	N7—C9—H9	122.8
C10—N8—C9	102.87 (18)	N8—C9—H9	122.8
Cu1—O4—H41O	121 (2)	N8—C10—N6	111.12 (18)
Cu1—O4—H42O	123 (2)	N8—C10—H10	124.4
H41O—O4—H42O	112 (3)	N6—C10—H10	124.4
H51O—O5—H52O	107 (3)
C10—N6—N7—C9	0.2 (2)	N4—C3—C4—C5	−0.6 (3)
C8—N6—N7—C9	178.21 (17)	C3—C4—C5—C6	0.9 (3)
C10—N6—N7—Cu1	165.14 (14)	N4—C2—C6—C5	−1.3 (3)
C8—N6—N7—Cu1	−16.9 (2)	C1—C2—C6—C5	176.53 (18)
N5i—N2—C1—N3	0.8 (2)	C4—C5—C6—C2	0.0 (3)
Cu1—N2—C1—N3	168.39 (13)	N2i—N5—C7—N3i	0.0 (2)
N5i—N2—C1—C2	179.30 (16)	Cu1—N5—C7—N3i	178.11 (12)
Cu1—N2—C1—C2	−13.1 (2)	N2i—N5—C7—C8	−178.85 (17)
C7i—N3—C1—N2	−0.8 (2)	Cu1—N5—C7—C8	−0.8 (3)
C7i—N3—C1—C2	−179.06 (19)	C10—N6—C8—C7	−127.1 (2)
C3—N4—C2—C6	1.6 (3)	N7—N6—C8—C7	55.3 (2)
Cu1—N4—C2—C6	−179.68 (15)	N5—C7—C8—N6	−46.0 (2)
C3—N4—C2—C1	−176.44 (16)	N3i—C7—C8—N6	135.26 (19)
Cu1—N4—C2—C1	2.2 (2)	N6—N7—C9—N8	−0.5 (2)
N2—C1—C2—N4	7.0 (2)	Cu1—N7—C9—N8	−162.96 (15)
N3—C1—C2—N4	−174.73 (18)	C10—N8—C9—N7	0.5 (2)
N2—C1—C2—C6	−171.04 (18)	C9—N8—C10—N6	−0.3 (2)
N3—C1—C2—C6	7.2 (3)	N7—N6—C10—N8	0.1 (2)
C2—N4—C3—C4	−0.7 (3)	C8—N6—C10—N8	−177.76 (18)
Cu1—N4—C3—C4	−179.13 (14)

D—H···A	D—H	H···A	D···A	D—H···A
O4—H41O···O5ii	0.71 (3)	2.03 (3)	2.735 (2)	172 (3)
O4—H42O···O5iii	0.79 (3)	1.96 (3)	2.735 (2)	168 (3)
O5—H51O···O2iv	0.78 (3)	2.02 (3)	2.773 (2)	163 (3)
O5—H52O···N3i	0.76 (3)	2.08 (3)	2.836 (2)	177 (3)
C5—H5···O1ii	0.95	2.43	3.360 (3)	166
C8—H8A···O4	0.99	2.56	3.160 (3)	119
C8—H8B···O2iv	0.99	2.36	3.319 (3)	162
C9—H9···O3v	0.95	2.44	3.205 (3)	137