(Nitrato-κO)(2,2′:6′,2′′-terpyridine-κ³ N,N′,N′′)palladium(II) nitrate

The central Pd^II ion of the complex cation has an N₃O square-planar coordination sphere defined by the three N atoms of the tridentate 2,2′:6′,2′′-terpyridine ligand and one O atom from the NO₃ ⁻ anion.

Abstract

The title complex, [Pd(NO₃)(C₁₅H₁₁N₃)]NO₃, comprises a cationic Pd^II complex and a nitrate anion. In the complex, the Pd^II cation is four-coordinated in a distorted square-planar coordination geometry defined by the three N atoms of the tridentate 2,2′:6′,2′′-terpyridine ligand and one O atom from the NO₃ ⁻ anion. In the crystal, the complex mol­ecules are stacked in columns along the a axis being connected by π–π stacking [closest inter-centroid separation between pyridyl rings = 3.878 (3) Å]. The connections between columns and anions to sustain a three-dimensional architecture are C—H⋯O hydrogen bonds.

Structure description

With reference to the title complex, [Pd(terpy)(NO₃)](NO₃) (terpy = 2,2′:6′,26′6′-terpyridine), the crystal structures of related Pd^II complexes [Pd(terpy)(pyridine)](ClO₄)₂ (Bugarčić et al., 2004 ▸), [Pd(terpy)(NO₃)](NTf₂) [NTf₂ = bis­(tri­fluoro­methyl­sulfon­yl)amide anion; Illner et al., 2009 ▸) and [Pd₂(terpy)₂(NO₃)]₂(PF₆)₆·CH₃CN (Mei et al., 2007 ▸) have been determined previously.

The title complex comprises a cationic Pd^II complex [Pd(terpy)(NO₃)]⁺ and an NO₃ ⁻ anion (Fig. 1 ▸). In the complex, the central Pd^II cation is four-coordinated in a distorted square-planar coordination geometry defined by the pyridyl N1, N2 and N3 atoms derived from the tridentate terpy ligand and the O1 atom from the nitrato ligand. The tight N—Pd—N chelating angles of <N1—Pd1—N2 = 81.26 (17)° and <N2—Pd1—N8 = 81.03 (16)° contribute to the distortion of the square-plane. The Pd—N [1.917 (4) to 2.030 (4) Å] and Pd—O [2.028 (3) Å] bond lengths are close. The pyridine rings of the terpy ligand are located approximately parallel to the least-squares plane of the PdN₃O unit [maximum deviation = 0.023 (2) Å], with dihedral angles of 1.4 (2)° (ring N1/C1–C5), 3.1 (2)° (ring N2/C6–C10) and 3.0 (2)° (ring N3/C11–C15). In the crystal (Fig. 2 ▸), the complex mol­ecules are stacked in columns along the a axis. Within the columns, numerous inter­molecular π–π inter­actions between adjacent pyridine rings are present. For Cg1 (the centroid of ring N2/C6–C10) and Cg2ⁱ [the centroid of ring N3/C11–C15; symmetry code: (i) x + 1, y, z], the centroid-centroid distance is 3.878 (3) Å and the dihedral angle between the ring planes is 3.2 (3)° (Spek, 2020 ▸). The complex cations and anions form inter­molecular C—H⋯O hydrogen bonds (Table 1 ▸) to stabilize the three-dimensional packing.

Figure 1.

The mol­ecular structure of the title complex showing the atom labelling and displacement ellipsoids drawn at the 50% probability level for non-H atoms.

Figure 2.

A view of the packing in the crystal of the title complex, viewed approximately along the a axis. Hydrogen-bonding inter­actions are drawn as dashed lines.

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C3—H3⋯O2i	0.94	2.55	3.419 (7)	153
C4—H4⋯O6ii	0.94	2.37	3.303 (7)	172
C7—H7⋯O6ii	0.94	2.30	3.231 (6)	171
C8—H8⋯O5iii	0.94	2.43	3.088 (6)	127
C9—H9⋯O6iv	0.94	2.35	3.254 (6)	160
C13—H13⋯O5v	0.94	2.46	3.402 (7)	176
C15—H15⋯O3vi	0.94	2.38	3.280 (7)	161

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

Synthesis and crystallization

To a solution of Pd(NO₃)₂·2H₂O (0.1320 g, 0.495 mmol) in acetone (30 ml) was added 2,2′:6′,2′′-terpyridine (0.1179 g, 0.505 mmol) followed by stirring for 3 h at room temperature. The formed precipitate was separated by filtration, washed with acetone and dried at 323 K to give a light-yellow powder (0.2123 g). Yellow crystals of the product suitable for X-ray analysis were obtained by slow evaporation of its CH₃NO₂ solution at room temperature.

Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2 ▸.

Table 2. Experimental details.

Crystal data
Chemical formula	[Pd(NO3)(C15H11N3)]NO3
M r	463.69
Crystal system, space group	Orthorhombic, P n a21
Temperature (K)	223
a, b, c (Å)	6.2190 (2), 33.9728 (15), 7.4819 (3)
V (Å3)	1580.75 (11)
Z	4
Radiation type	Mo Kα
μ (mm−1)	1.22
Crystal size (mm)	0.21 × 0.14 × 0.06
Data collection
Diffractometer	PHOTON 100 CMOS detector
Absorption correction	Multi-scan (SADABS; Bruker, 2016 ▸)
T min, T max	0.688, 0.745
No. of measured, independent and observed [I > 2σ(I)] reflections	41749, 3116, 2745
R int	0.084
(sin θ/λ)max (Å−1)	0.618
Refinement
R[F 2 > 2σ(F 2)], wR(F 2), S	0.027, 0.048, 1.09
No. of reflections	3116
No. of parameters	244
No. of restraints	1
H-atom treatment	H-atom parameters constrained
Δρmax, Δρmin (e Å−3)	0.34, −0.43
Absolute structure	Flack x determined using 1141 quotients [(I +)−(I −)]/[(I +)+(I −)] Parsons et al. (2013 ▸).
Absolute structure parameter	0.006 (16)

Computer programs: APEX2 and SAINT (Bruker, 2016 ▸), SHELXT2014/7 (Sheldrick, 2015a ▸), SHELXL2014/7 (Sheldrick, 2015b ▸) and ORTEP-3 for Windows (Farrugia, 2012 ▸).

Supplementary Material

CCDC reference: 2058389

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

full crystallographic data

Crystal data

[Pd(C15H11N3)(NO3)]NO3	Dx = 1.948 Mg m−3
Mr = 463.69	Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, Pna21	Cell parameters from 9942 reflections
a = 6.2190 (2) Å	θ = 2.4–27.7°
b = 33.9728 (15) Å	µ = 1.22 mm−1
c = 7.4819 (3) Å	T = 223 K
V = 1580.75 (11) Å3	Plate, yellow
Z = 4	0.21 × 0.14 × 0.06 mm
F(000) = 920

Data collection

PHOTON 100 CMOS detector diffractometer	2745 reflections with I > 2σ(I)
Radiation source: sealed tube	Rint = 0.084
φ and ω scans	θmax = 26.1°, θmin = 2.4°
Absorption correction: multi-scan (SADABS; Bruker, 2016)	h = −7→7
Tmin = 0.688, Tmax = 0.745	k = −41→42
41749 measured reflections	l = −9→9
3116 independent reflections

Refinement

Refinement on F2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.027	H-atom parameters constrained
wR(F2) = 0.048	w = 1/[σ2(Fo2) + (0.0152P)2 + 0.8349P] where P = (Fo2 + 2Fc2)/3
S = 1.09	(Δ/σ)max = 0.001
3116 reflections	Δρmax = 0.34 e Å−3
244 parameters	Δρmin = −0.43 e Å−3
1 restraint	Absolute structure: Flack x determined using 1141 quotients [(I+)-(I-)]/[(I+)+(I-)] Parsons et al. (2013).
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: 0.006 (16)

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.

Refinement. Hydrogen atoms on C atoms were positioned geometrically and allowed to ride on their respective parent atoms: C—H = 0.94 Å and Uiso(H) = 1.2Ueq(C). The Flack parameter = 0.006 (16) after the final cycles of refinement.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
Pd1	0.22807 (4)	0.15784 (2)	0.48682 (9)	0.02233 (10)
O1	0.1702 (6)	0.21529 (10)	0.4313 (4)	0.0343 (10)
O2	0.2291 (7)	0.19950 (12)	0.1521 (6)	0.0463 (10)
O3	0.1758 (7)	0.26017 (11)	0.2256 (6)	0.0540 (13)
N1	0.4977 (6)	0.16769 (12)	0.6321 (6)	0.0261 (10)
N2	0.2920 (6)	0.10452 (11)	0.5520 (5)	0.0220 (9)
N3	−0.0259 (6)	0.13077 (12)	0.3685 (5)	0.0214 (9)
N4	0.1927 (7)	0.22538 (14)	0.2626 (7)	0.0364 (12)
C1	0.5913 (9)	0.20210 (16)	0.6668 (8)	0.0344 (13)
H1	0.5322	0.2252	0.6180	0.041*
C2	0.7726 (9)	0.2048 (2)	0.7722 (8)	0.0450 (16)
H2	0.8307	0.2295	0.8015	0.054*
C3	0.8672 (9)	0.17072 (19)	0.8340 (8)	0.0415 (15)
H3	0.9939	0.1719	0.9023	0.050*
C4	0.7740 (9)	0.13467 (19)	0.7944 (8)	0.0323 (13)
H4	0.8378	0.1112	0.8343	0.039*
C5	0.5864 (9)	0.13370 (17)	0.6959 (7)	0.0232 (12)
C6	0.4710 (8)	0.09759 (15)	0.6481 (6)	0.0232 (11)
C7	0.5267 (8)	0.05923 (15)	0.6877 (7)	0.0293 (13)
H7	0.6493	0.0536	0.7566	0.035*
C8	0.3979 (8)	0.02930 (15)	0.6235 (7)	0.0308 (13)
H8	0.4354	0.0031	0.6481	0.037*
C9	0.2163 (7)	0.03682 (14)	0.5247 (7)	0.0282 (16)
H9	0.1295	0.0161	0.4828	0.034*
C10	0.1642 (6)	0.07567 (11)	0.4881 (12)	0.0219 (8)
C11	−0.0190 (8)	0.09089 (14)	0.3876 (7)	0.0222 (11)
C12	−0.1803 (8)	0.06726 (16)	0.3173 (7)	0.0285 (12)
H12	−0.1745	0.0398	0.3300	0.034*
C13	−0.3493 (8)	0.08484 (17)	0.2285 (7)	0.0302 (13)
H13	−0.4597	0.0694	0.1793	0.036*
C14	−0.3552 (9)	0.12527 (18)	0.2122 (8)	0.0266 (14)
H14	−0.4706	0.1376	0.1535	0.032*
C15	−0.1895 (8)	0.14736 (16)	0.2831 (8)	0.0269 (12)
H15	−0.1927	0.1749	0.2705	0.032*
O4	0.1900 (5)	0.09192 (10)	1.0047 (10)	0.0396 (10)
O5	0.2336 (6)	0.03043 (12)	1.0689 (6)	0.0505 (11)
O6	−0.0235 (6)	0.04770 (11)	0.8974 (5)	0.0425 (10)
N5	0.1345 (5)	0.05686 (11)	0.9909 (9)	0.0287 (8)

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
Pd1	0.02599 (16)	0.01582 (15)	0.02517 (16)	0.00131 (14)	−0.0033 (4)	−0.0007 (3)
O1	0.049 (2)	0.0166 (18)	0.037 (3)	0.0048 (15)	−0.0099 (16)	0.0013 (15)
O2	0.064 (3)	0.036 (2)	0.040 (2)	−0.010 (2)	−0.010 (2)	0.000 (2)
O3	0.059 (3)	0.020 (2)	0.083 (3)	−0.003 (2)	−0.020 (2)	0.021 (2)
N1	0.030 (2)	0.025 (3)	0.023 (2)	−0.0059 (18)	−0.0040 (19)	−0.0003 (19)
N2	0.0229 (19)	0.019 (2)	0.024 (2)	0.0028 (17)	0.0051 (17)	0.0003 (16)
N3	0.025 (2)	0.019 (2)	0.020 (2)	−0.0004 (17)	0.0018 (18)	−0.0021 (19)
N4	0.030 (2)	0.026 (3)	0.054 (3)	−0.007 (2)	−0.016 (2)	0.011 (3)
C1	0.042 (3)	0.024 (3)	0.037 (3)	−0.002 (3)	−0.004 (3)	0.000 (3)
C2	0.051 (4)	0.047 (4)	0.038 (3)	−0.021 (3)	−0.008 (3)	−0.002 (3)
C3	0.035 (3)	0.063 (4)	0.027 (3)	−0.014 (3)	−0.009 (3)	0.003 (3)
C4	0.029 (3)	0.044 (4)	0.025 (3)	0.003 (3)	0.001 (3)	0.006 (3)
C5	0.026 (3)	0.026 (3)	0.018 (3)	0.000 (2)	0.000 (2)	0.003 (2)
C6	0.025 (3)	0.027 (3)	0.018 (3)	0.003 (2)	0.003 (2)	0.005 (2)
C7	0.027 (3)	0.029 (3)	0.031 (3)	0.003 (2)	0.002 (2)	0.009 (3)
C8	0.034 (3)	0.020 (3)	0.039 (3)	0.008 (2)	0.007 (3)	0.012 (2)
C9	0.029 (2)	0.019 (2)	0.037 (5)	−0.0034 (19)	0.008 (2)	0.000 (2)
C10	0.0234 (19)	0.018 (2)	0.024 (2)	0.0004 (15)	0.000 (5)	−0.001 (4)
C11	0.026 (3)	0.018 (3)	0.022 (3)	0.002 (2)	0.006 (2)	0.000 (2)
C12	0.028 (3)	0.024 (3)	0.033 (3)	−0.006 (2)	0.007 (2)	−0.004 (2)
C13	0.024 (3)	0.037 (4)	0.030 (3)	−0.004 (2)	0.003 (2)	−0.009 (3)
C14	0.021 (3)	0.034 (4)	0.024 (4)	0.006 (3)	0.004 (3)	0.001 (3)
C15	0.029 (3)	0.024 (3)	0.027 (3)	0.007 (2)	0.003 (3)	−0.002 (2)
O4	0.0415 (17)	0.0291 (18)	0.048 (3)	−0.0045 (14)	−0.002 (3)	−0.003 (3)
O5	0.041 (2)	0.042 (3)	0.068 (3)	0.011 (2)	−0.020 (2)	0.013 (2)
O6	0.039 (2)	0.039 (2)	0.050 (2)	−0.0026 (18)	−0.0192 (19)	0.002 (2)
N5	0.0249 (17)	0.035 (2)	0.027 (2)	0.0011 (16)	0.004 (4)	−0.007 (4)

Geometric parameters (Å, º)

Pd1—N2	1.917 (4)	C5—C6	1.466 (8)
Pd1—N1	2.026 (4)	C6—C7	1.381 (7)
Pd1—O1	2.028 (3)	C7—C8	1.380 (7)
Pd1—N3	2.030 (4)	C7—H7	0.9400
O1—N4	1.315 (6)	C8—C9	1.374 (7)
O2—N4	1.228 (6)	C8—H8	0.9400
O3—N4	1.218 (6)	C9—C10	1.386 (6)
N1—C1	1.332 (6)	C9—H9	0.9400
N1—C5	1.366 (7)	C10—C11	1.460 (7)
N2—C6	1.346 (6)	C11—C12	1.388 (7)
N2—C10	1.349 (6)	C12—C13	1.379 (7)
N3—C15	1.328 (6)	C12—H12	0.9400
N3—C11	1.363 (6)	C13—C14	1.379 (8)
C1—C2	1.379 (7)	C13—H13	0.9400
C1—H1	0.9400	C14—C15	1.381 (8)
C2—C3	1.379 (9)	C14—H14	0.9400
C2—H2	0.9400	C15—H15	0.9400
C3—C4	1.387 (8)	O4—N5	1.245 (5)
C3—H3	0.9400	O5—N5	1.236 (6)
C4—C5	1.380 (7)	O6—N5	1.245 (5)
C4—H4	0.9400
N2—Pd1—N1	81.26 (17)	N2—C6—C7	119.1 (5)
N2—Pd1—O1	176.54 (15)	N2—C6—C5	112.9 (4)
N1—Pd1—O1	95.62 (15)	C7—C6—C5	128.0 (5)
N2—Pd1—N3	81.03 (16)	C8—C7—C6	118.4 (5)
N1—Pd1—N3	162.23 (16)	C8—C7—H7	120.8
O1—Pd1—N3	102.04 (15)	C6—C7—H7	120.8
N4—O1—Pd1	115.4 (3)	C9—C8—C7	121.8 (5)
C1—N1—C5	119.8 (5)	C9—C8—H8	119.1
C1—N1—Pd1	127.7 (4)	C7—C8—H8	119.1
C5—N1—Pd1	112.5 (4)	C8—C9—C10	118.4 (5)
C6—N2—C10	123.3 (4)	C8—C9—H9	120.8
C6—N2—Pd1	118.2 (3)	C10—C9—H9	120.8
C10—N2—Pd1	118.3 (3)	N2—C10—C9	118.9 (5)
C15—N3—C11	119.8 (4)	N2—C10—C11	112.6 (4)
C15—N3—Pd1	127.9 (3)	C9—C10—C11	128.4 (4)
C11—N3—Pd1	112.4 (3)	N3—C11—C12	120.8 (5)
O3—N4—O2	123.9 (5)	N3—C11—C10	115.5 (4)
O3—N4—O1	117.5 (5)	C12—C11—C10	123.7 (4)
O2—N4—O1	118.6 (4)	C13—C12—C11	118.9 (5)
N1—C1—C2	121.9 (6)	C13—C12—H12	120.6
N1—C1—H1	119.1	C11—C12—H12	120.6
C2—C1—H1	119.1	C12—C13—C14	119.6 (5)
C1—C2—C3	118.9 (6)	C12—C13—H13	120.2
C1—C2—H2	120.5	C14—C13—H13	120.2
C3—C2—H2	120.5	C13—C14—C15	119.1 (5)
C2—C3—C4	119.5 (5)	C13—C14—H14	120.4
C2—C3—H3	120.3	C15—C14—H14	120.4
C4—C3—H3	120.3	N3—C15—C14	121.8 (5)
C5—C4—C3	119.2 (6)	N3—C15—H15	119.1
C5—C4—H4	120.4	C14—C15—H15	119.1
C3—C4—H4	120.4	O5—N5—O4	121.2 (5)
N1—C5—C4	120.5 (5)	O5—N5—O6	118.5 (4)
N1—C5—C6	115.1 (5)	O4—N5—O6	120.3 (5)
C4—C5—C6	124.3 (5)
Pd1—O1—N4—O3	−174.4 (3)	C6—C7—C8—C9	−0.9 (8)
Pd1—O1—N4—O2	5.6 (6)	C7—C8—C9—C10	0.6 (8)
C5—N1—C1—C2	−2.6 (8)	C6—N2—C10—C9	1.0 (9)
Pd1—N1—C1—C2	178.2 (4)	Pd1—N2—C10—C9	175.9 (5)
N1—C1—C2—C3	4.2 (9)	C6—N2—C10—C11	−179.7 (4)
C1—C2—C3—C4	−2.4 (9)	Pd1—N2—C10—C11	−4.8 (7)
C2—C3—C4—C5	−0.9 (8)	C8—C9—C10—N2	−0.6 (9)
C1—N1—C5—C4	−0.8 (8)	C8—C9—C10—C11	−179.7 (6)
Pd1—N1—C5—C4	178.5 (4)	C15—N3—C11—C12	0.5 (7)
C1—N1—C5—C6	−179.4 (5)	Pd1—N3—C11—C12	179.3 (4)
Pd1—N1—C5—C6	−0.2 (5)	C15—N3—C11—C10	−178.3 (5)
C3—C4—C5—N1	2.5 (8)	Pd1—N3—C11—C10	0.5 (6)
C3—C4—C5—C6	−179.0 (5)	N2—C10—C11—N3	2.6 (8)
C10—N2—C6—C7	−1.4 (8)	C9—C10—C11—N3	−178.2 (6)
Pd1—N2—C6—C7	−176.3 (4)	N2—C10—C11—C12	−176.1 (5)
C10—N2—C6—C5	177.7 (5)	C9—C10—C11—C12	3.0 (11)
Pd1—N2—C6—C5	2.8 (5)	N3—C11—C12—C13	−0.4 (8)
N1—C5—C6—N2	−1.6 (6)	C10—C11—C12—C13	178.3 (5)
C4—C5—C6—N2	179.8 (5)	C11—C12—C13—C14	−0.3 (8)
N1—C5—C6—C7	177.4 (5)	C12—C13—C14—C15	1.0 (8)
C4—C5—C6—C7	−1.2 (8)	C11—N3—C15—C14	0.1 (8)
N2—C6—C7—C8	1.3 (7)	Pd1—N3—C15—C14	−178.4 (4)
C5—C6—C7—C8	−177.7 (5)	C13—C14—C15—N3	−0.9 (9)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C3—H3···O2i	0.94	2.55	3.419 (7)	153
C4—H4···O6ii	0.94	2.37	3.303 (7)	172
C7—H7···O6ii	0.94	2.30	3.231 (6)	171
C8—H8···O5iii	0.94	2.43	3.088 (6)	127
C9—H9···O6iv	0.94	2.35	3.254 (6)	160
C13—H13···O5v	0.94	2.46	3.402 (7)	176
C15—H15···O3vi	0.94	2.38	3.280 (7)	161

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

Funding Statement

This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (grant No. 2018R1D1A1B07050550).