supplementary materials


Acta Cryst. (2009). E65, m449    [ doi:10.1107/S1600536809010538 ]

Tris(3,5-dimethyl-1H-pyrazole-[kappa]N2)(pyridine-2,6-dicarboxylato-[kappa]3O2,N,O6)cobalt(II) monohydrate

K.-H. Lin, Z.-Y. Yu, Y.-H. Zhong and M. Shao

Abstract top

The reaction of Co(NO3)2·3H2O with pyridine-2,6-dicarboxylic acid and 3,5-dimethyl-1H-pyrazole in a 1:1:3 molar ratio affords the title complex, [Co(C7H3NO4)(C5H8N2)3]·H2O. The CoII atom is coordinated by one pyridine-2,6-dicarboxylate chelating ligand and three 3,5-dimethyl-1H-pyrazole ligands in a distorted octahedral geometry. Hydrogen-bonding interactions involving the coordinated carboxylate group, 3,5-dimethyl-1H-pyrazole and water help to consolidate the crystal structure

Comment top

Complexes with pyrazole-based ligands are a frequent subject of chemical investigations giving an opportunity for a better understanding of the relationship between the structure and the activity of the active site of metalloproteins (Haanstra et al., 1990). Nowadays, attention is paid to the design of various pyrazole ligands, and some coordination modes of pyrazole complexes were reported (Grotjahn et al., 2003). In our systematic studies on transition metal comlexes with the pyrazole derivatives, the title compound was prepared and its X-ray structure is presented here.

The molecular structure of the title compound is shown in Fig. 1. The compound assumes a distorted octahedron geometry, formed by three 3,5-Dimethyl-1-H-pyrazole molecules and a pyridine-2,6-dicarboxylate. Tridentate ligand pyridine-2,6-dicarboxylate dianion chelates to the Co atom by a N atom of pyridine ring and two O atoms of carboxyl groups with a meridional configuration. Monodentate ligand 3,5-Dimethyl-1-H-pyrazole coordinated to the Co atom by N atoms of pyrazole rings. The bond distances of Co1—N1 and Co1—N4 are 2.0407 (16)Å and 2.0798 (16)Å (Table 1), which are shorter than the the bond distances of Co1—N2 and Co1—N6 with 2.2336 (17)Å and 2.2477 (17)Å.

Related literature top

For the use of complexes with pyrazole-based ligands in studying the relationship between the structure and the activity of the active site of metalloproteins, see: Haanstra et al. (1990). For the coordination modes of pyrazole complexes, see: Grotjahn et al. (2003).

Experimental top

An ethanol solution (6 ml) containing 3,5-Dimethyl-1-H-pyrazole(0.1153 g, 1.2 mmol) and Co(NO3)2.3H2O(0.0870 g, 0.3 mmol) was mixed with an aqueous solution (6 ml) of pyridine-2,6-dicarboxylic acid(0.0501 g, 0.3 mmol) and NaOH (0.0240 g, 0.6 mmol). The mixture was refluxed for 6 h. The solution was filtered after cooling to room temperature. Pink single crystals suitable for X-ray diffraction were obtained from the filtrate after 11 d.

Refinement top

The H atoms of water molecule were located in a difference Fourier map and refined freely. Methyl H atoms were placed in caculated positions with C—H distances = 0.96 Å and Uiso(H) = 1.5Ueq(C). Other H atoms were placed in caculated positions with C—H distances = 0.93 Å and N—H distances = 0.86 Å, and Uiso(H) = 1.5Ueq(C,N).

Computing details top

Data collection: SMART (Bruker, 2000); cell refinement: SAINT (Bruker, 2000); data reduction: SAINT (Bruker, 2000); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. Molecular structure of (I) with displacement ellipsoids drawn at the 30% probability level.
[Figure 2] Fig. 2. A packing diagram of (I).
Tris(3,5-dimethyl-1H-pyrazole-κN2)(pyridine-2,6- dicarboxylato-κ3O2,N,O6)cobalt(II) monohydrate top
Crystal data top
[Co(C7H3NO4)(C5H8N2)3]·H2OZ = 2
Mr = 530.45F(000) = 554
Triclinic, P1Dx = 1.460 Mg m3
Hall symbol: -P 1Mo Kα radiation, λ = 0.71073 Å
a = 8.4220 (8) ÅCell parameters from 4060 reflections
b = 11.9936 (12) Åθ = 2.7–27.5°
c = 13.1418 (13) ŵ = 0.76 mm1
α = 75.129 (1)°T = 296 K
β = 84.772 (1)°Block, pink
γ = 70.094 (1)°0.30 × 0.30 × 0.25 mm
V = 1206.3 (2) Å3
Data collection top
Bruker SMART CCD area-detector
diffractometer
4183 independent reflections
Radiation source: fine-focus sealed tube3769 reflections with I > 2σ(I)
graphiteRint = 0.014
φ and ω scansθmax = 25.1°, θmin = 2.1°
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)
h = 109
Tmin = 0.804, Tmax = 0.833k = 1414
6298 measured reflectionsl = 1315
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.030H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.077 w = 1/[σ2(Fo2) + (0.0334P)2 + 0.7243P]
where P = (Fo2 + 2Fc2)/3
S = 1.03(Δ/σ)max = 0.002
4183 reflectionsΔρmax = 0.25 e Å3
331 parametersΔρmin = 0.24 e Å3
2 restraintsExtinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.0176 (11)
Crystal data top
[Co(C7H3NO4)(C5H8N2)3]·H2Oγ = 70.094 (1)°
Mr = 530.45V = 1206.3 (2) Å3
Triclinic, P1Z = 2
a = 8.4220 (8) ÅMo Kα radiation
b = 11.9936 (12) ŵ = 0.76 mm1
c = 13.1418 (13) ÅT = 296 K
α = 75.129 (1)°0.30 × 0.30 × 0.25 mm
β = 84.772 (1)°
Data collection top
Bruker SMART CCD area-detector
diffractometer
4183 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)
3769 reflections with I > 2σ(I)
Tmin = 0.804, Tmax = 0.833Rint = 0.014
6298 measured reflectionsθmax = 25.1°
Refinement top
R[F2 > 2σ(F2)] = 0.030H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.077Δρmax = 0.25 e Å3
S = 1.03Δρmin = 0.24 e Å3
4183 reflectionsAbsolute structure: ?
331 parametersFlack parameter: ?
2 restraintsRogers parameter: ?
Special details top

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.

Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and

goodness of fit S are based on F2, conventional R-factors R are based

on F, with F set to zero for negative F2. The threshold expression of

F2 > σ(F2) is used only for calculating R-factors(gt) etc. and is

not relevant to the choice of reflections for refinement. R-factors based

on F2 are statistically about twice as large as those based on F, and R-

factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Co10.33263 (3)0.28250 (2)0.246751 (19)0.02818 (10)
C10.5981 (2)0.24913 (18)0.39330 (15)0.0295 (4)
C20.6852 (3)0.2085 (2)0.48700 (17)0.0392 (5)
H20.78590.22280.49140.047*
C30.6195 (3)0.1461 (2)0.57368 (17)0.0457 (6)
H30.67700.11710.63730.055*
C40.4680 (3)0.1260 (2)0.56719 (17)0.0398 (5)
H40.42200.08530.62590.048*
C50.3884 (3)0.16841 (17)0.47115 (15)0.0308 (4)
C60.6491 (2)0.31692 (18)0.28856 (16)0.0310 (4)
C70.2218 (3)0.15601 (18)0.44770 (17)0.0339 (5)
C80.7310 (3)0.0243 (2)0.15919 (17)0.0369 (5)
C90.5995 (3)0.0532 (2)0.13323 (17)0.0400 (5)
H90.60680.11790.10420.048*
C100.4521 (3)0.03249 (19)0.15849 (15)0.0330 (4)
C110.2751 (3)0.0397 (2)0.14480 (18)0.0418 (5)
H11A0.20670.06750.20170.063*
H11B0.27260.03970.14460.063*
H11C0.23180.09600.07920.063*
C120.9178 (3)0.0810 (2)0.1495 (2)0.0549 (7)
H12A0.96110.02640.09710.082*
H12B0.94240.15650.12920.082*
H12C0.96990.09650.21600.082*
C130.2400 (2)0.34373 (19)0.00957 (15)0.0327 (4)
C140.1089 (3)0.3533 (2)0.05258 (16)0.0361 (5)
H140.11060.36310.12520.043*
C150.0231 (3)0.34544 (19)0.01417 (16)0.0340 (5)
C160.1946 (3)0.3455 (3)0.0043 (2)0.0491 (6)
H16A0.18630.26930.01900.074*
H16B0.24500.41140.06320.074*
H16C0.26320.35580.05720.074*
C170.4138 (3)0.3448 (3)0.02341 (18)0.0479 (6)
H17A0.46120.36770.02860.072*
H17B0.40890.40270.08990.072*
H17C0.48320.26490.03020.072*
C180.0812 (3)0.5490 (2)0.36524 (17)0.0381 (5)
C190.0209 (3)0.6189 (2)0.35379 (19)0.0439 (5)
H190.00570.69410.37040.053*
C200.1734 (3)0.5549 (2)0.31215 (17)0.0375 (5)
C210.3282 (3)0.5905 (2)0.2884 (2)0.0546 (6)
H21A0.39270.56660.35160.082*
H21B0.29660.67740.26150.082*
H21C0.39500.55040.23680.082*
C220.2576 (3)0.5668 (3)0.4048 (2)0.0580 (7)
H22A0.33510.62810.35340.087*
H22B0.27090.59260.46940.087*
H22C0.28040.49130.41720.087*
N10.45453 (19)0.22688 (14)0.38745 (12)0.0272 (3)
N20.4898 (2)0.11200 (15)0.19911 (13)0.0322 (4)
N30.6621 (2)0.07452 (16)0.19804 (14)0.0342 (4)
H3A0.72010.11050.22000.041*
N40.1920 (2)0.33111 (15)0.11058 (13)0.0309 (4)
N50.0297 (2)0.33282 (16)0.11091 (13)0.0316 (4)
H50.03180.32650.16660.038*
N60.1671 (2)0.45011 (15)0.29795 (13)0.0330 (4)
N70.0095 (2)0.44975 (16)0.33138 (13)0.0343 (4)
H70.02800.39160.33080.041*
O10.55090 (18)0.33974 (14)0.21281 (11)0.0362 (3)
O20.77947 (18)0.34440 (15)0.28302 (12)0.0418 (4)
O30.18031 (17)0.18992 (13)0.35129 (11)0.0353 (3)
O40.1395 (2)0.11702 (16)0.52179 (13)0.0552 (5)
O1W0.0578 (2)0.93763 (17)0.67852 (14)0.0487 (4)
H1WA0.073 (4)0.989 (2)0.6251 (17)0.063 (9)*
H1WB0.006 (4)0.898 (3)0.661 (2)0.071 (10)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Co10.02400 (16)0.03763 (17)0.02563 (15)0.01357 (12)0.00029 (10)0.00758 (11)
C10.0247 (10)0.0335 (11)0.0329 (10)0.0085 (8)0.0003 (8)0.0137 (8)
C20.0330 (12)0.0478 (13)0.0395 (12)0.0118 (10)0.0058 (9)0.0153 (10)
C30.0481 (14)0.0498 (14)0.0333 (12)0.0075 (11)0.0119 (10)0.0076 (10)
C40.0483 (13)0.0369 (12)0.0299 (11)0.0115 (10)0.0013 (9)0.0046 (9)
C50.0355 (11)0.0271 (10)0.0296 (10)0.0097 (8)0.0037 (8)0.0086 (8)
C60.0268 (11)0.0354 (11)0.0362 (11)0.0132 (9)0.0039 (8)0.0153 (9)
C70.0353 (11)0.0289 (10)0.0399 (12)0.0137 (9)0.0074 (9)0.0110 (9)
C80.0319 (11)0.0424 (12)0.0374 (11)0.0109 (9)0.0036 (9)0.0145 (9)
C90.0385 (12)0.0447 (13)0.0433 (12)0.0144 (10)0.0036 (10)0.0225 (10)
C100.0330 (11)0.0400 (11)0.0289 (10)0.0154 (9)0.0009 (8)0.0092 (9)
C110.0355 (12)0.0514 (14)0.0454 (13)0.0200 (10)0.0013 (10)0.0161 (11)
C120.0348 (13)0.0628 (16)0.0710 (17)0.0104 (12)0.0068 (12)0.0330 (14)
C130.0281 (11)0.0414 (12)0.0303 (10)0.0142 (9)0.0014 (8)0.0083 (9)
C140.0319 (11)0.0495 (13)0.0277 (10)0.0148 (10)0.0011 (8)0.0086 (9)
C150.0268 (11)0.0412 (12)0.0344 (11)0.0106 (9)0.0042 (8)0.0090 (9)
C160.0282 (12)0.0743 (17)0.0508 (14)0.0197 (12)0.0037 (10)0.0206 (12)
C170.0347 (12)0.0744 (17)0.0414 (13)0.0274 (12)0.0070 (10)0.0151 (12)
C180.0337 (11)0.0404 (12)0.0400 (12)0.0073 (9)0.0020 (9)0.0155 (10)
C190.0463 (14)0.0381 (12)0.0518 (14)0.0129 (10)0.0001 (11)0.0203 (10)
C200.0400 (12)0.0408 (12)0.0369 (11)0.0180 (10)0.0015 (9)0.0113 (9)
C210.0520 (15)0.0570 (16)0.0689 (17)0.0317 (13)0.0074 (13)0.0232 (13)
C220.0368 (13)0.0637 (17)0.0790 (19)0.0108 (12)0.0106 (13)0.0379 (15)
N10.0257 (8)0.0297 (8)0.0276 (8)0.0098 (7)0.0012 (7)0.0090 (7)
N20.0254 (9)0.0382 (9)0.0344 (9)0.0105 (7)0.0008 (7)0.0113 (7)
N30.0262 (9)0.0398 (10)0.0410 (10)0.0130 (8)0.0003 (7)0.0147 (8)
N40.0228 (8)0.0404 (10)0.0309 (9)0.0122 (7)0.0008 (7)0.0083 (7)
N50.0230 (8)0.0447 (10)0.0288 (9)0.0138 (7)0.0028 (7)0.0090 (7)
N60.0285 (9)0.0383 (10)0.0350 (9)0.0130 (7)0.0016 (7)0.0117 (7)
N70.0284 (9)0.0369 (10)0.0430 (10)0.0132 (8)0.0024 (7)0.0167 (8)
O10.0334 (8)0.0495 (9)0.0309 (7)0.0221 (7)0.0011 (6)0.0073 (6)
O20.0316 (8)0.0559 (10)0.0486 (9)0.0259 (7)0.0041 (7)0.0168 (7)
O30.0315 (8)0.0417 (8)0.0382 (8)0.0186 (6)0.0023 (6)0.0108 (6)
O40.0571 (11)0.0660 (11)0.0486 (10)0.0381 (9)0.0155 (8)0.0056 (8)
O1W0.0543 (11)0.0579 (11)0.0447 (10)0.0330 (9)0.0035 (8)0.0123 (9)
Geometric parameters (Å, °) top
Co1—N12.0407 (16)C13—N41.337 (3)
Co1—N42.0798 (16)C13—C141.389 (3)
Co1—O12.1453 (14)C13—C171.492 (3)
Co1—O32.1522 (14)C14—C151.366 (3)
Co1—N22.2336 (17)C14—H140.9300
Co1—N62.2477 (17)C15—N51.340 (3)
C1—N11.337 (2)C15—C161.486 (3)
C1—C21.380 (3)C16—H16A0.9600
C1—C61.515 (3)C16—H16B0.9600
C2—C31.376 (3)C16—H16C0.9600
C2—H20.9300C17—H17A0.9600
C3—C41.390 (3)C17—H17B0.9600
C3—H30.9300C17—H17C0.9600
C4—C51.376 (3)C18—N71.337 (3)
C4—H40.9300C18—C191.367 (3)
C5—N11.331 (2)C18—C221.491 (3)
C5—C71.526 (3)C19—C201.398 (3)
C6—O21.241 (2)C19—H190.9300
C6—O11.267 (2)C20—N61.336 (3)
C7—O41.229 (2)C20—C211.489 (3)
C7—O31.270 (2)C21—H21A0.9600
C8—N31.338 (3)C21—H21B0.9600
C8—C91.362 (3)C21—H21C0.9600
C8—C121.494 (3)C22—H22A0.9600
C9—C101.393 (3)C22—H22B0.9600
C9—H90.9300C22—H22C0.9600
C10—N21.339 (3)N2—N31.365 (2)
C10—C111.488 (3)N3—H3A0.8600
C11—H11A0.9600N4—N51.359 (2)
C11—H11B0.9600N5—H50.8600
C11—H11C0.9600N6—N71.361 (2)
C12—H12A0.9600N7—H70.8600
C12—H12B0.9600O1W—H1WA0.844 (17)
C12—H12C0.9600O1W—H1WB0.828 (17)
N1—Co1—N4174.52 (6)C13—C14—H14126.9
N1—Co1—O175.49 (6)N5—C15—C14106.49 (17)
N4—Co1—O1109.98 (6)N5—C15—C16121.66 (19)
N1—Co1—O376.60 (6)C14—C15—C16131.8 (2)
N4—Co1—O397.92 (6)C15—C16—H16A109.5
O1—Co1—O3152.00 (5)C15—C16—H16B109.5
N1—Co1—N291.87 (6)H16A—C16—H16B109.5
N4—Co1—N288.21 (6)C15—C16—H16C109.5
O1—Co1—N286.36 (6)H16A—C16—H16C109.5
O3—Co1—N292.37 (6)H16B—C16—H16C109.5
N1—Co1—N688.03 (6)C13—C17—H17A109.5
N4—Co1—N691.67 (6)C13—C17—H17B109.5
O1—Co1—N695.87 (6)H17A—C17—H17B109.5
O3—Co1—N685.33 (6)C13—C17—H17C109.5
N2—Co1—N6177.66 (6)H17A—C17—H17C109.5
N1—C1—C2120.37 (19)H17B—C17—H17C109.5
N1—C1—C6112.56 (16)N7—C18—C19105.87 (19)
C2—C1—C6127.04 (18)N7—C18—C22121.8 (2)
C3—C2—C1118.3 (2)C19—C18—C22132.4 (2)
C3—C2—H2120.8C18—C19—C20106.28 (19)
C1—C2—H2120.8C18—C19—H19126.9
C2—C3—C4120.7 (2)C20—C19—H19126.9
C2—C3—H3119.6N6—C20—C19110.63 (19)
C4—C3—H3119.6N6—C20—C21122.0 (2)
C5—C4—C3117.9 (2)C19—C20—C21127.3 (2)
C5—C4—H4121.1C20—C21—H21A109.5
C3—C4—H4121.1C20—C21—H21B109.5
N1—C5—C4120.88 (19)H21A—C21—H21B109.5
N1—C5—C7113.15 (17)C20—C21—H21C109.5
C4—C5—C7125.96 (19)H21A—C21—H21C109.5
O2—C6—O1125.78 (19)H21B—C21—H21C109.5
O2—C6—C1119.27 (18)C18—C22—H22A109.5
O1—C6—C1114.94 (16)C18—C22—H22B109.5
O4—C7—O3126.1 (2)H22A—C22—H22B109.5
O4—C7—C5118.49 (19)C18—C22—H22C109.5
O3—C7—C5115.42 (17)H22A—C22—H22C109.5
N3—C8—C9106.06 (18)H22B—C22—H22C109.5
N3—C8—C12122.1 (2)C5—N1—C1121.79 (17)
C9—C8—C12131.8 (2)C5—N1—Co1118.58 (13)
C8—C9—C10106.82 (19)C1—N1—Co1119.63 (13)
C8—C9—H9126.6C10—N2—N3104.33 (16)
C10—C9—H9126.6C10—N2—Co1133.05 (14)
N2—C10—C9110.16 (18)N3—N2—Co1122.35 (12)
N2—C10—C11122.52 (19)C8—N3—N2112.62 (16)
C9—C10—C11127.32 (19)C8—N3—H3A123.7
C10—C11—H11A109.5N2—N3—H3A123.7
C10—C11—H11B109.5C13—N4—N5104.78 (15)
H11A—C11—H11B109.5C13—N4—Co1130.69 (13)
C10—C11—H11C109.5N5—N4—Co1123.41 (12)
H11A—C11—H11C109.5C15—N5—N4112.05 (16)
H11B—C11—H11C109.5C15—N5—H5124.0
C8—C12—H12A109.5N4—N5—H5124.0
C8—C12—H12B109.5C20—N6—N7104.03 (16)
H12A—C12—H12B109.5C20—N6—Co1140.31 (14)
C8—C12—H12C109.5N7—N6—Co1115.57 (12)
H12A—C12—H12C109.5C18—N7—N6113.19 (17)
H12B—C12—H12C109.5C18—N7—H7123.4
N4—C13—C14110.39 (17)N6—N7—H7123.4
N4—C13—C17121.13 (18)C6—O1—Co1117.38 (12)
C14—C13—C17128.48 (19)C7—O3—Co1115.59 (12)
C15—C14—C13106.29 (18)H1WA—O1W—H1WB110 (3)
C15—C14—H14126.9
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
N3—H3A···O1Wi0.862.222.926 (2)139
N3—H3A···O10.862.613.048 (2)113
N5—H5···O2ii0.862.102.945 (2)168
N7—H7···O2ii0.862.082.838 (2)146
N7—H7···O30.862.422.906 (2)116
O1W—H1WA···O4iii0.84 (2)1.97 (2)2.797 (2)168 (3)
O1W—H1WB···O3iv0.83 (2)2.20 (2)3.009 (2)164 (3)
Symmetry codes: (i) −x+1, −y+1, −z+1; (ii) x−1, y, z; (iii) x, y+1, z; (iv) −x, −y+1, −z+1.
Table 1
Selected geometric parameters (Å, °)
top
Co1—N12.0407 (16)Co1—O32.1522 (14)
Co1—N42.0798 (16)Co1—N22.2336 (17)
Co1—O12.1453 (14)Co1—N62.2477 (17)
N1—Co1—N4174.52 (6)N4—Co1—N288.21 (6)
N1—Co1—O175.49 (6)N4—Co1—N691.67 (6)
N1—Co1—O376.60 (6)N2—Co1—N6177.66 (6)
Table 2
Hydrogen-bond geometry (Å, °)
top
D—H···AD—HH···AD···AD—H···A
N3—H3A···O1Wi0.862.222.926 (2)139
N3—H3A···O10.862.613.048 (2)113
N5—H5···O2ii0.862.102.945 (2)168
N7—H7···O2ii0.862.082.838 (2)146
N7—H7···O30.862.422.906 (2)116
O1W—H1WA···O4iii0.84 (2)1.97 (2)2.797 (2)168 (3)
O1W—H1WB···O3iv0.83 (2)2.20 (2)3.009 (2)164 (3)
Symmetry codes: (i) −x+1, −y+1, −z+1; (ii) x−1, y, z; (iii) x, y+1, z; (iv) −x, −y+1, −z+1.
references
References top

Bruker (2000). SMART and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.

Grotjahn, D. B., Van, S., Combs, D., Daniel, A., Schneider, C., Incarvito, C. D., Lam, K.-C., Rossi, G., Rheingold, A. L., Rideout, M., Meyer, C., Hernandez, G. & Mejorado, L. (2003). Inorg. Chem. 42, 3347–3355.

Haanstra, W. G., Van der Donk, W. A. J. W., Driessen, W. L., Reedijk, J., Wood, J. S. & Drew, M. G. B. (1990). J. Chem. Soc. Dalton Trans. 10, 3123–3128.

Sheldrick, G. M. (1996). SADABS. University of Göttingen, Germany.

Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122.