cis,trans-Di­carbonyl­dichlorido­(1,10-phenanthroline-5,6-dione-κ2N,N′)ruthenium(II)

Takase, T.; Takahashi, K.; Oyama, D.

doi:10.1107/S2414314617002887

metal-organic compounds

IUCrDATA

ISSN: 2414-3146

Volume 2| Part 2| February 2017| x170288

https://doi.org/10.1107/S2414314617002887

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cis,trans-Dicarbonyldichlorido(1,10-phenanthroline-5,6-dione-κ²N,N′)ruthenium(II)

Tsugiko Takase,^a Kasumi Takahashi ^b,^c and Dai Oyama ^b ^*

^aInstitute of Environmental Radioactivity, Fukushima University, 1 Kanayagawa, Fukushima 960-1296, Japan, ^bDepartment of Industrial Systems Engineering, Cluster of Science and Engineering, Fukushima University, 1 Kanayagawa, Fukushima 960-1296, Japan, and ^cDepartment of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aramaki, Aoba-ku, Sendai 980-8578, Japan
^*Correspondence e-mail: daio@sss.fukushima-u.ac.jp

Edited by M. Weil, Vienna University of Technology, Austria (Received 13 February 2017; accepted 21 February 2017; online 28 February 2017)

In the title compound, [RuCl₂(C₁₂H₆N₂O₂)(CO)₂], the Ru^II atom (site symmetry ..2) adopts a distorted octahedral coordination sphere defined by two carbonyl C atoms, two Cl⁻ anions and two N atoms from the chelating 1,10-phenanthroline-5,6-dione (phendione) ligand. The carbonyl ligands are cis to each other, while the Cl atoms are trans. In the phendione ligand, the C=O [1.239 (5) Å] and the C—C [1.537 (5) Å] bond lengths in the diketone moiety have typical values. In the crystal, C—H⋯Cl and C—H⋯O hydrogen bonds lead to the formation of a three-dimensional supramolecular network.

Keywords: crystal structure; ruthenium(II) complex; o-quinonoid framework; phenanthroline derivative.

CCDC reference: 1533844

Structure description

Dicarbonylruthenium(II) complexes bearing bidentate polypyridyl co-ligands such as 2,2'-bipyridine and 1,10-phenanthroline can catalyse a variety of useful chemical reactions such as multi-electron reductions of CO₂ (Machan et al., 2015 ). In addition, metal complexes with 1,10-phenanthroline-5,6-dione (phendione) are also of interest due to its dual chelating ability as either a diimine (N,N′-bidentate) or a dioxolene (O,O′-bidentate) (Calderazzo et al., 1999 ; Fujihara et al., 2003 ). We report here the synthesis and structural characterization of [Ru(CO)₂Cl₂(phendione)].

The neutral complex crystallizes without disorder or solvent. The molecule has crystallographically imposed twofold symmetry with the Ru^II atom located on the twofold rotation axis. As shown in Fig. 1, the Ru^II atom has a distorted octahedral coordination environment, with two N atoms of the bidentate phendione ligand, two carbonyl carbon atoms and two chloride ions completing the first coordination sphere. Thus, the crystal structure indicates that the phendione ligand selectively coordinates to the Ru^II atom in the N,N′-bidentate mode. The title compound displays a cis orientation of the carbonyl ligands and a trans orientation of the chlorido ligands. The Ru—C—O bond angle of the complex [176.1 (3)°] is nearly linear, and the C≡O [1.128 (4) Å], Ru—C [1.893 (4) Å], Ru—Cl [2.3880 (7) Å] and Ru—N [2.116 (3) Å] distances are comparable to those in similar complexes (Ding et al., 2016 ; Oyama et al., 2009 ).

Figure 1
The molecular structure of the title compound, with atom labels and displacement ellipsoids for non-H atoms drawn at the 50% probability level. Unlabelled atoms are related to labelled atoms by the symmetry operation (y, x, −z + 1).

It is important to utilize the results of the structure determination in order to distinguish the carbon–oxygen bond as double or as single in quinone-based ligands. The C=O bond length of metal-free phendione is 1.210 Å (averaged) (Calderazzo et al., 1999), while C=O bond lengths of metal complexes containing phendione as a ligand are in the range 1.154–1.264 Å (Fujihara et al., 2003, 2004 ; Larsson & Öhrström, 2004 ; Yokoyama et al., 2006 ) and the C—O bond lengths of the corresponding diol ligand are 1.364–1.367 Å (Guan et al., 2008 ; Larsson & Öhrström, 2004). The C=O bond length of the phendione ligand in the complex [1.239 (5) Å] is nearly the same as that of metal-free phendione (Calderazzo et al., 1999) or those of other Ru^II–phendione complexes (Fujihara et al., 2003, 2004; Yokoyama et al., 2006), indicating that the phendione ligand in the complex retains its double-bond character. Additionally, the C7—C7ⁱ [symmetry code: (i) y, x, −z + 1] distance in the diketone moiety of phendione represents a typical single bond [1.537 (5) Å], compared with 1.534 Å in the metal-free compound (Calderazzo et al., 1999).

In the crystal, (aryl)C—H⋯Cl and (aryl)C—H⋯O hydrogen-bonds (Table 1) lead to the formation of a three-dimensional supramolecular network (Fig. 2).

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C2—H1⋯Cl1ⁱ	0.95	2.66	3.478 (4)	145
C3—H2⋯O2ⁱⁱ	0.95	2.53	3.206 (4)	128
C4—H3⋯Cl1ⁱⁱⁱ	0.95	2.78	3.660 (4)	155
Symmetry codes: (i) $[y-{\script{1\over 2}}, -x+{\script{3\over 2}}, z+{\script{1\over 4}}]$ ; (ii) $[-x-{\script{1\over 2}}, y+{\script{5\over 2}}, -z+{\script{7\over 4}}]$ ; (iii) y, x+1, -z+1.

Figure 2
A view approximately along the b axis of the title compound, with hydrogen bonds shown as dashed lines (for numerical values see Table 1

Synthesis and crystallization

The ligand 1,10-phenanthroline-5,6-dione (phendione) was prepared as described by Yamada et al. (1992 ). It proved to be analytically and spectroscopically pure (IR and ¹H NMR data). A methanol solution (5 ml) containing [Ru(CO)₂Cl₂]_n (50 mg) and phendione (70 mg) was refluxed for 1 h. The reaction mixture was allowed to stand at 277 K overnight. The light-brown-colored precipitate was collected by filtration and washed with diethyl ether, and then dried under vacuum (yield 56 mg, 38%). Crystals suitable for the X-ray diffraction experiment were grown by diffusion of diethyl ether into a DMF solution of the complex over a few days.

Refinement

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

Table 2
Experimental details

Crystal data
Chemical formula	[RuCl₂(C₁₂H₆N₂O₂)(CO)₂]
M_r	438.19
Crystal system, space group	Tetragonal, P4₃2₁2
Temperature (K)	93
a, c (Å)	8.8003 (6), 19.772 (2)
V (Å³)	1531.3 (3)
Z	4
Radiation type	Mo Kα
μ (mm⁻¹)	1.39
Crystal size (mm)	0.15 × 0.15 × 0.10

Data collection
Diffractometer	Rigaku Saturn724
Absorption correction	Multi-scan (REQAB; Rigaku, 1998 )
T_min, T_max	0.812, 0.870
No. of measured, independent and observed [F² > 2.0σ(F²)] reflections	15312, 1728, 1653
R_int	0.039
(sin θ/λ)_max (Å⁻¹)	0.646

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.025, 0.061, 1.08
No. of reflections	1728
No. of parameters	105
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.89, −0.26
Absolute structure	Flack (1983 ), 657 Friedel pairs
Absolute structure parameter	−0.02 (5)
Computer programs: CrystalClear (Rigaku, 2008 ), SIR97 (Altomare et al., 1999 ), SHELXL97 (Sheldrick, 2008 ), Mercury (Macrae et al., 2008 ), CrystalStructure (Rigaku, 2010 ), PLATON (Spek, 2009 ) and publCIF (Westrip, 2010 ).

Structural data

CCDC reference: 1533844

Crystal structure: contains datablocks General, I. DOI: https://doi.org/10.1107/S2414314617002887/wm4039sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2414314617002887/wm4039Isup2.hkl

Supporting information file. DOI: https://doi.org/10.1107/S2414314617002887/wm4039Isup3.mol

checkCIF report

Computing details top

Data collection: CrystalClear (Rigaku, 2008); cell refinement: CrystalClear (Rigaku, 2008); data reduction: CrystalClear (Rigaku, 2008); program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: Mercury (Macrae et al., 2008); software used to prepare material for publication: CrystalStructure (Rigaku, 2010), PLATON (Spek, 2009) and publCIF (Westrip, 2010).

cis,trans-Dicarbonyldichlorido(1,10-phenanthroline-5,6-dione-κ²N,N')ruthenium(II) top

Crystal data top

[RuCl₂(C₁₂H₆N₂O₂)(CO)₂]	D_x = 1.901 Mg m⁻³
M_r = 438.19	Mo Kα radiation, λ = 0.71075 Å
Tetragonal, P4₃2₁2	Cell parameters from 4550 reflections
Hall symbol: P 4nw 2abw	θ = 3.1–27.5°
a = 8.8003 (6) Å	µ = 1.39 mm⁻¹
c = 19.772 (2) Å	T = 93 K
V = 1531.3 (3) Å³	Prism, brown
Z = 4	0.15 × 0.15 × 0.10 mm
F(000) = 856.00

Data collection top

Rigaku Saturn724 diffractometer	1653 reflections with F² > 2.0σ(F²)
Detector resolution: 7.111 pixels mm^-1	R_int = 0.039
ω scans	θ_max = 27.3°
Absorption correction: multi-scan (REQAB; Rigaku, 1998)	h = −10→11
T_min = 0.812, T_max = 0.870	k = −11→11
15312 measured reflections	l = −25→25
1728 independent reflections

Refinement top

Refinement on F²	Hydrogen site location: inferred from neighbouring sites
R[F² > 2σ(F²)] = 0.025	H-atom parameters constrained
wR(F²) = 0.061	w = 1/[σ²(F_o²) + (0.0355P)² + 0.6276P] where P = (F_o² + 2F_c²)/3
S = 1.08	(Δ/σ)_max = 0.002
1728 reflections	Δρ_max = 0.89 e Å⁻³
105 parameters	Δρ_min = −0.26 e Å⁻³
0 restraints	Absolute structure: Flack (1983), 657 Friedel pairs
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: −0.02 (5)
Secondary atom site location: difference Fourier map

Special details top

Refinement. Refinement was performed using all reflections. The weighted R-factor (wR) and goodness of fit (S) are based on F². R-factor (gt) are based on F. The threshold expression of F² > 2.0 sigma(F²) is used only for calculating R-factor (gt).

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
Ru1	0.62055 (3)	0.62055 (3)	0.5000	0.02048 (10)
Cl1	0.54739 (9)	0.70536 (9)	0.38999 (3)	0.02686 (17)
O1	0.5929 (4)	0.3029 (3)	0.44361 (13)	0.0466 (7)
O2	1.0393 (4)	1.2397 (3)	0.52859 (11)	0.0386 (7)
N1	0.6585 (3)	0.8483 (3)	0.52981 (13)	0.0229 (6)
C1	0.6036 (4)	0.4194 (4)	0.46692 (15)	0.0311 (7)
C2	0.5590 (4)	0.9404 (4)	0.56163 (16)	0.0306 (8)
C3	0.5959 (5)	1.0865 (4)	0.58117 (16)	0.0360 (9)
C4	0.7374 (5)	1.1435 (4)	0.56831 (16)	0.0326 (8)
C5	0.8430 (4)	1.0512 (4)	0.53461 (14)	0.0239 (7)
C6	0.7996 (4)	0.9032 (4)	0.51691 (13)	0.0210 (6)
C7	0.9973 (4)	1.1078 (5)	0.51736 (14)	0.0293 (7)
H1	0.4598	0.9034	0.5709	0.0368*
H2	0.5226	1.1476	0.6037	0.0432*
H3	0.7638	1.2436	0.5819	0.0391*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Ru1	0.02169 (12)	0.02169 (12)	0.01805 (14)	−0.00119 (14)	−0.00289 (9)	0.00289 (9)
Cl1	0.0252 (4)	0.0342 (5)	0.0211 (4)	−0.0016 (3)	−0.0024 (3)	0.0085 (3)
O1	0.072 (3)	0.0292 (14)	0.0389 (14)	−0.0112 (14)	−0.0159 (14)	−0.0037 (12)
O2	0.0642 (18)	0.0247 (13)	0.0270 (12)	−0.0067 (12)	−0.0128 (12)	0.0002 (10)
N1	0.0259 (14)	0.0229 (14)	0.0198 (11)	0.0057 (10)	0.0031 (10)	0.0028 (10)
C1	0.0369 (18)	0.0338 (18)	0.0226 (14)	−0.0064 (15)	−0.0094 (14)	0.0043 (13)
C2	0.0307 (18)	0.0354 (19)	0.0258 (15)	0.0123 (15)	0.0056 (14)	0.0015 (14)
C3	0.048 (3)	0.0335 (19)	0.0271 (16)	0.0165 (16)	0.0025 (15)	−0.0074 (13)
C4	0.049 (3)	0.0230 (17)	0.0260 (16)	0.0075 (15)	−0.0040 (15)	−0.0040 (13)
C5	0.0314 (18)	0.0228 (15)	0.0175 (13)	0.0008 (13)	−0.0047 (11)	0.0008 (12)
C6	0.0209 (14)	0.0255 (16)	0.0166 (12)	0.0045 (13)	−0.0011 (11)	0.0029 (11)
C7	0.0389 (19)	0.0285 (17)	0.0205 (14)	−0.0058 (15)	−0.0084 (13)	0.0033 (13)

Geometric parameters (Å, º) top

Ru1—Cl1	2.3880 (7)	C2—C3	1.381 (5)
Ru1—Cl1ⁱ	2.3880 (7)	C3—C4	1.366 (6)
Ru1—N1	2.116 (3)	C4—C5	1.403 (5)
Ru1—N1ⁱ	2.116 (3)	C5—C6	1.401 (5)
Ru1—C1	1.893 (4)	C5—C7	1.486 (5)
Ru1—C1ⁱ	1.893 (4)	C6—C6ⁱ	1.452 (4)
O1—C1	1.128 (4)	C7—C7ⁱ	1.537 (5)
O2—C7	1.239 (5)	C2—H1	0.950
N1—C2	1.349 (5)	C3—H2	0.950
N1—C6	1.356 (4)	C4—H3	0.950

Ru1···O1ⁱ	3.020 (3)	C7···Cl1^ix	3.331 (4)
Ru1···C2ⁱ	3.115 (4)	C7···Cl1^vi	3.251 (3)
Ru1···C6ⁱ	2.963 (3)	Ru1···H1	3.1883
O1···C1ⁱ	3.531 (5)	Ru1···H1ⁱ	3.1883
O2···O2ⁱ	2.739 (4)	O1···H1ⁱ	3.0752
O2···C4	2.897 (5)	O2···H3	2.6443
N1···C4	2.794 (5)	N1···H2	3.2400
C1···C2ⁱ	3.258 (5)	C1···H1ⁱ	2.7657
C2···C5	2.735 (5)	C2···H3	3.2444
C3···C6	2.726 (5)	C4···H1	3.2305
C5···C5ⁱ	2.930 (5)	C5···H2	3.2454
C6···C7ⁱ	2.916 (5)	C6···H1	3.1755
Cl1···O2ⁱⁱ	3.433 (3)	C6···H3	3.2750
Cl1···C2ⁱⁱⁱ	3.478 (4)	C7···H3	2.6986
Cl1···C7^iv	3.331 (4)	H1···H2	2.3113
Cl1···C7ⁱⁱ	3.251 (3)	H2···H3	2.3241
O1···N1^iv	3.517 (4)	Cl1···H1ⁱⁱⁱ	2.6578
O1···C2^iv	3.391 (5)	Cl1···H2ⁱⁱⁱ	3.3550
O1···C3^v	3.320 (5)	Cl1···H3^xi	2.7786
O1···C3^iv	3.279 (5)	O1···H2^v	3.5019
O1···C4^v	3.109 (5)	O1···H3^v	3.1641
O1···C4^iv	3.286 (5)	O2···H1^vii	3.0084
O1···C5^iv	3.408 (4)	O2···H2^viii	2.5348
O1···C6^iv	3.494 (4)	O2···H3^viii	3.3956
O2···Cl1^vi	3.433 (3)	C1···H3^v	3.0904
O2···C2^vii	3.440 (5)	C4···H2^viii	3.4731
O2···C3^viii	3.206 (4)	C7···H2^viii	3.3448
N1···O1^ix	3.517 (4)	H1···Cl1^x	2.6578
C1···C4^v	3.362 (5)	H1···O2^xi	3.0084
C2···Cl1^x	3.478 (4)	H2···Cl1^x	3.3550
C2···O1^ix	3.391 (5)	H2···O1^xii	3.5019
C2···O2^xi	3.440 (5)	H2···O2^xiii	2.5348
C3···O1^xii	3.320 (5)	H2···C4^xiii	3.4731
C3···O1^ix	3.279 (5)	H2···C7^xiii	3.3448
C3···O2^xiii	3.206 (4)	H2···H3^xiii	2.7802
C4···O1^xii	3.109 (5)	H3···Cl1^vii	2.7786
C4···O1^ix	3.286 (5)	H3···O1^xii	3.1641
C4···C1^xii	3.362 (5)	H3···O2^xiii	3.3956
C5···O1^ix	3.408 (4)	H3···C1^xii	3.0904
C6···O1^ix	3.494 (4)	H3···H2^viii	2.7802

Cl1—Ru1—Cl1ⁱ	176.52 (3)	N1—C2—C3	122.5 (4)
Cl1—Ru1—N1	90.01 (8)	C2—C3—C4	120.3 (4)
Cl1—Ru1—N1ⁱ	87.27 (8)	C3—C4—C5	118.7 (3)
Cl1—Ru1—C1	87.50 (10)	C4—C5—C6	118.4 (3)
Cl1—Ru1—C1ⁱ	95.00 (10)	C4—C5—C7	121.3 (3)
Cl1ⁱ—Ru1—N1	87.27 (8)	C6—C5—C7	120.2 (3)
Cl1ⁱ—Ru1—N1ⁱ	90.01 (8)	N1—C6—C5	122.2 (3)
Cl1ⁱ—Ru1—C1	95.00 (10)	N1—C6—C6ⁱ	116.0 (3)
Cl1ⁱ—Ru1—C1ⁱ	87.50 (10)	C5—C6—C6ⁱ	121.8 (3)
N1—Ru1—N1ⁱ	77.18 (10)	O2—C7—C5	123.1 (3)
N1—Ru1—C1	174.02 (13)	O2—C7—C7ⁱ	119.0 (3)
N1—Ru1—C1ⁱ	97.26 (13)	C5—C7—C7ⁱ	117.9 (3)
N1ⁱ—Ru1—C1	97.26 (13)	N1—C2—H1	118.764
N1ⁱ—Ru1—C1ⁱ	174.02 (13)	C3—C2—H1	118.772
C1—Ru1—C1ⁱ	88.38 (15)	C2—C3—H2	119.871
Ru1—N1—C2	126.6 (3)	C4—C3—H2	119.866
Ru1—N1—C6	115.43 (19)	C3—C4—H3	120.672
C2—N1—C6	117.9 (3)	C5—C4—H3	120.668
Ru1—C1—O1	176.1 (3)

Cl1—Ru1—N1—C2	94.41 (19)	C6—N1—C2—C3	−0.0 (5)
Cl1—Ru1—N1—C6	−87.72 (16)	N1—C2—C3—C4	0.3 (5)
Cl1—Ru1—N1ⁱ—C2ⁱ	−87.76 (19)	C2—C3—C4—C5	0.5 (5)
Cl1—Ru1—N1ⁱ—C6ⁱ	90.11 (16)	C3—C4—C5—C6	−1.4 (5)
Cl1ⁱ—Ru1—N1—C2	−87.76 (19)	C3—C4—C5—C7	178.2 (3)
Cl1ⁱ—Ru1—N1—C6	90.11 (16)	C4—C5—C6—N1	1.6 (4)
Cl1ⁱ—Ru1—N1ⁱ—C2ⁱ	94.41 (19)	C4—C5—C6—C6ⁱ	−178.8 (3)
Cl1ⁱ—Ru1—N1ⁱ—C6ⁱ	−87.72 (16)	C4—C5—C7—O2	−3.4 (5)
N1—Ru1—N1ⁱ—C2ⁱ	−178.4 (3)	C4—C5—C7—C7ⁱ	177.9 (3)
N1—Ru1—N1ⁱ—C6ⁱ	−0.53 (16)	C6—C5—C7—O2	176.2 (3)
N1ⁱ—Ru1—N1—C2	−178.4 (3)	C6—C5—C7—C7ⁱ	−2.5 (4)
N1ⁱ—Ru1—N1—C6	−0.53 (16)	C7—C5—C6—N1	−178.0 (3)
C1ⁱ—Ru1—N1—C2	−0.6 (3)	C7—C5—C6—C6ⁱ	1.6 (4)
C1ⁱ—Ru1—N1—C6	177.23 (18)	N1—C6—C6ⁱ—N1ⁱ	−1.9 (4)
C1—Ru1—N1ⁱ—C2ⁱ	−0.6 (3)	N1—C6—C6ⁱ—C5ⁱ	178.5 (3)
C1—Ru1—N1ⁱ—C6ⁱ	177.23 (18)	C5—C6—C6ⁱ—N1ⁱ	178.5 (3)
Ru1—N1—C2—C3	177.77 (18)	C5—C6—C6ⁱ—C5ⁱ	−1.1 (4)
Ru1—N1—C6—C5	−178.98 (16)	O2—C7—C7ⁱ—O2ⁱ	5.5 (4)
Ru1—N1—C6—C6ⁱ	1.4 (3)	O2—C7—C7ⁱ—C5ⁱ	−175.8 (3)
C2—N1—C6—C5	−0.9 (4)	C5—C7—C7ⁱ—O2ⁱ	−175.8 (3)
C2—N1—C6—C6ⁱ	179.5 (3)	C5—C7—C7ⁱ—C5ⁱ	2.9 (4)

Symmetry codes: (i) y, x, −z+1; (ii) −x+3/2, y−1/2, −z+3/4; (iii) −y+3/2, x+1/2, z−1/4; (iv) −y+3/2, x−1/2, z−1/4; (v) x, y−1, z; (vi) −x+3/2, y+1/2, −z+3/4; (vii) y, x+1, −z+1; (viii) x+1/2, −y+5/2, −z+5/4; (ix) y+1/2, −x+3/2, z+1/4; (x) y−1/2, −x+3/2, z+1/4; (xi) y−1, x, −z+1; (xii) x, y+1, z; (xiii) x−1/2, −y+5/2, −z+5/4.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C2—H1···Cl1^x	0.95	2.66	3.478 (4)	145
C3—H2···O2^xiv	0.95	2.53	3.206 (4)	128
C4—H3···Cl1^vii	0.95	2.78	3.660 (4)	155

Symmetry codes: (vii) y, x+1, −z+1; (x) y−1/2, −x+3/2, z+1/4; (xiv) −x−1/2, y+5/2, −z+7/4.

Funding information

Funding for this research was provided by: Japan Society for the Promotion of Science (award No. 25410059; Grant-in-Aid for Scientific Research (C)).

References

Altomare, A., Burla, M. C., Camalli, M., Cascarano, G. L., Giacovazzo, C., Guagliardi, A., Moliterni, A. G. G., Polidori, G. & Spagna, R. (1999). J. Appl. Cryst. 32, 115–119. Web of Science CrossRef CAS IUCr Journals Google Scholar
Calderazzo, F., Marchetti, F., Pampaloni, G. & Passarelli, V. (1999). J. Chem. Soc. Dalton Trans. pp. 4389–4396. Web of Science CSD CrossRef Google Scholar
Ding, X., Tuikka, M. J., Hirva, P., Kukushkin, V. Y., Novikov, A. S. & Haukka, M. (2016). CrystEngComm, 18, 1987–1995. CrossRef CAS Google Scholar
Flack, H. D. (1983). Acta Cryst. A39, 876–881. CrossRef CAS Web of Science IUCr Journals Google Scholar
Fujihara, T., Okamura, R., Wada, T. & Tanaka, K. (2003). Dalton Trans. pp. 3221–3226. Web of Science CSD CrossRef Google Scholar
Fujihara, T., Wada, T. & Tanaka, K. (2004). Dalton Trans. pp. 645–652. Web of Science CSD CrossRef Google Scholar
Guan, X.-H., Wu, J.-Z., Yu, Y. & Yang, P. (2008). Acta Cryst. C64, m311–m313. CrossRef IUCr Journals Google Scholar
Larsson, K. & Öhrström, L. (2004). Inorg. Chim. Acta, 357, 657–664. Web of Science CSD CrossRef CAS Google Scholar
Machan, C. W., Sampson, M. D. & Kubiak, C. P. (2015). J. Am. Chem. Soc. 137, 8564–8571. CrossRef CAS PubMed Google Scholar
Macrae, C. F., Bruno, I. J., Chisholm, J. A., Edgington, P. R., McCabe, P., Pidcock, E., Rodriguez-Monge, L., Taylor, R., van de Streek, J. & Wood, P. A. (2008). J. Appl. Cryst. 41, 466–470. Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
Oyama, D., Asuma, A., Hamada, T. & Takase, T. (2009). Inorg. Chim. Acta, 362, 2581–2588. CrossRef CAS Google Scholar
Rigaku (1998). REQAB. Rigaku Corporation, Tokyo, Japan. Google Scholar
Rigaku (2008). CrystalClear. Rigaku Corporation, Tokyo, Japan. Google Scholar
Rigaku (2010). CrystalStructure. Rigaku Corporation, Tokyo, Japan. Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Spek, A. L. (2009). Acta Cryst. D65, 148–155. Web of Science CrossRef CAS IUCr Journals Google Scholar
Westrip, S. P. (2010). J. Appl. Cryst. 43, 920–925. Web of Science CrossRef CAS IUCr Journals Google Scholar
Yamada, M., Tanaka, Y., Yoshimoto, Y., Kuroda, S. & Shimao, I. (1992). Bull. Chem. Soc. Jpn, 65, 1006–1011. CrossRef CAS Web of Science Google Scholar
Yokoyama, K., Wakabayashi, A., Noguchi, K., Nakamura, N. & Ohno, H. (2006). Inorg. Chim. Acta, 359, 807–814. CrossRef CAS Google Scholar

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