catena-Poly[[(2,9-dimethyl-1,10-phenanthroline-κ2N,N′)cobalt(II)]-μ-malonato-κ4O1,O1′:O3,O3′]

Qiu, L.-F.; Zhou, B.-L.; Xu, W.

doi:10.1107/S1600536810038043

metal-organic compounds

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ISSN: 2056-9890

Volume 66| Part 10| October 2010| Page m1327

doi:10.1107/S1600536810038043

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catena-Poly[[(2,9-dimethyl-1,10-phenanthroline-κ²N,N′)cobalt(II)]-μ-malonato-κ⁴O¹,O^1′:O³,O^3′]

Ling-Feng Qiu,^a Bai-Lu Zhou ^a and Wei Xu ^a ^*

^aCenter of Applied Solid State Chemistry Research, Ningbo University, Ningbo 315211, People's Republic of China
^*Correspondence e-mail: xuwei@nbu.edu.cn

(Received 11 September 2010; accepted 23 September 2010; online 30 September 2010)

In the title compound, [Co(C₃H₂O₄)(C₁₄H₁₂N₂)]_n, the Co^II ion is in a distorted octahedral coordination being chelated by a 2,9-dimethyl-1,10-phenanthroline molecule (dmphen) and two carboxylate groups of two malonate ligands The malonate ligand acts in a bridging mode, forming coordination chains along [100]. π–π stacking interactions between dmphen ligands [interplanar distances = 3.414 (4) and 3.447 (4) Å] organize the coordination polymers into supramolecular double chains.

Related literature

For coordination polymers with dicarboxylate ligands, see: Rao et al. (2004 ); Zheng et al. (2004 ).

Experimental

Crystal data

[Co(C₃H₂O₄)(C₁₄H₁₂N₂)]
M_r = 369.23
Triclinic, $[P \overline 1]$
a = 6.8767 (14) Å
b = 9.5293 (19) Å
c = 11.149 (2) Å
α = 86.83 (3)°
β = 89.53 (3)°
γ = 89.52 (3)°
V = 729.4 (2) Å³
Z = 2
Mo Kα radiation
μ = 1.20 mm⁻¹
T = 295 K
0.33 × 0.11 × 0.07 mm

Data collection

Rigaku R-AXIS RAPID diffractometer
Absorption correction: multi-scan (ABSCOR; Higashi, 1995 ) T_min = 0.653, T_max = 0.782
7245 measured reflections
3309 independent reflections
2590 reflections with I > 2σ(I)
R_int = 0.032

Refinement

R[F² > 2σ(F²)] = 0.048
wR(F²) = 0.127
S = 1.06
3309 reflections
222 parameters
H-atom parameters constrained
Δρ_max = 0.58 e Å⁻³
Δρ_min = −0.40 e Å⁻³

Table 1
Selected bond lengths (Å)

Co1—O1	2.180 (3)
Co1—O2	2.145 (3)
Co1—O3ⁱ	2.229 (3)
Co1—O4ⁱ	2.126 (4)
Co1—N1	2.122 (3)
Co1—N2	2.103 (3)
Symmetry code: (i) x-1, y, z.

Data collection: RAPID-AUTO (Rigaku, 1998 ); cell refinement: RAPID-AUTO; data reduction: RAPID-AUTO; 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: SHELXL97.

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536810038043/gk2299sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536810038043/gk2299Isup2.hkl

checkCIF report

Comment top

Metal-phenanthroline complexes and their derivatives have attracted much attention because of their peculiar features. In turn dicarboxylate ligands play an important role in modern coordination chemistry and many complexes have been published with them as ligands (Rao et al., 2004; Zheng et al., 2004). The title complex, (I), was recently prepared and its crystal structure is reported here.

The crystal structure of the title compound consists of [Co(C₁₄H₁₂N₂)(C₃H₂O₄)]_n chains (Fig. 1). Each Co atom is surrounded by two nitrogen atoms of one 2,9-dimethyl-1,10-phenanthroline ligand and four oxygen atoms of two bis-chelating malonate anions to complete a seriously distorted octahedral coordination (Table 1). The malonate ligands bridge the Co atoms to form neutral one-dimensional chains [Co(C₁₄H₁₂N₂)(C₃H₂O₄)]_n along [100] with parallel orientated phen ligands at the same side. As shown in Fig. 2, through π-π stacking interactions the dmphen ligands of two adjacent coordination chains form supramolecular double chains. The interplanar distances between the neighbouring dmphen ligands are 3.414 (4) and 3.447 (4) Å.

Related literature top

For coordination polymers with dicarboxylate ligands, see: Rao et al. (2004); Zheng et al. (2004).

Experimental top

Addition of 2.0 ml (1 M) NaOH to an aqueous solution of CoCl₂.6H₂O (0.238 g, 1.00 mmol) in 10.0 ml H₂O produced a pink precipitate, which was centrifugated and washed with doubly destilled water for several times until no Cl^- anions were detectable. The fresh precipitate was then added to a stirred solution of malonic acid (0.104 g, 1.00 mmol) and 2,9-dimethyl-1,10-phenanthroline hydrate (0.226 g, 1 mmol) in CH₃OH/H₂O (1:1 30 ml). The red mixture was allowed to stand at room temperature and after several days, red plate-like crystals suitable for X-ray analysis were formed. grown by slow evaporation.

Computing details top

Data collection: RAPID-AUTO (Rigaku, 1998); cell refinement: RAPID-AUTO (Rigaku, 1998); data reduction: RAPID-AUTO (Rigaku, 1998); 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: SHELXL97 (Sheldrick, 2008).

Figures top

	Fig. 1. ORTEP view of the title compound. The displacement ellipsoids are drawn at the 30% probability level [symmetry code: (i) x - 1, y, z; (ii) x + 1, y, z].
	Fig. 2. A double chain formed through π–π stacking interactions between dmphen ligands.

catena-Poly[[(2,9-dimethyl-1,10-phenanthroline- κ²N,N')cobalt(II)]-µ-malonato- κ⁴O¹,O^1':O³,O^3'] top

Crystal data top

[Co(C₃H₂O₄)(C₁₄H₁₂N₂)]	Z = 2
M_r = 369.23	F(000) = 378
Triclinic, P1	D_x = 1.681 Mg m⁻³
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 6.8767 (14) Å	Cell parameters from 5667 reflections
b = 9.5293 (19) Å	θ = 3.5–27.5°
c = 11.149 (2) Å	µ = 1.20 mm⁻¹
α = 86.83 (3)°	T = 295 K
β = 89.53 (3)°	Plate, red
γ = 89.52 (3)°	0.33 × 0.11 × 0.07 mm
V = 729.4 (2) Å³

Data collection top

Rigaku R-AXIS RAPID diffractometer	3309 independent reflections
Radiation source: fine-focus sealed tube	2590 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.032
Detector resolution: 0 pixels mm^-1	θ_max = 27.5°, θ_min = 3.5°
ω scans	h = −8→8
Absorption correction: multi-scan (ABSCOR; Higashi, 1995)	k = −12→12
T_min = 0.653, T_max = 0.782	l = −14→14
7245 measured reflections

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.048	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.127	H-atom parameters constrained
S = 1.06	w = 1/[σ²(F_o²) + (0.0568P)² + 0.8449P] where P = (F_o² + 2F_c²)/3
3309 reflections	(Δ/σ)_max = 0.015
222 parameters	Δρ_max = 0.58 e Å⁻³
0 restraints	Δρ_min = −0.40 e Å⁻³

Crystal data top

[Co(C₃H₂O₄)(C₁₄H₁₂N₂)]	γ = 89.52 (3)°
M_r = 369.23	V = 729.4 (2) Å³
Triclinic, P1	Z = 2
a = 6.8767 (14) Å	Mo Kα radiation
b = 9.5293 (19) Å	µ = 1.20 mm⁻¹
c = 11.149 (2) Å	T = 295 K
α = 86.83 (3)°	0.33 × 0.11 × 0.07 mm
β = 89.53 (3)°

Data collection top

Rigaku R-AXIS RAPID diffractometer	3309 independent reflections
Absorption correction: multi-scan (ABSCOR; Higashi, 1995)	2590 reflections with I > 2σ(I)
T_min = 0.653, T_max = 0.782	R_int = 0.032
7245 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.048	0 restraints
wR(F²) = 0.127	H-atom parameters constrained
S = 1.06	Δρ_max = 0.58 e Å⁻³
3309 reflections	Δρ_min = −0.40 e Å⁻³
222 parameters

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

	x	y	z	U_iso*/U_eq
Co1	0.23932 (7)	0.27775 (5)	0.73432 (4)	0.03063 (16)
N1	0.2539 (4)	0.0677 (3)	0.6805 (2)	0.0283 (6)
N2	0.2379 (4)	0.1661 (3)	0.9024 (2)	0.0264 (5)
C1	0.2526 (5)	0.0223 (4)	0.5691 (3)	0.0346 (7)
C2	0.2653 (5)	−0.1224 (4)	0.5494 (4)	0.0435 (9)
H2A	0.2659	−0.1521	0.4713	0.052*
C3	0.2765 (5)	−0.2181 (4)	0.6433 (4)	0.0439 (9)
H3A	0.2860	−0.3133	0.6297	0.053*
C4	0.2737 (5)	−0.1737 (3)	0.7614 (3)	0.0347 (7)
C5	0.2824 (5)	−0.2671 (4)	0.8659 (4)	0.0437 (9)
H5A	0.2923	−0.3633	0.8571	0.052*
C6	0.2766 (5)	−0.2182 (4)	0.9773 (4)	0.0413 (9)
H6A	0.2831	−0.2812	1.0439	0.050*
C7	0.2604 (5)	−0.0702 (3)	0.9941 (3)	0.0322 (7)
C8	0.2485 (5)	−0.0137 (4)	1.1072 (3)	0.0396 (8)
H8A	0.2515	−0.0724	1.1766	0.048*
C9	0.2326 (5)	0.1280 (4)	1.1146 (3)	0.0382 (8)
H9A	0.2249	0.1660	1.1896	0.046*
C10	0.2276 (5)	0.2173 (3)	1.0107 (3)	0.0312 (7)
C11	0.2530 (4)	0.0242 (3)	0.8937 (3)	0.0266 (6)
C12	0.2620 (4)	−0.0274 (3)	0.7747 (3)	0.0281 (7)
C13	0.2325 (6)	0.1281 (5)	0.4669 (3)	0.0461 (9)
H13A	0.1190	0.1850	0.4789	0.069*
H13B	0.2202	0.0809	0.3935	0.069*
H13C	0.3455	0.1867	0.4623	0.069*
C14	0.2121 (6)	0.3725 (4)	1.0190 (3)	0.0424 (9)
H14A	0.3391	0.4104	1.0304	0.064*
H14B	0.1298	0.3933	1.0858	0.064*
H14C	0.1574	0.4137	0.9462	0.064*
O1	0.4924 (4)	0.3945 (4)	0.7882 (3)	0.0622 (9)
O2	0.4560 (5)	0.3466 (4)	0.6052 (3)	0.0675 (9)
O3	0.9214 (4)	0.2696 (3)	0.6983 (3)	0.0646 (9)
O4	1.0687 (5)	0.4640 (4)	0.7095 (5)	0.0950 (15)
C15	0.5528 (5)	0.4017 (3)	0.6837 (3)	0.0331 (7)
C16	0.7380 (5)	0.4791 (4)	0.6502 (3)	0.0360 (8)
H16A	0.7421	0.4975	0.5638	0.043*
H16C	0.7359	0.5691	0.6869	0.043*
C17	0.9200 (5)	0.3999 (4)	0.6886 (3)	0.0343 (7)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Co1	0.0319 (2)	0.0274 (2)	0.0321 (3)	−0.00231 (17)	−0.00176 (17)	0.00297 (17)
N1	0.0266 (13)	0.0290 (13)	0.0292 (14)	−0.0007 (11)	0.0004 (11)	−0.0026 (11)
N2	0.0265 (13)	0.0237 (12)	0.0289 (14)	−0.0015 (10)	−0.0022 (10)	−0.0008 (10)
C1	0.0240 (15)	0.045 (2)	0.0350 (18)	−0.0042 (14)	0.0005 (13)	−0.0083 (15)
C2	0.040 (2)	0.052 (2)	0.040 (2)	−0.0062 (17)	0.0002 (16)	−0.0192 (18)
C3	0.0363 (19)	0.0362 (19)	0.061 (3)	−0.0042 (16)	−0.0004 (17)	−0.0184 (18)
C4	0.0284 (16)	0.0271 (16)	0.049 (2)	−0.0028 (13)	0.0011 (15)	−0.0025 (15)
C5	0.0397 (19)	0.0227 (16)	0.068 (3)	−0.0011 (15)	−0.0021 (18)	0.0024 (16)
C6	0.0390 (19)	0.0301 (18)	0.053 (2)	−0.0029 (15)	−0.0025 (17)	0.0164 (16)
C7	0.0245 (15)	0.0318 (17)	0.0393 (19)	−0.0044 (13)	−0.0043 (13)	0.0089 (14)
C8	0.0374 (18)	0.047 (2)	0.0331 (19)	−0.0060 (16)	−0.0018 (15)	0.0127 (16)
C9	0.0413 (19)	0.050 (2)	0.0238 (17)	−0.0036 (16)	−0.0022 (14)	−0.0013 (15)
C10	0.0293 (16)	0.0340 (17)	0.0303 (17)	−0.0014 (14)	−0.0010 (13)	−0.0011 (13)
C11	0.0210 (14)	0.0272 (15)	0.0314 (17)	−0.0034 (12)	−0.0024 (12)	0.0022 (12)
C12	0.0223 (14)	0.0261 (15)	0.0360 (18)	−0.0014 (12)	0.0002 (12)	−0.0006 (13)
C13	0.046 (2)	0.064 (3)	0.0282 (19)	−0.0095 (19)	−0.0032 (16)	−0.0023 (17)
C14	0.052 (2)	0.0385 (19)	0.037 (2)	0.0000 (17)	0.0006 (17)	−0.0080 (16)
O1	0.0481 (16)	0.097 (3)	0.0412 (17)	−0.0195 (17)	0.0000 (13)	0.0045 (16)
O2	0.063 (2)	0.083 (2)	0.059 (2)	−0.0335 (18)	0.0073 (16)	−0.0249 (18)
O3	0.0481 (17)	0.0449 (17)	0.101 (3)	0.0117 (14)	−0.0200 (17)	−0.0033 (17)
O4	0.0404 (17)	0.059 (2)	0.183 (5)	−0.0152 (16)	−0.040 (2)	0.027 (2)
C15	0.0266 (15)	0.0300 (16)	0.042 (2)	0.0048 (13)	−0.0038 (14)	0.0032 (14)
C16	0.0349 (17)	0.0307 (17)	0.042 (2)	−0.0006 (14)	−0.0031 (15)	0.0068 (14)
C17	0.0327 (17)	0.0369 (18)	0.0327 (18)	0.0018 (15)	−0.0001 (14)	0.0021 (14)

Geometric parameters (Å, º) top

Co1—O1	2.180 (3)	C7—C8	1.400 (5)
Co1—O2	2.145 (3)	C8—C9	1.361 (5)
Co1—O3ⁱ	2.229 (3)	C8—H8A	0.9300
Co1—O4ⁱ	2.126 (4)	C9—C10	1.399 (5)
Co1—N1	2.122 (3)	C9—H9A	0.9300
Co1—N2	2.103 (3)	C10—C14	1.489 (5)
Co1—C15	2.512 (4)	C11—C12	1.440 (5)
Co1—C17ⁱ	2.519 (3)	C13—H13A	0.9600
N1—C1	1.338 (4)	C13—H13B	0.9600
N1—C12	1.350 (4)	C13—H13C	0.9600
N2—C10	1.328 (4)	C14—H14A	0.9600
N2—C11	1.364 (4)	C14—H14B	0.9600
C1—C2	1.410 (5)	C14—H14C	0.9600
C1—C13	1.485 (5)	O1—C15	1.233 (4)
C2—C3	1.352 (6)	O2—C15	1.246 (5)
C2—H2A	0.9300	O3—C17	1.240 (4)
C3—C4	1.405 (5)	O3—Co1ⁱⁱ	2.229 (3)
C3—H3A	0.9300	O4—C17	1.226 (5)
C4—C12	1.411 (4)	O4—Co1ⁱⁱ	2.126 (4)
C4—C5	1.428 (5)	C15—C16	1.511 (5)
C5—C6	1.350 (6)	C16—C17	1.509 (5)
C5—H5A	0.9300	C16—H16A	0.9700
C6—C7	1.436 (5)	C16—H16C	0.9700
C6—H6A	0.9300	C17—Co1ⁱⁱ	2.519 (3)
C7—C11	1.398 (4)

N2—Co1—N1	79.24 (10)	C9—C8—H8A	120.3
N2—Co1—O4ⁱ	119.53 (16)	C7—C8—H8A	120.3
N1—Co1—O4ⁱ	140.97 (13)	C8—C9—C10	120.8 (3)
N2—Co1—O2	136.06 (13)	C8—C9—H9A	119.6
N1—Co1—O2	92.45 (12)	C10—C9—H9A	119.6
O4ⁱ—Co1—O2	93.90 (16)	N2—C10—C9	120.9 (3)
N2—Co1—O1	89.80 (11)	N2—C10—C14	118.4 (3)
N1—Co1—O1	123.50 (12)	C9—C10—C14	120.7 (3)
O4ⁱ—Co1—O1	92.30 (13)	N2—C11—C7	122.8 (3)
O2—Co1—O1	59.10 (12)	N2—C11—C12	117.3 (3)
N2—Co1—O3ⁱ	97.95 (12)	C7—C11—C12	119.9 (3)
N1—Co1—O3ⁱ	86.71 (11)	N1—C12—C4	123.0 (3)
O4ⁱ—Co1—O3ⁱ	58.47 (12)	N1—C12—C11	117.8 (3)
O2—Co1—O3ⁱ	124.82 (14)	C4—C12—C11	119.2 (3)
O1—Co1—O3ⁱ	149.76 (13)	C1—C13—H13A	109.5
C1—N1—C12	119.0 (3)	C1—C13—H13B	109.5
C1—N1—Co1	128.3 (2)	H13A—C13—H13B	109.5
C12—N1—Co1	112.6 (2)	C1—C13—H13C	109.5
C10—N2—C11	118.9 (3)	H13A—C13—H13C	109.5
C10—N2—Co1	128.1 (2)	H13B—C13—H13C	109.5
C11—N2—Co1	113.0 (2)	C10—C14—H14A	109.5
N1—C1—C2	120.9 (3)	C10—C14—H14B	109.5
N1—C1—C13	118.2 (3)	H14A—C14—H14B	109.5
C2—C1—C13	120.9 (3)	C10—C14—H14C	109.5
C3—C2—C1	120.4 (3)	H14A—C14—H14C	109.5
C3—C2—H2A	119.8	H14B—C14—H14C	109.5
C1—C2—H2A	119.8	C15—O1—Co1	90.4 (2)
C2—C3—C4	120.0 (3)	C15—O2—Co1	91.7 (2)
C2—C3—H3A	120.0	O1—C15—O2	118.8 (3)
C4—C3—H3A	120.0	O1—C15—C16	120.9 (3)
C3—C4—C12	116.7 (3)	O2—C15—C16	120.3 (3)
C3—C4—C5	123.9 (3)	O1—C15—Co1	60.2 (2)
C12—C4—C5	119.4 (3)	O2—C15—Co1	58.6 (2)
C6—C5—C4	121.2 (3)	C16—C15—Co1	178.2 (2)
C6—C5—H5A	119.4	C17—C16—C15	113.5 (3)
C4—C5—H5A	119.4	C17—C16—H16A	108.9
C5—C6—C7	120.8 (3)	C15—C16—H16A	108.9
C5—C6—H6A	119.6	C17—C16—H16C	108.9
C7—C6—H6A	119.6	C15—C16—H16C	108.9
C11—C7—C8	117.2 (3)	H16A—C16—H16C	107.7
C11—C7—C6	119.4 (3)	O4—C17—O3	119.4 (4)
C8—C7—C6	123.4 (3)	O4—C17—C16	120.1 (3)
C9—C8—C7	119.4 (3)	O3—C17—C16	120.5 (3)

Symmetry codes: (i) x−1, y, z; (ii) x+1, y, z.

Experimental details

Crystal data
Chemical formula	[Co(C₃H₂O₄)(C₁₄H₁₂N₂)]
M_r	369.23
Crystal system, space group	Triclinic, P1
Temperature (K)	295
a, b, c (Å)	6.8767 (14), 9.5293 (19), 11.149 (2)
α, β, γ (°)	86.83 (3), 89.53 (3), 89.52 (3)
V (Å³)	729.4 (2)
Z	2
Radiation type	Mo Kα
µ (mm⁻¹)	1.20
Crystal size (mm)	0.33 × 0.11 × 0.07

Data collection
Diffractometer	Rigaku R-AXIS RAPID diffractometer
Absorption correction	Multi-scan (ABSCOR; Higashi, 1995)
T_min, T_max	0.653, 0.782
No. of measured, independent and observed [I > 2σ(I)] reflections	7245, 3309, 2590
R_int	0.032
(sin θ/λ)_max (Å⁻¹)	0.649

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.048, 0.127, 1.06
No. of reflections	3309
No. of parameters	222
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.58, −0.40

Computer programs: RAPID-AUTO (Rigaku, 1998), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).

Selected bond lengths (Å) top

Co1—O1	2.180 (3)	Co1—O4ⁱ	2.126 (4)
Co1—O2	2.145 (3)	Co1—N1	2.122 (3)
Co1—O3ⁱ	2.229 (3)	Co1—N2	2.103 (3)

Symmetry code: (i) x−1, y, z.

Acknowledgements

This project was sponsored by the K. C. Wong Magna Fund in Ningbo University and the Scientific Research Fund of Ningbo University (grant No. XYL09078).

References

Higashi, T. (1995). ABSCOR. Rigaku Corporation, Tokyo, Japan. Google Scholar
Rao, C. N. R., Natarajan, S. & Vaidhyanathan, R. (2004). Angew. Chem. Int. Ed. 43, 1466–1496. Web of Science CrossRef CAS Google Scholar
Rigaku (1998). RAPID-AUTO. Rigaku Corporation, Tokyo, Japan. Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Zheng, Y.-Q., Lin, J.-L. & Kong, Z.-P. (2004). Inorg. Chem. 43, 2590–2596. Web of Science CSD CrossRef PubMed CAS Google Scholar

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