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Journal logoCRYSTALLOGRAPHIC
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ISSN: 2056-9890
Volume 71| Part 7| July 2015| Pages 870-874
doi:10.1107/S2056989015012086

The crystal structure of 4′-{4-[(2,2,5,5-tetra­methyl-N-oxyl-3-pyrrolin-3-yl)ethyn­yl]phen­yl}-2,2′:6′,2′′-terpyridine

CROSSMARK_Color_square_no_text.svg
Andreas Meyer,a Jennifer Wiecek,a Gregor Schnakenburgb and Olav Schiemanna*

aUniversity of Bonn, Institute of Physical and Theoretical Chemistry, Wegelerstrasse 12, 53115 Bonn, Germany, and bUniversity of Bonn, Institute of Inorganic Chemistry, Gerhard-Domagk-Strasse 1, 53121 Bonn, Germany
*Correspondence e-mail: schiemann@pc.uni-bonn.de

Edited by A. J. Lough, University of Toronto, Canada (Received 28 May 2015; accepted 23 June 2015; online 30 June 2015)

The terpyridine group of the title compound, C31H27N4O, assumes an all-transoid conformation and is essentially planar with the dihedral angles between the mean planes of the central pyridine and the two outer rings amounting to 3.87 (5) and 1.98 (5)°. The pyrroline-N-oxyl group commonly seen in such nitroxyls is found in the title structure and the mean plane of the pyrroline ring subtends a dihedral angle of 88.44 (7)° to the mean plane of the central pyridine ring. The intra­molecular separation between the nitrogen atom of the central pyridine unit of the terpyridine group and the nitroxyl group is 14.120 (2) Å. In the crystal, the mol­ecules are arranged in layers stacked along [001]. Slipped face-to-face π–π inter­actions between the pyridine rings are observed along this direction with the shortest centroid–centroid distances amounting to 3.700 (1) and 3.781 (1) Å. Furthermore, edge-on C—H⋯π inter­actions between the phenyl­ene rings of neighbouring mol­ecules are observed along this direction. A two-dimensional C—H⋯O hydrogen-bonded network is formed within the (010) plane. The shortest O⋯O separation between neighbouring mol­ecules is 5.412 (3) Å.

CCDC reference: 1408457

1. Chemical context

The title compound, (1), was synthesized as a ligand for 3d metal ions as part of a pulsed EPR study on metal–nitroxyl model systems. The mol­ecule contains a paramagnetic nitroxyl group and a terpyridine group. Nitroxyls have been the subject of magnetic studies in which exchange inter­actions have been detected (see, for example, Rajca et al., 2006[Rajca, A., Mukherjee, S., Pink, M. & Rajca, S. (2006). J. Am. Chem. Soc. 128, 13497-13507.]; Fritscher et al., 2002[Fritscher, J., Beyer, M. & Schiemann, O. (2002). Chem. Phys. Lett. 364, 393-401.]). Furthermore, nitroxyls are used as spin labels for structural investigations of biological macromolecules (Reginsson & Schiemann, 2011[Reginsson, G. W. & Schiemann, O. (2011). Biochem. Soc. Trans. 39, 128-139.]). The structures of terpyridines have been investigated by Fallahpour et al. (1999[Fallahpour, R.-A., Neuburger, M. & Zehnder, M. (1999). Polyhedron, 18, 2445-2454.]), Eryazici et al. (2006[Eryazici, I., Moorefield, C. N., Durmus, S. & Newkome, G. R. (2006). J. Org. Chem. 71, 1009-1014.]), Bessel et al. (1992[Bessel, C. A., See, R. F., Jameson, D. L., Churchill, M. R. & Takeuchi, K. J. (1992). J. Chem. Soc. Dalton Trans. pp. 3223-3228.]) and Grave et al. (2003[Grave, C., Lentz, D., Schäfer, A., Samorì, P., Rabe, P. J., Franke, P. & Schlüter, A. D. (2003). J. Am. Chem. Soc. 125, 6907-6918.]) to name a few examples. The terpyridine moiety is known to form complexes with various metals. Numerous studies on metal complexes of terpyridine have been conducted, examples include those by Hogg & Wilkins (1962[Hogg, R. & Wilkins, R. G. (1962). J. Chem. Soc. pp. 341-350.]), Constable et al. (1999[Constable, E. C., Baum, G., Bill, E., Dyson, R., van Eldik, R., Fenske, D., Kaderli, D., Morris, D., Neubrand, A., Neuburger, M., Smith, D. R., Wieghardt, K., Zehnder, M. & Zuberbühler, A. D. (1999). Chem. Eur. J. 5, 498-508.]), Narr et al. (2002[Narr, E., Godt, A. & Jeschke, G. (2002). Angew. Chem. Int. Ed. 41, 3907-3910.]) and Folgado et al. (1990[Folgado, J. V., Henke, W., Allmann, R., Stratemeier, H., Beltrán-Porter, D., Rojo, T. & Reinen, D. (1990). Inorg. Chem. 29, 2035-2042.]).

[Scheme 1]

2. Structural commentary

The structure of the title compound (1) is shown in Fig. 1[link]. The terpyridine group of (1) assumes an all-transoid conformation and is essentially planar with angles between the mean planes of the central pyridine (N1, C1–C5, r.m.s deviation from the mean plane = 0.006 Å) and the two outer rings amounting to 3.87 (5)° (N4, C27–C31, r.m.s. deviation from the mean plane = 0.003 Å) and 1.98 (5)° (N2, C6–C10, r.m.s deviation from the mean plane = 0.006 Å), respectively. The pyrroline-N-oxyl unit commonly found for such nitroxyls is seen in the structure and its mean plane (N3, C19–C22, r.m.s deviation from the mean plane = 0.006 Å) subtends a dihedral angle of 88.44 (7)° to the mean plane of the central pyridine ring (for similar structural motifs, see Margraf et al., 2009[Margraf, D., Schuetz, D., Prisner, T. F. & Bats, J. W. (2009). Acta Cryst. E65, o1784.] and Schuetz et al., 2010[Schuetz, D., Margraf, D., Prisner, T. F. & Bats, J. W. (2010). Acta Cryst. E66, o729-o730.]). The subunits are linked by a 4-ethinylene­phenyl­ene group. The mean plane of the phenyl­ene group (C11–C16, r.m.s deviation from the mean plane < 0.001 Å) is tilted with respect to both the central pyridine ring [dihedral angle of 51.36 (5)°] and the pyrroline-N-oxyl [dihedral angle of 37.62 (7)°]. The angles C18—C17—C14 [177.35 (19)°] and C17—C18—C19 [175.64 (18)°] are slightly lower than the 180° expected for a strictly linear shape of the mol­ecular backbone. Two short intra­molecular hydrogen–nitro­gen distances are observed between the two meta-protons of the central pyridine subunit and the nitro­gen atoms of the external pyridine rings (Table 1[link]). Murguly et al. (1999[Murguly, E., Norsten, T. B. & Branda, N. (1999). J. Chem. Soc. Perkin Trans. 2, pp. 2789-2794.]) propose weak intra­molecular hydrogen bonds for these atoms. The intra­molecular separation between the terpyridine group and the nitroxyl amounts to 14.120 (2) Å (measured between O1 and N1).

Table 1
Hydrogen-bond geometry (Å, °)

Cg is the centroid of the C11–C16 ring.
D—H⋯A D—H H⋯A D⋯A D—H⋯A
C2—H2⋯N2 0.95 2.50 2.815 (2) 99
C4—H4⋯N4 0.95 2.46 2.778 (2) 100
C8—H8⋯O1i 0.95 2.59 3.529 (2) 170
C16—H16⋯Cgii 0.95 2.81 3.669 (2) 151
C22—H22⋯O1iii 0.95 2.55 3.485 (2) 170
Symmetry codes: (i) x-1, y, z+1; (ii) [x, -y+{\script{1\over 2}}, z+{\script{1\over 2}}]; (iii) x, y, z+1.
[Figure 1]
Figure 1
The mol­ecular structure of the title compound with displacement ellipsoids drawn at the 50% probability level. H atoms have been omitted for clarity.

3. Supra­molecular features

The packing within the crystal structure is shown in Figs. 2[link]–4[link][link]. The mol­ecules are stacked in layers along [001] (Fig. 2[link].) The oxygen atom of the nitroxyl group forms weak hydrogen bonds to the protons of the para-C—H group and the pyrroline C—H group of neighbouring mol­ecules (Table 1[link]). These hydrogen bonds span a two-dimensional network within the (010) plane (Figs. 3[link] and 4[link]). π–π inter­actions are observed along [001] between the terpyridine subunits of neighbouring mol­ecules (Figs. 3[link] and 5[link]). These terpyridine subunits are arranged in a slipped face-to-face alignment (Janiak, 2000[Janiak, C. (2000). J. Chem. Soc. Dalton Trans. pp. 3885-3896.]) with the shortest inter­molecular distances between the pyridine rings amounting to 3.700 (1) Å (measured from the centroid of N2, C6–C10 to the centroid of N4, C27–C31) and 3.781 (1) Å (centroid of N1, C1–C5 to the centroid of N4, C27–C31, see Fig. 5[link]). Furthermore, the phenyl­ene rings of neighbouring mol­ecules show an edge-on C—H⋯π inter­action along the same axis (Table 1[link] and Fig. 5[link]). The nitroxyl groups are arranged in an alternating manner pointing in opposite directions. The shortest oxygen–oxygen separation between neighbouring mol­ecules amounts to 5.412 (3) Å. The oxygen–oxygen distance is an important factor determining the strength of through space exchange inter­actions of nitroxyls (Rajca et al. 2006[Rajca, A., Mukherjee, S., Pink, M. & Rajca, S. (2006). J. Am. Chem. Soc. 128, 13497-13507.]).

[Figure 2]
Figure 2
Crystal packing of the title compound viewed along the b axis. Weak C—H⋯O hydrogen bonds are shown as dashed lines
[Figure 3]
Figure 3
Crystal packing of the title compound viewed along the c axis.
[Figure 4]
Figure 4
Crystal packing of the title compound viewed along the a axis.
[Figure 5]
Figure 5
Closest distances between pyridine rings and edge-on C—H⋯π contact.

4. Database survey

The Cambridge Structural Database (CSD, Version 5.36; Groom & Allen, 2014[Groom, C. R. & Allen, F. H. (2014). Angew. Chem. Int. Ed. 53, 662-671.]) has been queried to find other terpyridine or 2,2,5,5-tetra­methyl-N-oxyl-3-pyrroline derivatives. The terpyridine query revealed 3473 entries in the CSD if metal complexes of terpyridine were included. For purely organic terpyridine compounds, the number of hits was reduced to 348. Only 33 results for 2,2,5,5-tetra­methyl-N-oxyl-3-pyrroline derivatives were found in the CSD. A combined query for structures which include both terpyridine and 2,2,5,5-tetra­methyl-N-oxyl-3-pyrroline derivatives did not result in any hit. However, the authors are aware of at least one published crystal structure of a compound which contains both structural motifs (Ackermann et al., 2015[Ackermann, K., Giannoulis, A., Cordes, D. B., Slawin, A. M. Z. & Bode, B. E. (2015). Chem. Commun. 51, 5257-5260.]).

5. Synthesis and crystallization

The title compound (1) is formed from 3-ethinyl-2,2,5,5-tetra­methyl-3-pyrroline-N-oxyl and 4′-(4-bromo­phen­yl)-2,2′:6′,2′′-terpyridine using a Sonogashira–Hagihara cross-coupling reaction, as shown in Fig. 6[link]. 222 mg (0.57 mmol) of 4′-(4-bromo­phen­yl)-2,2′:6′,2′′-terpyridine, 100 mg (0.61 mmol) of 3-ethinyl-2,2,5,5-tetra­methyl-3-pyrroline-N-oxyl, 20 mg (0.076 mmol) of PPh3 and 40 mg (0.035 mmol) of Pd(PPh3)4 were dissolved in 17 ml of i-Pr2NH and stirred at 313 K, yielding a yellow solution which turned orange over the course of 5 min. Additionally, an orange precipitate was formed simultaneously. After 5.5 h, 2 ml of di­methyl­formamide were added to the orange suspension. The stirring at 313 K was continued for 16 h, after which time the solvents were removed under reduced pressure. The orange residues were suspended in a mixture of di­chloro­methane and cyclo­hexane (1:2) and subsequently subjected to column chromatography using aluminum oxide as stationary phase. A mixture of di­chloro­methane and cyclo­hexane was used as eluent. The volumetric ratio of both solvents was changed stepwise during the purification (from 1:8 to 8:1). The desired product was obtained in a yellow fraction and could be isolated by removing the eluents under reduced pressure (yield 80%). The crystallization of (1) was achieved by slow evaporation of a solution of (1) in a 1:1 mixture of aceto­nitrile and di­chloro­methane. 4′-(4-Bromo­phen­yl)-2,2′:6′,2′′-terpyridine was purchased from TCI Europe. 3-Ethinyl-2,2,5,5-tetra­methyl-3-pyrroline-N-oxyl was synthesized as described by Schiemann et al. (2007[Schiemann, O., Piton, N., Plackmeyer, J., Bode, B. E., Prisner, T. F. & Engels, J. W. (2007). Nat. Protoc. 2, 904-923.]).

[Figure 6]
Figure 6
Scheme illustrating the synthesis of (1).

6. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2[link]. All H atoms were fixed geometrically and allowed to ride on their parent C atoms, with 0.98 Å with Uiso(H) = 1.5Ueq(C) for methyl H atoms and C—H = 0.95 Å and Uiso(H) = 1.2Ueq(C) for all other H atoms.

Table 2
Experimental details

Crystal data
Chemical formula C31H27N4O
Mr 471.56
Crystal system, space group Monoclinic, P21/c
Temperature (K) 123
a, b, c (Å) 18.5666 (8), 20.2009 (9), 6.7749 (2)
β (°) 92.743 (3)
V (Å3) 2538.10 (17)
Z 4
Radiation type Mo Kα
μ (mm−1) 0.08
Crystal size (mm) 0.34 × 0.12 × 0.08
 
Data collection
Diffractometer Nonius KappaCCD
Absorption correction Multi-scan (Blessing, 1995[Blessing, R. H. (1995). Acta Cryst. A51, 33-38.])
Tmin, Tmax 0.883, 1.078
No. of measured, independent and observed [I > 2σ(I)] reflections 35758, 6691, 3221
Rint 0.118
(sin θ/λ)max (Å−1) 0.685
 
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.049, 0.122, 0.89
No. of reflections 6691
No. of parameters 329
H-atom treatment H-atom parameters constrained
Δρmax, Δρmin (e Å−3) 0.19, −0.23
Computer programs: DENZO and SCALEPACK (Otwinowski & Minor, 1997[Otwinowski, Z. & Minor, W. (1997). Methods in Enzymology, Vol. 276, Macromolecular Crystallography, Part A, edited by C. W. Carter Jr & R. M. Sweet, pp. 307-326. New York: Academic Press.]), SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]), SHELXL97 (Sheldrick, 2015[Sheldrick, G. M. (2015). Acta Cryst. C71, 3-8.]) and OLEX2 (Dolomanov et al., 2009[Dolomanov, O. V., Bourhis, L. J., Gildea, R. J., Howard, J. A. K. & Puschmann, H. (2009). J. Appl. Cryst. 42, 339-341.]).

Supporting information

CCDC reference: 1408457

Crystal structure: contains datablock I. DOI: 10.1107/S2056989015012086/lh5769sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S2056989015012086/lh5769Isup2.hkl

Supporting information file. DOI: 10.1107/S2056989015012086/lh5769Isup3.cdx

checkCIF report


Chemical context top

The title compound, (1), was synthesized as a ligand for 3d metal ions in the framework of a pulsed EPR study on metal–nitroxyl model systems. The molecule contains a paramagnetic nitroxyl group and a terpyridine group. Nitroxyls have been the subject of magnetic studies in which exchange inter­actions have been detected (see, for example, Rajca et al., 2006; Fritscher et al., 2002). Furthermore, nitroxyls are used as spin labels for structural investigations of biological macromolecules (Reginsson & Schiemann, 2011). The structures of terpyridines have been investigated by Fallahpour et al. (1999), Eryazici et al. (2006), Bessel et al. (1992) and Grave et al. (2003) to name a few examples. The terpyridine moiety is known to form complexes with various metals. Numerous studies on metal complexes of terpyridine have been conducted, examples include Hogg & Wilkins (1962), Constable et al. (1999), Narr et al. (2002) and Folgado et al. (1990).

Structural commentary top

The structure of the title compound (1) is shown in Fig.1. The terpyridine group of (1) assumes an all-transoid conformation and is essentially planar with angles between the mean planes of the central pyridine (N1, C1–C5, r.m.s deviation from the mean plane = 0.006 Å) and the two outer rings amounting to 3.87 (5)° (N4, C27–C31, r.m.s. deviation from the mean plane = 0.003 Å) and 1.98 (5)° (N2, C6–C10, r.m.s deviation from the mean plane = 0.006 Å), respectively. The pyrroline-N-oxyl unit commonly found for such nitroxyls is seen in the structure and its mean plane (N3, C19–C22, r.m.s deviation from the mean plane = 0.006 Å) subtends a dihedral angle of 88.44 (7)° to the mean plane of the central pyridine ring (for similar structural motifs, see Margraf et al., 2009 and Schuetz et al., 2010). Both subunits are linked by a 4-ethinylene­phenyl­ene group. The mean plane of the phenyl­ene group (C11–C16, r.m.s deviation from the mean plane < 0.001 Å) is tilted with respect to both the central pyridine ring [dihedral angle of 51.36 (5)°] and the pyrroline-N-oxyl [dihedral angle of 37.62 (7)°]. The angles C18—C17—C14 [177.35 (19)°] and C17—C18—C19 [175.64 (18)°] are slightly lower than the 180° expected for a strictly linear shape of the molecular backbone. Two close intra­molecular hydrogen–nitro­gen distances are observed between the two meta-protons of the central pyridine subunit and the nitro­gen atoms of the external pyridine rings (Table 1). Murguly et al. (1999) propose weak intra­molecular hydrogen bonds for these atoms. The intra­molecular separation between the chelating terpyridine group and the nitroxyl amounts to 14.120 (2) Å (measured between O1 and N1).

Supra­molecular features top

The packing within the crystal structure is shown in Figs. 2–4. The molecules are stacked in layers along [001] (Fig. 2.) The oxygen atom of the nitroxyl forms weak hydrogen bonds to the protons of the para-C—H group and the pyrroline C—H group of neighbouring molecules (Table 1). These hydrogen bonds span a two-dimensional network within the (010) plane (Figs. 3 and 4). π–π inter­actions are observed along [001] between the terpyridine subunits of neighbouring molecules (Figs. 3 and 5). These terpyridine subunits are arranged in a slipped face-to-face alignment (Janiak, 2000) with the shortest inter­molecular distances between the pyridine rings amounting to 3.700 (1) Å (measured from the centroid of N2, C6–C10 to the centroid of N4, C27–C31) and 3.781 (1) Å (centroid of N1, C1–C5 to the centroid of N4, C27–C31, see Fig. 5). Furthermore, the phenyl­ene rings of neighbouring molecules show an edge-on C—H···π inter­action along the same axis (Table 1 and Fig. 5). The nitroxyl groups are arranged in an alternating manner pointing in opposite directions. The shortest oxygen–oxygen separation between neighbouring molecules amounts to 5.412 (3) Å. The oxygen–oxygen distance is an important factor determining the strength of through space exchange inter­actions of nitroxyls (Rajca et al. 2006).

Database survey top

The Cambridge Structural Database (CSD, Version 5.36; Groom & Allen, 2014) has been queried to find other terpyridine or 2,2,5,5-tetra­methyl-N-oxyl-3-pyrroline derivatives. The terpyridine query revealed 3473 entries in the CSD if metal complexes of terpyridine were included. For purely organic terpyridine compounds, the number of hits was reduced to 348. Only 33 results for 2,2,5,5-tetra­methyl-N-oxyl-3-pyrroline derivatives were found in the CSD. A combined query for structures which include both terpyridine and 2,2,5,5-tetra­methyl-N-oxyl-3-pyrroline derivatives did not result in any hit. However, the authors are aware of at least one published crystal structure of a compound which contains both structural motifs (Ackermann et al., 2015).

Synthesis and crystallization top

The title compound (1) is formed from 3-ethinyl-2,2,5,5-tetra­methyl-3-pyrroline-N-oxyl and 4'-(4-bromo­phenyl)-2,2':6',2''-terpyridine using a Sonogashira–Hagihara cross-coupling reaction, as shown in Fig. 6. 222 mg (0.57 mmol) of 4'-(4-bromo­phenyl)-2,2':6',2''-terpyridine, 100 mg (0.61 mmol) of 3-ethinyl-2,2,5,5-tetra­methyl-3-pyrroline-N-oxyl, 20 mg (0.076 mmol) of PPh3 and 40 mg (0.035 mmol) of Pd(PPh3)4 were dissolved in 17 ml of i-Pr2NH and stirred at 313 K, yielding a yellow solution which turned orange over the course of 5 min. Additionally, an orange precipitate was formed simultaneously. After 5.5 h, 2 ml of di­methyl­formamide were added to the orange suspension. The stirring at 313 K was continued for 16 h, after which time the solvents were removed under reduced pressure. The orange residues were suspended in a mixture of di­chloro­methane and cyclo­hexane (1:2) and subsequently subjected to column chromatography using aluminum oxide as stationary phase. A mixture of di­chloro­methane and cyclo­hexane was used as eluent. The volumetric ratio of both solvents was changed stepwise during the purification (from 1:8 to 8:1). The desired product was obtained in a yellow fraction and could be isolated by removing the eluents under reduced pressure (yield 80%). The crystallization of (1) was achieved by slow evaporation of a solution of (1) in a 1:1 mixture of aceto­nitrile and di­chloro­methane. 4'-(4-Bromo­phenyl)-2,2':6',2''-terpyridine was purchased from TCI Europe. 3-Ethinyl-2,2,5,5-tetra­methyl- 3-pyrroline-N-oxyl was synthesized as described by Schiemann et al. (2007).

Refinement top

Crystal data, data collection and structure refinement details are summarized in Table 2. All H atoms were fixed geometrically and allowed to ride on their parent C atoms, with 0.98 Å with Uiso(H) = 1.5Ueq(C) for methyl H atoms and C—H = 0.95 Å and Uiso(H) = 1.2Ueq(C) for all other H atoms.

Related literature top

For related literature, see: Ackermann et al. (2015); Bessel et al. (1992); Constable et al. (1999); Eryazici et al. (2006); Fallahpour et al. (1999); Folgado et al. (1990); Fritscher et al. (2002); Grave et al. (2003); Groom & Allen (2014); Hogg & Wilkins (1962); Janiak (2000); Margraf et al. (2009); Murguly et al. (1999); Narr et al. (2002); Rajca et al. (2006); Reginsson & Schiemann (2011); Schiemann et al. (2007); Schuetz et al. (2010);

Computing details top

Data collection: DENZO and SCALEPACK (Otwinowski & Minor, 1997); cell refinement: SCALEPACK (Otwinowski & Minor, 1997); data reduction: DENZO and SCALEPACK (Otwinowski & Minor, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2015); molecular graphics: OLEX2 (Dolomanov et al., 2009); software used to prepare material for publication: OLEX2 (Dolomanov et al., 2009).

Figures top
[Figure 1] Fig. 1. The molecular structure of the title compound with displacement ellipsoids drawn at the 50% probability level. H atoms have been omitted for clarity.
[Figure 2] Fig. 2. Crystal packing of the title compound viewed along the b axis. Weak C—H···O hydrogen bonds are shown as dashed lines
[Figure 3] Fig. 3. Crystal packing of the title compound viewed along the c axis.
[Figure 4] Fig. 4. Crystal packing of the title compound viewed along the a axis.
[Figure 5] Fig. 5. Closest distances between pyridine rings and edge-on C—H···π contact.
[Figure 6] Fig. 6. Scheme illustrating the synthesis of (1).
4'-{4-[(2,2,5,5-Tetramethyl-N-oxyl-3-pyrrolin-3-yl)ethynyl]phenyl}-2,2':6',2''-terpyridine top
Crystal data top
C31H27N4OF(000) = 996
Mr = 471.56Dx = 1.234 Mg m−3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
a = 18.5666 (8) ÅCell parameters from 9616 reflections
b = 20.2009 (9) Åθ = 1.0–29.1°
c = 6.7749 (2) ŵ = 0.08 mm−1
β = 92.743 (3)°T = 123 K
V = 2538.10 (17) Å3Needle, clear yellow
Z = 40.34 × 0.12 × 0.08 mm
Data collection top
Nonius KappaCCD
diffractometer		6691 independent reflections
Radiation source: sealed tube3221 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.118
Detector resolution: 8 pixels mm-1θmax = 29.2°, θmin = 3.0°
fine slicing ω and ϕ scansh = −25→24
Absorption correction: multi-scan
(Blessing, 1995)		k = −24→27
Tmin = 0.883, Tmax = 1.078l = −9→6
35758 measured reflections
Refinement top
Refinement on F20 restraints
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.049H-atom parameters constrained
wR(F2) = 0.122 w = 1/[σ2(Fo2) + (0.052P)2]
where P = (Fo2 + 2Fc2)/3
S = 0.89(Δ/σ)max < 0.001
6691 reflectionsΔρmax = 0.19 e Å−3
329 parametersΔρmin = −0.23 e Å−3
Crystal data top
C31H27N4OV = 2538.10 (17) Å3
Mr = 471.56Z = 4
Monoclinic, P21/cMo Kα radiation
a = 18.5666 (8) ŵ = 0.08 mm−1
b = 20.2009 (9) ÅT = 123 K
c = 6.7749 (2) Å0.34 × 0.12 × 0.08 mm
β = 92.743 (3)°
Data collection top
Nonius KappaCCD
diffractometer		6691 independent reflections
Absorption correction: multi-scan
(Blessing, 1995)		3221 reflections with I > 2σ(I)
Tmin = 0.883, Tmax = 1.078Rint = 0.118
35758 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0490 restraints
wR(F2) = 0.122H-atom parameters constrained
S = 0.89Δρmax = 0.19 e Å−3
6691 reflectionsΔρmin = −0.23 e Å−3
329 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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
O10.58556 (7)0.39166 (8)0.02921 (17)0.0449 (4)
N1−0.08706 (7)0.29387 (7)0.87301 (18)0.0235 (3)
N2−0.09424 (7)0.47223 (8)0.87295 (19)0.0264 (4)
N30.55647 (8)0.38695 (8)0.1947 (2)0.0332 (4)
N4−0.01906 (7)0.12743 (7)0.83306 (19)0.0262 (3)
C1−0.06315 (9)0.35653 (9)0.8599 (2)0.0221 (4)
C20.00840 (9)0.37160 (9)0.8258 (2)0.0228 (4)
H20.02340.41640.81580.027*
C30.05751 (9)0.32063 (9)0.8067 (2)0.0224 (4)
C40.03323 (9)0.25616 (9)0.8239 (2)0.0236 (4)
H40.06580.22020.81490.028*
C5−0.03946 (9)0.24445 (9)0.8545 (2)0.0223 (4)
C6−0.11788 (9)0.40962 (9)0.8820 (2)0.0244 (4)
C7−0.19006 (9)0.39411 (9)0.9094 (2)0.0280 (4)
H7−0.20540.34930.91300.034*
C8−0.23880 (10)0.44516 (10)0.9310 (2)0.0316 (5)
H8−0.28820.43590.94940.038*
C9−0.21466 (10)0.50989 (10)0.9254 (2)0.0319 (5)
H9−0.24670.54590.94260.038*
C10−0.14220 (10)0.52080 (9)0.8941 (2)0.0292 (4)
H10−0.12580.56530.88720.035*
C110.13389 (9)0.33241 (9)0.7586 (2)0.0228 (4)
C120.14938 (9)0.37194 (9)0.5973 (2)0.0260 (4)
H120.11130.39370.52450.031*
C130.21936 (9)0.37982 (9)0.5426 (2)0.0273 (4)
H130.22900.40690.43230.033*
C140.27657 (9)0.34827 (9)0.6476 (2)0.0244 (4)
C150.26114 (9)0.30872 (9)0.8088 (2)0.0273 (4)
H150.29920.28700.88180.033*
C160.19076 (9)0.30096 (9)0.8632 (2)0.0273 (4)
H160.18100.27380.97330.033*
C170.34837 (10)0.35565 (9)0.5825 (2)0.0275 (4)
C180.40740 (9)0.36297 (9)0.5209 (2)0.0294 (4)
C190.47510 (9)0.37261 (9)0.4332 (2)0.0267 (4)
C200.47826 (9)0.37532 (10)0.2098 (2)0.0294 (4)
C210.59915 (9)0.38953 (10)0.3860 (2)0.0305 (4)
C220.53960 (9)0.38011 (10)0.5256 (3)0.0308 (4)
H220.54710.37960.66530.037*
C230.45763 (11)0.30952 (11)0.1131 (3)0.0445 (6)
H23A0.46430.3122−0.02930.067*
H23B0.40700.29970.13570.067*
H23C0.48830.27430.17060.067*
C240.43549 (11)0.43246 (11)0.1165 (3)0.0444 (6)
H24A0.45110.47410.17910.067*
H24B0.38400.42570.13540.067*
H24C0.44380.4344−0.02520.067*
C250.63565 (10)0.45658 (10)0.4093 (3)0.0374 (5)
H25A0.66860.46310.30230.056*
H25B0.66280.45840.53680.056*
H25C0.59900.49150.40390.056*
C260.65362 (10)0.33278 (11)0.3968 (3)0.0421 (5)
H26A0.62800.29040.38490.063*
H26B0.68120.33440.52360.063*
H26C0.68660.33710.28870.063*
C27−0.06712 (9)0.17596 (9)0.8639 (2)0.0230 (4)
C28−0.13860 (9)0.16253 (9)0.9022 (2)0.0268 (4)
H28−0.17140.19760.92380.032*
C29−0.16099 (10)0.09759 (9)0.9083 (2)0.0295 (4)
H29−0.20950.08730.93480.035*
C30−0.11244 (10)0.04767 (9)0.8756 (2)0.0295 (4)
H30−0.12680.00250.87890.035*
C31−0.04244 (10)0.06489 (9)0.8381 (2)0.0290 (4)
H31−0.00910.03040.81450.035*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0353 (8)0.0713 (12)0.0294 (7)−0.0087 (7)0.0138 (6)−0.0024 (7)
N10.0240 (8)0.0271 (9)0.0196 (7)0.0008 (7)0.0026 (6)−0.0010 (6)
N20.0257 (9)0.0283 (10)0.0253 (7)0.0025 (7)0.0029 (6)0.0004 (6)
N30.0245 (9)0.0507 (12)0.0250 (8)−0.0073 (8)0.0075 (6)−0.0021 (7)
N40.0273 (8)0.0282 (10)0.0231 (7)−0.0011 (7)0.0018 (6)−0.0003 (6)
C10.0209 (10)0.0277 (11)0.0179 (8)−0.0020 (8)0.0016 (6)0.0002 (7)
C20.0224 (9)0.0242 (10)0.0219 (8)−0.0020 (8)0.0033 (6)0.0002 (7)
C30.0188 (9)0.0301 (11)0.0183 (8)−0.0022 (8)0.0025 (6)0.0000 (7)
C40.0218 (10)0.0274 (11)0.0221 (8)0.0017 (8)0.0043 (7)0.0012 (7)
C50.0218 (9)0.0284 (11)0.0171 (7)−0.0018 (8)0.0032 (6)0.0008 (7)
C60.0234 (10)0.0314 (11)0.0187 (8)0.0007 (8)0.0029 (7)0.0003 (7)
C70.0239 (10)0.0345 (12)0.0259 (9)−0.0004 (9)0.0041 (7)0.0001 (8)
C80.0225 (10)0.0445 (14)0.0282 (9)0.0035 (9)0.0055 (7)0.0023 (8)
C90.0287 (11)0.0387 (13)0.0285 (9)0.0104 (9)0.0040 (7)0.0033 (8)
C100.0329 (11)0.0287 (11)0.0261 (9)0.0028 (9)0.0018 (7)0.0013 (8)
C110.0207 (9)0.0234 (10)0.0243 (8)−0.0003 (8)0.0026 (7)−0.0023 (7)
C120.0234 (10)0.0253 (11)0.0293 (9)0.0017 (8)0.0020 (7)0.0017 (7)
C130.0241 (10)0.0316 (11)0.0267 (9)−0.0001 (8)0.0053 (7)0.0062 (8)
C140.0204 (9)0.0255 (11)0.0277 (9)−0.0011 (8)0.0060 (7)−0.0007 (7)
C150.0213 (10)0.0310 (11)0.0297 (9)0.0007 (8)0.0011 (7)0.0040 (8)
C160.0244 (10)0.0314 (11)0.0263 (9)−0.0024 (8)0.0035 (7)0.0049 (8)
C170.0261 (11)0.0279 (11)0.0288 (9)−0.0010 (8)0.0035 (8)0.0025 (7)
C180.0257 (11)0.0320 (12)0.0306 (9)−0.0015 (9)0.0031 (8)0.0027 (8)
C190.0216 (10)0.0292 (11)0.0302 (9)−0.0006 (8)0.0085 (7)0.0005 (8)
C200.0206 (10)0.0379 (12)0.0300 (9)−0.0058 (9)0.0042 (7)0.0007 (8)
C210.0208 (10)0.0406 (13)0.0304 (9)−0.0031 (9)0.0039 (7)−0.0028 (8)
C220.0236 (10)0.0409 (13)0.0281 (9)−0.0031 (9)0.0047 (7)−0.0003 (8)
C230.0447 (13)0.0543 (15)0.0347 (11)−0.0176 (11)0.0054 (9)−0.0079 (10)
C240.0350 (12)0.0571 (16)0.0414 (11)0.0052 (11)0.0050 (9)0.0139 (10)
C250.0267 (11)0.0446 (14)0.0416 (11)−0.0060 (9)0.0078 (8)−0.0031 (9)
C260.0297 (11)0.0444 (14)0.0526 (13)0.0000 (10)0.0070 (9)0.0015 (10)
C270.0229 (10)0.0299 (11)0.0164 (8)0.0001 (8)0.0006 (6)0.0003 (7)
C280.0234 (10)0.0322 (12)0.0248 (9)−0.0010 (9)0.0023 (7)0.0017 (8)
C290.0245 (10)0.0365 (12)0.0276 (9)−0.0069 (9)0.0024 (7)0.0021 (8)
C300.0336 (11)0.0279 (11)0.0270 (9)−0.0070 (9)0.0007 (7)0.0022 (8)
C310.0327 (11)0.0270 (11)0.0273 (9)−0.0020 (9)0.0011 (7)−0.0019 (8)
Geometric parameters (Å, º) top
O1—N31.2712 (17)C15—H150.9500
N1—C11.346 (2)C15—C161.383 (2)
N1—C51.343 (2)C16—H160.9500
N2—C61.341 (2)C17—C181.200 (2)
N2—C101.337 (2)C18—C191.429 (2)
N3—C201.479 (2)C19—C201.519 (2)
N3—C211.487 (2)C19—C221.333 (2)
N4—C271.349 (2)C20—C231.523 (3)
N4—C311.337 (2)C20—C241.521 (3)
C1—C21.393 (2)C21—C221.501 (2)
C1—C61.490 (2)C21—C251.519 (3)
C2—H20.9500C21—C261.528 (3)
C2—C31.386 (2)C22—H220.9500
C3—C41.385 (2)C23—H23A0.9800
C3—C111.489 (2)C23—H23B0.9800
C4—H40.9500C23—H23C0.9800
C4—C51.396 (2)C24—H24A0.9800
C5—C271.478 (2)C24—H24B0.9800
C6—C71.397 (2)C24—H24C0.9800
C7—H70.9500C25—H25A0.9800
C7—C81.384 (2)C25—H25B0.9800
C8—H80.9500C25—H25C0.9800
C8—C91.383 (3)C26—H26A0.9800
C9—H90.9500C26—H26B0.9800
C9—C101.389 (2)C26—H26C0.9800
C10—H100.9500C27—C281.391 (2)
C11—C121.395 (2)C28—H280.9500
C11—C161.396 (2)C28—C291.377 (2)
C12—H120.9500C29—H290.9500
C12—C131.377 (2)C29—C301.377 (3)
C13—H130.9500C30—H300.9500
C13—C141.403 (2)C30—C311.381 (2)
C14—C151.394 (2)C31—H310.9500
C14—C171.432 (2)
C5—N1—C1118.19 (14)C22—C19—C18127.46 (16)
C10—N2—C6117.76 (15)C22—C19—C20112.80 (15)
O1—N3—C20122.18 (13)N3—C20—C1999.16 (13)
O1—N3—C21122.33 (13)N3—C20—C23109.66 (15)
C20—N3—C21115.43 (12)N3—C20—C24110.21 (15)
C31—N4—C27117.70 (15)C19—C20—C23112.11 (16)
N1—C1—C2122.47 (16)C19—C20—C24113.40 (16)
N1—C1—C6116.22 (15)C24—C20—C23111.60 (16)
C2—C1—C6121.31 (16)N3—C21—C2299.62 (13)
C1—C2—H2120.3N3—C21—C25109.78 (15)
C3—C2—C1119.35 (16)N3—C21—C26109.83 (15)
C3—C2—H2120.3C22—C21—C25112.68 (15)
C2—C3—C11122.65 (16)C22—C21—C26112.36 (16)
C4—C3—C2118.22 (15)C25—C21—C26111.89 (15)
C4—C3—C11119.06 (15)C19—C22—C21112.98 (15)
C3—C4—H4120.2C19—C22—H22123.5
C3—C4—C5119.52 (17)C21—C22—H22123.5
C5—C4—H4120.2C20—C23—H23A109.5
N1—C5—C4122.23 (16)C20—C23—H23B109.5
N1—C5—C27117.40 (15)C20—C23—H23C109.5
C4—C5—C27120.36 (16)H23A—C23—H23B109.5
N2—C6—C1116.62 (15)H23A—C23—H23C109.5
N2—C6—C7122.39 (16)H23B—C23—H23C109.5
C7—C6—C1120.99 (17)C20—C24—H24A109.5
C6—C7—H7120.6C20—C24—H24B109.5
C8—C7—C6118.88 (18)C20—C24—H24C109.5
C8—C7—H7120.6H24A—C24—H24B109.5
C7—C8—H8120.4H24A—C24—H24C109.5
C9—C8—C7119.14 (17)H24B—C24—H24C109.5
C9—C8—H8120.4C21—C25—H25A109.5
C8—C9—H9120.9C21—C25—H25B109.5
C8—C9—C10118.13 (17)C21—C25—H25C109.5
C10—C9—H9120.9H25A—C25—H25B109.5
N2—C10—C9123.68 (18)H25A—C25—H25C109.5
N2—C10—H10118.2H25B—C25—H25C109.5
C9—C10—H10118.2C21—C26—H26A109.5
C12—C11—C3119.82 (15)C21—C26—H26B109.5
C12—C11—C16118.62 (15)C21—C26—H26C109.5
C16—C11—C3121.41 (15)H26A—C26—H26B109.5
C11—C12—H12119.7H26A—C26—H26C109.5
C13—C12—C11120.64 (16)H26B—C26—H26C109.5
C13—C12—H12119.7N4—C27—C5116.10 (15)
C12—C13—H13119.6N4—C27—C28122.10 (17)
C12—C13—C14120.79 (16)C28—C27—C5121.80 (16)
C14—C13—H13119.6C27—C28—H28120.5
C13—C14—C17119.32 (15)C29—C28—C27118.90 (17)
C15—C14—C13118.61 (15)C29—C28—H28120.5
C15—C14—C17122.03 (16)C28—C29—H29120.3
C14—C15—H15119.8C28—C29—C30119.45 (17)
C16—C15—C14120.38 (16)C30—C29—H29120.3
C16—C15—H15119.8C29—C30—H30120.9
C11—C16—H16119.5C29—C30—C31118.29 (18)
C15—C16—C11120.96 (16)C31—C30—H30120.9
C15—C16—H16119.5N4—C31—C30123.55 (17)
C18—C17—C14177.35 (19)N4—C31—H31118.2
C17—C18—C19175.64 (18)C30—C31—H31118.2
C18—C19—C20119.74 (15)
O1—N3—C20—C19178.70 (16)C6—C7—C8—C9−0.2 (2)
O1—N3—C20—C2361.1 (2)C7—C8—C9—C101.3 (2)
O1—N3—C20—C24−62.1 (2)C8—C9—C10—N2−1.4 (2)
O1—N3—C21—C22−178.63 (17)C10—N2—C6—C1−179.46 (13)
O1—N3—C21—C2562.9 (2)C10—N2—C6—C71.0 (2)
O1—N3—C21—C26−60.5 (2)C11—C3—C4—C5−175.31 (13)
N1—C1—C2—C3−0.7 (2)C11—C12—C13—C140.0 (3)
N1—C1—C6—N2178.75 (13)C12—C11—C16—C150.1 (3)
N1—C1—C6—C7−1.7 (2)C12—C13—C14—C150.0 (3)
N1—C5—C27—N4176.14 (13)C12—C13—C14—C17177.81 (16)
N1—C5—C27—C28−3.8 (2)C13—C14—C15—C160.0 (3)
N2—C6—C7—C8−1.0 (2)C14—C15—C16—C11−0.1 (3)
N3—C21—C22—C190.7 (2)C16—C11—C12—C13−0.1 (3)
N4—C27—C28—C29−0.1 (2)C17—C14—C15—C16−177.74 (17)
C1—N1—C5—C40.5 (2)C18—C19—C20—N3178.91 (16)
C1—N1—C5—C27−178.37 (13)C18—C19—C20—C23−65.4 (2)
C1—C2—C3—C4−0.5 (2)C18—C19—C20—C2462.1 (2)
C1—C2—C3—C11176.34 (14)C18—C19—C22—C21−179.71 (19)
C1—C6—C7—C8179.43 (14)C20—N3—C21—C22−1.4 (2)
C2—C1—C6—N2−1.8 (2)C20—N3—C21—C25−119.89 (17)
C2—C1—C6—C7177.78 (15)C20—N3—C21—C26116.68 (17)
C2—C3—C4—C51.6 (2)C20—C19—C22—C210.1 (2)
C2—C3—C11—C12−51.0 (2)C21—N3—C20—C191.5 (2)
C2—C3—C11—C16133.51 (18)C21—N3—C20—C23−116.05 (17)
C3—C4—C5—N1−1.7 (2)C21—N3—C20—C24120.71 (17)
C3—C4—C5—C27177.14 (13)C22—C19—C20—N3−1.0 (2)
C3—C11—C12—C13−175.65 (16)C22—C19—C20—C23114.73 (18)
C3—C11—C16—C15175.58 (16)C22—C19—C20—C24−117.78 (18)
C4—C3—C11—C12125.74 (17)C25—C21—C22—C19117.02 (18)
C4—C3—C11—C16−49.7 (2)C26—C21—C22—C19−115.47 (18)
C4—C5—C27—N4−2.7 (2)C27—N4—C31—C30−0.9 (2)
C4—C5—C27—C28177.36 (14)C27—C28—C29—C30−0.3 (2)
C5—N1—C1—C20.7 (2)C28—C29—C30—C310.1 (2)
C5—N1—C1—C6−179.79 (13)C29—C30—C31—N40.5 (2)
C5—C27—C28—C29179.78 (14)C31—N4—C27—C5−179.19 (13)
C6—N2—C10—C90.3 (2)C31—N4—C27—C280.7 (2)
C6—C1—C2—C3179.82 (13)
Hydrogen-bond geometry (Å, º) top
Cg is the centroid of the C11–C16 ring.
D—H···AD—HH···AD···AD—H···A
C2—H2···N20.952.502.815 (2)99
C4—H4···N40.952.462.778 (2)100
C8—H8···O1i0.952.593.529 (2)170
C16—H16···Cgii0.952.813.669 (2)151
C22—H22···O1iii0.952.553.485 (2)170
Symmetry codes: (i) x−1, y, z+1; (ii) x, −y+1/2, z+1/2; (iii) x, y, z+1.
Hydrogen-bond geometry (Å, º) top
Cg is the centroid of the C11–C16 ring.
D—H···AD—HH···AD···AD—H···A
C2—H2···N20.952.502.815 (2)99.1
C4—H4···N40.952.462.778 (2)99.7
C8—H8···O1i0.952.593.529 (2)169.9
C16—H16···Cgii0.952.813.669 (2)151.4
C22—H22···O1iii0.952.553.485 (2)170.0
Symmetry codes: (i) x−1, y, z+1; (ii) x, −y+1/2, z+1/2; (iii) x, y, z+1.

Experimental details

Crystal data
Chemical formulaC31H27N4O
Mr471.56
Crystal system, space groupMonoclinic, P21/c
Temperature (K)123
a, b, c (Å)18.5666 (8), 20.2009 (9), 6.7749 (2)
β (°) 92.743 (3)
V (Å3)2538.10 (17)
Z4
Radiation typeMo Kα
µ (mm−1)0.08
Crystal size (mm)0.34 × 0.12 × 0.08
Data collection
DiffractometerNonius KappaCCD
diffractometer
Absorption correctionMulti-scan
(Blessing, 1995)
Tmin, Tmax0.883, 1.078
No. of measured, independent and
observed [I > 2σ(I)] reflections		35758, 6691, 3221
Rint0.118
(sin θ/λ)max (Å−1)0.685
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.049, 0.122, 0.89
No. of reflections6691
No. of parameters329
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å−3)0.19, −0.23

Computer programs: DENZO and SCALEPACK (Otwinowski & Minor, 1997), SCALEPACK (Otwinowski & Minor, 1997), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2015), OLEX2 (Dolomanov et al., 2009).

 

Acknowledgements

The authors thank Professor Dr A. C. Filippou for providing X-ray infrastructure. OS thanks the DFG for funding via SFB 813.

References

First citationAckermann, K., Giannoulis, A., Cordes, D. B., Slawin, A. M. Z. & Bode, B. E. (2015). Chem. Commun. 51, 5257–5260.  CSD CrossRef CAS Google Scholar
 First citationBessel, C. A., See, R. F., Jameson, D. L., Churchill, M. R. & Takeuchi, K. J. (1992). J. Chem. Soc. Dalton Trans. pp. 3223–3228.  CSD CrossRef Web of Science Google Scholar
 First citationBlessing, R. H. (1995). Acta Cryst. A51, 33–38.  CrossRef CAS Web of Science IUCr Journals Google Scholar
 First citationConstable, E. C., Baum, G., Bill, E., Dyson, R., van Eldik, R., Fenske, D., Kaderli, D., Morris, D., Neubrand, A., Neuburger, M., Smith, D. R., Wieghardt, K., Zehnder, M. & Zuberbühler, A. D. (1999). Chem. Eur. J. 5, 498–508.  CrossRef CAS Google Scholar
 First citationDolomanov, O. V., Bourhis, L. J., Gildea, R. J., Howard, J. A. K. & Puschmann, H. (2009). J. Appl. Cryst. 42, 339–341.  Web of Science CrossRef CAS IUCr Journals Google Scholar
 First citationEryazici, I., Moorefield, C. N., Durmus, S. & Newkome, G. R. (2006). J. Org. Chem. 71, 1009–1014.  Web of Science CSD CrossRef PubMed CAS Google Scholar
 First citationFallahpour, R.-A., Neuburger, M. & Zehnder, M. (1999). Polyhedron, 18, 2445–2454.  Web of Science CSD CrossRef CAS Google Scholar
 First citationFolgado, J. V., Henke, W., Allmann, R., Stratemeier, H., Beltrán-Porter, D., Rojo, T. & Reinen, D. (1990). Inorg. Chem. 29, 2035–2042.  CSD CrossRef CAS Google Scholar
 First citationFritscher, J., Beyer, M. & Schiemann, O. (2002). Chem. Phys. Lett. 364, 393–401.  Web of Science CSD CrossRef CAS Google Scholar
 First citationGrave, C., Lentz, D., Schäfer, A., Samorì, P., Rabe, P. J., Franke, P. & Schlüter, A. D. (2003). J. Am. Chem. Soc. 125, 6907–6918.  CSD CrossRef PubMed CAS Google Scholar
 First citationGroom, C. R. & Allen, F. H. (2014). Angew. Chem. Int. Ed. 53, 662–671.  Web of Science CrossRef CAS Google Scholar
 First citationHogg, R. & Wilkins, R. G. (1962). J. Chem. Soc. pp. 341–350.  CrossRef Google Scholar
 First citationJaniak, C. (2000). J. Chem. Soc. Dalton Trans. pp. 3885–3896.  Web of Science CrossRef Google Scholar
 First citationMargraf, D., Schuetz, D., Prisner, T. F. & Bats, J. W. (2009). Acta Cryst. E65, o1784.  Web of Science CSD CrossRef IUCr Journals Google Scholar
 First citationMurguly, E., Norsten, T. B. & Branda, N. (1999). J. Chem. Soc. Perkin Trans. 2, pp. 2789–2794.  CSD CrossRef Google Scholar
 First citationNarr, E., Godt, A. & Jeschke, G. (2002). Angew. Chem. Int. Ed. 41, 3907–3910.  CrossRef CAS Google Scholar
 First citationOtwinowski, Z. & Minor, W. (1997). Methods in Enzymology, Vol. 276, Macromolecular Crystallography, Part A, edited by C. W. Carter Jr & R. M. Sweet, pp. 307–326. New York: Academic Press.  Google Scholar
 First citationRajca, A., Mukherjee, S., Pink, M. & Rajca, S. (2006). J. Am. Chem. Soc. 128, 13497–13507.  CSD CrossRef PubMed CAS Google Scholar
 First citationReginsson, G. W. & Schiemann, O. (2011). Biochem. Soc. Trans. 39, 128–139.  CrossRef CAS PubMed Google Scholar
 First citationSchiemann, O., Piton, N., Plackmeyer, J., Bode, B. E., Prisner, T. F. & Engels, J. W. (2007). Nat. Protoc. 2, 904–923.  Web of Science CrossRef PubMed CAS Google Scholar
 First citationSchuetz, D., Margraf, D., Prisner, T. F. & Bats, J. W. (2010). Acta Cryst. E66, o729–o730.  CrossRef IUCr Journals Google Scholar
 First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar
 First citationSheldrick, G. M. (2015). Acta Cryst. C71, 3–8.  Web of Science CrossRef IUCr Journals Google Scholar

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ISSN: 2056-9890
Volume 71| Part 7| July 2015| Pages 870-874
doi:10.1107/S2056989015012086
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