organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

Journal logoIUCrDATA
ISSN: 2414-3146

N-(3,5-Di­methyl­phen­yl)-P,P-di­phenyl­phosphinic amide

CROSSMARK_Color_square_no_text.svg

aDepartment of Chemistry, Southern Illinois University Edwardsville, Edwardsville, IL 62026-1652, USA, and bDepartment of Chemistry and Biochemistry, and Center of Nanoscience, University of Missouri-St. Louis, St. Louis, MO 63121-4400, USA
*Correspondence e-mail: myrjone@siue.edu

Edited by W. T. A. Harrison, University of Aberdeen, Scotland (Received 21 August 2018; accepted 22 August 2018; online 31 August 2018)

In the title compound, C20H20NOP, the P atom, with a distorted tetra­hedral geometry, is attached to an O atom, two phenyl groups, and a 3,5-di­methyl­aniline group. The N—P—C [102.29 (12) and 108.97 (12)°] and C—P—C [107.14 (12)°] bond angles are all smaller than the ideal 109.5° tetra­hedral bond angle, whereas the O—P—C [113.07 (12) and 110.62 (12)°] and O—P—N [114.24 (13)°] angles are all larger than 109.5°. A weak intra­molecular C—H⋯O hydrogen bond helps to establish the mol­ecular conformation. In the crystal, the mol­ecules are linked by N—H⋯O hydrogen bonds, generating [001] chains.

3D view (loading...)
[Scheme 3D1]
Chemical scheme
[Scheme 1]

Structure description

Phosphinamide derivatives have applications as ligands in transition and rare earth metal chemistry and in catalysis (Priya et al., 2005[Priya, S., Balakrishna, M. S. & Mobin, S. M. (2005). Polyhedron, 24, 1641-1650.]; Gusev et al., 2009[Gusev, O. V., Ustynyuk, N. A., Peganova, T. A., Gonchar, A. V., Petrovskii, P. V. & Lyssenko, K. A. (2009). Phosphorus Sulfur Silicon, 184, 322-331.]; Naktode et al., 2012[Naktode, K., Kottalanka, R. K. & Panda, T. K. (2012). New J. Chem. 36, 2280-2285.]; Naktode et al., 2013[Naktode, K., Kottalanka, R. K., Jana, S. K. & Panda, T. K. (2013). Z. Anorg. Allg. Chem. 639, 999-1003.]; Sun & Cramer, 2017[Sun, Y. & Cramer, N. (2017). Angew. Chem. Int. Ed. 56, 364-367.]) and are of general synthetic inter­est, partic­ularly in the pharmaceutical field (Xu et al., 2017[Xu, Y., Su, Q., Dong, W., Peng, Z. & An, D. (2017). Tetrahedron, 73, 4602-4609.]; Hong et al., 2016[Hong, G., Zhu, X., Hu, C., Aruma, A. N., Wu, S. & Wang, L. (2016). J. Org. Chem. 81, 6867-6874.]). As part of our studies in this area, the title compound was serendipitously isolated and its structure is reported here. Structures for the [Ph2P(O)NH(2,6-(CH3)2(C6H3)] structural isomer (Naktode et al., 2012[Naktode, K., Kottalanka, R. K. & Panda, T. K. (2012). New J. Chem. 36, 2280-2285.]) and related [Ph2P(O)NHPh] (Priya et al., 2005[Priya, S., Balakrishna, M. S. & Mobin, S. M. (2005). Polyhedron, 24, 1641-1650.]) are known.

The mol­ecular structure of the title compound is shown in Fig. 1[link]. The phospho­rus atom exhibits slightly distorted tetra­hedral geometry. The four P—X bonds [X = O:1.477 (2), N:1.653 (2), C:1.797 (3) and 1.803 (3) Å] are similar to those found in [Ph2P(O)NH(2,6-(CH3)2(C6H3)] and [Ph2P(O)NHPh] as are the bond angles about the phospho­rus atom. The N—P—C [102.29 (12) and 108.97 (12)°] and C—P—C [107.14 (12)°] angles are all slightly smaller than the ideal 109.5° bond angle for tetra­hedral geometry, while the O—P—C [113.07 (12) and 110.62 (12)°] and O—P—N [114.24 (13)°] bond angles are all larger than 109.5°. The N—H and P—O bonds are anti to each other, which facilitates the formation of an [001] chain of N—H⋯O hydrogen bonds (Table 1[link]) in the crystal (Fig. 2[link]). An intra­molecular C—H⋯O hydrogen bond in each mol­ecule helps to position the ring.

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
C2—H2⋯O1 0.95 2.48 3.148 (3) 128
N1—H1⋯O1i 0.88 2.12 2.788 (3) 133
Symmetry code: (i) [-x+{\script{3\over 2}}, y, z+{\script{1\over 2}}].
[Figure 1]
Figure 1
Mol­ecular structure of [Ph2P(O)NH(3,5-(CH3)2(C6H3)] with displacement ellipsoids drawn at the 50% probability level.
[Figure 2]
Figure 2
Unit-cell packing viewed along the b axis showing N—H⋯O hydrogen-bonding contacts as dotted lines.

Synthesis and crystallization

The title compound was obtained during our attempt to crystallize [(Ph2P)2N(3,5-(CH3)2(C6H3)], which had been prepared by a literature method (Shozi & Friedrich, 2012[Shozi, M. L. & Friedrich, H. B. (2012). S. Afr. J. Chem. 65, 214-222.]). A di­chloro­methane solution of [(Ph2P)2N(3,5-(CH3)2(C6H3)] was allowed to evaporate slowly at room temperature under argon. After 24 h, crystals suitable for single-crystal structure determination were obtained. However, [Ph2P(O)NH(3,5-(CH3)2(C6H3)] rather than the expected [(Ph2P)2N(3,5-(CH3)2(C6H3)] was serendipitously isolated. The title compound may have formed as a result of the adventitious exposure of the sample to moisture and/or oxygen.

Refinement

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

Table 2
Experimental details

Crystal data
Chemical formula C20H20NOP
Mr 321.34
Crystal system, space group Orthorhombic, Pca21
Temperature (K) 100
a, b, c (Å) 15.9713 (9), 10.7495 (7), 9.8286 (6)
V3) 1687.41 (18)
Z 4
Radiation type Mo Kα
μ (mm−1) 0.17
Crystal size (mm) 0.36 × 0.28 × 0.11
 
Data collection
Diffractometer Bruker SMART APEX CCD
Absorption correction Multi-scan (SADABS; Bruker, 2016[Bruker (2016). SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.])
Tmin, Tmax 0.829, 0.942
No. of measured, independent and observed [I > 2σ(I)] reflections 25376, 5327, 4160
Rint 0.061
(sin θ/λ)max−1) 0.725
 
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.048, 0.108, 1.04
No. of reflections 5327
No. of parameters 210
No. of restraints 1
H-atom treatment H-atom parameters constrained
Δρmax, Δρmin (e Å−3) 0.37, −0.38
Absolute structure Flack x determined using 1497 quotients [(I+)−(I)]/[(I+)+(I)] (Parsons et al., 2013[Parsons, S., Flack, H. D. & Wagner, T. (2013). Acta Cryst. B69, 249-259.])
Absolute structure parameter 0.07 (5)
Computer programs: APEX2 and SAINT (Bruker, 2013[Bruker (2013). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]), SHELXT2014 (Sheldrick, 2015a[Sheldrick, G. M. (2015a). Acta Cryst. A71, 3-8.]), SHELXL2016 (Sheldrick, 2015b[Sheldrick, G. M. (2015b). Acta Cryst. C71, 3-8.]), Mercury (Macrae et al., 2006[Macrae, C. F., Edgington, P. R., McCabe, P., Pidcock, E., Shields, G. P., Taylor, R., Towler, M. & van de Streek, J. (2006). J. Appl. Cryst. 39, 453-457.]) and SHELXTL (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]).

Structural data


Computing details top

Data collection: APEX2 (Bruker, 2013); cell refinement: SAINT (Bruker, 2013); data reduction: SAINT (Bruker, 2013); program(s) used to solve structure: SHELXT2014 (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2016 (Sheldrick, 2015b); molecular graphics: Mercury (Macrae et al., 2006); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

N-(3,5-Dimethylphenyl)-P,P-diphenylphosphinic amide top
Crystal data top
C20H20NOPDx = 1.265 Mg m3
Mr = 321.34Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, Pca21Cell parameters from 5345 reflections
a = 15.9713 (9) Åθ = 3.1–29.8°
b = 10.7495 (7) ŵ = 0.17 mm1
c = 9.8286 (6) ÅT = 100 K
V = 1687.41 (18) Å3Rectangular, colourless
Z = 40.36 × 0.28 × 0.11 mm
F(000) = 680
Data collection top
Bruker SMART APEX CCD
diffractometer
5327 independent reflections
Radiation source: sealed tube4160 reflections with I > 2σ(I)
Detector resolution: 8 pixels mm-1Rint = 0.061
ω and φ scansθmax = 31.0°, θmin = 1.9°
Absorption correction: multi-scan
(SADABS; Bruker, 2016)
h = 1623
Tmin = 0.829, Tmax = 0.942k = 1515
25376 measured reflectionsl = 1414
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: mixed
R[F2 > 2σ(F2)] = 0.048H-atom parameters constrained
wR(F2) = 0.108 w = 1/[σ2(Fo2) + (0.0495P)2 + 0.1102P]
where P = (Fo2 + 2Fc2)/3
S = 1.04(Δ/σ)max < 0.001
5327 reflectionsΔρmax = 0.37 e Å3
210 parametersΔρmin = 0.38 e Å3
1 restraintAbsolute structure: Flack x determined using 1497 quotients [(I+)-(I-)]/[(I+)+(I-)] (Parsons et al., 2013)
Primary atom site location: dualAbsolute structure parameter: 0.07 (5)
Special details top

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. All H atoms were positioned geometrically and refined using a riding model with C—H = 0.95–0.99 Å and with Uiso(H) = 1.2 (1.5 for methyl groups) times Ueq(C).

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
P10.69664 (4)0.49044 (6)0.38310 (8)0.01446 (14)
O10.70603 (12)0.5330 (2)0.2410 (2)0.0234 (5)
N10.71536 (13)0.5990 (2)0.4983 (2)0.0162 (5)
H10.7091590.5654870.5794400.019*
C10.68182 (15)0.7201 (2)0.5019 (3)0.0154 (5)
C20.63941 (14)0.7720 (2)0.3912 (3)0.0171 (5)
H20.6308380.7239250.3112690.020*
C30.60956 (15)0.8938 (3)0.3973 (3)0.0201 (6)
C40.62074 (16)0.9628 (3)0.5159 (3)0.0219 (6)
H40.5994811.0451870.5207520.026*
C50.66277 (16)0.9125 (3)0.6280 (3)0.0204 (6)
C60.69365 (15)0.7911 (3)0.6188 (3)0.0170 (5)
H60.7231960.7564590.6936380.020*
C70.56648 (18)0.9491 (3)0.2749 (3)0.0276 (7)
H7A0.6016770.9374690.1942490.041*
H7B0.5572221.0381540.2899940.041*
H7C0.5125260.9075740.2610020.041*
C80.67299 (19)0.9845 (3)0.7585 (3)0.0267 (7)
H8A0.6676921.0736690.7398480.040*
H8B0.7283430.9674490.7973120.040*
H8C0.6295860.9590410.8232770.040*
C90.77031 (15)0.3712 (2)0.4290 (3)0.0162 (5)
C100.85145 (16)0.3818 (3)0.3759 (4)0.0230 (6)
H100.8647810.4488420.3167080.028*
C110.91222 (16)0.2954 (3)0.4091 (3)0.0259 (7)
H110.9671110.3034520.3729580.031*
C120.89351 (17)0.1976 (3)0.4945 (3)0.0231 (6)
H120.9353530.1382660.5172170.028*
C130.81298 (18)0.1860 (3)0.5474 (3)0.0273 (7)
H130.7998570.1187410.6063240.033*
C140.75191 (18)0.2725 (3)0.5141 (3)0.0234 (6)
H140.6970040.2638920.5500830.028*
C150.59332 (15)0.4278 (2)0.4110 (3)0.0162 (5)
C160.54908 (17)0.4479 (3)0.5302 (3)0.0221 (6)
H160.5722310.4987760.5996680.026*
C170.47006 (18)0.3932 (3)0.5484 (4)0.0313 (7)
H170.4390770.4080130.6292560.038*
C180.43792 (18)0.3179 (3)0.4481 (4)0.0334 (8)
H180.3851940.2788450.4614490.040*
C190.48081 (19)0.2982 (3)0.3290 (4)0.0300 (7)
H190.4572700.2471310.2600430.036*
C200.55888 (17)0.3533 (3)0.3091 (3)0.0236 (6)
H200.5885240.3400670.2266040.028*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
P10.0130 (2)0.0162 (3)0.0142 (3)0.0003 (3)0.0002 (3)0.0005 (3)
O10.0247 (10)0.0268 (11)0.0188 (10)0.0004 (9)0.0030 (8)0.0033 (9)
N10.0179 (10)0.0146 (11)0.0159 (11)0.0010 (9)0.0010 (9)0.0010 (9)
C10.0107 (10)0.0155 (13)0.0200 (13)0.0019 (10)0.0017 (10)0.0025 (11)
C20.0134 (10)0.0191 (12)0.0187 (12)0.0023 (9)0.0009 (11)0.0014 (12)
C30.0118 (10)0.0211 (13)0.0274 (15)0.0015 (10)0.0026 (11)0.0083 (12)
C40.0133 (11)0.0161 (13)0.0363 (17)0.0004 (10)0.0060 (12)0.0008 (12)
C50.0135 (12)0.0194 (14)0.0283 (15)0.0023 (11)0.0063 (11)0.0044 (12)
C60.0130 (11)0.0187 (14)0.0194 (13)0.0005 (10)0.0010 (10)0.0025 (11)
C70.0234 (14)0.0248 (16)0.0346 (18)0.0019 (13)0.0025 (13)0.0111 (14)
C80.0235 (14)0.0218 (16)0.0349 (17)0.0004 (12)0.0031 (13)0.0110 (14)
C90.0133 (11)0.0161 (13)0.0192 (13)0.0010 (10)0.0005 (10)0.0052 (11)
C100.0190 (11)0.0216 (13)0.0285 (14)0.0002 (11)0.0067 (13)0.0015 (14)
C110.0145 (11)0.0259 (15)0.0374 (19)0.0016 (11)0.0037 (12)0.0072 (14)
C120.0199 (13)0.0233 (15)0.0260 (15)0.0070 (12)0.0054 (12)0.0077 (13)
C130.0258 (15)0.0233 (15)0.0328 (17)0.0039 (13)0.0029 (13)0.0084 (13)
C140.0151 (11)0.0228 (14)0.0322 (16)0.0009 (12)0.0047 (11)0.0046 (13)
C150.0134 (10)0.0177 (13)0.0176 (14)0.0022 (10)0.0019 (9)0.0004 (10)
C160.0206 (13)0.0248 (15)0.0209 (14)0.0001 (12)0.0035 (11)0.0010 (12)
C170.0227 (14)0.0325 (18)0.0387 (19)0.0000 (14)0.0128 (14)0.0061 (15)
C180.0132 (13)0.0242 (16)0.063 (2)0.0020 (12)0.0027 (14)0.0056 (17)
C190.0181 (13)0.0279 (18)0.0439 (19)0.0021 (13)0.0095 (13)0.0053 (15)
C200.0204 (13)0.0248 (16)0.0256 (14)0.0023 (12)0.0022 (12)0.0057 (12)
Geometric parameters (Å, º) top
P1—O11.477 (2)C9—C141.383 (4)
P1—N11.653 (2)C9—C101.402 (4)
P1—C91.797 (3)C10—C111.383 (4)
P1—C151.803 (3)C10—H100.9500
N1—C11.409 (3)C11—C121.378 (4)
N1—H10.8805C11—H110.9500
C1—C61.393 (4)C12—C131.393 (4)
C1—C21.397 (4)C12—H120.9500
C2—C31.395 (4)C13—C141.387 (4)
C2—H20.9500C13—H130.9500
C3—C41.393 (4)C14—H140.9500
C3—C71.507 (4)C15—C161.385 (4)
C4—C51.398 (4)C15—C201.395 (4)
C4—H40.9500C16—C171.404 (4)
C5—C61.398 (4)C16—H160.9500
C5—C81.507 (4)C17—C181.374 (5)
C6—H60.9500C17—H170.9500
C7—H7A0.9800C18—C191.373 (5)
C7—H7B0.9800C18—H180.9500
C7—H7C0.9800C19—C201.394 (4)
C8—H8A0.9800C19—H190.9500
C8—H8B0.9800C20—H200.9500
C8—H8C0.9800
O1—P1—N1114.24 (13)H8B—C8—H8C109.5
O1—P1—C9113.07 (12)C14—C9—C10119.0 (2)
N1—P1—C9102.29 (12)C14—C9—P1124.1 (2)
O1—P1—C15110.62 (12)C10—C9—P1117.0 (2)
N1—P1—C15108.97 (12)C11—C10—C9120.4 (3)
C9—P1—C15107.14 (12)C11—C10—H10119.8
C1—N1—P1126.92 (19)C9—C10—H10119.8
C1—N1—H1108.2C12—C11—C10120.3 (3)
P1—N1—H1108.1C12—C11—H11119.9
C6—C1—C2119.3 (2)C10—C11—H11119.9
C6—C1—N1118.4 (2)C11—C12—C13119.7 (3)
C2—C1—N1122.3 (2)C11—C12—H12120.2
C3—C2—C1120.4 (3)C13—C12—H12120.2
C3—C2—H2119.8C14—C13—C12120.1 (3)
C1—C2—H2119.8C14—C13—H13119.9
C4—C3—C2119.4 (3)C12—C13—H13119.9
C4—C3—C7121.1 (3)C9—C14—C13120.5 (3)
C2—C3—C7119.5 (3)C9—C14—H14119.7
C3—C4—C5121.0 (3)C13—C14—H14119.7
C3—C4—H4119.5C16—C15—C20119.7 (2)
C5—C4—H4119.5C16—C15—P1122.5 (2)
C6—C5—C4118.6 (3)C20—C15—P1117.8 (2)
C6—C5—C8119.7 (3)C15—C16—C17120.1 (3)
C4—C5—C8121.6 (3)C15—C16—H16120.0
C1—C6—C5121.1 (3)C17—C16—H16120.0
C1—C6—H6119.4C18—C17—C16119.4 (3)
C5—C6—H6119.4C18—C17—H17120.3
C3—C7—H7A109.5C16—C17—H17120.3
C3—C7—H7B109.5C19—C18—C17121.0 (3)
H7A—C7—H7B109.5C19—C18—H18119.5
C3—C7—H7C109.5C17—C18—H18119.5
H7A—C7—H7C109.5C18—C19—C20120.0 (3)
H7B—C7—H7C109.5C18—C19—H19120.0
C5—C8—H8A109.5C20—C19—H19120.0
C5—C8—H8B109.5C19—C20—C15119.7 (3)
H8A—C8—H8B109.5C19—C20—H20120.1
C5—C8—H8C109.5C15—C20—H20120.1
H8A—C8—H8C109.5
O1—P1—N1—C149.7 (2)C14—C9—C10—C110.5 (4)
C9—P1—N1—C1172.3 (2)P1—C9—C10—C11178.5 (2)
C15—P1—N1—C174.5 (2)C9—C10—C11—C120.2 (5)
P1—N1—C1—C6169.28 (19)C10—C11—C12—C130.0 (5)
P1—N1—C1—C212.5 (4)C11—C12—C13—C140.1 (5)
C6—C1—C2—C30.4 (4)C10—C9—C14—C130.6 (4)
N1—C1—C2—C3177.9 (2)P1—C9—C14—C13178.4 (2)
C1—C2—C3—C41.4 (4)C12—C13—C14—C90.4 (5)
C1—C2—C3—C7178.0 (2)O1—P1—C15—C16141.0 (2)
C2—C3—C4—C51.2 (4)N1—P1—C15—C1614.7 (3)
C7—C3—C4—C5178.2 (2)C9—P1—C15—C1695.3 (2)
C3—C4—C5—C60.0 (4)O1—P1—C15—C2041.0 (3)
C3—C4—C5—C8178.1 (2)N1—P1—C15—C20167.4 (2)
C2—C1—C6—C50.9 (4)C9—P1—C15—C2082.6 (2)
N1—C1—C6—C5179.2 (2)C20—C15—C16—C170.2 (4)
C4—C5—C6—C11.1 (4)P1—C15—C16—C17177.7 (2)
C8—C5—C6—C1177.0 (2)C15—C16—C17—C181.2 (5)
O1—P1—C9—C14143.4 (2)C16—C17—C18—C191.8 (5)
N1—P1—C9—C1493.3 (3)C17—C18—C19—C201.1 (5)
C15—P1—C9—C1421.2 (3)C18—C19—C20—C150.3 (5)
O1—P1—C9—C1037.7 (3)C16—C15—C20—C190.9 (4)
N1—P1—C9—C1085.7 (2)P1—C15—C20—C19177.1 (2)
C15—P1—C9—C10159.8 (2)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C2—H2···O10.952.483.148 (3)128
N1—H1···O1i0.882.122.788 (3)133
Symmetry code: (i) x+3/2, y, z+1/2.
 

Acknowledgements

The authors thank Mr Trevahn M. Williams for his assistance in preparing some of the starting materials for this work.

Funding information

Funding for this research was provided by: National Science Foundation, Division of Chemistry (award No. MRI, CHE-0420497 to UMSL); College of Arts and Sciences, Southern Illinois University Edwardsville; Graduate School, Southern Illinois University Edwardsville.

References

First citationBruker (2013). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.  Google Scholar
First citationBruker (2016). SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.  Google Scholar
First citationGusev, O. V., Ustynyuk, N. A., Peganova, T. A., Gonchar, A. V., Petrovskii, P. V. & Lyssenko, K. A. (2009). Phosphorus Sulfur Silicon, 184, 322–331.  CrossRef Google Scholar
First citationHong, G., Zhu, X., Hu, C., Aruma, A. N., Wu, S. & Wang, L. (2016). J. Org. Chem. 81, 6867–6874.  CrossRef Google Scholar
First citationMacrae, C. F., Edgington, P. R., McCabe, P., Pidcock, E., Shields, G. P., Taylor, R., Towler, M. & van de Streek, J. (2006). J. Appl. Cryst. 39, 453–457.  Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
First citationNaktode, K., Kottalanka, R. K., Jana, S. K. & Panda, T. K. (2013). Z. Anorg. Allg. Chem. 639, 999–1003.  CrossRef Google Scholar
First citationNaktode, K., Kottalanka, R. K. & Panda, T. K. (2012). New J. Chem. 36, 2280–2285.  CrossRef Google Scholar
First citationParsons, S., Flack, H. D. & Wagner, T. (2013). Acta Cryst. B69, 249–259.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationPriya, S., Balakrishna, M. S. & Mobin, S. M. (2005). Polyhedron, 24, 1641–1650.  Web of Science CSD CrossRef CAS 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. (2015a). Acta Cryst. A71, 3–8.  Web of Science CrossRef IUCr Journals Google Scholar
First citationSheldrick, G. M. (2015b). Acta Cryst. C71, 3–8.  Web of Science CrossRef IUCr Journals Google Scholar
First citationShozi, M. L. & Friedrich, H. B. (2012). S. Afr. J. Chem. 65, 214–222.  Google Scholar
First citationSun, Y. & Cramer, N. (2017). Angew. Chem. Int. Ed. 56, 364–367.  CrossRef Google Scholar
First citationXu, Y., Su, Q., Dong, W., Peng, Z. & An, D. (2017). Tetrahedron, 73, 4602–4609.  CrossRef Google Scholar

This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.

Journal logoIUCrDATA
ISSN: 2414-3146
Follow IUCr Journals
Sign up for e-alerts
Follow IUCr on Twitter
Follow us on facebook
Sign up for RSS feeds