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

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890

(Z)-Ethyl 2,4-di­phenyl-3-(propyl­amino)­but-2-enoate

aDepartment of Pharmaceuticals, Tianjin Medical College, Tianjin 300222, People's Republic of China
*Correspondence e-mail: huiminjin@yahoo.cn

(Received 23 December 2008; accepted 25 December 2008; online 8 January 2009)

The title compound, C21H25NO2, adopts a Z conformation about the C=C double bond. The mol­ecular structure is stabilized by an intra­molecular N—H⋯O hydrogen bond and the dihedral angle between the aromatic ring planes is 76.04 (12)°. The atoms of the ethyl substituent are disordered over two sets of sites in a 0.60 (2):0.40 (2) ratio.

Related literature

For the synthesis, see: Du et al. (2006[Du, Y., Liu, R., Linn, G. & Zhao, K. (2006). Org. Lett. 8, 5919-5922.]). For background, see: Xue et al. (2007[Xue, J. Y., Xiao, Z. P., Shi, L., Tan, S. H., Li, H. Q. & Zhu, H. L. (2007). Aust. J. Chem. 60, 957-962.]).

[Scheme 1]

Experimental

Crystal data
  • C21H25NO2

  • Mr = 323.42

  • Monoclinic, P 21 /n

  • a = 12.186 (2) Å

  • b = 8.4771 (17) Å

  • c = 19.080 (4) Å

  • β = 106.33 (3)°

  • V = 1891.4 (7) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 0.07 mm−1

  • T = 293 (2) K

  • 0.28 × 0.22 × 0.18 mm

Data collection
  • Rigaku Saturn diffractometer

  • Absorption correction: multi-scan (CrystalClear; Rigaku/MSC, 2005[Rigaku/MSC (2005). CrystalClear. Rigaku Corporation, Tokyo, Japan.]) Tmin = 0.980, Tmax = 0.987

  • 12325 measured reflections

  • 3323 independent reflections

  • 2290 reflections with I > 2σ(I)

  • Rint = 0.034

Refinement
  • R[F2 > 2σ(F2)] = 0.060

  • wR(F2) = 0.198

  • S = 1.06

  • 3323 reflections

  • 232 parameters

  • 5 restraints

  • H atoms treated by a mixture of independent and constrained refinement

  • Δρmax = 0.24 e Å−3

  • Δρmin = −0.19 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
N1—H1A⋯O2 0.905 (16) 1.925 (17) 2.653 (3) 136.3 (14)

Data collection: CrystalClear (Rigaku/MSC, 2005[Rigaku/MSC (2005). CrystalClear. Rigaku Corporation, Tokyo, Japan.]); cell refinement: CrystalClear; data reduction: CrystalClear; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: SHELXTL (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); software used to prepare material for publication: SHELXTL.

Supporting information


Comment top

Enamine compounds have been considered to be potential antibacterial agents (Xue et al., 2007) and found important application in the synthesis of N-containint heterocylcles (Du et al., 2006). To further study the structure and activity relationship, we determine the crystal structure of the title compound, (I).

In the molecular structure (Fig. 1), the torsion angles of N1—C11—C7—C6 and C8—C7—C11—C12 are -177.32 (17) and -175.14 (16)°, respectively. Furthermore, the distances C7—C11 and C11—N1 are 1.381 (3), 1.348 (3)Å, respectively. Both of these features confirm the enamine structure formation. The two phenyl rings constructed an angle of 76.04 (12)°. The molecule adopts a Z-conformation, being stabilised by an intramolecular N—H···O hydrogen bond (Table 1).

Related literature top

For the synthesis, see: Du et al. (2006). For background, see: Xue et al. (2007).

Experimental top

The title compound was prepared according to the method of the literature (Du, et al., 2006). Colourless blocks of (I) were grown from a mixture of ethyl actate and petroleum ether.

Refinement top

The non-N H atoms were positioned geometrically (C—H = 0.93–0.98 Å) and refined as riding with Uiso(H) = 1.2Ueq(CH and CH2) or 1.5Ueq(CH3). The N—H distance was refined with the restraint of 0.90 (1) Å, and the C19—C20, C20—C21, C9—C10 and C9—C10' with the restraint of 1.54 (1) Å. The ethyl radical of the ester moiety was found to be disordered, with the site occupancy ratio of 0.40 (2):0.60 (2).

Computing details top

Data collection: CrystalClear (Rigaku/MSC, 2005); cell refinement: CrystalClear (Rigaku/MSC, 2005); data reduction: CrystalClear (Rigaku/MSC, 2005); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. The molecular structure of (I) with 50% probability displacement ellipsoids. The dashed line indicates the intramolecular N—H···O hydrogen bond.
(Z)-Ethyl 2,4-diphenyl-3-(propylamino)but-2-enoate top
Crystal data top
C21H25NO2F(000) = 696
Mr = 323.42Dx = 1.136 Mg m3
Monoclinic, P21/nMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ynCell parameters from 4099 reflections
a = 12.186 (2) Åθ = 2.2–27.1°
b = 8.4771 (17) ŵ = 0.07 mm1
c = 19.080 (4) ÅT = 293 K
β = 106.33 (3)°Block, colourless
V = 1891.4 (7) Å30.28 × 0.22 × 0.18 mm
Z = 4
Data collection top
Rigaku Saturn
diffractometer
3323 independent reflections
Radiation source: rotating anode2290 reflections with I > 2σ(I)
Confocal monochromatorRint = 0.034
Detector resolution: 7.31 pixels mm-1θmax = 25.0°, θmin = 2.2°
ω scansh = 1414
Absorption correction: multi-scan
(CrystalClear; Rigaku/MSC, 2005)
k = 910
Tmin = 0.980, Tmax = 0.987l = 2122
12325 measured reflections
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.060H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.198 w = 1/[σ2(Fo2) + (0.1207P)2 + 0.019P]
where P = (Fo2 + 2Fc2)/3
S = 1.06(Δ/σ)max = 0.001
3323 reflectionsΔρmax = 0.24 e Å3
232 parametersΔρmin = 0.19 e Å3
5 restraintsExtinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.079 (13)
Crystal data top
C21H25NO2V = 1891.4 (7) Å3
Mr = 323.42Z = 4
Monoclinic, P21/nMo Kα radiation
a = 12.186 (2) ŵ = 0.07 mm1
b = 8.4771 (17) ÅT = 293 K
c = 19.080 (4) Å0.28 × 0.22 × 0.18 mm
β = 106.33 (3)°
Data collection top
Rigaku Saturn
diffractometer
3323 independent reflections
Absorption correction: multi-scan
(CrystalClear; Rigaku/MSC, 2005)
2290 reflections with I > 2σ(I)
Tmin = 0.980, Tmax = 0.987Rint = 0.034
12325 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0605 restraints
wR(F2) = 0.198H atoms treated by a mixture of independent and constrained refinement
S = 1.06Δρmax = 0.24 e Å3
3323 reflectionsΔρmin = 0.19 e Å3
232 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
xyzUiso*/UeqOcc. (<1)
O10.98880 (16)0.7415 (2)0.24987 (10)0.0936 (6)
O21.07264 (14)0.97745 (19)0.24972 (8)0.0791 (5)
N10.95170 (17)1.1941 (2)0.16036 (11)0.0710 (6)
C10.7770 (2)0.7362 (3)0.07667 (13)0.0723 (7)
H10.82130.76550.04630.087*
C20.6935 (2)0.6239 (3)0.05278 (16)0.0864 (8)
H2A0.68120.57940.00670.104*
C30.6286 (2)0.5778 (3)0.09719 (18)0.0906 (8)
H3A0.57190.50180.08140.109*
C40.6473 (2)0.6434 (4)0.16427 (18)0.0977 (9)
H4A0.60380.61150.19470.117*
C50.7302 (2)0.7568 (3)0.18764 (14)0.0829 (8)
H5A0.74150.80070.23380.099*
C60.79728 (17)0.8072 (2)0.14437 (11)0.0591 (6)
C70.88662 (17)0.9301 (2)0.16911 (10)0.0572 (6)
C80.99038 (19)0.8903 (3)0.22513 (12)0.0654 (6)
C91.0852 (3)0.6899 (4)0.30878 (18)0.1159 (11)0.60 (2)
H9A1.10750.58550.29710.139*0.60 (2)
H9B1.14890.76020.31120.139*0.60 (2)
C101.0665 (11)0.684 (2)0.3778 (4)0.133 (4)0.60 (2)
H10A1.13530.65120.41330.199*0.60 (2)
H10B1.00630.61060.37700.199*0.60 (2)
H10C1.04500.78710.39040.199*0.60 (2)
C9'1.0852 (3)0.6899 (4)0.30878 (18)0.1159 (11)0.40 (2)
H9'A1.13280.77870.33060.139*0.40 (2)
H9'B1.13140.61460.29130.139*0.40 (2)
C10'1.0339 (12)0.616 (2)0.3618 (8)0.111 (4)0.40 (2)
H10D1.09350.57880.40300.166*0.40 (2)
H10E0.98710.52850.33920.166*0.40 (2)
H10F0.98790.69180.37790.166*0.40 (2)
C110.87065 (17)1.0815 (2)0.14123 (11)0.0588 (6)
C120.75990 (17)1.1280 (2)0.08755 (11)0.0618 (6)
H12A0.73361.22500.10450.074*
H12B0.70361.04710.08760.074*
C130.76341 (16)1.1525 (2)0.00975 (11)0.0565 (5)
C140.6757 (2)1.2334 (3)0.03842 (14)0.0745 (7)
H14A0.61501.27160.02280.089*
C150.6773 (3)1.2584 (3)0.11014 (15)0.0918 (8)
H15A0.61851.31480.14190.110*
C160.7651 (2)1.2003 (3)0.13433 (14)0.0849 (8)
H16A0.76631.21750.18220.102*
C170.8495 (2)1.1182 (3)0.08805 (14)0.0803 (7)
H17A0.90851.07660.10450.096*
C180.84946 (18)1.0953 (3)0.01624 (12)0.0706 (6)
H18A0.90931.03970.01510.085*
C190.9397 (2)1.3609 (3)0.14108 (16)0.0837 (8)
H19A0.90851.41670.17550.100*
H19B0.88671.37280.09280.100*
C201.0546 (3)1.4324 (3)0.14196 (19)0.1120 (11)
H20A1.04461.54520.13440.134*
H20B1.10701.41670.19020.134*
C211.1081 (3)1.3697 (4)0.0878 (3)0.1381 (14)
H21A1.18171.41770.09460.207*
H21B1.06051.39290.03960.207*
H21C1.11691.25760.09370.207*
H1A1.0180 (11)1.163 (2)0.1924 (9)0.065 (6)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0861 (12)0.0898 (12)0.0851 (13)0.0094 (9)0.0083 (10)0.0275 (9)
O20.0732 (11)0.0914 (11)0.0625 (10)0.0011 (8)0.0026 (8)0.0069 (8)
N10.0710 (13)0.0671 (11)0.0688 (13)0.0032 (9)0.0099 (11)0.0003 (9)
C10.0817 (16)0.0716 (13)0.0667 (15)0.0068 (11)0.0257 (13)0.0040 (11)
C20.0884 (17)0.0779 (15)0.0873 (18)0.0122 (13)0.0156 (15)0.0051 (13)
C30.0755 (16)0.0790 (16)0.107 (2)0.0092 (12)0.0090 (16)0.0195 (15)
C40.0823 (18)0.119 (2)0.094 (2)0.0134 (16)0.0297 (17)0.0302 (18)
C50.0798 (17)0.1103 (19)0.0628 (15)0.0056 (14)0.0270 (14)0.0115 (13)
C60.0591 (12)0.0645 (12)0.0522 (12)0.0079 (9)0.0132 (10)0.0094 (10)
C70.0629 (12)0.0659 (12)0.0428 (11)0.0084 (9)0.0148 (9)0.0027 (9)
C80.0712 (14)0.0745 (13)0.0487 (12)0.0090 (11)0.0138 (11)0.0020 (11)
C90.096 (2)0.133 (2)0.094 (2)0.0225 (18)0.0132 (18)0.040 (2)
C100.102 (6)0.194 (10)0.081 (5)0.043 (6)0.010 (4)0.022 (5)
C9'0.096 (2)0.133 (2)0.094 (2)0.0225 (18)0.0132 (18)0.040 (2)
C10'0.119 (8)0.129 (9)0.060 (6)0.016 (7)0.015 (5)0.041 (6)
C110.0645 (12)0.0669 (12)0.0475 (11)0.0055 (9)0.0197 (10)0.0032 (9)
C120.0585 (12)0.0668 (12)0.0617 (13)0.0101 (9)0.0196 (10)0.0044 (10)
C130.0568 (12)0.0509 (10)0.0576 (12)0.0005 (8)0.0092 (10)0.0023 (9)
C140.0717 (15)0.0751 (14)0.0690 (16)0.0136 (11)0.0071 (12)0.0039 (12)
C150.095 (2)0.0952 (18)0.0692 (17)0.0136 (14)0.0033 (15)0.0173 (14)
C160.0953 (19)0.0984 (18)0.0556 (14)0.0162 (15)0.0123 (14)0.0129 (13)
C170.0747 (16)0.1049 (18)0.0626 (15)0.0008 (13)0.0213 (13)0.0083 (13)
C180.0618 (13)0.0874 (15)0.0608 (14)0.0117 (11)0.0144 (11)0.0121 (11)
C190.0904 (17)0.0636 (14)0.099 (2)0.0011 (12)0.0290 (15)0.0085 (13)
C200.129 (3)0.0726 (16)0.138 (3)0.0143 (16)0.044 (2)0.0030 (17)
C210.136 (3)0.100 (2)0.205 (4)0.006 (2)0.092 (3)0.004 (2)
Geometric parameters (Å, º) top
O1—C81.349 (3)C10'—H10E0.9600
O1—C91.446 (3)C10'—H10F0.9600
O2—C81.227 (3)C11—C121.499 (3)
N1—C111.348 (3)C12—C131.511 (3)
N1—C191.458 (3)C12—H12A0.9700
N1—H1A0.905 (10)C12—H12B0.9700
C1—C21.374 (3)C13—C181.369 (3)
C1—C61.383 (3)C13—C141.381 (3)
C1—H10.9300C14—C151.390 (4)
C2—C31.369 (4)C14—H14A0.9300
C2—H2A0.9300C15—C161.370 (4)
C3—C41.355 (4)C15—H15A0.9300
C3—H3A0.9300C16—C171.346 (3)
C4—C51.375 (4)C16—H16A0.9300
C4—H4A0.9300C17—C181.384 (3)
C5—C61.383 (3)C17—H17A0.9300
C5—H5A0.9300C18—H18A0.9300
C6—C71.485 (3)C19—C201.522 (3)
C7—C111.381 (3)C19—H19A0.9700
C7—C81.448 (3)C19—H19B0.9700
C9—C101.399 (7)C20—C211.467 (4)
C9—H9A0.9700C20—H20A0.9700
C9—H9B0.9700C20—H20B0.9700
C10—H10A0.9600C21—H21A0.9600
C10—H10B0.9600C21—H21B0.9600
C10—H10C0.9600C21—H21C0.9600
C10'—H10D0.9600
C8—O1—C9117.8 (2)N1—C11—C12116.66 (18)
C11—N1—C19127.2 (2)C7—C11—C12120.63 (19)
C11—N1—H1A114.9 (13)C11—C12—C13116.00 (16)
C19—N1—H1A117.5 (13)C11—C12—H12A108.3
C2—C1—C6122.2 (2)C13—C12—H12A108.3
C2—C1—H1118.9C11—C12—H12B108.3
C6—C1—H1118.9C13—C12—H12B108.3
C3—C2—C1119.7 (3)H12A—C12—H12B107.4
C3—C2—H2A120.2C18—C13—C14117.6 (2)
C1—C2—H2A120.2C18—C13—C12122.92 (19)
C4—C3—C2119.6 (3)C14—C13—C12119.44 (18)
C4—C3—H3A120.2C13—C14—C15120.5 (2)
C2—C3—H3A120.2C13—C14—H14A119.7
C3—C4—C5120.4 (2)C15—C14—H14A119.7
C3—C4—H4A119.8C16—C15—C14120.4 (2)
C5—C4—H4A119.8C16—C15—H15A119.8
C4—C5—C6121.8 (2)C14—C15—H15A119.8
C4—C5—H5A119.1C17—C16—C15119.3 (2)
C6—C5—H5A119.1C17—C16—H16A120.3
C1—C6—C5116.3 (2)C15—C16—H16A120.3
C1—C6—C7121.66 (17)C16—C17—C18120.6 (2)
C5—C6—C7122.1 (2)C16—C17—H17A119.7
C11—C7—C8120.0 (2)C18—C17—H17A119.7
C11—C7—C6121.21 (19)C13—C18—C17121.5 (2)
C8—C7—C6118.74 (18)C13—C18—H18A119.2
O2—C8—O1121.3 (2)C17—C18—H18A119.2
O2—C8—C7126.3 (2)N1—C19—C20110.9 (2)
O1—C8—C7112.4 (2)N1—C19—H19A109.5
C10—C9—O1115.5 (5)C20—C19—H19A109.5
C10—C9—H9A108.4N1—C19—H19B109.5
O1—C9—H9A108.4C20—C19—H19B109.5
C10—C9—H9B108.4H19A—C19—H19B108.0
O1—C9—H9B108.4C21—C20—C19115.9 (3)
H9A—C9—H9B107.5C21—C20—H20A108.3
C9—C10—H10A109.5C19—C20—H20A108.3
C9—C10—H10B109.5C21—C20—H20B108.3
H10A—C10—H10B109.5C19—C20—H20B108.3
C9—C10—H10C109.5H20A—C20—H20B107.4
H10A—C10—H10C109.5C20—C21—H21A109.5
H10B—C10—H10C109.5C20—C21—H21B109.5
H10D—C10'—H10E109.5H21A—C21—H21B109.5
H10D—C10'—H10F109.5C20—C21—H21C109.5
H10E—C10'—H10F109.5H21A—C21—H21C109.5
N1—C11—C7122.7 (2)H21B—C21—H21C109.5
C6—C1—C2—C30.9 (4)C19—N1—C11—C127.4 (3)
C1—C2—C3—C40.0 (4)C8—C7—C11—N14.6 (3)
C2—C3—C4—C50.6 (4)C6—C7—C11—N1177.32 (17)
C3—C4—C5—C60.3 (4)C8—C7—C11—C12175.14 (16)
C2—C1—C6—C51.2 (3)C6—C7—C11—C122.9 (3)
C2—C1—C6—C7179.1 (2)N1—C11—C12—C1371.9 (2)
C4—C5—C6—C10.5 (4)C7—C11—C12—C13108.3 (2)
C4—C5—C6—C7179.7 (2)C11—C12—C13—C1817.9 (3)
C1—C6—C7—C1174.3 (3)C11—C12—C13—C14163.29 (19)
C5—C6—C7—C11105.9 (2)C18—C13—C14—C151.5 (3)
C1—C6—C7—C8107.6 (2)C12—C13—C14—C15179.6 (2)
C5—C6—C7—C872.1 (3)C13—C14—C15—C161.2 (4)
C9—O1—C8—O22.7 (3)C14—C15—C16—C170.3 (4)
C9—O1—C8—C7176.8 (2)C15—C16—C17—C181.4 (4)
C11—C7—C8—O23.9 (3)C14—C13—C18—C170.4 (3)
C6—C7—C8—O2178.02 (18)C12—C13—C18—C17179.3 (2)
C11—C7—C8—O1175.63 (17)C16—C17—C18—C131.1 (4)
C6—C7—C8—O12.5 (2)C11—N1—C19—C20154.4 (2)
C8—O1—C9—C10103.2 (10)N1—C19—C20—C2164.4 (4)
C19—N1—C11—C7172.39 (19)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1A···O20.91 (2)1.93 (2)2.653 (3)136 (1)

Experimental details

Crystal data
Chemical formulaC21H25NO2
Mr323.42
Crystal system, space groupMonoclinic, P21/n
Temperature (K)293
a, b, c (Å)12.186 (2), 8.4771 (17), 19.080 (4)
β (°) 106.33 (3)
V3)1891.4 (7)
Z4
Radiation typeMo Kα
µ (mm1)0.07
Crystal size (mm)0.28 × 0.22 × 0.18
Data collection
DiffractometerRigaku Saturn
diffractometer
Absorption correctionMulti-scan
(CrystalClear; Rigaku/MSC, 2005)
Tmin, Tmax0.980, 0.987
No. of measured, independent and
observed [I > 2σ(I)] reflections
12325, 3323, 2290
Rint0.034
(sin θ/λ)max1)0.595
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.060, 0.198, 1.06
No. of reflections3323
No. of parameters232
No. of restraints5
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.24, 0.19

Computer programs: CrystalClear (Rigaku/MSC, 2005), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1A···O20.905 (16)1.925 (17)2.653 (3)136.3 (14)
 

Acknowledgements

We thank the Technology Fund of Tianjin Bureau of Public Health (grant No. 04KY36) for financial support.

References

First citationDu, Y., Liu, R., Linn, G. & Zhao, K. (2006). Org. Lett. 8, 5919–5922.  Web of Science CSD CrossRef PubMed CAS Google Scholar
First citationRigaku/MSC (2005). CrystalClear. Rigaku Corporation, Tokyo, Japan.  Google Scholar
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationXue, J. Y., Xiao, Z. P., Shi, L., Tan, S. H., Li, H. Q. & Zhu, H. L. (2007). Aust. J. Chem. 60, 957–962.  Web of Science CrossRef CAS 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 logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890
Follow Acta Cryst. E
Sign up for e-alerts
Follow Acta Cryst. on Twitter
Follow us on facebook
Sign up for RSS feeds