addenda and errata\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

Journal logoSTRUCTURAL
CHEMISTRY
ISSN: 2053-2296

Tricoccin R2. Erratum

aDepartment of Crystallography and Biophysics, University of Madras, Guindy Campus, Chennai 600 025, India, bLaboratory Voor Kristallografie, Nieuwe Achtergracht 166, 1018 WU, Amsterdam, The Netherlands, and cInstitute of Organic Chemistry, University of Kiel, D-2300 Kiel, Olshausenstrasse, Be 40-60, Germany
*Correspondence e-mail: partha24@hotmail.com

(Received 6 December 2000; accepted 18 December 2000)

The crystal structure of the title compound, C25H26O7, was published with erroneous positions for a C atom and the O atom in ring F [Sekar et al. (1996[Sekar, K., Parthasarathy, S., Schenk, H., Epe, B. & Mondon, A. (1996). Acta Cryst. C52, 92-94.]). Acta Cryst. (1996), C52, 92–94 ]. This has now been corrected and leads to a more sensible bond length and angle geometry.

1. Comment

During a comparative study of the molecular structure of Tricoccin R6 (Abdul Ajees et al., 2001[Abdul Ajees, A., Sekar, K., Parthasarathy, S., Schenk, H., Epe, B. & Mondon, A. (2001). Acta Cryst. E57 o116-117.]) with that of the related compound Tricoccin R2[link] (Sekar et al., 1996[Sekar, K., Parthasarathy, S., Schenk, H., Epe, B. & Mondon, A. (1996). Acta Cryst. C52, 92-94.]) it was found that

[Scheme 1]
the geometry of the mol­ecules in the two structures agreed well except in the region of ring F of Tricoccin R2[link]. This could be traced to a wrong assignment of two of the atoms in ring F of Tricoccin R2[link]. That is, the neighbours of atoms C21 and C22 in ring F of Tricoccin R2 are to be taken as O and C atoms, respectively, instead of C and O as in the original report. The structure of Tricoccin R2[link] thus modified was refined and converged to a lower R value and the final difference Fourier was better. There is now better agreement of the geometry of ring F of Tricoccin R2[link] with that of Tricoccin R6.
[Figure 1]
Figure 1
The molecular structure of the title compound with 30% probability displacement ellipsoids

2. Experimental

2.1.1. Crystal data
  • C25H26O7

  • Mr = 438.46

  • Monoclinic, C2

  • a = 22.939 (1) Å

  • b = 6.574 (2) Å

  • c = 16.481 (2) Å

  • β = 114.67 (1)°

  • V = 2258.5 (7) Å3

  • Z = 4

  • Dx = 1.289 Mg m−3

  • Cu Kα radiation

  • Cell parameters from 25 reflections

  • θ = 20–30°

  • μ = 0.78 mm−1

  • T = 293 (2) K

  • Needle, colourless

  • 0.30 × 0.25 × 0.20 mm

2.1.2. Data collection
  • Enraf–Nonius CAD-4 diffractometer

  • ω/2θ scans

  • Absorption correction: empirical ψ scan (North et al., 1968[North, A. C. T., Phillips, D. C. & Mathews, F. S. (1968). Acta Cryst. A24, 351-359.])Tmin = 0.961, Tmax = 0.991

  • 2312 measured reflections

  • 2230 independent reflections

  • 2054 reflections with I > 2σ(I)

  • Rint = 0.027

  • θmax = 70.3°

  • h = −25 → 27

  • k = 0 → 8

  • l = −19 → 0

  • 2 standard reflections frequency: 120 min intensity decay: <1%

2.1.3. Refinement
  • Refinement on F2

  • R[F2 > 2σ(F2)] = 0.036

  • wR(F2) = 0.103

  • S = 1.07

  • 2230 reflections

  • 293 parameters

  • H-atom parameters constrained

  • w = 1/[σ2(Fo2) + (0.0588P)2 + 0.6138P] where P = (Fo2 + 2Fc2)/3

  • (Δ/σ)max < 0.001

  • Δρmax = 0.27 e Å−3

  • Δρmin = −0.12 e Å−3

  • Extinction correction: SHELXL97

  • Extinction coefficient: 0.0018 (2)

  • Absolute structure: Flack (1983[Flack, H. D. (1983). Acta Cryst. A39, 876-881.])

  • Flack parameter = 0.1 (3)

Data collection: CAD-4 Software (Enraf–Nonius, 1989[Enraf-Nonius (1989). CAD-4 Software. Version 5.0. Enraf-Nonius, Delft, The Netherlands.]); cell refinement: SDP (Frenz, 1978[Frenz, B. A. (1978). The Enraf-Nonius CAD-4 SDP. Computing in Crystallography, edited by H. Schenk, R. Olthof-Hazekamp, H. van Koningsveld & G. C. Bassi, pp. 64-71. Delft University Press.]); data reduction: CAD-4 Software; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997[Sheldrick, G. M. (1997). SHELXS97 and SHELXL97. Release 97-2. Uni­versity of Göttingen, Germany.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997[Sheldrick, G. M. (1997). SHELXS97 and SHELXL97. Release 97-2. Uni­versity of Göttingen, Germany.]).

Supporting information


Comment top

During a comparative study of the molecular structure of Tricoccin R6 (Abdul Ajees et al., 2000) with that of the related compound Tricoccin R2 (Sekar et al., 1996) it was found that the geometry of the molecules in the two structures agreed well except in the region of ring F of Tricoccin R2. This could be traced to a wrong assignment of two of the atoms in ring F of Tricoccin R2. That is, the neighbours of atoms C21 and C22 in ring F of Tricoccin R2 are to be taken as O and C atoms, respectively, instead of C and O as was done in the original report of Sekar et al. (1996). The structure of Tricoccin R2 thus modified was refined. The refinement converged to a lower R value and the final difference Fourier was better. There is now better agreement of the geometry of ring F of Tricoccin R2 with that of Tricoccin R6.

Experimental top

Crystals were grown at room temp

Refinement top

H-atom parameters were constrained with C—H distances in the range 0.00–0.00 Å.

Computing details top

Data collection: CAD-4 Software (Enraf-Nonius, 1989); cell refinement: SDP (Frenz, 1978); data reduction: CAD-4 Software; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997).

Figures top
[Figure 1] Fig. 1. Molecular structure of the title compound with 30% probability displacement ellipsoids
(I) top
Crystal data top
C25H26O7F(000) = 928
Mr = 438.46Dx = 1.289 Mg m3
Monoclinic, C2Cu Kα radiation, λ = 1.54180 Å
a = 22.939 (1) ÅCell parameters from 25 reflections
b = 6.574 (2) Åθ = 20–30°
c = 16.481 (2) ŵ = 0.78 mm1
β = 114.67 (1)°T = 293 K
V = 2258.5 (7) Å3Needle, colourless
Z = 40.30 × 0.25 × 0.20 mm
Data collection top
Enraf-Nonius CAD-4
diffractometer
2054 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.027
Graphite monochromatorθmax = 70.3°, θmin = 3.0°
ω/2θ scansh = 2527
Absorption correction: empirical (using intensity measurements) ψ scan
?
k = 08
Tmin = 0.961, Tmax = 0.991l = 190
2312 measured reflections2 standard reflections every 120 min
2230 independent reflections intensity decay: <1%
Refinement top
Refinement on F2Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: fullH-atom parameters constrained
R[F2 > 2σ(F2)] = 0.036 w = 1/[σ2(Fo2) + (0.0588P)2 + 0.6138P]
where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.103(Δ/σ)max < 0.001
S = 1.07Δρmax = 0.27 e Å3
2230 reflectionsΔρmin = 0.12 e Å3
293 parametersExtinction correction: SHELXL97, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
1 restraintExtinction coefficient: 0.0018 (2)
Primary atom site location: structure-invariant direct methodsAbsolute structure: Flack (1983)
Secondary atom site location: difference Fourier mapAbsolute structure parameter: 0.1 (3)
Crystal data top
C25H26O7V = 2258.5 (7) Å3
Mr = 438.46Z = 4
Monoclinic, C2Cu Kα radiation
a = 22.939 (1) ŵ = 0.78 mm1
b = 6.574 (2) ÅT = 293 K
c = 16.481 (2) Å0.30 × 0.25 × 0.20 mm
β = 114.67 (1)°
Data collection top
Enraf-Nonius CAD-4
diffractometer
2054 reflections with I > 2σ(I)
Absorption correction: empirical (using intensity measurements) ψ scan
?
Rint = 0.027
Tmin = 0.961, Tmax = 0.9912 standard reflections every 120 min
2312 measured reflections intensity decay: <1%
2230 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.036H-atom parameters constrained
wR(F2) = 0.103Δρmax = 0.27 e Å3
S = 1.07Δρmin = 0.12 e Å3
2230 reflectionsAbsolute structure: Flack (1983)
293 parametersAbsolute structure parameter: 0.1 (3)
1 restraint
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*/Ueq
C10.5001 (2)0.3359 (8)0.1535 (2)0.0884 (13)
H10.48210.45900.15890.106*
C20.5380 (3)0.3143 (15)0.1124 (3)0.138 (3)
H20.55150.41710.08540.165*
C30.55499 (19)0.0986 (16)0.1168 (2)0.136 (3)
C40.51095 (12)0.0319 (5)0.35079 (16)0.0495 (6)
C50.51555 (12)0.1521 (4)0.29493 (16)0.0451 (6)
H50.49180.26280.30720.054*
C60.58606 (12)0.2103 (6)0.34162 (16)0.0543 (7)
H6A0.59190.35490.33600.065*
H6B0.61140.13560.31700.065*
C70.60510 (12)0.1507 (5)0.44081 (16)0.0506 (7)
C80.66748 (11)0.2699 (4)0.58414 (15)0.0432 (6)
C90.69709 (11)0.0774 (4)0.56993 (15)0.0453 (6)
H90.68730.03490.60130.054*
C100.48957 (12)0.1400 (5)0.19060 (16)0.0529 (7)
C110.76878 (11)0.0952 (5)0.60159 (16)0.0517 (7)
H11A0.77890.20610.57090.062*
H11B0.78590.02960.58880.062*
C120.79923 (11)0.1359 (5)0.70458 (16)0.0516 (7)
H12A0.79540.01360.73490.062*
H12B0.84460.16390.72400.062*
C130.76875 (11)0.3117 (5)0.73265 (16)0.0465 (6)
C140.70042 (11)0.3743 (4)0.67166 (16)0.0431 (6)
C150.66908 (13)0.4280 (4)0.73307 (17)0.0493 (6)
O160.71301 (9)0.4229 (4)0.82068 (12)0.0587 (5)
C170.77399 (12)0.3345 (5)0.82997 (16)0.0507 (6)
H170.80850.43110.86230.061*
C180.75748 (14)0.5110 (5)0.6846 (2)0.0596 (7)
H18A0.77000.52250.63540.072*
H18B0.76300.63410.71950.072*
C190.42104 (14)0.0723 (7)0.14383 (18)0.0683 (9)
H19A0.40780.07920.08040.102*
H19B0.39430.15950.16050.102*
H19C0.41720.06520.16060.102*
C200.78499 (13)0.1459 (5)0.88397 (16)0.0528 (7)
C210.74541 (17)0.0300 (6)0.8694 (2)0.0687 (8)
H210.70640.05410.82110.082*
C220.83659 (18)0.1101 (6)0.9619 (2)0.0756 (10)
H220.87070.20000.98800.091*
O240.83239 (17)0.0739 (5)0.99729 (18)0.0999 (10)
C230.7759 (2)0.1549 (7)0.9400 (3)0.0874 (12)
H230.76010.28000.94790.105*
O250.61416 (9)0.4682 (4)0.71455 (14)0.0655 (6)
O260.66502 (8)0.0429 (4)0.47372 (11)0.0558 (5)
O270.55533 (8)0.0248 (4)0.44137 (11)0.0595 (6)
C280.44694 (13)0.0560 (6)0.3563 (2)0.0662 (8)
H28A0.45160.14890.40360.099*
H28B0.41580.10820.30070.099*
H28C0.43300.07380.36820.099*
C290.5324 (2)0.2330 (6)0.3265 (3)0.0832 (11)
H29A0.57470.21790.32860.125*
H29B0.50310.27200.26730.125*
H29C0.53300.33590.36810.125*
C300.61627 (12)0.3144 (5)0.50991 (16)0.0512 (7)
H300.59090.42970.50170.061*
O310.52773 (10)0.0018 (5)0.16438 (13)0.0861 (9)
O320.58593 (15)0.0036 (14)0.08401 (18)0.219 (4)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.098 (3)0.100 (3)0.0397 (16)0.021 (2)0.0024 (17)0.0130 (19)
C20.090 (3)0.257 (9)0.047 (2)0.057 (5)0.009 (2)0.037 (4)
C30.056 (2)0.315 (11)0.0362 (17)0.033 (4)0.0190 (14)0.017 (4)
C40.0511 (13)0.0536 (16)0.0412 (12)0.0019 (13)0.0167 (11)0.0039 (12)
C50.0413 (12)0.0560 (16)0.0351 (12)0.0055 (12)0.0130 (10)0.0039 (11)
C60.0451 (13)0.076 (2)0.0357 (12)0.0020 (14)0.0111 (10)0.0050 (13)
C70.0429 (12)0.0677 (19)0.0373 (12)0.0046 (13)0.0130 (10)0.0030 (13)
C80.0417 (11)0.0492 (15)0.0380 (12)0.0029 (11)0.0160 (10)0.0047 (11)
C90.0441 (12)0.0532 (16)0.0335 (11)0.0063 (12)0.0110 (10)0.0024 (11)
C100.0482 (13)0.071 (2)0.0347 (12)0.0096 (14)0.0128 (10)0.0019 (13)
C110.0433 (12)0.0691 (19)0.0422 (12)0.0093 (13)0.0174 (10)0.0024 (13)
C120.0365 (11)0.0706 (19)0.0441 (12)0.0059 (13)0.0132 (10)0.0039 (14)
C130.0392 (11)0.0554 (16)0.0398 (12)0.0049 (11)0.0114 (10)0.0011 (12)
C140.0412 (11)0.0427 (14)0.0424 (12)0.0001 (10)0.0144 (10)0.0031 (11)
C150.0547 (14)0.0418 (14)0.0486 (13)0.0029 (12)0.0186 (11)0.0009 (12)
O160.0614 (11)0.0674 (14)0.0441 (9)0.0082 (10)0.0188 (8)0.0053 (10)
C170.0443 (12)0.0588 (17)0.0410 (13)0.0051 (12)0.0098 (10)0.0067 (12)
C180.0637 (16)0.0551 (18)0.0582 (16)0.0135 (15)0.0235 (13)0.0033 (14)
C190.0568 (15)0.095 (3)0.0409 (13)0.0041 (17)0.0088 (11)0.0081 (16)
C200.0542 (14)0.0654 (18)0.0383 (12)0.0036 (14)0.0188 (11)0.0014 (13)
C210.0706 (18)0.073 (2)0.0688 (19)0.0051 (18)0.0352 (16)0.0017 (18)
C220.082 (2)0.079 (3)0.0464 (16)0.007 (2)0.0073 (15)0.0028 (17)
O240.135 (2)0.091 (2)0.0618 (14)0.025 (2)0.0296 (15)0.0204 (15)
C230.131 (4)0.067 (2)0.091 (3)0.007 (2)0.072 (3)0.014 (2)
O250.0542 (11)0.0703 (14)0.0711 (13)0.0134 (11)0.0251 (9)0.0040 (12)
O260.0495 (9)0.0735 (14)0.0363 (8)0.0124 (10)0.0099 (7)0.0062 (9)
O270.0553 (10)0.0818 (15)0.0365 (8)0.0099 (11)0.0144 (8)0.0048 (10)
C280.0594 (16)0.082 (2)0.0561 (16)0.0122 (17)0.0236 (13)0.0050 (18)
C290.111 (3)0.062 (2)0.078 (2)0.028 (2)0.041 (2)0.0074 (19)
C300.0467 (13)0.0605 (18)0.0420 (13)0.0115 (13)0.0142 (10)0.0068 (13)
O310.0720 (13)0.142 (3)0.0431 (10)0.0408 (16)0.0228 (10)0.0083 (14)
O320.100 (2)0.500 (12)0.0690 (16)0.110 (5)0.0482 (16)0.015 (4)
Geometric parameters (Å, º) top
C1—C21.312 (7)C9—C111.508 (3)
C1—C101.488 (5)C10—O311.462 (4)
C2—C31.464 (11)C10—C191.501 (4)
C3—O321.228 (7)C11—C121.566 (3)
C3—O311.360 (7)C12—C131.520 (4)
C4—O271.461 (3)C13—C181.497 (4)
C4—C281.517 (4)C13—C141.523 (3)
C4—C291.522 (5)C13—C171.565 (3)
C4—C51.550 (4)C14—C151.508 (4)
C5—C61.522 (4)C14—C181.527 (4)
C5—C101.569 (3)C15—O251.195 (3)
C6—C71.556 (3)C15—O161.374 (3)
C7—O271.413 (3)O16—C171.463 (3)
C7—O261.437 (3)C17—C201.485 (4)
C7—C301.509 (4)C20—C221.355 (4)
C8—C301.328 (3)C20—C211.427 (5)
C8—C141.487 (3)C21—C231.355 (5)
C8—C91.500 (4)C22—O241.364 (5)
C9—O261.461 (3)O24—C231.354 (6)
C2—C1—C10112.0 (5)C9—C11—C12108.48 (19)
C1—C2—C3107.4 (5)C13—C12—C11114.0 (2)
O32—C3—O31119.7 (9)C18—C13—C12120.3 (2)
O32—C3—C2131.4 (8)C18—C13—C1460.76 (18)
O31—C3—C2108.8 (4)C12—C13—C14118.8 (2)
O27—C4—C28104.1 (2)C18—C13—C17112.4 (2)
O27—C4—C29109.1 (3)C12—C13—C17122.5 (2)
C28—C4—C29110.7 (3)C14—C13—C17105.6 (2)
O27—C4—C5102.5 (2)C8—C14—C15124.6 (2)
C28—C4—C5115.1 (2)C8—C14—C13118.8 (2)
C29—C4—C5114.3 (2)C15—C14—C13105.5 (2)
C6—C5—C4102.5 (2)C8—C14—C18117.7 (2)
C6—C5—C10113.8 (2)C15—C14—C18112.9 (2)
C4—C5—C10121.5 (2)C13—C14—C1858.75 (18)
C5—C6—C7103.9 (2)O25—C15—O16120.4 (2)
O27—C7—O26110.9 (3)O25—C15—C14128.9 (2)
O27—C7—C30107.2 (2)O16—C15—C14110.7 (2)
O26—C7—C30103.5 (2)C15—O16—C17111.70 (19)
O27—C7—C6106.3 (2)O16—C17—C20108.1 (2)
O26—C7—C6109.0 (2)O16—C17—C13105.65 (19)
C30—C7—C6119.9 (3)C20—C17—C13117.1 (2)
C30—C8—C14133.5 (3)C13—C18—C1460.49 (17)
C30—C8—C9109.0 (2)C22—C20—C21105.1 (3)
C14—C8—C9117.4 (2)C22—C20—C17125.1 (3)
O26—C9—C8104.17 (19)C21—C20—C17129.7 (3)
O26—C9—C11111.71 (19)C23—C21—C20106.4 (3)
C8—C9—C11112.3 (2)C20—C22—O24111.7 (4)
O31—C10—C1102.1 (3)C23—O24—C22105.6 (3)
O31—C10—C19106.7 (3)O24—C23—C21111.2 (4)
C1—C10—C19111.2 (3)C7—O26—C9107.59 (18)
O31—C10—C5110.9 (2)C7—O27—C4111.29 (18)
C1—C10—C5110.7 (3)C8—C30—C7110.1 (3)
C19—C10—C5114.5 (2)C3—O31—C10109.7 (5)

Experimental details

Crystal data
Chemical formulaC25H26O7
Mr438.46
Crystal system, space groupMonoclinic, C2
Temperature (K)293
a, b, c (Å)22.939 (1), 6.574 (2), 16.481 (2)
β (°) 114.67 (1)
V3)2258.5 (7)
Z4
Radiation typeCu Kα
µ (mm1)0.78
Crystal size (mm)0.30 × 0.25 × 0.20
Data collection
DiffractometerEnraf-Nonius CAD-4
diffractometer
Absorption correctionEmpirical (using intensity measurements) ψ scan
Tmin, Tmax0.961, 0.991
No. of measured, independent and
observed [I > 2σ(I)] reflections
2312, 2230, 2054
Rint0.027
(sin θ/λ)max1)0.610
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.036, 0.103, 1.07
No. of reflections2230
No. of parameters293
No. of restraints1
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.27, 0.12
Absolute structureFlack (1983)
Absolute structure parameter0.1 (3)

Computer programs: CAD-4 Software (Enraf-Nonius, 1989), SDP (Frenz, 1978), CAD-4 Software, SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997).

 

References

First citationAbdul Ajees, A., Sekar, K., Parthasarathy, S., Schenk, H., Epe, B. & Mondon, A. (2001). Acta Cryst. E57 o116–117. CrossRef IUCr Journals
First citationEnraf–Nonius (1989). CAD-4 Software. Version 5.0. Enraf–Nonius, Delft, The Netherlands.
First citationFlack, H. D. (1983). Acta Cryst. A39, 876–881. CrossRef CAS Web of Science IUCr Journals
First citationFrenz, B. A. (1978). The Enraf–Nonius CAD-4 SDP. Computing in Crystallography, edited by H. Schenk, R. Olthof-Hazekamp, H. van Koningsveld & G. C. Bassi, pp. 64–71. Delft University Press.
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