organic compounds
Tris(5-methyl-3-phenyl-1H-pyrazol-1-yl)methane
aMolecular Technology Unit Cell, Department of Chemistry, Walailak University, Thasala, Nakorn Si Thammarat 80161, Thailand, and bDepartment of Chemistry, Faculty of Science, University of Sheffield, Brook Hill, Sheffield S3 7HF, England
*Correspondence e-mail: hdavid@wu.ac.th
The first 31H28N6, is reported. The molecule exhibits a helical conformation with an average twist of 35.1°. In addition, there are C—H⋯π interactions of 3.202 (2) Å between the pyrazole C—H group and neighbouring phenyl groups.
of a second-generation tris(pyrazolyl)methane, namely the title compound, CRelated literature
For related literature, see: Astley et al. (1993); Fujisawa et al. (2004); Goodman & Bateman (2001); Ochando et al. (1997); Pettinari & Pettinari (2005); Reger et al. (2000, 2002); Riche & Pascard-Billy (1974); Declercq & Van Meerssche (1984).
Experimental
Crystal data
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Data collection: SMART (Bruker, 1997); cell SMART; data reduction: SAINT (Bruker, 1997); 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.
Supporting information
10.1107/S1600536808010866/rk2085sup1.cif
contains datablocks I, global. DOI:Structure factors: contains datablock I. DOI: 10.1107/S1600536808010866/rk2085Isup2.hkl
Distilled water (20 ml) was added to a 250 ml flask containing a mixture of HpzPh,Me (6.33 g, 40 mmol) and NBu4Br (0.68 g, 2 mmol). With vigorous stirring Na2CO3 (8.5 g, 80 mmol) was added to the reaction mixture. After cooling CHCl3 (75 ml) was added and the mixture refluxed for four days yielding a dark yellow–orange emulsion. The mixture was allowed to cool to room temperature and filtered through a Buchner funnel. The organic layer was separated from the aqueous layer, washed with water (3 × 30 ml) and dried over sodium sulfate. The solution was filtered to remove the δ 8.42 (s, 1H, CH), 7.77–7.72 [m, 6H, o–H (Ph)], 7.38–7.33 [m, 6H, m–H (Ph)], 7.30–7.28 [m, 3H, p–H, (Ph)], 6.47 [s, 3H, 4–H (pz)] and 2.22 (s, 9H, CH3). It should be noted that I (see Fig. 3) was previously reported as a by–product in the synthesis of more complex tris–(pyrazolyl)methanes (Goodman & Bateman, 2001). However, it was not isolated and the above represents the first designed synthesis of I.
and the solvent removed on a rotary evapourator to give a yellow solid. The solid was redissolved in toluene (70 ml) and a catalytic amount of p–toluenesulfonic acid (0.1 g, 0.53 mmol) was added. The solution was refluxed for a day giving a yellow solution. The solution was then cooled to room temperature, neutralized with a 5% aqueous Na2CO3 solution and washed with distilled water (3 × 15 ml). The solution was then dried over sodium sulfate, filtered and the solvent removed on a rotary evapourator resulting in a light brown solid. The solid was dissolved in CH2Cl2 (20 ml) and chromatographed on a silica gel column that was packed with a CH2Cl2:toluene (1:1) solution. The fractions containing the desired product were combined and the solvent removed by rotary evapouration to give an off–white solid (1.83 g, 29%). Analysis calculated for C31H28N6: C 76.8, H 5.8, N 17.3%; found: C 76.7, H 5.8, N 17.0%. ESI+ MS: (m/z) Anal. Calc. 484.60; found: [MH]+ 485.65. 1H–NMR (CDCl3)H atoms were placed geometrically and refined with a riding model (including torsional freedom for methyl groups) and with Uĩso~ constrained to be 1.2 (1.5 for CH~3~ groups) times U~eq~ of the carrier atom.
The two restraints are generated automatically to prevent the whole structure from wandering in the a– and c–directions. The 1950 Friedel pairs were merged.
Data collection: SMART (Bruker, 1997); cell
SMART (Bruker, 1997); data reduction: SAINT (Bruker, 1997); 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).C31H28N6 | F(000) = 1024 |
Mr = 484.59 | Dx = 1.249 Mg m−3 |
Monoclinic, Cc | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: C -2yc | Cell parameters from 879 reflections |
a = 6.678 (3) Å | θ = 4.6–46.9° |
b = 21.730 (9) Å | µ = 0.08 mm−1 |
c = 17.831 (7) Å | T = 150 K |
β = 94.922 (7)° | Block, colourless |
V = 2578.2 (19) Å3 | 0.38 × 0.34 × 0.21 mm |
Z = 4 |
Bruker SMART CCD area-detector diffractometer | 2932 independent reflections |
Radiation source: Fine-focus sealed tube | 2129 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.039 |
Detector resolution: 100 pixels mm-1 | θmax = 27.6°, θmin = 1.9° |
ϕ and ω scans | h = −8→8 |
Absorption correction: multi-scan (SADABS; Bruker, 1997) | k = −27→25 |
Tmin = 0.972, Tmax = 0.984 | l = −19→22 |
9586 measured reflections |
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)] = 0.041 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.071 | H-atom parameters constrained |
S = 0.98 | w = 1/[σ2(Fo2) + (0.0288P)2] where P = (Fo2 + 2Fc2)/3 |
2932 reflections | (Δ/σ)max < 0.001 |
337 parameters | Δρmax = 0.12 e Å−3 |
2 restraints | Δρmin = −0.14 e Å−3 |
C31H28N6 | V = 2578.2 (19) Å3 |
Mr = 484.59 | Z = 4 |
Monoclinic, Cc | Mo Kα radiation |
a = 6.678 (3) Å | µ = 0.08 mm−1 |
b = 21.730 (9) Å | T = 150 K |
c = 17.831 (7) Å | 0.38 × 0.34 × 0.21 mm |
β = 94.922 (7)° |
Bruker SMART CCD area-detector diffractometer | 2932 independent reflections |
Absorption correction: multi-scan (SADABS; Bruker, 1997) | 2129 reflections with I > 2σ(I) |
Tmin = 0.972, Tmax = 0.984 | Rint = 0.039 |
9586 measured reflections |
R[F2 > 2σ(F2)] = 0.041 | 2 restraints |
wR(F2) = 0.071 | H-atom parameters constrained |
S = 0.98 | Δρmax = 0.12 e Å−3 |
2932 reflections | Δρmin = −0.14 e Å−3 |
337 parameters |
Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'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. |
x | y | z | Uiso*/Ueq | ||
N1 | 0.8396 (3) | 0.83570 (9) | 0.68651 (11) | 0.0408 (5) | |
N2 | 0.6619 (3) | 0.85821 (9) | 0.65488 (11) | 0.0414 (5) | |
N3 | 0.8952 (3) | 0.73399 (9) | 0.73501 (11) | 0.0401 (5) | |
N4 | 1.0565 (3) | 0.69625 (9) | 0.75166 (11) | 0.0399 (5) | |
N5 | 0.7907 (3) | 0.74998 (8) | 0.60399 (11) | 0.0396 (5) | |
N6 | 0.6231 (3) | 0.71502 (9) | 0.61064 (11) | 0.0398 (5) | |
C1 | 0.9043 (4) | 0.77355 (10) | 0.67027 (14) | 0.0420 (6) | |
H1A | 1.0482 | 0.7759 | 0.6589 | 0.050* | |
C2 | 0.9315 (4) | 0.87441 (12) | 0.73918 (14) | 0.0460 (6) | |
C3 | 0.8081 (4) | 0.92398 (12) | 0.74119 (15) | 0.0493 (7) | |
H3A | 0.8289 | 0.9592 | 0.7724 | 0.059* | |
C4 | 0.6429 (4) | 0.91297 (11) | 0.68788 (15) | 0.0410 (6) | |
C5 | 0.4662 (4) | 0.95123 (10) | 0.66896 (14) | 0.0424 (6) | |
C6 | 0.3172 (4) | 0.93283 (12) | 0.61469 (16) | 0.0551 (7) | |
H6A | 0.3321 | 0.8955 | 0.5880 | 0.066* | |
C7 | 0.1474 (5) | 0.96829 (13) | 0.59919 (17) | 0.0646 (8) | |
H7A | 0.0455 | 0.9546 | 0.5625 | 0.077* | |
C8 | 0.1229 (5) | 1.02323 (13) | 0.63600 (19) | 0.0625 (8) | |
H8A | 0.0065 | 1.0477 | 0.6244 | 0.075* | |
C9 | 0.2681 (5) | 1.04169 (12) | 0.68914 (18) | 0.0609 (8) | |
H9A | 0.2528 | 1.0794 | 0.7149 | 0.073* | |
C10 | 0.4385 (4) | 1.00619 (12) | 0.70633 (16) | 0.0548 (7) | |
H10A | 0.5375 | 1.0197 | 0.7442 | 0.066* | |
C11 | 0.7515 (3) | 0.72783 (11) | 0.78425 (14) | 0.0399 (6) | |
C12 | 0.8255 (3) | 0.68485 (11) | 0.83497 (14) | 0.0407 (6) | |
H12A | 0.7622 | 0.6704 | 0.8773 | 0.049* | |
C13 | 1.0131 (3) | 0.66587 (11) | 0.81285 (13) | 0.0372 (6) | |
C14 | 1.1513 (4) | 0.61970 (11) | 0.84821 (14) | 0.0396 (6) | |
C15 | 1.0996 (4) | 0.58720 (12) | 0.91093 (15) | 0.0502 (7) | |
H15A | 0.9766 | 0.5960 | 0.9318 | 0.060* | |
C16 | 1.2253 (5) | 0.54219 (12) | 0.94321 (17) | 0.0597 (8) | |
H16A | 1.1882 | 0.5204 | 0.9861 | 0.072* | |
C17 | 1.4041 (5) | 0.52873 (12) | 0.91364 (17) | 0.0582 (8) | |
H17A | 1.4890 | 0.4972 | 0.9353 | 0.070* | |
C18 | 1.4588 (4) | 0.56126 (12) | 0.85242 (16) | 0.0520 (7) | |
H18A | 1.5836 | 0.5528 | 0.8327 | 0.062* | |
C19 | 1.3338 (4) | 0.60609 (11) | 0.81947 (15) | 0.0443 (6) | |
H19A | 1.3726 | 0.6278 | 0.7768 | 0.053* | |
C20 | 0.8150 (4) | 0.76617 (11) | 0.53141 (14) | 0.0404 (6) | |
C21 | 0.6590 (4) | 0.73918 (10) | 0.48918 (14) | 0.0412 (6) | |
H21A | 0.6326 | 0.7412 | 0.4360 | 0.049* | |
C22 | 0.5452 (4) | 0.70774 (10) | 0.53982 (13) | 0.0377 (6) | |
C23 | 0.3596 (4) | 0.67181 (10) | 0.52414 (14) | 0.0394 (6) | |
C24 | 0.2386 (4) | 0.65752 (11) | 0.58115 (15) | 0.0471 (7) | |
H24A | 0.2784 | 0.6699 | 0.6313 | 0.057* | |
C25 | 0.0610 (4) | 0.62552 (12) | 0.56614 (18) | 0.0548 (7) | |
H25A | −0.0209 | 0.6165 | 0.6058 | 0.066* | |
C26 | 0.0024 (4) | 0.60663 (12) | 0.49386 (19) | 0.0565 (8) | |
H26A | −0.1195 | 0.5844 | 0.4837 | 0.068* | |
C27 | 0.1197 (4) | 0.61980 (12) | 0.43680 (18) | 0.0589 (8) | |
H27A | 0.0792 | 0.6067 | 0.3870 | 0.071* | |
C28 | 0.2975 (4) | 0.65226 (12) | 0.45144 (16) | 0.0521 (7) | |
H28A | 0.3780 | 0.6613 | 0.4114 | 0.063* | |
C29 | 1.1317 (4) | 0.86029 (13) | 0.77999 (16) | 0.0595 (8) | |
H29A | 1.2324 | 0.8556 | 0.7435 | 0.089* | |
H29B | 1.1226 | 0.8220 | 0.8085 | 0.089* | |
H29C | 1.1711 | 0.8940 | 0.8146 | 0.089* | |
C30 | 0.5591 (3) | 0.76287 (12) | 0.78100 (15) | 0.0480 (7) | |
H30A | 0.4767 | 0.7475 | 0.8199 | 0.072* | |
H30B | 0.4864 | 0.7575 | 0.7313 | 0.072* | |
H30C | 0.5879 | 0.8066 | 0.7897 | 0.072* | |
C31 | 0.9840 (4) | 0.80561 (11) | 0.51083 (16) | 0.0507 (7) | |
H31A | 1.1115 | 0.7841 | 0.5231 | 0.076* | |
H31B | 0.9839 | 0.8443 | 0.5391 | 0.076* | |
H31C | 0.9678 | 0.8144 | 0.4567 | 0.076* |
U11 | U22 | U33 | U12 | U13 | U23 | |
N1 | 0.0423 (12) | 0.0441 (11) | 0.0359 (12) | 0.0008 (10) | 0.0025 (9) | −0.0004 (10) |
N2 | 0.0439 (12) | 0.0417 (11) | 0.0386 (13) | 0.0028 (10) | 0.0028 (10) | −0.0013 (9) |
N3 | 0.0347 (11) | 0.0516 (12) | 0.0345 (12) | 0.0015 (10) | 0.0054 (10) | 0.0045 (10) |
N4 | 0.0364 (12) | 0.0466 (12) | 0.0365 (13) | 0.0008 (10) | 0.0019 (9) | 0.0010 (10) |
N5 | 0.0442 (12) | 0.0422 (11) | 0.0328 (12) | 0.0058 (10) | 0.0060 (9) | 0.0017 (10) |
N6 | 0.0423 (12) | 0.0414 (11) | 0.0369 (13) | 0.0030 (10) | 0.0107 (10) | 0.0002 (9) |
C1 | 0.0382 (14) | 0.0485 (14) | 0.0396 (15) | 0.0011 (12) | 0.0062 (11) | 0.0061 (12) |
C2 | 0.0451 (15) | 0.0576 (17) | 0.0359 (15) | −0.0132 (13) | 0.0060 (12) | −0.0006 (12) |
C3 | 0.0578 (17) | 0.0462 (15) | 0.0442 (17) | −0.0088 (14) | 0.0069 (14) | −0.0074 (12) |
C4 | 0.0465 (16) | 0.0419 (14) | 0.0361 (15) | −0.0053 (12) | 0.0126 (12) | −0.0019 (12) |
C5 | 0.0493 (15) | 0.0375 (13) | 0.0416 (16) | −0.0019 (12) | 0.0107 (13) | 0.0032 (12) |
C6 | 0.0687 (19) | 0.0474 (15) | 0.0473 (18) | 0.0085 (15) | −0.0057 (15) | −0.0020 (13) |
C7 | 0.068 (2) | 0.0641 (19) | 0.060 (2) | 0.0108 (17) | −0.0085 (16) | 0.0016 (16) |
C8 | 0.0616 (19) | 0.0496 (17) | 0.078 (2) | 0.0107 (15) | 0.0150 (17) | 0.0142 (16) |
C9 | 0.0630 (19) | 0.0450 (16) | 0.078 (2) | −0.0001 (15) | 0.0269 (17) | −0.0077 (15) |
C10 | 0.0533 (18) | 0.0496 (16) | 0.063 (2) | −0.0092 (14) | 0.0164 (15) | −0.0113 (14) |
C11 | 0.0350 (14) | 0.0517 (15) | 0.0334 (14) | −0.0044 (12) | 0.0053 (11) | −0.0031 (12) |
C12 | 0.0401 (15) | 0.0504 (15) | 0.0322 (15) | −0.0063 (12) | 0.0075 (12) | 0.0014 (12) |
C13 | 0.0401 (15) | 0.0416 (13) | 0.0294 (14) | −0.0063 (11) | −0.0001 (11) | −0.0031 (11) |
C14 | 0.0452 (16) | 0.0396 (13) | 0.0332 (15) | −0.0083 (11) | −0.0006 (12) | −0.0033 (11) |
C15 | 0.0564 (16) | 0.0508 (16) | 0.0432 (17) | −0.0055 (14) | 0.0030 (14) | 0.0046 (14) |
C16 | 0.077 (2) | 0.0524 (17) | 0.0489 (19) | −0.0083 (16) | −0.0014 (17) | 0.0121 (14) |
C17 | 0.076 (2) | 0.0380 (15) | 0.058 (2) | 0.0083 (15) | −0.0095 (17) | −0.0016 (14) |
C18 | 0.0573 (17) | 0.0461 (15) | 0.0511 (18) | 0.0056 (14) | −0.0031 (14) | −0.0081 (14) |
C19 | 0.0487 (15) | 0.0450 (14) | 0.0385 (15) | −0.0038 (12) | 0.0000 (12) | −0.0035 (12) |
C20 | 0.0498 (15) | 0.0391 (13) | 0.0336 (15) | 0.0142 (12) | 0.0100 (12) | 0.0057 (11) |
C21 | 0.0550 (16) | 0.0388 (13) | 0.0300 (14) | 0.0104 (12) | 0.0052 (12) | 0.0031 (11) |
C22 | 0.0464 (15) | 0.0364 (13) | 0.0306 (15) | 0.0123 (11) | 0.0058 (12) | 0.0000 (11) |
C23 | 0.0469 (15) | 0.0329 (12) | 0.0392 (15) | 0.0096 (11) | 0.0071 (12) | 0.0007 (11) |
C24 | 0.0551 (18) | 0.0460 (15) | 0.0415 (17) | 0.0071 (13) | 0.0109 (13) | −0.0008 (13) |
C25 | 0.0552 (18) | 0.0478 (15) | 0.063 (2) | 0.0039 (14) | 0.0157 (16) | 0.0076 (15) |
C26 | 0.0553 (17) | 0.0434 (15) | 0.071 (2) | −0.0035 (13) | 0.0063 (17) | 0.0008 (15) |
C27 | 0.067 (2) | 0.0563 (17) | 0.052 (2) | −0.0106 (16) | −0.0026 (16) | −0.0054 (14) |
C28 | 0.0645 (19) | 0.0527 (16) | 0.0399 (16) | −0.0016 (14) | 0.0089 (13) | −0.0022 (13) |
C29 | 0.0482 (17) | 0.0744 (19) | 0.0541 (19) | −0.0096 (15) | −0.0048 (14) | 0.0007 (15) |
C30 | 0.0402 (15) | 0.0602 (17) | 0.0444 (16) | 0.0039 (13) | 0.0087 (12) | −0.0032 (13) |
C31 | 0.0552 (17) | 0.0533 (16) | 0.0447 (17) | 0.0041 (14) | 0.0098 (13) | 0.0089 (13) |
N1—N2 | 1.360 (3) | C14—C19 | 1.394 (4) |
N1—C2 | 1.367 (3) | C15—C16 | 1.382 (4) |
N1—C1 | 1.455 (3) | C15—H15A | 0.9500 |
N2—C4 | 1.338 (3) | C16—C17 | 1.378 (4) |
N3—C11 | 1.361 (3) | C16—H16A | 0.9500 |
N3—N4 | 1.366 (3) | C17—C18 | 1.376 (4) |
N3—C1 | 1.445 (3) | C17—H17A | 0.9500 |
N4—C13 | 1.328 (3) | C18—C19 | 1.381 (3) |
N5—C20 | 1.364 (3) | C18—H18A | 0.9500 |
N5—N6 | 1.366 (3) | C19—H19A | 0.9500 |
N5—C1 | 1.443 (3) | C20—C21 | 1.364 (3) |
N6—C22 | 1.334 (3) | C20—C31 | 1.488 (3) |
C1—H1A | 1.0000 | C21—C22 | 1.406 (3) |
C2—C3 | 1.358 (4) | C21—H21A | 0.9500 |
C2—C29 | 1.498 (4) | C22—C23 | 1.471 (3) |
C3—C4 | 1.414 (3) | C23—C24 | 1.387 (3) |
C3—H3A | 0.9500 | C23—C28 | 1.393 (4) |
C4—C5 | 1.459 (3) | C24—C25 | 1.381 (4) |
C5—C6 | 1.386 (3) | C24—H24A | 0.9500 |
C5—C10 | 1.388 (3) | C25—C26 | 1.377 (4) |
C6—C7 | 1.379 (4) | C25—H25A | 0.9500 |
C6—H6A | 0.9500 | C26—C27 | 1.366 (4) |
C7—C8 | 1.379 (4) | C26—H26A | 0.9500 |
C7—H7A | 0.9500 | C27—C28 | 1.387 (4) |
C8—C9 | 1.357 (4) | C27—H27A | 0.9500 |
C8—H8A | 0.9500 | C28—H28A | 0.9500 |
C9—C10 | 1.387 (4) | C29—H29A | 0.9800 |
C9—H9A | 0.9500 | C29—H29B | 0.9800 |
C10—H10A | 0.9500 | C29—H29C | 0.9800 |
C11—C12 | 1.363 (3) | C30—H30A | 0.9800 |
C11—C30 | 1.490 (3) | C30—H30B | 0.9800 |
C12—C13 | 1.407 (3) | C30—H30C | 0.9800 |
C12—H12A | 0.9500 | C31—H31A | 0.9800 |
C13—C14 | 1.468 (3) | C31—H31B | 0.9800 |
C14—C15 | 1.391 (3) | C31—H31C | 0.9800 |
N2—N1—C2 | 112.83 (19) | C14—C15—H15A | 119.6 |
N2—N1—C1 | 120.99 (19) | C17—C16—C15 | 120.4 (3) |
C2—N1—C1 | 125.8 (2) | C17—C16—H16A | 119.8 |
C4—N2—N1 | 104.46 (19) | C15—C16—H16A | 119.8 |
C11—N3—N4 | 112.77 (19) | C18—C17—C16 | 119.5 (3) |
C11—N3—C1 | 130.86 (19) | C18—C17—H17A | 120.2 |
N4—N3—C1 | 116.37 (19) | C16—C17—H17A | 120.2 |
C13—N4—N3 | 104.67 (19) | C17—C18—C19 | 120.5 (3) |
C20—N5—N6 | 113.01 (19) | C17—C18—H18A | 119.7 |
C20—N5—C1 | 126.1 (2) | C19—C18—H18A | 119.7 |
N6—N5—C1 | 120.23 (19) | C18—C19—C14 | 120.6 (3) |
C22—N6—N5 | 103.87 (19) | C18—C19—H19A | 119.7 |
N5—C1—N3 | 112.83 (19) | C14—C19—H19A | 119.7 |
N5—C1—N1 | 110.38 (18) | N5—C20—C21 | 105.4 (2) |
N3—C1—N1 | 111.1 (2) | N5—C20—C31 | 122.5 (2) |
N5—C1—H1A | 107.4 | C21—C20—C31 | 132.1 (2) |
N3—C1—H1A | 107.4 | C20—C21—C22 | 106.5 (2) |
N1—C1—H1A | 107.4 | C20—C21—H21A | 126.8 |
C3—C2—N1 | 105.6 (2) | C22—C21—H21A | 126.8 |
C3—C2—C29 | 131.9 (3) | N6—C22—C21 | 111.2 (2) |
N1—C2—C29 | 122.5 (3) | N6—C22—C23 | 119.8 (2) |
C2—C3—C4 | 106.8 (2) | C21—C22—C23 | 129.0 (2) |
C2—C3—H3A | 126.6 | C24—C23—C28 | 117.9 (2) |
C4—C3—H3A | 126.6 | C24—C23—C22 | 120.9 (2) |
N2—C4—C3 | 110.4 (2) | C28—C23—C22 | 121.1 (2) |
N2—C4—C5 | 120.7 (2) | C25—C24—C23 | 121.0 (3) |
C3—C4—C5 | 128.9 (2) | C25—C24—H24A | 119.5 |
C6—C5—C10 | 117.8 (3) | C23—C24—H24A | 119.5 |
C6—C5—C4 | 121.0 (2) | C26—C25—C24 | 120.1 (3) |
C10—C5—C4 | 121.2 (2) | C26—C25—H25A | 119.9 |
C7—C6—C5 | 120.5 (3) | C24—C25—H25A | 119.9 |
C7—C6—H6A | 119.7 | C27—C26—C25 | 120.0 (3) |
C5—C6—H6A | 119.7 | C27—C26—H26A | 120.0 |
C6—C7—C8 | 121.1 (3) | C25—C26—H26A | 120.0 |
C6—C7—H7A | 119.4 | C26—C27—C28 | 120.2 (3) |
C8—C7—H7A | 119.4 | C26—C27—H27A | 119.9 |
C9—C8—C7 | 118.8 (3) | C28—C27—H27A | 119.9 |
C9—C8—H8A | 120.6 | C27—C28—C23 | 120.8 (3) |
C7—C8—H8A | 120.6 | C27—C28—H28A | 119.6 |
C8—C9—C10 | 120.9 (3) | C23—C28—H28A | 119.6 |
C8—C9—H9A | 119.6 | C2—C29—H29A | 109.5 |
C10—C9—H9A | 119.6 | C2—C29—H29B | 109.5 |
C9—C10—C5 | 120.9 (3) | H29A—C29—H29B | 109.5 |
C9—C10—H10A | 119.6 | C2—C29—H29C | 109.5 |
C5—C10—H10A | 119.6 | H29A—C29—H29C | 109.5 |
N3—C11—C12 | 105.1 (2) | H29B—C29—H29C | 109.5 |
N3—C11—C30 | 125.3 (2) | C11—C30—H30A | 109.5 |
C12—C11—C30 | 129.6 (2) | C11—C30—H30B | 109.5 |
C11—C12—C13 | 107.2 (2) | H30A—C30—H30B | 109.5 |
C11—C12—H12A | 126.4 | C11—C30—H30C | 109.5 |
C13—C12—H12A | 126.4 | H30A—C30—H30C | 109.5 |
N4—C13—C12 | 110.3 (2) | H30B—C30—H30C | 109.5 |
N4—C13—C14 | 121.3 (2) | C20—C31—H31A | 109.5 |
C12—C13—C14 | 128.4 (2) | C20—C31—H31B | 109.5 |
C15—C14—C19 | 118.2 (2) | H31A—C31—H31B | 109.5 |
C15—C14—C13 | 120.2 (2) | C20—C31—H31C | 109.5 |
C19—C14—C13 | 121.6 (2) | H31A—C31—H31C | 109.5 |
C16—C15—C14 | 120.7 (3) | H31B—C31—H31C | 109.5 |
C16—C15—H15A | 119.6 |
Experimental details
Crystal data | |
Chemical formula | C31H28N6 |
Mr | 484.59 |
Crystal system, space group | Monoclinic, Cc |
Temperature (K) | 150 |
a, b, c (Å) | 6.678 (3), 21.730 (9), 17.831 (7) |
β (°) | 94.922 (7) |
V (Å3) | 2578.2 (19) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.08 |
Crystal size (mm) | 0.38 × 0.34 × 0.21 |
Data collection | |
Diffractometer | Bruker SMART CCD area-detector diffractometer |
Absorption correction | Multi-scan (SADABS; Bruker, 1997) |
Tmin, Tmax | 0.972, 0.984 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 9586, 2932, 2129 |
Rint | 0.039 |
(sin θ/λ)max (Å−1) | 0.651 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.041, 0.071, 0.98 |
No. of reflections | 2932 |
No. of parameters | 337 |
No. of restraints | 2 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.12, −0.14 |
Computer programs: SMART (Bruker, 1997), SAINT (Bruker, 1997), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).
Acknowledgements
The authors gratefully acknowledge the Institute for Research and Development, Walailak University for supporting this work (grant No. 5/2550).
References
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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.
Tris–(pyrazolyl)methanes (tpzmR,R'), neutral analogues of the more widely studied tris–(pyrazolyl)borates (tpR,R'), are an increasing important class of ligands with a wide variety of coordination and organometallic complexes now reported (Pettinari & Pettinari, 2005). In most of these studies only the simplest members of the series tpzm and tpzmMe,Me which generally form inert sandwich complexes with first row transition metals are utilized (Astley et al., 1993; Reger et al., 2002). In contrast, second generation tris–(pyrazolyl)methane ligands (tpzmPh, tpzmi–Pr and tpzmt–Bu) remain poorly represented owing to their time consuming synthesis and low yields. However, Reger (Reger et al., 2000) recently reported an improved procedure for these ligands, while Fujisawa and co–workers (Fujisawa et al., 2004) have shown that even tzpmi–Pr,i–Pr may be prepared. Structural studies of tris–(pyrazolyl)methanes are even rarer and to date only tpzmMe,Me has been reported (Declercq & Van Meerssche, 1984; Ochando et al., 1997). Herein, we report the synthesis and the first structural characterization of a second generation tris–(pyrazolyl)methane ligand namely, tpzmPh,Me (I).
Colourless block shaped crystals of I were grown from CH2Cl2/n–hexane, the compound crystallizing in a monoclinic Cc space group. The structure of the molecule I is shown on Fig. 1. The pyrazoles are bonded to the central CH–group in a tetrahedral fashion with N—C1—N angles [112.8 (2)°, 110.4 (2)° and 111.1 (2)°] close to the ideal tetrahedral value of 109.5° and similar to those found in tpzmMe,Me [110°, 111°, 111° (Declercq & Van Meerssche, 1984)]. In addition, the structure shows that the methyl groups are in the 5–position of the pyrazole rings with the phenyl rings in the 3–position thereby minimizing steric congestion around the central CH–group and confirming the presence of a single regioisomer.
The propeller–like conformation of the molecule can be defined by the angle between the plane formed by H1A, C1 and the first pyrazole N atom and the mean plane of the pyrazole ring. The values for I are 50.4 (2)°, 18.7 (3)° and 36.3 (2)° and are comparable to those observed in the structures of tpzmMe,Me [the values of each ring averaged over four molecules are 29 (3)°, 23 (2)° and 62 (1)° (Declercq & Van Meerssche, 1984)] and triphenylmethane [30°, 34° and 53°, and 21°, 38° and 47° for each one of the two molecules in the asymmetric unit (Riche & Pascard-Billy, 1974)]. A further method for describing this helical twist is through H1A–C1–N–N torsion angles (Ochando et al., 1997). The torsion angles for I are 133.7 (3)°, -18.3 (4)° and 148.9 (3)° for H1A–C1–N1–N2, H1A–C1–N3–N4 and H1A–C1–N5–N6, respectively. These are in good agreement with the values observed in tpzmMe,Me [121 (1)°, -21 (1)° and 147 (1)° (Declercq & Van Meerssche, 1984)]. Assuming an α–conformation when the torsion angle is negative and β– when positive, it follows that the conformation in the case of I is β–α–β–, identical to the most stable conformer of tpzmMe,Me (Declercq & Van Meerssche, 1984).
The pyrazole bond lengths in I vary between 1.328 (3)Å and 1.414 (3)Å and are very similar to those found in tpzmMe,Me [1.33–1.40Å (Declercq & Van Meerssche, 1984)]. The phenyl rings are essentially co-planar with the pyrazole rings (dihedral angles: 3.4 (1)° and 2.8 (1)°) except in the case of the C20—N5 pyrazole ring in which the dihedral angles between the two planes is 15.7 (2)°.
A further point of interest is the packing within the structure of I which reveals C—H···π interactions between the pyrazole C3—H3 and the centroid of the ring C14/C15/C16/C17/C18/C19 (Cg), the phenyl group attached to the α–pyrazole (Fig. 2). All these interactions occur within a single layer of molecules with adjacent layers, which are related by inversion, exhibiting interactions in the opposite direction. Thus, the interactions H3 (x+1/2, y-1/2, z)···Cg (x, y, z) and H3 (x-1/2, -y+3/2, z-1/2)···Cgii (x-1, -y+1, z-1/2) are both 3.202 (2)Å.