2-[3-(Trifluoro­meth­yl)phen­yl]perhydro-1,2,4-triazolo[1,2-a]pyridazine-1,3-dione

Sun, Z.-G.; Li, X.-Q.; Xu, W.; Du, X.-H.

doi:10.1107/S1600536807039748

Buy article online - an online subscription or single-article purchase is required to access this article.

2-[3-(Trifluoromethyl)phenyl]perhydro-1,2,4-triazolo[1,2-a]pyridazine-1,3-dione

Z.-G. Sun, X.-Q. Li, W. Xu and X.-H. Du

In the title compound, C₁₃H₁₂F₃N₃O₂, the tetrahydropyridazine ring adopts a chair conformation. The amide ring is twisted away from the attached benzene ring by 27.3 (2)°. The F atoms are disordered over two positions, with site occupancy factors of 0.52 (2) and 0.48 (2).

Read article Similar articles

Supporting information

	Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536807039748/cs2041sup1.cif Contains datablocks global, I
	Structure factor file (CIF format) https://doi.org/10.1107/S1600536807039748/cs2041Isup2.hkl Contains datablock I

CCDC reference: 660310

checkCIF report

Key indicators

Single-crystal X-ray study
T = 293 K
Mean (C-C) = 0.003 Å
Disorder in main residue
R factor = 0.056
wR factor = 0.148
Data-to-parameter ratio = 11.0

checkCIF/PLATON results

No syntax errors found



Alert level B
PLAT242_ALERT_2_B Check Low       Ueq as Compared to Neighbors for        C13

Alert level C
ABSTM02_ALERT_3_C  The ratio of expected to reported Tmax/Tmin(RR') is < 0.90
            Tmin and Tmax reported:      0.751     1.000
            Tmin(prime) and Tmax expected:      0.934     0.961
            RR(prime) =      0.773
            Please check that your absorption correction is appropriate.
RINTA01_ALERT_3_C  The value of Rint is greater than 0.10
            Rint given   0.131
PLAT020_ALERT_3_C The value of Rint is greater than 0.10 .........       0.13
PLAT061_ALERT_3_C Tmax/Tmin Range Test RR' too Large .............       0.77
PLAT062_ALERT_4_C Rescale T(min) & T(max) by .....................       0.96
PLAT125_ALERT_4_C No _symmetry_space_group_name_Hall Given .......          ?
PLAT213_ALERT_2_C Atom F2'     has ADP max/min Ratio .............       3.60 oblat
PLAT301_ALERT_3_C Main Residue  Disorder .........................      13.00 Perc.
PLAT779_ALERT_2_C Suspect or Irrelevant (Bond) Angle in CIF ......      19.80 Deg.
              F1'  -C13  -F1      1.555   1.555   1.555
PLAT779_ALERT_2_C Suspect or Irrelevant (Bond) Angle in CIF ......      31.00 Deg.
              F3   -C13  -F3'     1.555   1.555   1.555
PLAT779_ALERT_2_C Suspect or Irrelevant (Bond) Angle in CIF ......      21.30 Deg.
              F2'  -C13  -F2      1.555   1.555   1.555

Alert level G
ABSTM02_ALERT_3_G  When printed, the submitted absorption T values will be
            replaced by the scaled T values. Since the ratio of scaled T's
            is identical to the ratio of reported T values, the scaling
            does not imply a change to the absorption corrections used in
            the study.
            Ratio of Tmax expected/reported      0.961
            Tmax scaled      0.961 Tmin scaled      0.722
PLAT199_ALERT_1_G Check the Reported _cell_measurement_temperature        293 K
PLAT200_ALERT_1_G Check the Reported _diffrn_ambient_temperature .        293 K
PLAT860_ALERT_3_G Note: Number of Least-Squares Restraints .......          6

   0 ALERT level A = In general: serious problem
   1 ALERT level B = Potentially serious problem
  11 ALERT level C = Check and explain
   4 ALERT level G = General alerts; check

   2 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   5 ALERT type 2 Indicator that the structure model may be wrong or deficient
   7 ALERT type 3 Indicator that the structure quality may be low
   2 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

Comment top

The title compound, (I), shows pesticidal activity. X-ray analysis was undertaken in order to establish its structure. The tetrahydropyridazine ring adopts a chair conformation and the five-membered ring lies close to the plane of the molecule. The C1—N1—C7—C12 torsion angle is 27.3 (2)°.

Related literature top

For related literature, see: Li et al. (2007).

Experimental top

Perhydropyridazine-1-carboxylic acid (3-trifluoromethylphenyl)-amide was prepared as described by Li et al. (2007). To a solution of perhydropyridazine-1-carboxylic acid (3-trifluoromethylphenyl)-amide (1.37 g, 5 mmol) in 1.2-dichloroethane (10 ml) were added the solution of bis(trichloromethyl)carbonate (0.59 g, 2 mmol) and pyridine (0.79 g, 10 mmol) in 1.2-dichloroethane (10 ml). The mixture was stirred at room temperature for 24 h. After the completion of the reaction, the mixture was washed with water and extracted with diethyl ether. The solvent was removed under reduced pressure and the residue was purified by silica gel column chromatography (eluant: petroleum ether-ethyl acetate, 1:1). Single crystals were obtained by slow evaporation of a petroleum ether-ethyl acetate solution (v/v: 1/1) (m.p. 417–418 K).

Structure description top

For related literature, see: Li et al. (2007).

Computing details top

Data collection: SMART (Bruker, 2001); cell refinement: SAINT-Plus (Bruker, 2000); data reduction: SAINT-Plus (Bruker, 2000); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Bruker, 2000); software used to prepare material for publication: SHELXTL (Bruker, 2000).

Figures top

Fig. 1. The molecular structure of (I), showing the atom-labelling scheme with only one disorder component of the –CF3 group. Displacement ellipsoids are drawn at the 30% probability level.

2-[3-(Trifluoromethyl)phenyl]perhydro-1,2,4-triazolo[1,2-a]pyridazine-1,3-dione top

Crystal data top

C₁₃H₁₂F₃N₃O₂	F(000) = 308
M_r = 299.26	D_x = 1.514 Mg m⁻³
Triclinic, P1	Melting point: 417 K
a = 6.8348 (9) Å	Mo Kα radiation, λ = 0.71073 Å
b = 8.0756 (11) Å	Cell parameters from 1670 reflections
c = 12.0770 (17) Å	θ = 6.0–53.0°
α = 90.994 (2)°	µ = 0.13 mm⁻¹
β = 98.153 (2)°	T = 293 K
γ = 95.630 (3)°	Prism, colourless
V = 656.34 (15) Å³	0.50 × 0.37 × 0.30 mm
Z = 2

Data collection top

Bruker SMART APEX diffractometer	2409 independent reflections
Radiation source: fine-focus sealed tube	1887 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.131
φ and ω scans	θ_max = 25.5°, θ_min = 1.7°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −7→8
T_min = 0.751, T_max = 1.000	k = −9→9
3486 measured reflections	l = −14→14

Refinement top

Refinement on F²	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F² > 2σ(F²)] = 0.056	H-atom parameters constrained
wR(F²) = 0.148	w = 1/[σ²(F_o²) + (0.0885P)²] where P = (F_o² + 2F_c²)/3
S = 0.97	(Δ/σ)_max = 0.021
2409 reflections	Δρ_max = 0.28 e Å⁻³
219 parameters	Δρ_min = −0.27 e Å⁻³
6 restraints	Extinction correction: SHELXL97 (Sheldrick, 1997), Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.37 (3)

Crystal data top

C₁₃H₁₂F₃N₃O₂	γ = 95.630 (3)°
M_r = 299.26	V = 656.34 (15) Å³
Triclinic, P1	Z = 2
a = 6.8348 (9) Å	Mo Kα radiation
b = 8.0756 (11) Å	µ = 0.13 mm⁻¹
c = 12.0770 (17) Å	T = 293 K
α = 90.994 (2)°	0.50 × 0.37 × 0.30 mm
β = 98.153 (2)°

Data collection top

Bruker SMART APEX diffractometer	2409 independent reflections
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	1887 reflections with I > 2σ(I)
T_min = 0.751, T_max = 1.000	R_int = 0.131
3486 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.056	6 restraints
wR(F²) = 0.148	H-atom parameters constrained
S = 0.97	Δρ_max = 0.28 e Å⁻³
2409 reflections	Δρ_min = −0.27 e Å⁻³
219 parameters

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq	Occ. (<1)
F1	0.0262 (13)	0.720 (3)	0.0498 (10)	0.156 (5)	0.48 (2)
F2	−0.188 (2)	0.8924 (8)	0.0078 (9)	0.145 (4)	0.48 (2)
F3	−0.2579 (15)	0.6501 (15)	−0.0441 (6)	0.095 (3)	0.48 (2)
F1'	0.0267 (11)	0.7751 (13)	0.0497 (7)	0.099 (3)	0.52 (2)
F2'	−0.2280 (14)	0.8564 (18)	−0.0211 (9)	0.151 (4)	0.52 (2)
F3'	−0.185 (3)	0.599 (2)	−0.0220 (14)	0.164 (5)	0.52 (2)
O1	0.1920 (2)	0.91691 (18)	0.39839 (12)	0.0596 (5)
O2	−0.2422 (2)	0.56464 (18)	0.56622 (13)	0.0639 (5)
N1	−0.0668 (2)	0.73406 (17)	0.45001 (12)	0.0402 (4)
N2	0.1823 (2)	0.83107 (19)	0.57773 (13)	0.0468 (4)
N3	0.0621 (2)	0.70819 (19)	0.62498 (13)	0.0478 (4)
C1	0.1134 (3)	0.8360 (2)	0.46708 (15)	0.0429 (5)
C2	−0.1003 (3)	0.6587 (2)	0.54966 (16)	0.0444 (5)
C3	0.3904 (3)	0.8445 (3)	0.62633 (17)	0.0532 (5)
H3A	0.4637	0.9350	0.5931	0.064*
H3B	0.4471	0.7422	0.6119	0.064*
C4	0.4049 (3)	0.8771 (3)	0.75127 (17)	0.0573 (6)
H4A	0.5414	0.8740	0.7860	0.069*
H4B	0.3666	0.9872	0.7651	0.069*
C5	0.2722 (4)	0.7491 (3)	0.80320 (17)	0.0581 (6)
H5A	0.2747	0.7795	0.8815	0.070*
H5B	0.3234	0.6416	0.7995	0.070*
C6	0.0601 (3)	0.7350 (3)	0.74499 (16)	0.0558 (5)
H6A	−0.0170	0.6425	0.7738	0.067*
H6B	0.0001	0.8362	0.7582	0.067*
C7	−0.1960 (3)	0.7115 (2)	0.34650 (15)	0.0397 (4)
C8	−0.3976 (3)	0.6728 (2)	0.34434 (18)	0.0488 (5)
H8	−0.4502	0.6599	0.4110	0.059*
C9	−0.5213 (3)	0.6532 (2)	0.24317 (19)	0.0550 (5)
H9	−0.6568	0.6252	0.2421	0.066*
C10	−0.4459 (3)	0.6747 (2)	0.14363 (18)	0.0533 (5)
H10	−0.5299	0.6633	0.0757	0.064*
C11	−0.2447 (3)	0.7132 (2)	0.14634 (16)	0.0465 (5)
C12	−0.1173 (3)	0.7311 (2)	0.24693 (15)	0.0431 (5)
H12	0.0187	0.7558	0.2478	0.052*
C13	−0.1607 (4)	0.7390 (3)	0.03994 (19)	0.0678 (7)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
F1	0.080 (6)	0.239 (15)	0.068 (4)	0.077 (8)	0.036 (4)	0.025 (7)
F2	0.181 (12)	0.073 (4)	0.084 (5)	−0.024 (5)	0.068 (6)	0.030 (3)
F3	0.101 (4)	0.137 (6)	0.034 (2)	−0.039 (3)	0.004 (2)	−0.019 (3)
F1'	0.076 (5)	0.169 (5)	0.045 (3)	−0.041 (5)	0.018 (3)	0.015 (2)
F2'	0.131 (5)	0.163 (13)	0.069 (4)	0.063 (6)	0.011 (3)	0.082 (5)
F3'	0.162 (13)	0.134 (7)	0.110 (7)	−0.058 (7)	0.102 (7)	−0.063 (6)
O1	0.0457 (8)	0.0851 (10)	0.0442 (8)	−0.0150 (7)	0.0069 (6)	0.0176 (7)
O2	0.0486 (9)	0.0841 (10)	0.0579 (9)	−0.0113 (7)	0.0145 (7)	0.0199 (8)
N1	0.0305 (8)	0.0538 (9)	0.0377 (8)	0.0042 (6)	0.0091 (6)	0.0052 (6)
N2	0.0362 (9)	0.0661 (10)	0.0383 (8)	−0.0009 (7)	0.0095 (6)	0.0085 (7)
N3	0.0411 (9)	0.0651 (10)	0.0384 (9)	0.0008 (7)	0.0121 (7)	0.0101 (7)
C1	0.0336 (10)	0.0569 (11)	0.0391 (10)	0.0034 (7)	0.0083 (7)	0.0050 (8)
C2	0.0355 (10)	0.0562 (10)	0.0434 (10)	0.0045 (8)	0.0122 (8)	0.0092 (8)
C3	0.0367 (11)	0.0726 (13)	0.0494 (12)	0.0034 (9)	0.0046 (8)	0.0050 (9)
C4	0.0580 (13)	0.0657 (12)	0.0454 (11)	0.0077 (10)	−0.0032 (9)	0.0039 (9)
C5	0.0684 (15)	0.0678 (12)	0.0393 (11)	0.0164 (10)	0.0048 (9)	0.0073 (9)
C6	0.0599 (13)	0.0737 (13)	0.0381 (11)	0.0107 (10)	0.0174 (9)	0.0105 (9)
C7	0.0339 (9)	0.0452 (9)	0.0413 (10)	0.0065 (7)	0.0079 (7)	0.0036 (7)
C8	0.0353 (10)	0.0599 (11)	0.0533 (12)	0.0066 (8)	0.0122 (8)	0.0029 (9)
C9	0.0312 (10)	0.0677 (12)	0.0643 (13)	0.0034 (8)	0.0027 (9)	0.0014 (10)
C10	0.0460 (11)	0.0588 (12)	0.0514 (12)	0.0056 (8)	−0.0056 (9)	0.0014 (9)
C11	0.0458 (11)	0.0500 (10)	0.0431 (11)	0.0041 (8)	0.0043 (8)	0.0031 (8)
C12	0.0340 (10)	0.0532 (10)	0.0425 (10)	0.0036 (7)	0.0079 (8)	0.0032 (8)
C13	0.0696 (17)	0.0860 (17)	0.0429 (13)	−0.0120 (13)	0.0051 (11)	0.0021 (12)

Geometric parameters (Å, º) top

F1—C13	1.290 (9)	C4—C5	1.511 (3)
F2—C13	1.327 (7)	C4—H4A	0.9700
F3—C13	1.295 (7)	C4—H4B	0.9700
F1'—C13	1.273 (7)	C5—C6	1.511 (3)
F2'—C13	1.291 (7)	C5—H5A	0.9700
F3'—C13	1.326 (10)	C5—H5B	0.9700
O1—C1	1.217 (2)	C6—H6A	0.9700
O2—C2	1.214 (2)	C6—H6B	0.9700
N1—C2	1.396 (2)	C7—C8	1.380 (3)
N1—C1	1.400 (2)	C7—C12	1.390 (2)
N1—C7	1.422 (2)	C8—C9	1.381 (3)
N2—C1	1.355 (3)	C8—H8	0.9300
N2—N3	1.406 (2)	C9—C10	1.381 (3)
N2—C3	1.453 (3)	C9—H9	0.9300
N3—C2	1.354 (3)	C10—C11	1.376 (3)
N3—C6	1.464 (3)	C10—H10	0.9300
C3—C4	1.515 (3)	C11—C12	1.387 (3)
C3—H3A	0.9700	C11—C13	1.490 (3)
C3—H3B	0.9700	C12—H12	0.9300

C2—N1—C1	109.80 (15)	C8—C7—C12	120.05 (18)
C2—N1—C7	125.31 (15)	C8—C7—N1	120.65 (16)
C1—N1—C7	124.89 (15)	C12—C7—N1	119.29 (16)
C1—N2—N3	108.32 (15)	C7—C8—C9	119.93 (19)
C1—N2—C3	125.36 (15)	C7—C8—H8	120.0
N3—N2—C3	114.04 (15)	C9—C8—H8	120.0
C2—N3—N2	109.04 (14)	C10—C9—C8	120.72 (19)
C2—N3—C6	124.67 (16)	C10—C9—H9	119.6
N2—N3—C6	113.84 (17)	C8—C9—H9	119.6
O1—C1—N2	126.13 (18)	C11—C10—C9	119.07 (19)
O1—C1—N1	127.85 (18)	C11—C10—H10	120.5
N2—C1—N1	106.00 (15)	C9—C10—H10	120.5
O2—C2—N3	126.31 (18)	C10—C11—C12	121.19 (18)
O2—C2—N1	127.89 (19)	C10—C11—C13	119.88 (18)
N3—C2—N1	105.78 (15)	C12—C11—C13	118.92 (18)
N2—C3—C4	108.52 (15)	C11—C12—C7	119.03 (17)
N2—C3—H3A	110.0	C11—C12—H12	120.5
C4—C3—H3A	110.0	C7—C12—H12	120.5
N2—C3—H3B	110.0	F1'—C13—F1	19.8 (11)
C4—C3—H3B	110.0	F1'—C13—F2'	102.7 (6)
H3A—C3—H3B	108.4	F1—C13—F2'	119.0 (9)
C5—C4—C3	111.21 (18)	F1'—C13—F3	121.8 (6)
C5—C4—H4A	109.4	F1—C13—F3	110.6 (8)
C3—C4—H4A	109.4	F2'—C13—F3	80.6 (6)
C5—C4—H4B	109.4	F1'—C13—F3'	101.7 (9)
C3—C4—H4B	109.4	F1—C13—F3'	85.2 (8)
H4A—C4—H4B	108.0	F2'—C13—F3'	108.5 (8)
C4—C5—C6	112.16 (17)	F3—C13—F3'	31.0 (10)
C4—C5—H5A	109.2	F1'—C13—F2	90.1 (7)
C6—C5—H5A	109.2	F1—C13—F2	109.1 (9)
C4—C5—H5B	109.2	F2'—C13—F2	21.3 (6)
C6—C5—H5B	109.2	F3—C13—F2	101.7 (5)
H5A—C5—H5B	107.9	F3'—C13—F2	128.5 (8)
N3—C6—C5	108.21 (15)	F1'—C13—C11	116.0 (4)
N3—C6—H6A	110.1	F1—C13—C11	113.0 (6)
C5—C6—H6A	110.1	F2'—C13—C11	115.8 (5)
N3—C6—H6B	110.1	F3—C13—C11	113.8 (5)
C5—C6—H6B	110.1	F3'—C13—C11	110.9 (6)
H6A—C6—H6B	108.4	F2—C13—C11	107.9 (4)

C1—N2—N3—C2	−10.91 (19)	C2—N3—C6—C5	166.81 (17)
C3—N2—N3—C2	−155.52 (16)	N2—N3—C6—C5	−55.5 (2)
C1—N2—N3—C6	−155.05 (16)	C4—C5—C6—N3	52.4 (2)
C3—N2—N3—C6	60.3 (2)	C2—N1—C7—C8	28.0 (3)
N3—N2—C1—O1	−172.91 (17)	C1—N1—C7—C8	−151.84 (17)
C3—N2—C1—O1	−33.3 (3)	C2—N1—C7—C12	−152.87 (16)
N3—N2—C1—N1	8.75 (18)	C1—N1—C7—C12	27.3 (2)
C3—N2—C1—N1	148.32 (18)	C12—C7—C8—C9	0.1 (3)
C2—N1—C1—O1	177.87 (19)	N1—C7—C8—C9	179.26 (16)
C7—N1—C1—O1	−2.3 (3)	C7—C8—C9—C10	−1.1 (3)
C2—N1—C1—N2	−3.83 (18)	C8—C9—C10—C11	1.1 (3)
C7—N1—C1—N2	176.00 (14)	C9—C10—C11—C12	−0.2 (3)
N2—N3—C2—O2	−173.49 (18)	C9—C10—C11—C13	−179.22 (19)
C6—N3—C2—O2	−34.1 (3)	C10—C11—C12—C7	−0.8 (3)
N2—N3—C2—N1	8.17 (19)	C13—C11—C12—C7	178.26 (18)
C6—N3—C2—N1	147.51 (17)	C8—C7—C12—C11	0.8 (3)
C1—N1—C2—O2	178.92 (19)	N1—C7—C12—C11	−178.35 (15)
C7—N1—C2—O2	−0.9 (3)	C10—C11—C13—F1	−158.8 (11)
C1—N1—C2—N3	−2.77 (18)	C12—C11—C13—F1	22.2 (12)
C7—N1—C2—N3	177.40 (15)	C10—C11—C13—F3	−31.7 (7)
C1—N2—C3—C4	165.83 (17)	C12—C11—C13—F3	149.3 (7)
N3—N2—C3—C4	−56.6 (2)	C10—C11—C13—F2	80.4 (7)
N2—C3—C4—C5	52.8 (2)	C12—C11—C13—F2	−98.6 (7)
C3—C4—C5—C6	−53.3 (2)

Experimental details

Crystal data
Chemical formula	C₁₃H₁₂F₃N₃O₂
M_r	299.26
Crystal system, space group	Triclinic, P1
Temperature (K)	293
a, b, c (Å)	6.8348 (9), 8.0756 (11), 12.0770 (17)
α, β, γ (°)	90.994 (2), 98.153 (2), 95.630 (3)
V (Å³)	656.34 (15)
Z	2
Radiation type	Mo Kα
µ (mm⁻¹)	0.13
Crystal size (mm)	0.50 × 0.37 × 0.30

Data collection
Diffractometer	Bruker SMART APEX
Absorption correction	Multi-scan (SADABS; Sheldrick, 1996)
T_min, T_max	0.751, 1.000
No. of measured, independent and observed [I > 2σ(I)] reflections	3486, 2409, 1887
R_int	0.131
(sin θ/λ)_max (Å⁻¹)	0.606

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.056, 0.148, 0.97
No. of reflections	2409
No. of parameters	219
No. of restraints	6
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.28, −0.27

Computer programs: SMART (Bruker, 2001), SAINT-Plus (Bruker, 2000), SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), SHELXTL (Bruker, 2000).

Subscribe to Acta Crystallographica Section E: Crystallographic Communications

Buy online

You may purchase this article in PDF and/or HTML formats. For purchasers in the European Community who do not have a VAT number, VAT will be added at the local rate. Payments to the IUCr are handled by WorldPay, who will accept payment by credit card in several currencies. To purchase the article, please complete the form below (fields marked * are required), and then click on `Continue'.

E-mail address*
Repeat e-mail address* (for error checking)

Format*	PDF (US $40)
	HTML (US $40)
	PDF+HTML (US $50)
In order for VAT to be shown for your country javascript needs to be enabled.

VAT number (non-UK EC countries only)
Country*

Terms and conditions of use
Contact us

Format		BIBTeX
		EndNote
		RefMan
		Refer
		Medline
		CIF
		SGML
		Text
		Plain Text

Format		BIBTeX
		EndNote
		RefMan
		Refer
		Medline
		CIF
		SGML
		Text
		Plain Text

Search IUCr Journals		doi		Advanced search
Author		volume	page