Review Article

Crystal Packing and Supramolecular Motifs in Four Phenoxyalkanoic Acid Herbicides—Low-Temperature Redeterminations

Table 1

Crystal data and structural refinement details for compounds 14.

1234

Empirical formulaC9H9ClO3C10H11ClO3C8H6Cl2O3C10H10Cl2O3
Formula weight200.61214.64221.03249.08
Crystal systemTriclinicMonoclinicTriclinicTriclinic
Space group −1 21/ −1 −1
a (Å)5.0867 (3)4.2261 (3)7.1246 (2)7.4845 (4)
b (Å)7.7824 (4)6.8196 (5)7.8399 (2)8.7892 (5)
c (Å)12.2134 (7)35.176 (3)8.8991 (3)9.3777 (4)
α  (°)73.933 (1)9090.654 (1)81.0720 (14)
β  (°)84.610 (2)91.801 (2)104.565 (1)69.5538 (13)
γ  (°)77.009 (1)90110.527 (1)65.3163 (12)
(Å3), Z 452.45 (4), 21013.28 (13), 4447.82 (2), 2525.18 (5), 2
calc (g/cm3)1.4721.4071.6391.575
F(000)208448224256
Temperature (K)90909090
Radiation type, wavelength (Å)Mo Kα, 0.71073Mo Kα, 0.71073Mo Kα, 0.71073Mo Kα, 0.71073
Absorption coeff. (mm-1)0.3910.3540.6920.600
Theta range (°)1.7–27.02.3–25.02.4–27.02.3–27.0
Limiting indices, h, k, l −6 6,
−9 9,
−15 15
−5 5,
−8 8,
−41 41
−9 9,
−10 10,
−11 11
−9 9,
−11 11,
−11 11
Reflections collected986417135977711607
Unique reflections1974 [ int  = 0.0233]1756 [ int  = 0.0208]1928 [ int  = 0.0148]2287 [ int  = 0.0148]
Completeness to 99.7%99.7%99.2%99.6%
Data/Restraints/Parameters1974/0/1541756/0/1711928/0/1432287/0/176
Goodness-of-fit on 1.131.271.071.03
Final indices [I > 2σ(I)] = 0.0308,
= 0.0860
= 0.0347,
= 0.0811
= 0.0199,
= 0.0523
= 0.0206,
= 0.0583
Final indices [all data] = 0.0316,
= 0.0864
= 0.0349,
= 0.0812
= 0.0201,
= 0.0525
= 0.0209,
= 0.0585
Largest diff. peak and hole (e −3)0.398, −0.2720.274, −0.2280.407, −0.1930.404, −0.217

Compound 1: weight = 1/[σ 2( ) + (0.0418 )2 + 0.2516 ], where = (max( , 0) + 2 )/3,
Compound 2: weight = 1/[σ 2( ) + (0.0189 )2 + 1.0828 ], where = (max( , 0) + 2 )/3,
Compound 3: weight = 1/[σ 2( ) + (0.0235 )2 + 0.2140 ], where = (max( , 0) + 2 )/3,
Compound 4: weight = 1/[σ 2( ) + (0.0329 )2 + 0.2198 ], where = (max( , 0) + 2 )/3.