Conformational polymorphism. III. The crystal and molecular structures of form II and form III of iminodiacetic acid

Bernstein, Joel

doi:10.1107/s056774087900354x

Cited by 26 publications

(12 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Notable in the literature is the pioneering work of Hagler and Bernstein, who demonstrated that crystal packing is dominated by van der Waals forces, 39,40 except in crystals where strong intermolecular hydrogen bonding prevails. 41 The atomic coordinates derived from X-ray diffraction represent centers of maximum electron density rather than true nuclear coordinates, making the X-ray structure unsuitable for the calculation of molecular orbitals and electronic transition energies. Most prominently, the carbon hydrogen bond lengths are too short by about 10%, and the calculated potential energy of the X-ray structure is too high by ca.…”

Section: Crystal Structure Refinementmentioning

confidence: 99%

Crystal polymorphism in pendimethalin herbicide is driven by electronic delocalization and changes in intramolecular hydrogen bonding. A crystallographic, spectroscopic and computational study

Stockton¹,

Godfrey²,

Hitchcock³

et al. 1998

J. Chem. Soc., Perkin Trans. 2

View full text Add to dashboard Cite

Pendimethalin, N-(1-ethylpropyl)-3,4-dimethyl-2,6-dinitrobenzenamine, is a potent herbicide that exists in two differently coloured polymorphic crystal habits. Triclinic pendimethalin I (P1 ¯) is the orange-coloured thermodynamically stable form, whereas monoclinic pendimethalin II (P2 1 /c) is a bright-yellow metastable form. The latter is normally produced first upon cooling the molten chemical, whereas the orange form is formed by a polymorphic phase transition which occurs slowly upon long term storage of the yellow form at temperatures below its melting point. Such phase transitions are rapidly revealed by calorimetry. The crystal structures of the polymorphs have been determined using single crystal X-ray diffraction. Solid state NMR spectroscopy, vibrational spectroscopy and UV-VIS spectroscopy were applied to further study the nature of the polymorphism in terms of intra-and inter-molecular properties. Solid state CP-MAS 13 C NMR spectroscopy was shown to be the method of choice for quantitative analysis of polymorphic mixtures. The differences in spectral properties and crystal habits were investigated by computational methods which included molecular exciton, molecular orbital and molecular mechanics calculations. The dramatic colour change from yellow to orange-red during the polymorphic transition is discussed in terms of competing inter-and intra-molecular electronic effects. The driving force for the yellow (II) to orange (I) polymorphic transition is attributed to the change in the electronic delocalization achieved from shortening, strengthening, and partially straightening the 'bent' hydrogen bond between the secondary amino hydrogen and an oxygen of the 6Ј-nitro group. This results in increased overlap between the amino nitrogen's lone pair and the -electron orbitals of the aromatic ring. The calculated lattice stabilization energy due to this process is 4 to 5 kcal mol ؊1 , and the relative lattice energies are consistent with the observed stabilities of the polymorphs. The slow kinetics of the polymorphic transition are largely governed by the steric interaction of the 1-ethylpropyl side chain and the two nitro groups. During crystallization, the more compact side chain conformation required to form the energetically more stable orange (I) polymorph appears to be more difficult to achieve than that required for the yellow (II) polymorph.

show abstract

Section: Crystal Structure Refinementmentioning

confidence: 99%

Crystal polymorphism in pendimethalin herbicide is driven by electronic delocalization and changes in intramolecular hydrogen bonding. A crystallographic, spectroscopic and computational study

Stockton¹,

Godfrey²,

Hitchcock³

et al. 1998

J. Chem. Soc., Perkin Trans. 2

View full text Add to dashboard Cite

show abstract

“…Iminodiacetic acid (12) has three different crystalline HOOCCH2NHCH2COOH 12 forms in which bond angles and distances agree but torsional angles differ. 47 In a large molecule as 13 there perature two different tetragonal crystal structures, in which the molecular structure is the same, that are related by rotation of the molecule around one inertial axis with a major change in unit cell edges but not in cell volume.40,41 p-Dichlorobenzene has three different crystalline phases, all of which can exist at 100 K. 42 It is not clear how the structures can interconvert, but it is quite possible that extensive unpacking and repacking takes place at the transition boundary.43,44 On the other hand, sometimes a phase transition is reversible and a are two conformationally distinct crystal phases at room temperature. 48,49 Charge-transfer dimers and metal complexes with organic ligands forih a vast class of compounds with peculiar properties, a field that would deserve separate reviewing.…”

Section: Phase Transitionsmentioning

confidence: 99%

Crystal chemistry in organic solids

Gavezzotti¹,

Simonetta²

1982

Chem. Rev.

166

View full text Add to dashboard Cite

“…The crystals with several symmetry-independent molecules ( Z ′ > 1) have attracted considerable interest for years. − It was postulated that the increased Z ′ resulted from the inefficient packing of molecules in the crystal structure caused by specific directional interactions. The independent molecules can be present in different states (e.g., tautomers, − conformers, disproportionate molecules and ions, etc. ), and their crystal environment is different.…”

Section: Introductionmentioning

confidence: 99%

High-Pressure Preference for the Low Z′ Polymorph of a Molecular Crystal

Roszak

Katrusiak

2016

Crystal Growth & Design

View full text Add to dashboard Cite

High pressure destabilizes the high Z′ polymorph of 3-hydroxy-4,5-dimethyl-1-phenylpyridazin-6-one (1α); however, recrystallization is needed for obtaining a low Z′, more dense polymorph. Three polymorphs α, β, and γ can be monotonically compressed to 2.0 GPa at least. At ambient pressure 1 crystallizes in space group C2/c, Z′ = 4 as polymorph 1α, or as lower-density polymorph 1β, of space group P21/c and Z′ = 1. Polymorph β is metastable, and after about one year, it transforms to phase α. The isochoric recrystallization above 0.40 GPa yields a new polymorph γ of space group P21/a and Z′ reduced to 1. The γ polymorph retrieved to ambient conditions for months has showed no signs of transformations. The main motif of OH···O bonded chains is retained in all three phases, but high pressure enforced identical conformation of closely packed molecules and their identical crystal environment in phase γ.

show abstract

Conformational polymorphism. III. The crystal and molecular structures of form II and form III of iminodiacetic acid

Cited by 26 publications

References 2 publications

Crystal polymorphism in pendimethalin herbicide is driven by electronic delocalization and changes in intramolecular hydrogen bonding. A crystallographic, spectroscopic and computational study

Crystal polymorphism in pendimethalin herbicide is driven by electronic delocalization and changes in intramolecular hydrogen bonding. A crystallographic, spectroscopic and computational study

Crystal chemistry in organic solids

High-Pressure Preference for the Low Z′ Polymorph of a Molecular Crystal

Contact Info

Product

Resources

About