Two Dimensional Crystallization of Three Solid Lipid A‑Diphosphate Phases

Surface-tension-induced liquid-crystal growth of monomeric lipid A-diphosphate in aqueous dispersions is reported as a function of concentration, (<i>c</i>), and temperature, (<i>T</i>), and at low ionic strength (10^–3 M). As the temperature was varied, a solid–liquid transition was revealed in the surface layer at a fixed lipid A-diphosphate bulk concentration. Here, the development of different two-dimensional (<i>2-d</i>) faceted crystal morphologies was observed and, as growth proceeded, these faceted <i>2-d</i> crystals became unstable. Selected area electron microscopy diffraction (SAED) and X-ray diffraction (XRD) measurements of the faceted <i>2-d</i> crystalline lipid A-diphosphate layers exhibited a pseudohexagonal molecular arrangement. The crystalline layer was a smectic F, <i>S</i>_F, phase below the critical temperature, <i>T</i>_C, and a smectic I, <i>S</i>_I, phase above <i>T</i>_C (15 °C). Both phases could be described in terms of the same C-centered monoclinic unit cell. The in-plane order extended for a limited distance although the layers were coupled. The analysis of the SAED patterns revealed short-range order in the <i>S</i>_F phase (5–15 °C), but long-range order in the <i>S</i>_I phase, for the temperature range 15–30 °C. The observed <i>2-d</i> solid hexatic phase and the <i>2-d</i> liquid hexatic phase had correlation lengths of 220 Å. This, the hexatic phase, displayed short-range in-plane positional order and quasi long-range, sixfold bond-orientational order. The <i>S</i>_I phase showed long-range order characteristics of a hexatic <i>2-d</i> crystal. The two-, four-, or six-layer crystalline lipid A-diphosphate films exhibited <i>2-d</i> hexatic order and 6<i>n</i>-fold bond-orientational order. These films did not evolve into the <i>S</i>_F phase, demonstrating that the two phases were thermodynamically distinct. A finite tilt angle of φ = 15° was calculated for the lipid A-diphosphate molecule; the tilt was toward the small side of the rectangular <i>2-d</i> lattice. The constraint of six close-packed acyl chains in two distinct phases with the same symmetry suggests that the <i>S</i>_F → <i>S</i>_I transition was first-order

Elusive Forms and Structures of <i>N</i>-Hydroxyphthalimide: The Colorless and Yellow Crystal Forms of <i>N</i>-Hydroxyphthalimide

A comprehensive structural characterization of the colorless and yellow forms of N-hydroxyphthalimide (NHP), the deuterated form (NDP), and the ethoxylated form (ethoxy-NHP) has been carried out using single-crystal X-ray diffraction, FTIR and Raman spectroscopies, and scanning electron microscopy. Both NHP and NDP forms crystallize in the monoclinic space group (P21/c, No. 14). The various forms of NHP differ in the way in which the molecules adjoin one another through their N-hydroxyl groups and how the carbonyls of the isoindole-1,3-dione ring differ through intermolecular hydrogen bonding. Although the hydrogen bonding about the b axis is virtually the same, the isoindole-1,3-dione ring experiences different twists for the two NHP forms. Both the colorless and yellow forms of NHP exhibit strong intermolecular hydrogen bonding between O(3) and H(1). In the yellow form, the N-hydroxyl group is significantly out of the plane (∼1.19°), but the N-hydroxyl group in the colorless form is only ∼0.06° out of the plane. Both forms of NHP reveal an infinite chain of intermolecular hydrogen-bonded molecules in the direction of the b axis; however, the molecules are ordered differently within the unit cells. The hydrogen-bond geometry for the yellow form of NHP is O(2)−H(1)···O(3), with an angle of 185°, intermolecular distances of O(2)···O(3) = 2.68 Å and H(1)···O(3) = 1.70 Å, and an intramolecular hydrogen bond of O(1)···H(1) = 1.17 Å. The colorless form of NHP shows an intermolecular hydrogen-bond geometry between O(3) and H(1) with a distance of 1.78 Å; the O(2)−O(3) distance is 2.71 Å. The O(2)−H(1)···O(3) angle is 159°, and the intramolecular distance is O(1)···H(1) = 0.97 Å. The N-ethoxy derivative of NHP crystallizes in an orthorhombic space group (Pnma, No. 62) and exhibits no hydrogen bonding, displaying a strong head-to-tail stacking of the planar rings along the needle axis direction

Elusive Forms and Structures of <i>N</i>-Hydroxyphthalimide: The Colorless and Yellow Crystal Forms of <i>N</i>-Hydroxyphthalimide

A comprehensive structural characterization of the colorless and yellow forms of N-hydroxyphthalimide (NHP), the deuterated form (NDP), and the ethoxylated form (ethoxy-NHP) has been carried out using single-crystal X-ray diffraction, FTIR and Raman spectroscopies, and scanning electron microscopy. Both NHP and NDP forms crystallize in the monoclinic space group (P21/c, No. 14). The various forms of NHP differ in the way in which the molecules adjoin one another through their N-hydroxyl groups and how the carbonyls of the isoindole-1,3-dione ring differ through intermolecular hydrogen bonding. Although the hydrogen bonding about the b axis is virtually the same, the isoindole-1,3-dione ring experiences different twists for the two NHP forms. Both the colorless and yellow forms of NHP exhibit strong intermolecular hydrogen bonding between O(3) and H(1). In the yellow form, the N-hydroxyl group is significantly out of the plane (∼1.19°), but the N-hydroxyl group in the colorless form is only ∼0.06° out of the plane. Both forms of NHP reveal an infinite chain of intermolecular hydrogen-bonded molecules in the direction of the b axis; however, the molecules are ordered differently within the unit cells. The hydrogen-bond geometry for the yellow form of NHP is O(2)−H(1)···O(3), with an angle of 185°, intermolecular distances of O(2)···O(3) = 2.68 Å and H(1)···O(3) = 1.70 Å, and an intramolecular hydrogen bond of O(1)···H(1) = 1.17 Å. The colorless form of NHP shows an intermolecular hydrogen-bond geometry between O(3) and H(1) with a distance of 1.78 Å; the O(2)−O(3) distance is 2.71 Å. The O(2)−H(1)···O(3) angle is 159°, and the intramolecular distance is O(1)···H(1) = 0.97 Å. The N-ethoxy derivative of NHP crystallizes in an orthorhombic space group (Pnma, No. 62) and exhibits no hydrogen bonding, displaying a strong head-to-tail stacking of the planar rings along the needle axis direction

Elusive Forms and Structures of <i>N</i>-Hydroxyphthalimide: The Colorless and Yellow Crystal Forms of <i>N</i>-Hydroxyphthalimide

A comprehensive structural characterization of the colorless and yellow forms of N-hydroxyphthalimide (NHP), the deuterated form (NDP), and the ethoxylated form (ethoxy-NHP) has been carried out using single-crystal X-ray diffraction, FTIR and Raman spectroscopies, and scanning electron microscopy. Both NHP and NDP forms crystallize in the monoclinic space group (P21/c, No. 14). The various forms of NHP differ in the way in which the molecules adjoin one another through their N-hydroxyl groups and how the carbonyls of the isoindole-1,3-dione ring differ through intermolecular hydrogen bonding. Although the hydrogen bonding about the b axis is virtually the same, the isoindole-1,3-dione ring experiences different twists for the two NHP forms. Both the colorless and yellow forms of NHP exhibit strong intermolecular hydrogen bonding between O(3) and H(1). In the yellow form, the N-hydroxyl group is significantly out of the plane (∼1.19°), but the N-hydroxyl group in the colorless form is only ∼0.06° out of the plane. Both forms of NHP reveal an infinite chain of intermolecular hydrogen-bonded molecules in the direction of the b axis; however, the molecules are ordered differently within the unit cells. The hydrogen-bond geometry for the yellow form of NHP is O(2)−H(1)···O(3), with an angle of 185°, intermolecular distances of O(2)···O(3) = 2.68 Å and H(1)···O(3) = 1.70 Å, and an intramolecular hydrogen bond of O(1)···H(1) = 1.17 Å. The colorless form of NHP shows an intermolecular hydrogen-bond geometry between O(3) and H(1) with a distance of 1.78 Å; the O(2)−O(3) distance is 2.71 Å. The O(2)−H(1)···O(3) angle is 159°, and the intramolecular distance is O(1)···H(1) = 0.97 Å. The N-ethoxy derivative of NHP crystallizes in an orthorhombic space group (Pnma, No. 62) and exhibits no hydrogen bonding, displaying a strong head-to-tail stacking of the planar rings along the needle axis direction

Elusive Forms and Structures of <i>N</i>-Hydroxyphthalimide: The Colorless and Yellow Crystal Forms of <i>N</i>-Hydroxyphthalimide

A comprehensive structural characterization of the colorless and yellow forms of N-hydroxyphthalimide (NHP), the deuterated form (NDP), and the ethoxylated form (ethoxy-NHP) has been carried out using single-crystal X-ray diffraction, FTIR and Raman spectroscopies, and scanning electron microscopy. Both NHP and NDP forms crystallize in the monoclinic space group (P21/c, No. 14). The various forms of NHP differ in the way in which the molecules adjoin one another through their N-hydroxyl groups and how the carbonyls of the isoindole-1,3-dione ring differ through intermolecular hydrogen bonding. Although the hydrogen bonding about the b axis is virtually the same, the isoindole-1,3-dione ring experiences different twists for the two NHP forms. Both the colorless and yellow forms of NHP exhibit strong intermolecular hydrogen bonding between O(3) and H(1). In the yellow form, the N-hydroxyl group is significantly out of the plane (∼1.19°), but the N-hydroxyl group in the colorless form is only ∼0.06° out of the plane. Both forms of NHP reveal an infinite chain of intermolecular hydrogen-bonded molecules in the direction of the b axis; however, the molecules are ordered differently within the unit cells. The hydrogen-bond geometry for the yellow form of NHP is O(2)−H(1)···O(3), with an angle of 185°, intermolecular distances of O(2)···O(3) = 2.68 Å and H(1)···O(3) = 1.70 Å, and an intramolecular hydrogen bond of O(1)···H(1) = 1.17 Å. The colorless form of NHP shows an intermolecular hydrogen-bond geometry between O(3) and H(1) with a distance of 1.78 Å; the O(2)−O(3) distance is 2.71 Å. The O(2)−H(1)···O(3) angle is 159°, and the intramolecular distance is O(1)···H(1) = 0.97 Å. The N-ethoxy derivative of NHP crystallizes in an orthorhombic space group (Pnma, No. 62) and exhibits no hydrogen bonding, displaying a strong head-to-tail stacking of the planar rings along the needle axis direction

Elusive Forms and Structures of <i>N</i>-Hydroxyphthalimide: The Colorless and Yellow Crystal Forms of <i>N</i>-Hydroxyphthalimide

A comprehensive structural characterization of the colorless and yellow forms of N-hydroxyphthalimide (NHP), the deuterated form (NDP), and the ethoxylated form (ethoxy-NHP) has been carried out using single-crystal X-ray diffraction, FTIR and Raman spectroscopies, and scanning electron microscopy. Both NHP and NDP forms crystallize in the monoclinic space group (P21/c, No. 14). The various forms of NHP differ in the way in which the molecules adjoin one another through their N-hydroxyl groups and how the carbonyls of the isoindole-1,3-dione ring differ through intermolecular hydrogen bonding. Although the hydrogen bonding about the b axis is virtually the same, the isoindole-1,3-dione ring experiences different twists for the two NHP forms. Both the colorless and yellow forms of NHP exhibit strong intermolecular hydrogen bonding between O(3) and H(1). In the yellow form, the N-hydroxyl group is significantly out of the plane (∼1.19°), but the N-hydroxyl group in the colorless form is only ∼0.06° out of the plane. Both forms of NHP reveal an infinite chain of intermolecular hydrogen-bonded molecules in the direction of the b axis; however, the molecules are ordered differently within the unit cells. The hydrogen-bond geometry for the yellow form of NHP is O(2)−H(1)···O(3), with an angle of 185°, intermolecular distances of O(2)···O(3) = 2.68 Å and H(1)···O(3) = 1.70 Å, and an intramolecular hydrogen bond of O(1)···H(1) = 1.17 Å. The colorless form of NHP shows an intermolecular hydrogen-bond geometry between O(3) and H(1) with a distance of 1.78 Å; the O(2)−O(3) distance is 2.71 Å. The O(2)−H(1)···O(3) angle is 159°, and the intramolecular distance is O(1)···H(1) = 0.97 Å. The N-ethoxy derivative of NHP crystallizes in an orthorhombic space group (Pnma, No. 62) and exhibits no hydrogen bonding, displaying a strong head-to-tail stacking of the planar rings along the needle axis direction

Elusive Forms and Structures of <i>N</i>-Hydroxyphthalimide: The Colorless and Yellow Crystal Forms of <i>N</i>-Hydroxyphthalimide

A comprehensive structural characterization of the colorless and yellow forms of N-hydroxyphthalimide (NHP), the deuterated form (NDP), and the ethoxylated form (ethoxy-NHP) has been carried out using single-crystal X-ray diffraction, FTIR and Raman spectroscopies, and scanning electron microscopy. Both NHP and NDP forms crystallize in the monoclinic space group (P21/c, No. 14). The various forms of NHP differ in the way in which the molecules adjoin one another through their N-hydroxyl groups and how the carbonyls of the isoindole-1,3-dione ring differ through intermolecular hydrogen bonding. Although the hydrogen bonding about the b axis is virtually the same, the isoindole-1,3-dione ring experiences different twists for the two NHP forms. Both the colorless and yellow forms of NHP exhibit strong intermolecular hydrogen bonding between O(3) and H(1). In the yellow form, the N-hydroxyl group is significantly out of the plane (∼1.19°), but the N-hydroxyl group in the colorless form is only ∼0.06° out of the plane. Both forms of NHP reveal an infinite chain of intermolecular hydrogen-bonded molecules in the direction of the b axis; however, the molecules are ordered differently within the unit cells. The hydrogen-bond geometry for the yellow form of NHP is O(2)−H(1)···O(3), with an angle of 185°, intermolecular distances of O(2)···O(3) = 2.68 Å and H(1)···O(3) = 1.70 Å, and an intramolecular hydrogen bond of O(1)···H(1) = 1.17 Å. The colorless form of NHP shows an intermolecular hydrogen-bond geometry between O(3) and H(1) with a distance of 1.78 Å; the O(2)−O(3) distance is 2.71 Å. The O(2)−H(1)···O(3) angle is 159°, and the intramolecular distance is O(1)···H(1) = 0.97 Å. The N-ethoxy derivative of NHP crystallizes in an orthorhombic space group (Pnma, No. 62) and exhibits no hydrogen bonding, displaying a strong head-to-tail stacking of the planar rings along the needle axis direction

Elusive Forms and Structures of <i>N</i>-Hydroxyphthalimide: The Colorless and Yellow Crystal Forms of <i>N</i>-Hydroxyphthalimide

A comprehensive structural characterization of the colorless and yellow forms of N-hydroxyphthalimide (NHP), the deuterated form (NDP), and the ethoxylated form (ethoxy-NHP) has been carried out using single-crystal X-ray diffraction, FTIR and Raman spectroscopies, and scanning electron microscopy. Both NHP and NDP forms crystallize in the monoclinic space group (P21/c, No. 14). The various forms of NHP differ in the way in which the molecules adjoin one another through their N-hydroxyl groups and how the carbonyls of the isoindole-1,3-dione ring differ through intermolecular hydrogen bonding. Although the hydrogen bonding about the b axis is virtually the same, the isoindole-1,3-dione ring experiences different twists for the two NHP forms. Both the colorless and yellow forms of NHP exhibit strong intermolecular hydrogen bonding between O(3) and H(1). In the yellow form, the N-hydroxyl group is significantly out of the plane (∼1.19°), but the N-hydroxyl group in the colorless form is only ∼0.06° out of the plane. Both forms of NHP reveal an infinite chain of intermolecular hydrogen-bonded molecules in the direction of the b axis; however, the molecules are ordered differently within the unit cells. The hydrogen-bond geometry for the yellow form of NHP is O(2)−H(1)···O(3), with an angle of 185°, intermolecular distances of O(2)···O(3) = 2.68 Å and H(1)···O(3) = 1.70 Å, and an intramolecular hydrogen bond of O(1)···H(1) = 1.17 Å. The colorless form of NHP shows an intermolecular hydrogen-bond geometry between O(3) and H(1) with a distance of 1.78 Å; the O(2)−O(3) distance is 2.71 Å. The O(2)−H(1)···O(3) angle is 159°, and the intramolecular distance is O(1)···H(1) = 0.97 Å. The N-ethoxy derivative of NHP crystallizes in an orthorhombic space group (Pnma, No. 62) and exhibits no hydrogen bonding, displaying a strong head-to-tail stacking of the planar rings along the needle axis direction

The Phase Diagram of Charged Colloidal Lipid A-Diphosphate Dispersions

Small-angle X-ray-scattering, light-scattering, and electron microscope experiments were used to determine the phase transitions of colloidal lipid A-diphosphate aqueous dispersions. The phases detected were a correlated liquid phase, a face-centered cubic (Fd3m) and a body-centered cubic (Im3m) colloidal crystal phase and a new glass phase. These experimentally determined phases were shown to be in accord with theoretically predicted equilibrium phases

Nucleation of Calcium Carbonate as Polymorphic Crystals in the Presence of Lipid A-Diphosphate

The well-defined structure of lipid A-diphosphate in aqueous solutions provides a way of observing the formation of calcium carbonate crystals. The crystals are either tetrahedral or rhombohedral calcite at a volume fraction of ϕ = 5.4 × 10−4 at pH 5.8 or the vaterite polymorph of CaCO3 at a volume fraction of ϕ = 7.8 × 10−4 at pH 5.8. In both cases, nucleation, adsorption pH, and the shape-dependent template of lipid A-diphosphate control the formation of the calcite and vaterite