Structural Features, Phase Relationships and Transformation Behavior of the Polymorphs I−VI of Phenobarbital

Zencirci, Neslihan; Gelbrich, Thomas; Apperley, David C.; Harris, Robin K.; Kahlenberg, Volker; Griesser, Ulrich J.

doi:10.1021/cg901062n

Cited by 52 publications

(41 citation statements)

References 51 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Experimental solid-state NMR data under magic angle spinning (MAS) conditions were taken from the literature. CSD reference codes and citations to the experimental data for each crystal are given as follows: Acetaminophen: 27,80 form I (HXACAN26 81 ), form II (HXACAN23 82 ), and form III (HXACAN29 83 ); Phenobarbital: 19 form II (PHBARB06 84 ) and form III (PHBARB09 85 ); Testosterone: 17 α form (TESTON10 86 ) and β (monohydrate) form (TESTOM01 87 ).…”

Section: Computational Methodsmentioning

confidence: 99%

Enhanced NMR Discrimination of Pharmaceutically Relevant Molecular Crystal Forms through Fragment-Based Ab Initio Chemical Shift Predictions

Hartman

Day

Beran

2016

Crystal Growth & Design

View full text Add to dashboard Cite

Chemical shift prediction plays an important role in the determination or validation of crystal structures with solid-state nuclear magnetic resonance (NMR) spectroscopy. One of the fundamental theoretical challenges lies in discriminating variations in chemical shifts resulting from different crystallographic environments. Fragment-based electronic structure methods provide an alternative to the widely used plane wave gauge-including projector augmented wave (GIPAW) density functional technique for chemical shift prediction. Fragment methods allow hybrid density functionals to be employed routinely in chemical shift prediction, and we have recently demonstrated appreciable improvements in the accuracy of the predicted shifts when using the hybrid PBE0 functional instead of generalized gradient approximation (GGA) functionals like PBE. Here, we investigate the solid-state 13C and 15N NMR spectra for multiple crystal forms of acetaminophen, phenobarbital, and testosterone. We demonstrate that the use of the hybrid density functional instead of a GGA provides both higher accuracy in the chemical shifts and increased discrimination among the different crystallographic environments. Finally, these results also provide compelling evidence for the transferability of the linear regression parameters mapping predicted chemical shieldings to chemical shifts that were derived in an earlier study.

show abstract

Section: Computational Methodsmentioning

confidence: 99%

Enhanced NMR Discrimination of Pharmaceutically Relevant Molecular Crystal Forms through Fragment-Based Ab Initio Chemical Shift Predictions

Hartman

Day

Beran

2016

Crystal Growth & Design

View full text Add to dashboard Cite

show abstract

“…The escaping of NMP molecules led to the changes in packing and conformation . With increasing temperature, molecular restriction and heterogeneous nucleation of SD occurred on the surface of the particle . As the temperature continued to rise, the fine grains grew rapidly.…”

Section: Resultsmentioning

confidence: 99%

Crystal Structures and Phase Behavior of Sulfadiazine and a Method for the Preparation of Aggregates with Good Performance

Chen

et al. 2018

Chem Eng & Technol

View full text Add to dashboard Cite

The solvate and the solvent-free form of sulfadiazine (SD) were investigated. SD was found to exist in one solvent-free form and the N-methylpyrrolidone (NMP) solvate form. The NMP solvate was shown to be a channel-type compound. The intrinsic properties of the solvents were used to evaluate the effects of solubility on the phase transformation of SD and the NMP solvate. The SD phase could transform to the NMP solvate by NMP-mediated phase transformation, which was governed by crystallization of the NMP solvate. The crystalline NMP solvate could transform to the solvent-free solid state through solid-solid transformation upon heating or water penetration-mediated phase transformation. The rate of this water penetration-mediated phase transformation of the NMP solvate to SD was unusually fast. It can be used to obtain SD aggregates of well-defined shape and good powder properties.

show abstract

“…It is shown that compound 1 displays bluish violet fluorescence emission in these aprotic or protic solvents in a region of 325-337 nm. Since it is difficult to oxidize or reduce the Cd(II) cations due to their d 10 configuration [42][43][44] , the origin of the emission for compound 1 is neither metal-to-ligand charge transfer(MLCT) nor ligand-to-metal charge transfer(LMCT). The intense fluorescent emission of compound 1 is attributed to the intraligand π * →π transition of mpda ligand.…”

Section: Spectral Behavior Of Compound 1 In Different Solventsmentioning

confidence: 99%

Synthesis and crystal structure of 1D Cd-amine coordination polymer and its luminescent properties

Liu

Fan

et al. 2014

Chem. Res. Chin. Univ.

View full text Add to dashboard Cite

A novel one dimension(1D) cadmium coordination polymer {[Cd(mpda) 3 ]·2(NO 3 )} n (1) was synthesized via refluxing a mixture of tetradentate Schiff base ligand N,N′-bis(2-pyridinylethylidene)phenylene-1,3-diamine(L) and Cd(NO 3 ) 2 in acetonitrile, whose structure was characterized by means of single crystal X-ray diffraction, FTIR spectroscopy, elemental analysis and proton nuclear magnetic resonance( 1 H NMR). Center metal Cd(II) ion is six-coordinated by six nitrogen atoms from six different m-phenylenediamine(mpda), giving rise to a [CdN 6 ] octahedral coordination environment. The two adjacent cadmium centers are linked by three mpda molecules leading to the construction of 1D chain structure. The crystal structure is stabilized by N-H···O hydrogen bonds to form three-dimension supramolecule. Compound 1 exhibits intense yellow luminescence in solid state at 298 K(λ em =554 nm), which shows a blue shift at 77 K(ca. 147 nm). Additionally, fluorescence characteristics of compound 1 were investigated in different solvents(polarity: DMSO>CH 3 CN>CH 3 OH>CHCl 3 >toluene) at 298 and 77 K. The results show that the emission peak of compound 1 in solvent exhibits a slight bathochromic shift. However, the emission peaks of compound 1 in CH 3 OH and CHCl 3 are red shift compared with that in CH 3 CN. It is revealed that the luminescence behavior of compound 1 depends on not only the polarity of solvent but also the hydrogen bonding properties between solvent and solute. In addition, the emission peak of compound 1 in solution shows a red shift obviously at 77 K than that at 298 K(ca. 144-159 nm), with the fluorescence lifetime increased at 77 K. The lifetime in DMSO at 77 K(τ=12.470 μs) was the longest one. The quantum yield of compoud 1 increases with increasing the polarity of solvent within a range of 1.8%-8.3 %.

show abstract

Structural Features, Phase Relationships and Transformation Behavior of the Polymorphs I−VI of Phenobarbital

Cited by 52 publications

References 51 publications

Enhanced NMR Discrimination of Pharmaceutically Relevant Molecular Crystal Forms through Fragment-Based Ab Initio Chemical Shift Predictions

Enhanced NMR Discrimination of Pharmaceutically Relevant Molecular Crystal Forms through Fragment-Based Ab Initio Chemical Shift Predictions

Crystal Structures and Phase Behavior of Sulfadiazine and a Method for the Preparation of Aggregates with Good Performance

Synthesis and crystal structure of 1D Cd-amine coordination polymer and its luminescent properties

Contact Info

Product

Resources

About