Preparation, characterization and thermolysis of nitrate salt of aminopyridines, Part-85

Kapoor, Inder Pal Singh; Kapoor, Manisha; Singh, Gurdip; Goel, Nidhi

doi:10.1016/j.molstruc.2011.12.037

Cited by 6 publications

(6 citation statements)

References 26 publications

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“…For related 3-azaniumylpyridin-1-ium salts, see: Ali et al (2008); Kapoor et al (2012); Rao et al (2011); Sarma et al (2012); Willett et al (1988). For related hexahalogenidometalate salts, see: Reiss (1998Reiss ( , 2002; Reiss & Helmbrecht (2012).…”

Section: Related Literaturementioning

confidence: 99%

“…The majority of these are salts consisting of halogenidometalate anions such as [BiCl 6 ] 3- (Rao et al, 2011), [CuCl 4 ] 2- (Willett et al, 1988), [CuBr 4 ] 2- (Willett et al, 1988) and [HgBr 4 ] 2- (Ali et al, 2008). Furthermore, the dinitrate (Kapoor et al, 2012) and some complex crown ether compounds (Sarma et al, 2012) The asymmetric unit of the title compound, (C 5 H 8 N 2 ) 2 [SnCl 6 ]Cl 2 , consists of one 3-azaniumylpyridin-1-ium dication and one chloride ion in general positions and the hexachloridostannate(IV) dianion lying on a centre of inversion (Fig. 1).…”

Section: S1 Commentmentioning

confidence: 99%

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Bis(3-azaniumylpyridin-1-ium) hexachloridostannate(IV) dichloride

2013

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The asymmetric unit of the title compound, (C5H8N2)2[SnCl6]Cl2, consists of one 3-azaniumylpyridin-1-ium dication and one chloride ion in a general position and a hexachloridostannate(IV) dianion lying about a centre of inversion. The [SnCl6]2− anion exhibits almost perfect octahedral geometry. The 3-azaniumylpyridin-1-ium and chloride ions are connected via medium–strong charge-supported N—H⋯Cl hydrogen bonds, forming undulating layers in the (110) plane. The [SnCl6]2− ions are located between these layers and occupy cavities formed by two facing layer puckers.

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Section: Related Literaturementioning

confidence: 99%

Section: S1 Commentmentioning

confidence: 99%

Bis(3-azaniumylpyridin-1-ium) hexachloridostannate(IV) dichloride

2013

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“…In VAVHEH (Kapoor et al, 2012) (Fig. 1b) the ADPs and NÁ Á ÁO distances clearly indicate that three of the four symmetry-independent C/N pairs in the ring must be swapped.…”

Section: Optimization Of 200 Structures With Reported Missed Symmetrymentioning

confidence: 98%

Validation of missed space-group symmetry in X-ray powder diffraction structures with dispersion-corrected density functional theory

Hempler

Schmidt

Streek

2017

Acta Crystallogr B Struct Sci Cryst Eng Mater

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More than 600 molecular crystal structures with correct, incorrect and uncertain space-group symmetry were energy-minimized with dispersion-corrected density functional theory (DFT-D, PBE-D3). For the purpose of determining the correct space-group symmetry the required tolerance on the atomic coordinates of all non-H atoms is established to be 0.2 Å. For 98.5% of 200 molecular crystal structures published with missed symmetry, the correct space group is identified; there are no false positives. Very small, very symmetrical molecules can end up in artificially high space groups upon energy minimization, although this is easily detected through visual inspection. If the space group of a crystal structure determined from powder diffraction data is ambiguous, energy minimization with DFT-D provides a fast and reliable method to select the correct space group.

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“…This form has been published previously by Rademeyer, 7 and by Kapoor, Kapoor, Singh, Singh and Goel, but the latter authors reported, incorrectly we believe, protonation at the 4-amino position, not at the pyridine nitrogen atom. 8 By analogy, we were also able to trap the mononitrate of the 3,4-DAPNH + cation, via 1 : 1 titration ((ΔpK a = 10.36). The monoprotonation certainly occurs at the pyridine nitrogen, and this form also occurs as an anhydrate.…”

Section: The Nitratesmentioning

confidence: 99%

“…All formulations were confirmed by the X-ray study. Table 2 7,8,[10][11][12] summarizes the experiments performed, including proportions of acids and bases used, and the nature of the products obtained. Some of these products have been previously described in the literature, and reference is given to these earlier reports.…”

Section: Experimental Preparation Of Salt Formsmentioning

confidence: 99%

Anhydrates and/or hydrates in nitrate, sulphate and phosphate salts of 4-aminopyridine, (4-AP) and 3,4-diaminopyridine (3,4-DAP): the role of the water molecules in the hydrates

et al. 2014

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Several salt forms of 4-aminopyridine and 3,4-diaminopyridine with nitric, sulfuric, and phosphoric acids, comprising anhydrates and some hydrates, have been prepared and structurally characterized, and the role of water assessed in the latter cases. Our study has confirmed that anhydrates can be obtained even when water is present in the crystallizing solution. Protonation of the aminopyridines is consistent with ΔpK a differences. 4-Aminopyridine uniquely forms a mono cation only, with protonation at the pyridine nitrogen, whilst 3,4-diaminopyridine forms both a mono cation, again with protonation at the pyridine nitrogen, and a dication, with the second protonation at the 3-amino position. Thus, 4-aminopyridine forms a 1 : 1 nitrate anhydrate, a 1 : 1 bisulphate anhydrate, a 2 : 1 sulfate hydrate and a 1 : 1 dihydrogen phosphate hydrate. 3,4-Diaminopyridine forms a 1 : 1 nitrate anhydrate and 1 : 2 nitrate anhydrate and hydrate, 2 : 1 and 1 : 1 sulfate hydrates and a 1 : 1 dihydrogen phosphate anhydrate. Analysis of the structures found suggests that the H-bonding capability of the water O-H donors and O acceptor components have similar tendencies to N-H donors and other O acceptors. At the same time, we recognise that, whilst water molecules may occasionally be structure forming, they also act as spacers or fillers in the development of the primary H-bonded assemblies. These will mainly be controlled by the stoichiometries and H-bonding possibilities of the anion/cation components. It is also possible that, in some circumstances, the inclusion or otherwise of water in structures may be competitive with supplementary weak interactions such as C-H⋯O hydrogen bonding. pyridine with other, generally pharmaceutically acceptable acids, including the inorganic acids hydrochloric, hydrobromic, nitric, sulfuric, and phosphoric, and characterized the products, and their behaviour under humid conditions. The halide salts proved to be a complex group of compounds, particularly in the formation of hydrates, and the structures adopted. We will describe these results, still undergoing analysis, in separate papers, 2,3 but report here on the particular forms obtained with the three oxyacids. In this work, we were interested in assessing, on the one hand, the interplay between the acidities and basicities of the components, yielding, where relevant, mono-and/or di-acid or base salt forms, and on the other, the formation, or not, of hydrates.

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Preparation, characterization and thermolysis of nitrate salt of aminopyridines, Part-85

Cited by 6 publications

References 26 publications

Bis(3-azaniumylpyridin-1-ium) hexachloridostannate(IV) dichloride

Bis(3-azaniumylpyridin-1-ium) hexachloridostannate(IV) dichloride

Validation of missed space-group symmetry in X-ray powder diffraction structures with dispersion-corrected density functional theory

Anhydrates and/or hydrates in nitrate, sulphate and phosphate salts of 4-aminopyridine, (4-AP) and 3,4-diaminopyridine (3,4-DAP): the role of the water molecules in the hydrates

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