Molecular spectral analysis and crystal structure of the 4-aminopyridinium tetrachloropalladate(II) complex salt

Ivanova, Bojidarka; Arnaudov, M.; Mayer‐Figge, Heike

doi:10.1016/j.poly.2005.04.028

Cited by 38 publications

(41 citation statements)

References 21 publications

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“…The optical and magnetic properties both in solution and in solid state were studied by linear-polarized solid state IRspectroscopy, UV-spectroscopy, 1 H-and 13 C-NMR methods as well as quantum chemical calculations. In contrast to N1 protonated salts of 3,4-diaminopyridine and 4-aminopyridine, [15][16][17], where a partial aromatic distortion of the cation is observed, N1 and N4 diprotonation reverses the aromatic character of the pyridine ring. In the case of the 3,4-diaminopyridine dication an increase in the Fig.…”

Section: Resultsmentioning

confidence: 83%

“…The crystal structure of neutral compound has been reported [14] and two N1 protonated salts (Scheme 1(2)) with hydrogensquarate and hydrogentartarate anions [15,16]. For last two compounds, it has been discussed that the N1 protonation leads to a partial distortion of the aromatic character of pyridine ring, similar to that observed for 4-aminopyridinium salt [17,18]. In contrast, aromatic character is observed for N1 protonated or coordinated 3-aminopyridine [19].…”

Section: Introductionmentioning

confidence: 72%

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Crystal structure, optical and magnetic properties of the bis(perchlorate) of 3,4-diaminopyridine

et al. 2007

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3,4-diaminopyridinium bis(perchlorate) has been synthesized and its crystal structure has been solved by single crystal X-ray diffraction. The optical and magnetic properties of the N1, N4 protonated 3,4-diaminopyridinium dication have been elucidated in solution and in the solid-state by means of linear-polarized solid state IR-spectroscopy (IR-LD), UV-spectroscopy, TGA, DSC, and positive and negative ESI MS. Quantum chemical calculations were used to obtain the electronic structure, vibrational data, and electronic spectra of the dication. The studied compound crystallizes in the noncentrosymmetric space group Cc and exhibits infinite molecular chains formed by 3,4-diaminopyridinium dications and ClO 4 -anions along the c-axis by moderate intermolecular NH 3 + ÁÁÁOClO 3 -interactions with bond lengths of 3.031, 3.024, 2.825, and 2.875 Å . The NH group participates in intermolecular NHÁÁÁOClO 3 -contacts with bond lengths of 3.220 and 3.172 Å , respectively. The effect of N1, N4 diprotonation on the optical and magnetic properties of the 3,4-diaminopyridinium dication is discussed.

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Section: Resultsmentioning

confidence: 83%

Section: Introductionmentioning

confidence: 72%

Crystal structure, optical and magnetic properties of the bis(perchlorate) of 3,4-diaminopyridine

et al. 2007

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“…This data proposed a charge redistribution of the pyridine ring. In contrast to systems as 4-aminopyridinium and 4-dimethylaminopyridinium cations, where the N py protonation leads to appearance of only one absorption band about 350 nm and e 9 = 12 000 L mol -1 cm -1 [11,14], where the stabilization of ''imino'' form is proved. These data correlated well with the theoretically predicted electronic spectrum of N py protonated 2-aminopyridine, where two bands at 260 (E = 4.567 eV, f = 0.1131) and 325 nm (E = 3.245 eV, f = 0.2314) are predicted (Scheme 6).…”

Section: Resultsmentioning

confidence: 79%

“…The obtained assignments suppose that the N py protonation leads to partial charge redistribution (Scheme 1(2)) in the Absorbance / Wavenumber (cm-1) pyridine ring. The full imino tautomeric form has been observed only in the cases of N py protonated 4-aminopyridine [11] and 4-dimethylaminopyridine [14]. In the last systems the detail IR-LD analysis in solid-state, UVspectroscopic, and 1 H-NMR data indicate that the aromatic character is distorted and imino form is stabilized.…”

Section: Resultsmentioning

confidence: 99%

“…The theoretical results including STO-3G* ab initio calculations also predict the endocyclic nitrogen atom as a favorable position of protonation [8], but a final stabilization of the ''imino'' form have been established using IR-spectral studies of the hydrochloride and tetrchloropalladate (II) [9][10][11]. Similar conclusions have been obtained by means of a comparative 1 H-NMR-spectral analysis of 4-aminopyridine (AP) and its salts or in the case of 4-dimetylaminopyridinium hydrogensquarate [10][11][12][13][14]. The effect of the NH 2 substituent has been studied in the case of 3,4-diaminopyridine, where partial charge redistribution is discussed [15].…”

Section: Introductionmentioning

confidence: 99%

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On the tautomerism and color origin in solid state of Npy-protonated-2-aminopyridine: spectroscopic elucidation

Chapkanov

2009

Struct Chem

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A distortion of the aromatic character as a result of the N py protonation of 2-aminopyridine was established by conventional and linear-polarized IR-spectroscopy, UV-and 1 H-NMR-spectral analysis of model system 2-aminopyridinium tetrachlorocuprate (II) salt. Quantum chemical ab initio calculations are performed at MP2 and B3LYP levels of theory and 6-311 ??G** basis set in order to determine the changes in the geometrical parameters and IR-spectroscopic characteristics as a result of N py protonation. The observed crystallochromy effect is discussed as well.

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Novel pyridyl‐substituted coumarin and its perchlorate salt–crystal structure and spectroscopic properties

Koleva

Nikolova

Zareva

et al. 2009

J of Physical Organic Chem

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The novel pyridyl-substituted coumarin (1) and its perchlorate salt (2) have been synthesized and their structure and properties elucidated in detail spectroscopically, thermally and structurally, using single crystal X-ray diffraction for 2, linear-polarized solid state IR-spectroscopy, UV-spectroscopy, TGA, DSC, DTA, and positive and negative ESI MS. Quantum chemical calculations were used to obtain the electronic structure, vibrational data and electronic spectra. The studied compound crystallizes in the centrosymmetric space group P-1 and exhibits an infinite layered structure with the ions linked by means of the intermolecular N þ H. . .OClO 3 (2.795 Å ) interactions. The cations are disposed in a manner leading to a significant p-stacking effect with a distance of 3.163 Å . The effects of N py protonation on the optical and magnetic properties are elucidated by comparing the data of the protonated and neutral compounds.

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Molecular spectral analysis and crystal structure of the 4-aminopyridinium tetrachloropalladate(II) complex salt

Cited by 38 publications

References 21 publications

Crystal structure, optical and magnetic properties of the bis(perchlorate) of 3,4-diaminopyridine

Crystal structure, optical and magnetic properties of the bis(perchlorate) of 3,4-diaminopyridine

On the tautomerism and color origin in solid state of Npy-protonated-2-aminopyridine: spectroscopic elucidation

Novel pyridyl‐substituted coumarin and its perchlorate salt–crystal structure and spectroscopic properties

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