Diprotonated Tetra(2‐pyridyl)pyrazine and its Chemical Mimesis due to Different Hydrogen Bridges

Bock, Hans; Vaupel, Thorsten; Näther, Christian; Ruppert, Klaus; Havlas, Zdeněk

doi:10.1002/anie.199202991

Cited by 61 publications

(26 citation statements)

References 15 publications

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“…The N atoms are separated by 2.528 (3) A Ê , and this rather short intramolecular hydrogen bond [N3ÐH3 1.22 (3) and H3Á Á ÁN4 1.32 (3) A Ê , and N3ÐH3Á Á ÁN4 167 (3) ; Table 1] leads to a slight twist of the pyrazine ring (plane C1/N1/C4 to plane C2/N2/C3) of 3.6 (4) , as well as to two unusually large exocyclic angles, C3ÐC4ÐC5 [131.0 (3) ] and C4ÐC3ÐC10 [131.2 (2) ]. This type of hydrogen bond, with almost identical bond distances and angles, was also found in the diprotonated form of tetra(2-pyridyl)pyrazine by Bock et al (1992) and analysed theoretically. An analysis of hydrogen bonding in organoammonium H(N) atoms of this type has been made by Robertson et al (1998).…”

Section: Commentsupporting

confidence: 58%

Hydrogen bonding in the inner-salt zwitterion and in two different charged forms of 5,6-bis(2-pyridyl)pyrazine-2,3-dicarboxylic acid

2001

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5,6-Bis(2-pyridyl)pyrazine-2,3-dicarboxylic acid exists as an inner-salt zwitterion, 3-carboxy-5-(2-pyridinio)-6-(2-pyridyl)pyrazine-2-carboxylate, (Ia), C(16)H(10)N(4)O(4). The adjacent pyridine and pyridinium rings are almost coplanar due to the presence of an intramolecular hydrogen bond involving the pyridine N atom and the NH H atom of the pyridinium group. In the crystal of (Ia), symmetry-related molecules are hydrogen bonded via the carboxylic acid OH group and one of the carboxylate O atoms to form a polymer, which exhibits a channel-type structure. In the HCl, HClO(4) and HPF(6) salts, 6-carboxy-5-carboxylatopyrazine-2,3-diyldi-2-pyridinium chloride 2.25-hydrate, (II), C(16)H(11)N(4)O(4)(+).Cl(-).2.25H(2)O, 6-carboxy-5-carboxylatopyrazine-2,3-diyldi-2-pyridinium perchlorate trihydrate, (IIIa), C(16)H(11)N(4)O(4)(+).ClO(4)(-).3H(2)O, and 6-carboxy-5-carboxylatopyrazine-2,3-diyldi-2-pyridinium hexafluorophosphate trihydrate, (IIIb), C(16)H(11)N(4)O(4)(+).PF(6)(-).3H(2)O, both pyridine rings are protonated. In the perchlorate form, and in the isomorphous hexafluorophosphate form, the molecule possesses C(2) symmetry, with has a symmetrical intramolecular hydrogen bond involving the adjacent carboxylate and carboxylic acid substituents. In the crystals of the chloride and perchlorate (or hexafluorophosphate) salts, hydrogen-bonded polymers are formed which are three-dimensional and one-dimensional, respectively.

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Section: Commentsupporting

confidence: 58%

Hydrogen bonding in the inner-salt zwitterion and in two different charged forms of 5,6-bis(2-pyridyl)pyrazine-2,3-dicarboxylic acid

2001

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“…As observed for ðH 2 3 2þ Þ½BðC 6 H 5 Þ À 4 2 , these N-HÁ Á ÁN bridges are rather short even for proton sponges [8,37], and result in a deformation of the C(5)-C(6)-C(7) and C(6)-C(7)-C(8) angles, which are expanded to the very unusual values of 129.7(5) and 130.4(5)°. The H 2 3 2+ dication interacts with the ICl À 2 anions through an extended network of hydrogen bonds [C(10)-…”

Section: Crystal Structure Determinationsmentioning

confidence: 71%

Reactions of pyridyl donors with halogens and interhalogens: an X-ray diffraction and FT-Raman investigation

Aragoni

Arca

Devillanova

et al. 2005

Journal of Organometallic Chemistry

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“…The diprotonated tetra‐2‐pyridylpyrazine (tetra) cation (tetraH 2 2+ ) has been reported as BF 4 − and Cl − salts and chloranilic acid. It is known that the structures of diprotonated and tetraprotonated forms of tetra become planar …”

Section: Introductionmentioning

confidence: 99%

Syntheses, X-ray crystal structures, and emission properties of diprotonated tetrapyridylpyrazine and triprotonated terpyridine

Yoshikawa

Yamabe

Kanehisa

et al. 2015

J. Phys. Org. Chem.

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A series of metal-free compounds, that is, planar diprotonated tetraH 2 (PF 6 ) 2 (1), planar monoprotonated bppzHPF 6 (2), nonplanar diprotonated bppzH 2 (PF 6 ) 2 (3), and planar triprotonated terpyH 3 Cl(PF 6 ) 2 (4), were prepared and characterized by electrospray ionization mass spectrometry, Ultraviolet-visible spectroscopy and cyclic voltammetry. Abbreviations used are tetra = tetra-2-pyridylpyrazine, bppz = 2,3-bis(2-pyridyl)pyrazine, and terpy = 2,2′:6′,2″-terpyridine. The X-ray crystal structures of the four compounds 1, 2, 3, and 4 were determined. Both protonated pyridine rings are hydrogen bonded intramolecularly to the adjacent pyridine ring in compounds 1 and 3. The π-π* absorption bands in the ultraviolet region for 1, 2, 3, and 4 in acetonitrile were red-shifted relative to those of the corresponding neutral unprotonated compounds. All the cyclic voltammetry for the protonated species, 1, 2, 3, and 4, showed the first reduction waves from À0.37 to À1.18 V, that were more positive than those of the neutral ones. Density functional theory was applied to interpret the planarity in 1. The attachment of two protons to the two terminal tetra nitrogens in 1 leads to the remarkable emission (Φ = 0.031). The attachment of three protons to the three terpy nitrogens in 4 also gives the large quantum yield (Φ = 0.48). Figure 5. Normalized emission spectra of 1 (red line) and 4 (black line) in CH 3 CN solution (1.0 × 10 À5 M) at 25°C (λ ex = 329 nm and λ ex = 322 nm, respectively) REMARKABLE EMISSION OF DIPROTONATED TETRA-2-PYRIDYLPYRAZINE

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Diprotonated Tetra(2‐pyridyl)pyrazine and its Chemical Mimesis due to Different Hydrogen Bridges

Cited by 61 publications

References 15 publications

Hydrogen bonding in the inner-salt zwitterion and in two different charged forms of 5,6-bis(2-pyridyl)pyrazine-2,3-dicarboxylic acid

Hydrogen bonding in the inner-salt zwitterion and in two different charged forms of 5,6-bis(2-pyridyl)pyrazine-2,3-dicarboxylic acid

Reactions of pyridyl donors with halogens and interhalogens: an X-ray diffraction and FT-Raman investigation

Syntheses, X-ray crystal structures, and emission properties of diprotonated tetrapyridylpyrazine and triprotonated terpyridine

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