Intramolecular N−H...O hydrogen bonding, quinoid effect, and partial π-electron delocalization in N-aryl Schiff bases of 2-hydroxy-1-naphthaldehyde: the crystal structures of planar N-(α-naphthyl)- and N-(β-naphthyl)-2-oxy-1-naphthaldimine

Gavranić, Marijana; Kaitner, Branko; Meštrović, Ernest

doi:10.1007/bf02018692

Cited by 127 publications

(66 citation statements)

References 9 publications

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“…3 It was also claimed that the hydrogen bond type depends neither on the stereochemistry of the molecule nor on the type of the substituent bonded to the imino N atom, but on the type of aldehyde used, 2 with only an intramolecular O-H·N (phenol-imine form) type of hydrogen bond being observed in salicylaldimines and an O·H-N (ketoamine form) type in naphthaldimines. 2 However, naphthaldimine can also exist in the phenol-imine form 4 as in the title compound. Thus, the crystallographic results clearly reflect the importance of the stereochemistry of the molecule.…”

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confidence: 99%

Crystal Structure of 2-Hydroxynaphthaldehyde[(1E)-(2-hydroxynaphthyl)methylene]hydrazone

2006

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Intramolecular hydrogen bonds and tautomerism [phenol-imine (O-H·N) and keto-amine (O·H-N) forms] in 2-hydroxyaldimine Schiff bases have been investigated using spectroscopic and crystallographic techniques in solution and in the solid state. A good review of the hydrogen bonds has been published by Steiner. 1 In the solid state, it is generally specified by X-ray analysis that the keto-amine form is observed in naphthaldimines, while the phenol-imine form is found in salicylaldimines, 2 although, it is claimed that both keto-amine and phenol-imine forms are present in the crystalline state, based on NMR studies. 3 It was also claimed that the hydrogen bond type depends neither on the stereochemistry of the molecule nor on the type of the substituent bonded to the imino N atom, but on the type of aldehyde used, 2 with only an intramolecular O-H·N (phenol-imine form) type of hydrogen bond being observed in salicylaldimines and an O·H-N (ketoamine form) type in naphthaldimines. 2 However, naphthaldimine can also exist in the phenol-imine form 4 as in the title compound. Thus, the crystallographic results clearly reflect the importance of the stereochemistry of the molecule.The title compound was prepared from the reaction of 2-hydroxy-1-naphthaldehyde (0.87 g, 2.69 mmol) and hydrazine monohydrate (0.60 g, 2.69 mmol) in boiling ethanol (150 ml). The mixture was refluxed for 2 h, and then the solution was cooled and filtered. The product was crystallized from a CHCl3/hexane mixture (3:1), (yield 0.55 g, 63%, decompose point 583 K).The X-ray analysis results are given in Tables 1 -4. The H4 atom was positioned geometrically and refined by using a riding model; the remaining H atoms were located by a difference synthesis and refined isotropically.The molecular structure of the title compound is shown in Fig. 2. It contains short intramolecular O-H·N hydrogen bonds (Table 4), which means that the compound is in the phenolimine form,

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confidence: 99%

Crystal Structure of 2-Hydroxynaphthaldehyde[(1E)-(2-hydroxynaphthyl)methylene]hydrazone

2006

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“…Intra-molecular hydrogen binding and tautomerism in the synthesized N-(2-pyridyl)-2-oxo-1-naphthylidenemethylamine was reported by Nazir et al [45] using infrared spectroscopy and X-ray beam diffraction studies [46]. The impact of aromatic ring moiety with naphthalene has been examined.…”

Section: Introductionmentioning

confidence: 91%

“…Marijana-Gavranic et al [46] examined intra-molecular N···H−O hydrogen bonding, quinoid impact and partial π-electron delocalization in the crystal structure of planar N-(α-naphthyl) and N-(β-naphthyl)-2-oxy-1-naphthaldehyde (Fig. 10).…”

Section: Introductionmentioning

confidence: 99%

Schiff Bases Derived from 2-Hydroxynaphthalene-1-carbaldehyde and their Metal Complexes

Khalid¹

2018

Asian J. Chem.

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2-Hydroxynaphthalene-1-carbaldehyde is a key predecessor to an assortment coordinating agent and the Schiff bases derived from these ligands played a unique role in the development of important biomolecules which exhibit a widely range as a model system for biological macromolecules. Schiff bases formed from o-hydroxy aromatic ketones and aldehydes are stellar design for the study of keto-enol tautomerism in liquid and solid state. The metal-Schiff base complexes obtained from 2-hydroxynaphthalene-1-carbaldehyde had been revealed to show a broad area of biological effectiveness, catalytic reaction, sensors, selective electrodes and fluorescent.

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“…The low melting point of 3 may be explained by keto-enol tautomerism. A large number of Schiff bases was structurally determined so far, revealing that crystal structures of compounds of this class were dominated by the O-H···N (enol-imino) tautomeric form [44,45]. Some of Schiff bases exhibit the N-H···O tautomers [46][47][48][49][50][51] and their common feature is the presence of a hydroxyl [46,[49][50][51] or a nitro group [47,48] at the N-phenyl ring or the phenyl ring of parent aldehyde.…”

Section: Melting Pointsmentioning

confidence: 99%

<b>Synthesis, spectral characterizations and antimicrobial activity of some Schiff bases of 4-chloro-2-aminophenol</b>

Çınarli¹,

Gürbüz²,

Tavman³

et al. 2011

Bull. Chem. Soc. Eth.

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ABSTRACT ABSTRACT. A series of 4-chloro-2-[(arylmethylidene)amino]phenols (1-11) including methoxy group were synthesized using appropriate synthetic route. The structures of the Schiff bases were characterized by FT-IR, UV-Vis, ESI-MS, 1 H and 13 C-NMR spectroscopic techniques and analytical methods. A relation is observed between melting points and existence of intramolecular hydrogen bonding. IR spectra of the compounds including and not including hydrogen bonding were compared. The compounds 2 and 4 show the characteristic UV bands attributed to the NH-forms. According to the 1 H-NMR spectral data the compound 2 has the strongest intramolecular hydrogen bonding and the compound 6 shows two isomeric structure. On the other hand, antibacterial and antifungal activities of the compounds were investigated. Most of the compounds show selective activity toward S. epidermidis and C. albicans. KEY WORDS KEY WORDS KEY WORDS

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Intramolecular N−H...O hydrogen bonding, quinoid effect, and partial π-electron delocalization in N-aryl Schiff bases of 2-hydroxy-1-naphthaldehyde: the crystal structures of planar N-(α-naphthyl)- and N-(β-naphthyl)-2-oxy-1-naphthaldimine

Cited by 127 publications

References 9 publications

Crystal Structure of 2-Hydroxynaphthaldehyde[(1E)-(2-hydroxynaphthyl)methylene]hydrazone

Crystal Structure of 2-Hydroxynaphthaldehyde[(1E)-(2-hydroxynaphthyl)methylene]hydrazone

Schiff Bases Derived from 2-Hydroxynaphthalene-1-carbaldehyde and their Metal Complexes

<b>Synthesis, spectral characterizations and antimicrobial activity of some Schiff bases of 4-chloro-2-aminophenol</b>

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