Conformational preference of ortho-substituted diphenyl ethers and diphenyl thioethers

Montaudo, Giorgio; Finocchiaro, P.; Trivellone, E.; Bottino, Francesco A.; Maravigna, P.

doi:10.1016/s0040-4020(01)91611-4

Cited by 50 publications

(21 citation statements)

References 20 publications

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“…In fact, the intramolecular ring current shielding effect is sizeable for the H-inside form but sharply decreases for the other skew conformations, which become practically undetectable by this method (7,8). Skew conformations have been claimed a t times (9)(10)(11)(12) to be consistent with dipole moment data, but it has been recently (13,7,6) pointed out that dipole moments often do not provide unequivocal information about the conformational preferences of ortho-substituted DPO. 'Author to whom correspondence should be addressed.…”

Section: Introductionmentioning

confidence: 99%

“…Several studies (1)(2)(3)(4)(5)(6) indicate that the conformational preference of DPO can be reasonably established by 'H n.m.r. only if it is of the H-inside type (1) (the two phenyls lying perpendicular to each other).…”

Section: Introductionmentioning

confidence: 99%

“…(6) and X-ray diffraction (15) evidence has been produced showing that electron withdrawing groups (nitro) are able to induce a conformational preference in DPO by enhancing the conjugation between unshared electrons of the bridging atoms a n d the n electrons in the phenyl ring.…”

Section: Introductionmentioning

confidence: 99%

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Carbon-13 Nuclear Magnetic Resonance Studies of ortho-Substituted Anisoles and Diphenyl Ethers

Buchanan¹,

Montaudo²,

Finocchiaro³

1974

Can. J. Chem.

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Carbon-13 n.m.r. chemical shifts for 8 anisoles and 15 diphenyl ethers are reported. paraCarbon shieldings are found to be sensitive to the degree of steric interference to conjugative electron release by the ethereal oxygen atom. An empirical correlation between the para-carbcn shifts and the average twist angle of the phenyl rings from a reference plane has been developed. Satisfactory agreement has been found between the angles of twist derived from carbon chemical shifts and those based on other physical measurements.On rapporte les dCplacements chimiques en r.m.n, du carbone-13 de 8 anisoles et de 15 Cthers diphenylCs. On a trouvC que le blindage des carbones en para est sensible au degre d'interference sterique a la scission des Clectrons de I'atonie d'oxygtne de la fonction Cthtree par conjugaison. On a dtveloppC une corrClation empirique entre les dtplacements chimiques des carbones en para et les angles rnoyens de torsion du plan des noyaux phenyles par rapport a un plan de rtfirence. On a trouve une correlation satisfaisante entre les angles de torsion derives des deplacements chiniiques du carbone et ceux bases sur d'autres methodes physiques.[Traduit par le journal]Can. J. Chern., 52,767(1974) Introduction In recent years considerable effort, using a variety of techniques, has been directed toward the elucidation of the geometries of substituted diphenyl ethers (DPO) in solution. As it would be expected, no single technique yields all the desirable information, rather the dizerent methods appear complementary.Several studies (1-6) indicate that the conformational preference of DPO can be reasonably established by 'H n.m.r. only if it is of the H-inside type (1) (the two phenyls lying perpendicular to each other). In fact, the intramolecular ring current shielding effect is sizeable for the H-inside form but sharply decreases for the other skew conformations, which become practically undetectable by this method (7,8). Skew conformations have been claimed a t times (9-12) to be consistent with dipole moment data, but it has been recently (13, 7, 6) pointed out that dipole moments often do not provide unequivocal information about the conformational preferences of ortho-substituted DPO.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Carbon-13 Nuclear Magnetic Resonance Studies of ortho-Substituted Anisoles and Diphenyl Ethers

Buchanan¹,

Montaudo²,

Finocchiaro³

1974

Can. J. Chem.

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“…1) is the lowest energy conformation (1)(2)(3)(4)(5)(6)(7). In solution the two rings may oscillate about the skew equilibrium angles (4 = 0°, \ 1C = by +20°.…”

Section: Introductionmentioning

confidence: 99%

“…With three large ortho substituents, the skew, H-inside conformation is the net result; the diortho-substituted ring is perpendicular to the COC plane for steric reasons while the monoortho-substituted ring is coplanar with the COC plane for reasons of conjugation and lower steric repulsion. The conjugation is increased if that ring is substituted with electron withdrawing groups (3,8).…”

Section: Introductionmentioning

confidence: 99%

Conformations of Bridged Diphenyls. V. A Nuclear Magnetic Resonance Comparative Study of the Conformations of Identically Substituted Diphenyl Ethers, Sulfides, Methanes, Ketones, Sulfoxides, and Sulfones

Benjamins¹,

Chandler²

1974

Can. J. Chem.

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Using n.m.r. methods developed in earlier papers, the conformations of two series, one doubly ortlro-substituted and one triply ortho-substituted, of six identically substituted bridged diphenyls were compared. The ethers, sulfides, and niethanes have been shown to adopt the same conformation in which the di-ortho-substituted ring is perpendicular to the central bridge plane while the other ring lies in that plane and an ortho hydrogen takes LIP the "inside" o r "proximal" position. The benzophenones and sulfoxides prefer a conforniation in which the dihedral angle between each ring and the central plane is about 40-50" and an orflro hydrogen adopts the "outside" or "distal" position. The sulfones adopt a conformation in which the two rings are more nearly perpendicular to the central plane.

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The Synthesis of Some Phthalocyanines and Napthalocyanines Derived from Sterically Hindered Phenols

Brewis¹,

Clarkson²,

Humberstone³

et al. 1998

Chem. Eur. J.

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Abstract:The synthesis of a number of phthalocyanines (Pcs) and naphthalocyanines (NPcs) bearing bulky substituents is described. Precursors are prepared by using a nucleophilic aromatic substitution reaction between a sterically hindered phenol and 4-nitrophthalonitrile, 3-nitrophthalonitrile or 6-fluoro-2,3-napthalonitrile. Thus, Pcs and NPcs derived from 2,6-diisopropylphenol, 3,5-di-tert-butylphenol and 2,6-diphenylphenol possess substituents that are forced by steric constraints to adopt a non-planar conformation which enhances the solubility of the macrocycle.In particular, the Pc derived from 2,6-ditert-butyl-4-methylphenol displays exceptional solubility and a reduced tendency to aggregate in solution. 2,6-Ditert-butylphenol reacts as a carbon nucleophile to produce biphenyl phthalonitrile precursors to Pcs containing redox-active phenolic substituents.

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Conformational preference of ortho-substituted diphenyl ethers and diphenyl thioethers

Cited by 50 publications

References 20 publications

Carbon-13 Nuclear Magnetic Resonance Studies of ortho-Substituted Anisoles and Diphenyl Ethers

Carbon-13 Nuclear Magnetic Resonance Studies of ortho-Substituted Anisoles and Diphenyl Ethers

Conformations of Bridged Diphenyls. V. A Nuclear Magnetic Resonance Comparative Study of the Conformations of Identically Substituted Diphenyl Ethers, Sulfides, Methanes, Ketones, Sulfoxides, and Sulfones

The Synthesis of Some Phthalocyanines and Napthalocyanines Derived from Sterically Hindered Phenols

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