Pentacoordinated molecules. 82. Conformational preferences of monocyclic pentaoxyphosphoranes varying in ring size

Burton, Sarah D.; Swamy, K. C. Kumara; Holmes, Joan M.; Day, Roberta O.; Holmes, Robert R.

doi:10.1021/ja00172a029

Cited by 36 publications

(39 citation statements)

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“…When a methylene group is used in place of the sulfonyl group as a ligand bridging the two aryl functions of the cyclic system, another possibility reveals itself. Both C and D are examples containing this ring conformation where the ring system occupies axial−equatorial positions of a TBP. In these pentaoxyphosphoranes, the ring assumes a twist syn or boatlike conformation.…”

Section: Introductionmentioning

confidence: 99%

Sulfonyl-Containing Eight-Membered Rings Varying in Ring Conformation in Oxyphosphoranes. Hexacoordination vs Pentacoordination¹

1997

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The new cyclic phosphine O 2 S[(t-Bu)MeC 6 H 2 O] 2 PPh (1) was used to prepare the new cyclic tetraoxyphosphoranes O 2 S[(t-Bu)MeC 6 H 2 O] 2 PPh(O 2 C 6 Cl 4 ) (2) and O 2 S[(t-Bu)MeC 6 H 2 O] 2 PPh(O 2 C 6 H 4 ) (3) by oxidative addition reactions. In similar reactions, the new cyclic pentaoxyphosphoranes O 2 S[(t-Bu)MeC 6 H 2 O] 2 P(OCH 2 CCl 3 ) 3 (4), O 2 S-[Me 2 C 6 H 2 O] 2 P(OPh) 3 (5), and O 2 S[(t-Bu)MeC 6 H 2 O] 2 P(OC 6 F 5 ) 3 ( 6) were formed from acyclic phosphites and the appropriate diol. Yields ranged from 51% to 66%. X-ray studies revealed hexacoordinated representations for 2 and 6 while 3-5 are pentacoordinate in trigonal bipyramidal geometries. For 3 and 4, the eight-membered rings are positioned diequatorially in anti chair conformations, whereas for 5, this ring occupies axial-equatorial sites in a syn twist-boat form. Tetraoxyphosphorane 3 is unique in locating the least electronegative ligand, the phenyl group, in an axial position. Oxygen donor action from the sulfone SO 2 group led to a displacement from a square pyramid to an octahedron to the extent of 82.2% for the highly fluorinated member 6 in comparison with 27.9% for the tetrachlorocatecholate derivative 2. These two pentaoxyphosphoranes provide the longest and shortest P-O distance thus far from a sulfone donor group, 2.646 (5) Å for 2 and 1.936 (7) Å for 6. In comparison with oxyphosphoranes having bridging sulfur atoms in the eight-membered ring, it is apparent that sulfur atom coordination is greater than oxygen atom coordination from the sulfone group as measured by the tendencies toward hexacoordination. 31 P and 1 H NMR data indicate the presence of two isomeric forms for each of the phosphoranes 2-4. Structural comparisons are made with related cyclic phosphoranes containing sulfur atoms and sulfone groups relative to steric and electronic factors that influence the formation of hexacoordination.

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Section: Introductionmentioning

confidence: 99%

Sulfonyl-Containing Eight-Membered Rings Varying in Ring Conformation in Oxyphosphoranes. Hexacoordination vs Pentacoordination¹

1997

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“…Entsprechende σ 3 P-Verbindungen wurden bereits untersucht [12,14]. Entsprechende σ 3 P-Verbindungen wurden bereits untersucht [12,14].…”

Section: Schemaunclassified

“…Für Pentaoxyphosphorane mit ähnlichen Strukturen wurden NMR-Werte publiziert [3,12], die mit den gefundenen gut übereinstimmen. Es ist dem Tetraoxyphosphoniumsalz 15 zuzuordnen.…”

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Zur Reaktion von Dihydroxybiphenylen mit Phosphorpentachlorid - Phosphepine mit Phosphonium- und Phosphoranstruktur

Gloede¹,

Habicher

Schneider

2002

Z. anorg. allg. Chem.

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Bei der Redaktion eingegangen am 23. Juli 2001.Inhaltsübersicht. Die 2,2Ј-Dihydroxybiphenylderivate 1d-f reagieren mit Phosphorpentachlorid zu den Dioxaphosphepinium-hexachlorophosphaten 3a, 3b und 17. Als Zwischenstufen werden die Trichloro-dioxaphosphepine 8a, 8b und 21 diskutiert, deren Existenz durch Chlorierung der 6-Chloro-dioxaphosphepine 7a, 7b und 20 Abstract. The 2,2Ј-dihydroxybiphenyl derivatives 1d-f react with phosphorus pentachloride to give the dioxaphosphepinium hexachlorophosphates 3a, 3b, and 17. The trichloro-dioxaphosphepins 8a, 8b, and 21 were discussed as intermediates, which were obtained by chlorination of the 6-chloro-dioxaphosphepins 7a, 7b, and 20. The hydrolysis of the dioxaphosphepins leads to the stable, cyclic Einleitung Bei den Reaktionen von Dihydroxyaromaten mit Phosphorpentachlorid werden Trichlorodioxyphosphorane erhalten. So reagieren Brenzcatechinderivate (1a) zu 5-gliedrigen cyclischen Phosphoranen vom Typ 2a und Bis(o-hydroxyphenyl)-methanderivate (1b) zu 8-gliedrigen cyclischen Phosphoranen vom Typ 2b [1Ϫ4]. Die entsprechenden 7-gliedrigen cyclischen Derivate vom Typ 2c sind bisher noch nicht beschrieben. Die unsubstituierte Verbindung 2c (Y ϭ H) wurde als Zwischenprodukt bei der Umsetzung von 2,2Ј-Dihydroxybiphenyl (1d) mit PCl 5 (Molverhältnis: 3:1) vermutet, aber eine Isolierung oder Charakterisierung erfolgte nicht [3].Wir berichten hier über das Verhalten der unterschiedlich substituierten 2,2Ј-Dihydroxy-biphenylderivate 1d-1f gegenüber PCl 5 . bewiesen werden konnte. Die Hydrolyse der Dioxaphosphepinderivate führt zu den stabilen, cyclische Phosphorsäurederivaten 4a, 4b, 9a, 9b, 11a, 11b,19a und 19b. Vom Dioxaphosphepin 4a ist die Kristallstruktur bestimmt worden; in der asymmetrischen Einheit befinden sich zwei unterschiedliche Moleküle.phosphates 4a, 4b, 9a, 9b, 11a, 11b, 19a, and 19b. The crystal structure of 4a was determined; two different molecules was observed in the asymmetric unit. Ergebnisse und DiskussionReaktion von 2,2Ј-Dihydroxybiphenyl (1d) und 2,2Ј-Dihydroxybinaphthyl (1e) mit Phosphorpentachlorid Die Umsetzung des Diols 1d mit PCl 5 in Chloroform verläuft unter HCl-Entwicklung. Im 31 P-NMR-Spektrum der Reaktionslösung werden zwei Signale mit den δ-Werten von 8,6 und Ϫ298 beobachtet. Sie sprechen für das Vorliegen eines cyclischen Tetraoxyphosphonium-hexachlorophos-

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“…To address this problem, syntheses and structural studies have concentrated in the last few years on cyclic oxyphosphoranes with phosphorinane rings to ascertain geometrical and ring conformational requirements to obtain a−e and e−e ring orientations. ,− In this effort, studies have been extended to include a wide range of oxyphosphoranes possessing seven- and eight-membered rings. ,,− ,− …”

Section: Introductionmentioning

confidence: 99%

Molecular Orbital Approach to Cyclic Anionic Pentaoxysilicates, Fluorosilicates, and Isoelectronic Phosphoranes. Structural Comparisons¹^,²

Deiters

Holmes

1996

Organometallics

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Geometries and relative energies from ab initio calculations using Gaussian 92 on five-coordinated anionic cyclic pentaoxysilicates and isoelectronic cyclic pentaoxyphosphoranes containing saturated five- and six-membered rings in trigonal bipyramids (TBP) are compared with structural results from X-ray diffraction and VT NMR studies. The theoretical study is extended to cyclic C4H4SiF3 -, C4H8SiF3 -, and isoelectronic phosphorus species in trigonal-bipyramidal geometries. In agreement with structural results, the saturated five- and six-membered rings in pentaoxy species are located on the potential energy surface as local energy minima with the rings occupying axial−equatorial (a−e) sites. In the cyclic anionic organofluorosilicates and organofluorophosphoranes, the five-membered saturated rings reside in diequatorial (e−e) sites, whereas the five-membered unsaturated rings are located in (a−e) sites. It is suggested that these cyclic derivatives provide useful models for nucleophilic displacement reactions. Low calculated axial bond overlap populations found for anionic silicon compared to isoelectronic phosphorus entities correlate with accompanying longer axial Si−O and Si−F bond lengths. It is concluded that the long axial bond lengths accompany weaker bond strengths, as indicated by the ab initio results and represent a major factor responsible for enhanced reactivity of five-coordinated anionic organosilicon compounds. This bond length factor, associated with the reduced nuclear charge on silicon, suggests greater fluxional character, which is consistent with the lower ligand exchange activation energies involving ring reorientations found for five-coordinated silicon compared to that for phosphorus. Bond-lengthening effects are found in the series RR‘SiF3 - that correlate with the bulkiness of the organo substituents. Structural nonrigidity leads to axial bond shortening as the structure traverses from trigonal bipyramidal to square pyramidal, a feature which may reduce reactivity in nucleophilic displacement reactions for pentacoordinated molecules thus displaced.

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Pentacoordinated molecules. 82. Conformational preferences of monocyclic pentaoxyphosphoranes varying in ring size

Cited by 36 publications

References 2 publications

Sulfonyl-Containing Eight-Membered Rings Varying in Ring Conformation in Oxyphosphoranes. Hexacoordination vs Pentacoordination¹

Sulfonyl-Containing Eight-Membered Rings Varying in Ring Conformation in Oxyphosphoranes. Hexacoordination vs Pentacoordination¹

Zur Reaktion von Dihydroxybiphenylen mit Phosphorpentachlorid - Phosphepine mit Phosphonium- und Phosphoranstruktur

Molecular Orbital Approach to Cyclic Anionic Pentaoxysilicates, Fluorosilicates, and Isoelectronic Phosphoranes. Structural Comparisons¹^,²

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Pentacoordinated molecules. 82. Conformational preferences of monocyclic pentaoxyphosphoranes varying in ring size

Cited by 36 publications

References 2 publications

Sulfonyl-Containing Eight-Membered Rings Varying in Ring Conformation in Oxyphosphoranes. Hexacoordination vs Pentacoordination1

Sulfonyl-Containing Eight-Membered Rings Varying in Ring Conformation in Oxyphosphoranes. Hexacoordination vs Pentacoordination1

Zur Reaktion von Dihydroxybiphenylen mit Phosphorpentachlorid - Phosphepine mit Phosphonium- und Phosphoranstruktur

Molecular Orbital Approach to Cyclic Anionic Pentaoxysilicates, Fluorosilicates, and Isoelectronic Phosphoranes. Structural Comparisons1,2

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Sulfonyl-Containing Eight-Membered Rings Varying in Ring Conformation in Oxyphosphoranes. Hexacoordination vs Pentacoordination¹

Sulfonyl-Containing Eight-Membered Rings Varying in Ring Conformation in Oxyphosphoranes. Hexacoordination vs Pentacoordination¹

Molecular Orbital Approach to Cyclic Anionic Pentaoxysilicates, Fluorosilicates, and Isoelectronic Phosphoranes. Structural Comparisons¹^,²