Stereochemistry of aminophosphines

Cowley, Alan H.; Dewar, Michael J. S.; Jackson, W. R.; Jennings, W. Brian

doi:10.1021/ja00720a034

Cited by 72 publications

(17 citation statements)

References 2 publications

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“…Moreover, a long‐range coupling (five‐bond) between the ortho fluorines of the C 6 F 5 groups and the phosphonium methyl protons of the corresponding methyl phosphonium tetrafluoroborate salt was observed. Aminophosphines also offer scope for the study of their dynamic behaviour, especially in solution,80–85 as there exists the possibility of an inversion process occurring at the pyramidal shaped phosphorus and nitrogen and rotation around the PN bond. Both P‐ as well as N ‐substituents of aminophosphines account for the stabilization interaction of the PN bond and thus can affect the bond rotation process 86.…”

Section: Aminophosphinesmentioning

confidence: 99%

Aminophosphines: their chemistry and role as ligands and synthons

Gopalakrishnan

2009

Applied Organom Chemis

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In recent years, research in organophosphorus chemistry has mainly focused in designing newer and better phosphorus ligands for synthesizing novel metal complexes with improved catalytic activities. Aminophosphines [tricoordinate phosphorus(III)-nitrogen systems] are considered as versatile compounds owing to the presence of nitrogen centres which, in principle, can influence additional reactivity features. They are quite sensitive to air and moisture due to the presence of polar P-N bond(s). In spite of this, research in aminophosphine chemistry is gaining momentum day-by-day and this is due mainly to one reason: their rich behaviour as ligands in metal complex chemistry and subsequently in catalysis. Their role as synthons in inorganic heterocyclic chemistry has also helped produce new types of heterocycles. In this paper, the chemistry of simple acyclic aminophosphines (synthesis, characterization, reactivity and applications) is covered and particular focus is given to their ability to form chalcogenides along with their role played as ligands in coordination chemistry and as synthons in inorganic heterocyclic chemistry.

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Section: Aminophosphinesmentioning

confidence: 99%

Aminophosphines: their chemistry and role as ligands and synthons

Gopalakrishnan

2009

Applied Organom Chemis

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“…As an illustration of the lone-pair effects on a threebond coupling we invoke 3J(PH) in the rotational isomers of methylaminobis(trifluoromethy1)phosphine (VII), CH,NHP(CF,), , 23 observed when the phosphorus lone-pair is gauche rather than trans to the methyl group. In both VI and VII the lone-pair is centred on one of the coupled nuclei, whereas in the previous examples it is located one bond away.…”

Section: A Configurational and Conformational Informrtionmentioning

confidence: 99%

Effect of electron lone‐pairs on nuclear spin–spin coupling constants

Gil

Philipsborn

1989

Magnetic Reson in Chemistry

220

107

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The nature and types of lone-pair effects on nuclear spin coupling constants are reviewed in the context of a localized bond description of molecular electronic structure. Emphasis is placed on the importance of residual delocalization involving the otherwise lone-pair orbital, in terms of which the effect of an X lone-pair, when compared with an isoelectronic Y-H or X-H+ group or with an X-R group, and its orientational dependence can be interpreted. One-, two-and three-bond coupling constants are considered and the importance of lone-pair effects for configurational and conformational information is stressed and illustrated. They also serve for a better understanding of substituent inductive effects on coupling constants.A large collection of illustrative examples are presented, with particular attention paid to couplings involving H, C, N, F and P nuclei, organized in a systematic manner into nine categories. The signs of the lone-pair effects on the reduced coupling constants are found to be independent of the actual nuclei under study in the same category. This is taken as an indication that the electron lone-pairs mainly affect the Fermi contact contribution to the coupling and, accordingly, an interpretation is given in terms of simple sum-over-states models. In addition, symmetry-based relationship are established involving the sign of lone-pair effects in coupling constants between nuclei which are a different number of bonds apart.KEY WORDS NMR Multinuclear spin coupling Lone-pair effects Substituent effects Stereochemistry MO Sum-over-states models Electron delocalization CONTENTS

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“…However, the data in the 1 H and 31 P NMR spectra of 4a and 4b clearly indicate a more sterically congested environment around the phosphorus atom in the latter. Different patterns for the room temperature 1 H NMR signals of the methylene protons (-N(CH 2 CH 3 ) 2 ) for 4a (unresolved multiplet, 3.20 ppm) and 4b (very broad signal at 3.13 ppm) point to a more hindered rotation around the P-N bond [15] in the latter. The differences in the steric bulk of the alkylthio substituents are also most likely responsible for the substantially different 31 P NMR signals of 4a and 4b (45.2 ppm and 52.8 ppm, respectively).…”

Section: Resultsmentioning

confidence: 95%

Synthesis of 2,6‐Bis(bis(2‐(methylthio)phenyl)phosphino)‐4‐methylphenol, a Novel Polydentate Ligand Containing Two Tripodal [S,S,P,O] Coordination Pockets; Crystal Structure of the Dimeric Thallium(I) Complex

Beganskienė

Kongprakaiwoot

Luck

et al. 2006

Zeitschrift anorg allge chemie

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The reactions of bis(2-(methylthio)phenyl)chlorophosphine (5a) (2 equivalents) with the O-protected 2,6-dilithio-4-methylphenol followed by acidic workup led to the isolation of 2,6-bis(bis(2-(methylthio)phenyl)phosphino)-4-methylphenol (2). Analogous reactions do not proceed if the sterically bulkier bis(2-(tert-butylthio)phenyl)chlorophosphine (5b) is used instead of 5a. Compound 2 is a topological analog of binucleading ligands built on a 2,6-diaminophenol core, where two tripodal N-or Oligating compartments are flanking the phenolate functionality. A distinguishing feature of 2 is the "soft" donor environment of the potentially [S,S,P]-ligating pockets flanking the phenolic OH group. Reaction of 2 with TlOEt lead to the formation of the dimeric 1879 thallium(I) phenoxide (3), which was characterized by a single crystal X-ray diffraction study. In addition to µ-phenoxide ligation, in the solid state each thallium atom also interacts with two phosphorus atoms from the opposing ligands. The interactions are not equivalent, with the two Tl I ϪP distances differing by ca. 0.3 Å . No significant Tl···S interactions are present in the solid state. Room temperature 31 P NMR measurements indicate the dynamic behavior of 3 in solution.

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Stereochemistry of aminophosphines

Cited by 72 publications

References 2 publications

Aminophosphines: their chemistry and role as ligands and synthons

Aminophosphines: their chemistry and role as ligands and synthons

Effect of electron lone‐pairs on nuclear spin–spin coupling constants

Synthesis of 2,6‐Bis(bis(2‐(methylthio)phenyl)phosphino)‐4‐methylphenol, a Novel Polydentate Ligand Containing Two Tripodal [S,S,P,O] Coordination Pockets; Crystal Structure of the Dimeric Thallium(I) Complex

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