Diphosphonio‐isophosphindole, Phosphole mit planar umgebenem Phosphor

Schmidpeter, Alfred; Thiele, Martin

doi:10.1002/ange.19911030324

Cited by 42 publications

(10 citation statements)

References 19 publications

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“…The bonding between the 77'-coordinated cation 1 and a single Cu+ (d10) in 6 can be pictured as a superposition o f a dative P-^Cu a -and a retrodative Cu-^P 7r-bonding contribution [3]. However, since 1 is a weaker electrophile than an aminophosphenium ion [3,4] and exhibits further an additional occupied 7r-orbital of high energy which may inter act repulsively with filled metal d-orbitals, the back donation and thus the formal double bond character is lowered [3] and the bonding situation resembles more closely that of a phosphane or phospholide ligand. This explains why the P-Cu bond distance in 6 is close to that of phosphane complexes (vide supra), whereas P-M bonds in aminophosphenium com plexes are normally 4 -10% shorter than in comparable phosphane complexes [3].…”

Section: N M R Spectroscopic Investigationsmentioning

confidence: 98%

Bis-phosphonio-isophosphindolide Copper Complexes

Gudat

Holderberg

Korber

et al. 1999

Zeitschrift Für Naturforschung B

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Phosphorus Heterocycles, Copper Complexes, Crystal Structure, '' P NMR Data Bis-triphenylphosphonio-isophosphindolide salts 1[X] react with Cu(I)-halides CuX to give isolable products of composition [(l)Cu2X3]. X-ray crystal structure analyses confirmed that for X = Br, Cl dinuclear complexes [(/y-1 )(/i-X)Cu2X2] with /i2j;'(P)-bridging cations 1 are formed, while for X = I a solid phase containing a salt (l^lC u*^] and a complex [(l^C u .^] with a terminal ?/(P)-coordinated ligand 1 was obtained. The bonding parameters in the two types of complexes suggest that l i s a hybrid between a phosphenium cation and a phospholide anion whose 7T-system is less nucleophilic than the phosphorus lone-pair.31P NMR studies revealed that in solution in all cases binuclear complexes [(l)Cu2X3] are in dynamic equilibrium with small amounts of mononuclear species and free 1. The same equilibria were detected in the system l[OTf]/CuOTf. NMR studies of ligand exchange reactions indicated that the stability of complexes [(l)Cu2X3] increases in the order X = OTf < 1 < Br, Cl, and titration of [(l)Cu2Bn] with EuNBr allowed to determine the equilibrium constant of the complex formation reaction.

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Section: N M R Spectroscopic Investigationsmentioning

confidence: 98%

Bis-phosphonio-isophosphindolide Copper Complexes

Gudat

Holderberg

Korber

et al. 1999

Zeitschrift Für Naturforschung B

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“…[13] For instance, benzo[c]phospholes with no substituent at the benzo backbone readily undergo Diels-Alder reactions and have not been characterized well. [14] With this in mind, we designed bithiophene-fused benzo[c]phospholes as a new family of benzo[c]phosphole. It was anticipated that the fusion of bithiophene subunit at the benzo backbone would reduce the oquinonoid character and would then bring kinetic and thermal stabilization to the benzo[c]phosphole skeleton.…”

Section: Introductionmentioning

confidence: 99%

Comparative Study on the Structural, Optical, and Electrochemical Properties of Bithiophene‐Fused Benzo[c]phospholes

Matano

Miyajima

Fukushima

et al. 2008

Chemistry A European J

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Three types of bithiophene-fused benzo[c]phospholes were successfully prepared by Ti(II)-mediated cyclization of the corresponding dialkynylated bithiophene derivatives as a key step. Each sigma(3)-phosphorus center of the benzo[c]phosphole subunits was readily transformed into sigma(4)-phosphorus center by Au coordination or oxygenation. In addition, the bithiophene subunit was functionalized at the alpha,alpha'-carbon atoms by Pd-catalyzed cross-coupling reactions with heteroarylmetals and by an S(N)Ar reaction with hexafluorobenzene. The experimentally observed results (NMR spectroscopy, X-ray analysis, UV/Vis absorption/fluorescence spectroscopy, and cyclic/differential-pulse voltammetry) have revealed that the structural, optical, and electrochemical properties of the bithiophene-fused benzo[c]phospholes vary considerably depending on the pi-conjugation modes at the bithiophene subunits and the substituents of the heterocyclopentadiene components. The appropriately ring-annulated sigma(3)-P derivatives and sigma(4)-P-AuCl complexes were found to emit fluorescence in the orange-red region, and the sigma(4)-P-oxo derivatives proved to undergo reversible one-electron reduction at -1.4 to -1.8 V (vs ferrocene/ferrocenium). These results indicate that the bithiophene-fused benzo[c]phospholes possess narrow HOMO-LUMO gaps and low-lying LUMOs, which was confirmed by density functional theory calculations of their model compounds. The time-of-flight measurement of an ITO/benzo[c]phosphole/Al device showed that the electron mobility in the P-oxo derivative is one-order higher than that in Alq(3) at low electric fields. The present study demonstrates that the arene-fused benzo[c]phosphole skeleton could be a highly promising platform for the construction of a new class of phosphole-based optoelectrochemical materials.

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“…By such an arrangement, the center should switch from phosphide to phosphenium character. We first verified this type of compound in the diphosphonio isophosphindole cation 59 [153] (from which meanwhile a chemistry of its own was developed [154]), but found later on that even the acyclic system 61 is sufficient for the PCl bond to become ionic [155,156]. In accord with its syntheses and its behavior, we named it a bis(ylidyl) phosphenium ion.…”

Section: Alfred Schmidpetermentioning

confidence: 96%