Synthesis of a transition-metalated phosphinoborane dimer

Kubo, Kazuya; Kanemitsu, Ikue; Murakami, Eri; Mizuta, Tsutomu; Nakazawa, Hiroshi; Miyoshi, Katsuhiko

doi:10.1016/j.jorganchem.2004.04.024

Cited by 7 publications

(9 citation statements)

References 43 publications

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“…These coupling constants are greater than that observed for the dimer [Cp(CO) 2 FeP-(Ph)BCl 2 ] 2 (J CP = 10 Hz). 13 The larger couplings obtained in the monomers can be reasonably accounted for by the sp 2 -hybridization of the phosphorus in the monomers, which would cause more s-orbital character in the bonding than the sp 3 -hybridized phosphorus in the dimer. 1 H NMR spectral data provide further information on the nature of the P−B bonding in phosphinoboranes.…”

Section: ■ Results and Discussionmentioning

confidence: 95%

“…This behavior is in stark contrast to that of the aforementioned Cp(CO) 2 FeP-(Ph)BCl 2 , which promptly dimerizes, giving an upfield chemical shift at 4.6 ppm. 13 Furthermore, the VT 11 B{ 1 H} NMR spectrum of the dimer showed no apparent change in its chemical shift up to 70 °C, indicating that no dimer−monomer equilibrium exists at these temperatures (Scheme 3). 24 In this manner, the protection on the boron atom by bulky (and also less electronegative) substituents is shown to be crucial to avoid the association of the monomers.…”

Section: ■ Results and Discussionmentioning

confidence: 98%

“…Additionally, the zirconium atom, as a π acceptor, further suppressed the P–B π interaction to some extent (Chart , a). Previously, we reported that dehydrohalogenation from a trichloroborane adduct of an iron-phosphide complex provided a P -iron-substituted phosphinoborane dimer, probably via the immediate association of transient monomers during the course of the reaction (Scheme ) . The results indicated that the putative metalated phosphinoborane monomer was highly amphoteric.…”

Section: Introductionmentioning

confidence: 91%

“…13 The results indicated that the putative metalated phosphinoborane monomer was highly amphoteric. It seemed that the chloro substituents on the boron atom were sterically less demanding, which allowed the association to proceed.…”

Section: ■ Introductionmentioning

confidence: 98%

“…Previously, we reported that dehydrohalogenation from a trichloroborane adduct of an iron-phosphide complex provided a P-iron-substituted phosphinoborane dimer, probably via the immediate association of transient monomers during the course of the reaction (Scheme 1). 13 The results indicated that the putative metalated phosphinoborane monomer was highly amphoteric. It seemed that the chloro substituents on the boron atom were sterically less demanding, which allowed the association to proceed.…”

Section: ■ Introductionmentioning

confidence: 98%

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Synthesis and Crystal Structures of P-Iron-Substituted Phosphinoborane Monomers

et al. 2012

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A family of P-iron-substituted phosphinoboranes, Cp(CO) 2 Fe{P(Ar)BMes 2 } (Ar = Ph, Mes, Tipp, Mes*), have been prepared from the reaction of Cp(CO) 2 FeCl and (Li)(Ar)PBMes 2 . All the complexes have been characterized successfully by 1 H, 11 B, and 31 P NMR; IR spectroscopy; and Xray crystallography. In the IR spectra, all the complexes display similar carbonyl stretching frequencies that are remarkably higher than those of closely related phosphide complexes. These observations indicate that a repulsive interaction between the filled d orbital on the iron and the lone pair on the phosphorus is less severe in the studied iron-phosphinoboranes, which is most likely because of the P→B π interaction that occurs in them. The 31 P{ 1 H} NMR chemical shifts of the phosphinoborane phosphorus move upfield with the increasing steric bulk of the Ar groups in the order Ph (−51.4 ppm) < Mes (−68.8 ppm) < Tipp (−84.9 ppm). However, the phosphorus bearing the most sterically demanding Mes* group appears at an unexpectedly downfield value of −44.9 ppm, which is probably reflective of its structural peculiarities. The 1 H NMR spectrum of each complex displays two sets of signals, assignable to inequivalent Mes groups on the boron atom, as a consequence of a hindered rotation around the P−B bond. This high rotational barrier most likely results from the significant double-bond character in the P−B bond. The X-ray diffraction studies have confirmed the iron-phosphinoboranes considered herein to be monomeric species. Each molecule consists of a nearly planar phosphinoborane fragment with a short P−B bond. The Fe−P bond is notably elongated as the Ar group becomes larger, demonstrating its somewhat vulnerable nature with respect to steric congestion. In contrast, the variation in the P−B bond distance is relatively small throughout the series of iron-phosphinoboranes, suggesting that the PB double-bond character is balanced by steric and electronic effects of the substituents around the phosphorus.

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Section: ■ Results and Discussionmentioning

confidence: 95%

Section: ■ Results and Discussionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 91%

Section: ■ Introductionmentioning

confidence: 98%

Section: ■ Introductionmentioning

confidence: 98%

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Synthesis and Crystal Structures of P-Iron-Substituted Phosphinoborane Monomers

et al. 2012

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Synthesis and Molecular Structure of Tris[(trimethylsilyl)silyl](diisopropylamino)(diphenylphosphino)borane

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Paine

Duesler

et al. 2006

Zeitschrift anorg allge chemie

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The 1:1 reaction of [(Me3Si)3SiLi·3THF] with (iPr2N)BCl2 in hexane provides [{(Me3Si)3Si}·(iPr2N)BCl] (2) in good yield as a colorless crystalline solid. This compound combined in a 1:1 ratio with LiPPh2 in DME gives [{(Me3Si)3Si}·(iPr2N)B(PPh2)] (3) as a yellow crystalline solid. The new compounds were characterized by IR, MS and 1H, 13C{1H} and 11B NMR spectroscopy and the molecular structure of 3 was determined by X‐ray structure analysis.

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