The electronic structure,molecular properties and barriers to internal rotation of some conjugated boron compounds

Gropen, Odd

doi:10.1016/0022-2860(77)85011-4

Cited by 10 publications

(4 citation statements)

References 20 publications

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“…These data are in agreement with the theoretical pictures mentioned previously. [75][76][77][78][79] In the nonplanar form (ground state) of H2BPH2, the calculated B-P bond distance is 1.901 A, and the out-of-plane angle at phosphorus is 70°. The planar form (excited state), on the other hand, has a calculated B-P bond distance of 1.807 A.…”

Section: B Structural Characterizationmentioning

confidence: 99%

Recent Advances in Phosphinoborane Chemistry

Paine¹,

Noeth²

1995

Chem. Rev.

154

109

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Section: B Structural Characterizationmentioning

confidence: 99%

Recent Advances in Phosphinoborane Chemistry

Paine¹,

Noeth²

1995

Chem. Rev.

154

109

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“…Experimental and theoretical studies have shown the close relationship between the degrees of phosphorus pyramidalization (i.e., ϕ angle) and the PB double-bond length (see Introduction). Sterically less encumbered phosphinoboranes have a relatively larger ϕ angle.…”

Section: Resultsmentioning

confidence: 99%

“…The chemistry of group 13/15 compounds has extensively grown over the past decades and continues to be an active research area in academic and industrial laboratories. − Recent research focus in this area has mostly been application-driven, e.g., quests for novel semiconducting materials, advanced ceramics, promising inorganic polymers, , and hydrogen-storage materials . Nevertheless, fundamental interests in the bonding nature and reactivity of simple molecules remain unabated.…”

Section: Introductionmentioning

confidence: 99%

“…In particular, compounds containing a π bond between a lone pair on the group 15 element and an empty p orbital on the group 13 element are of special importance, partly because of their isoelectronic relationship to organic counterparts having a carbon–carbon π bond. , Unlike the planar geometry of the nitrogen atom in aminoborane H 2 NBH 2 , the phosphorus atom in phosphinoborane H 2 PBH 2 is significantly pyramidal. Phosphorus tends not to produce a planar geometry because of its higher inversion barrier as compared to that of nitrogen . This nonplanarity reduces the intramolecular π overlap, thereby increasing the basicity of the phosphorus and the acidity of the boron atom.…”

Section: Introductionmentioning

confidence: 99%

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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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Verbindungen mit Bor‐Phosphor‐Mehrfachbindung

Power

1990

Angewandte Chemie

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Bor-Phosphor-Verbindungen sind nicht annahernd so grundlich untersucht wie ihre BorStickstoff-Analoga. Bis vor kurzem waren ganze Klassen von B-P-Verbindungen, fur die es in der B-N-Chemie wohlbekannte Entsprechungen gibt, entweder unbekannt oder nur unzureichend charakterisiert. Neue Arbeiten zeigen nun aber, daD sich Bor-Phosphor-Verbindungen mit variierenden B-P-Mehrfachbindungsanteilen herstellen und charakterisieren lassen. Diese Verbindungen umfassen nicht nur monomere Phosphinoborane, sondern auch Phosphandiylborate (Borylphosphide), drei-(Diphosphaborirane) und viergliedrige Ringe (Diphosphadiboretane), B-P-Analoga von Borazin, von Allyl-Kationen und -Anionen sowie von Butadien und Kafigverbindungen. Die Unterschiede zwischen B-P-und B-N-Verbindungen konnen in vielen Fallen durch eine hohe Inversionsbarriere am Phosphor, die die x-Wechselwirkung vermindert, erklart werden. Dies fuhrt gewohnlich bei Verbindungen wie R,BPR2 zur Bildung von Assoziaten rnit B-P-a-Bindungen. x-Bindungen konnen unter Bildung eines annahernd planaren >BP:-Systems gezielt uber sterische und elektronische Faktoren begiinstigt werden. Weiterhin belegen theoretische Untersuchungen, daD die p-p-x-uberlappung in einem planaren B-P-System ahnlich gut ist wie im B-N-Analogon. Gute Beispiele bieten die Phosphandiylborate sowie die B-P-Analoga des Borazins und der x-Allyl-Kationen, in denen die Molekulstrukturen und Bindungslangen fur starke Bor-Phosphor-x-Bindungen sprechen.

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The electronic structure,molecular properties and barriers to internal rotation of some conjugated boron compounds

Cited by 10 publications

References 20 publications

Recent Advances in Phosphinoborane Chemistry

Recent Advances in Phosphinoborane Chemistry

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

Verbindungen mit Bor‐Phosphor‐Mehrfachbindung

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