Phosphorus–Boron‐Based Polymers Obtained by Dehydrocoupling of Ferrocenylphosphine–Borane Adducts

Abstract

Dehydrocoupling of the ferrocenylphosphine-borane adducts [FcPH 2 (BH 3 )] (1) [Fc = Fe(C 5 H 5 )(C 5 H 4 )] and [FcCH 2 PH 2 (BH 3 )] (2) with [{Rh(μ-Cl)(cod)} 2 ] (cod = 1,5-cyclooctadiene) as catalyst gave the corresponding phosphorusboron-based polymers [FcPH(BH 2 )] n (3) and [FcCH 2 -PH(BH 2 )] n (4) as low-(heating in toluene, 3 low and 4 low ) or high-molecular-weight (heating without solvent, 3 high or 4 high ) poly(ferrocenylphosphinoborane)s depending on the reaction conditions. Dehydrocoupling of a racemic mixture of [2-N,N-dimethyl(N-borane)aminomethyl-1-ferrocenyl]phosphine-borane (6) resulted in several products, as both BH 3 moieties are apparently involved in polymer formation. Quaternization of the amino group in planar-chiral [Fe(C 5 H 5 ){C 5 H 3 (CH 2 NMe 2 )PH 2 }] (5) with MeI and treatment of the corresponding ammonium salt [Fe(C 5 H 5 )- [a]2457 bond angles at phosphorus vary from 99.6(1) to 115.5(7)°, and those at boron from 102.7(1) to 113.9(2)°.

The Catalytic Dehydrocoupling of Amine–Boranes and Phosphine–Boranes

“…18). Low molecular weight polymer was formed when the reaction was carried out in toluene solution (110 C), but in melt conditions, higher molecular weights could be obtained (Scheme 71) [177].…”

Synthesis, Structure and Reactivities of Pentacoordinated Phosphorus–Boron Bonded Compounds

“…The combination of a phosphine and borane gives a phosphine‐borane (R 3 P–BR 3 ) through P–B bond formation . These compounds have been used as protecting groups for P ‐chiral tertiary phosphines and diphosphines, as well as precursors for P–B bond containing polymers . More recently, phosphino‐boranes, bearing the lower coordinated bond between a tricoordinated phosphorus and a tricoordinated boron atom (R 2 P–BR 2 ), have regained attention as they have been shown to activate H 2 and other small molecules and to coordinate to metals in a symmetric side‐on fashion .…”

Trihydroborates and Dihydroboranes Bearing a Pentacoordinated Phosphorus Atom: Double Ring Expansion To Balance the Coordination States

“…[1] Among the classical Lewis complexes, phosphine-boranes (R 3 PÀ BR' 3 ), which bear a P À B bond ( Figure 1, type I), have been used for the synthesis of P-chiral tertiary phosphines and diphosphines, [2] and as precursors for polymers containing PÀB bonds. [3] Other types of PÀB bonded compounds, such as phosphino-boranes (R 2 PÀBR' 2 ; type II), [4] have been shown to activate H 2 by behaving as an intramolecular frustrated Lewis pair and to coordinate to metal in a symmetric side-on fashion. [5] Further modification of the properties and reactivities could be achieved if the coordination numbers of the elements that constitute the bond were increased.…”