Amine–Borane Dehydropolymerization Using Rh-Based Precatalysts: Resting State, Chain Control, and Efficient Polymer Synthesis

Ryan, David E.; Andrea, Kori A.; Race, James J.; Boyd, Timothy M.; Lloyd‐Jones, Guy C.; Weller, Andrew S.

doi:10.1021/acscatal.0c02211

Cited by 22 publications

(54 citation statements)

References 41 publications

(105 reference statements)

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“…To date, this family of BN polymers remains relatively underdeveloped. While catalytic routes should offer interesting prospects for the efficient and tailored synthesis of polyaminoboranes (Scheme 1A), the polymerization process predominantly depends on the catalyst system [2a–l] . In terms of functionality, limitations are imposed by the compatibility between the catalyst, mostly based on late transition metals, and the nitrogen functional group of the amine‐borane substrate.…”

Section: Introductionmentioning

confidence: 99%

Uncatalyzed Formation of Polyaminoboranes from Diisopropylaminoborane and Primary Amines: a Kinetically Controlled Polymerization Reaction

et al. 2021

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Recently, we disclosed the uncatalyzed formation of polyaminoboranes (PABs) from monomeric diisopropylaminoborane (iPr2N−BH2) and primary amines (RNH2). Their structure is studied through a detailed multinuclear NMR study and their full spectroscopic characterization is presented revealing that N‐alkyl substituted PABs exhibit magnetically non‐equivalent methylenic protons in the close vicinity of the BN‐backbone. We also performed an in‐depth theoretical study of this global chemical process. The mechanism is fully apprehended and the strong influence of the temperature on the outcome of the reaction is unveiled. DFT‐calculations clearly show that the formation of the polyaminoboranes (RNH−BH2)n results from a kinetically controlled step‐growth polymerization reaction that can be globally viewed as a head‐to‐tail association process of the in situ generated transient monomeric monoalkylamino‐borane [RNH−BH2].

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Section: Introductionmentioning

confidence: 99%

Uncatalyzed Formation of Polyaminoboranes from Diisopropylaminoborane and Primary Amines: a Kinetically Controlled Polymerization Reaction

et al. 2021

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“…11,[15][16][17][18][19] The cationic Schrock-Osborn [Rh(chelating-phosphine)] + system is a widely used one in catalysis and synthesis, 20, 21 and the active species are often accessed via hydrogenation of a suitable diene precursor, such as [Rh(chelatingphosphine)(NBD)][anion] (NBD = norbornadiene), in a coordinating solvent such as acetone. We have particular interest in such systems with the DPEphos ligand, with regard to their use as pre-catalysts for amine-borane dehydropolymerisation, 22,23 alkene and alkyne hydroacylation, [24][25][26] and alkyne carbothiolation, 27 amongst other applications. We now report the synthesis of new Schrock-Osborn systems with ortho-substituted DPEphos ligands, including a new i Prsubstituted ligand (Figure 2).…”

Section: Introductionmentioning

confidence: 99%

Ortho-aryl substituted DPEphos ligands: rhodium complexes featuring C–H anagostic interactions and B–H agostic bonds

et al. 2021

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“…Weller’s group has proved that POP diphosphines are hemilabile ligands. 18 In 2010, we prepared 9,9-dimethyl-4,5-bis(diisopropylphosphino)xanthene (xant(P i Pr 2 ) 2 ), among other ether diphosphines. 19 This ligand displays more coordinating flexibility than the classical POP diphosphines.…”

Section: Introductionmentioning

confidence: 99%

C–Cl Oxidative Addition and C–C Reductive Elimination Reactions in the Context of the Rhodium-Promoted Direct Arylation

et al. 2022

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A cycle of stoichiometric elemental reactions defining the direct arylation promoted by a redox-pair Rh(I)–Rh(III) is reported. Starting from the rhodium(I)-aryl complex RhPh{κ 3 -P,O,P-[xant(P i Pr 2 ) 2 ]} (xant(P i Pr 2 ) 2 = 9,9-dimethyl-4,5-bis(diisopropylphosphino)xanthene), the reactions include C–Cl oxidative addition of organic chlorides, halide abstraction from the resulting six-coordinate rhodium(III) derivatives, C–C reductive coupling between the initial aryl ligand and the added organic group, oxidative addition of a C–H bond of a new arene, and deprotonation of the generated hydride-rhodium(III)-aryl species to form a new rhodium(I)-aryl derivative. In this context, the kinetics of the oxidative additions of 2-chloropyridine, chlorobenzene, benzyl chloride, and dichloromethane to RhPh{κ 3 -P,O,P-[xant(P i Pr 2 ) 2 ]} and the C–C reductive eliminations of biphenyl and benzylbenzene from [RhPh 2 {κ 3 -P,O,P-[xant(P i Pr 2 ) 2 ]}]BF 4 and [RhPh(CH 2 Ph){κ 3 -P,O,P-[xant(P i Pr 2 ) 2 ]}]BF 4 , respectively, have been studied. The oxidative additions generally involve the cis addition of the C–Cl bond of the organic chloride to the rhodium(I) complex, being kinetically controlled by the C–Cl bond dissociation energy; the weakest C–Cl bond is faster added. The C–C reductive elimination is kinetically governed by the dissociation energy of the formed bond. The C(sp 3 )–C(sp 2 ) coupling to give benzylbenzene is faster than the C(sp 2 )–C(sp 2 ) bond formation to afford biphenyl. In spite of that a most demanding orientation requirement is needed for the C(sp 3 )–C(sp 2 ) coupling than for the C(sp 2 )–C(sp 2 ) bond formation, the energetic effort for the pregeneration of the C(sp 3 )–C(sp 2 ) bond is lower. As a result, the weakest C–C bond is formed faster.

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Amine–Borane Dehydropolymerization Using Rh-Based Precatalysts: Resting State, Chain Control, and Efficient Polymer Synthesis

Cited by 22 publications

References 41 publications

Uncatalyzed Formation of Polyaminoboranes from Diisopropylaminoborane and Primary Amines: a Kinetically Controlled Polymerization Reaction

Uncatalyzed Formation of Polyaminoboranes from Diisopropylaminoborane and Primary Amines: a Kinetically Controlled Polymerization Reaction

Ortho-aryl substituted DPEphos ligands: rhodium complexes featuring C–H anagostic interactions and B–H agostic bonds

C–Cl Oxidative Addition and C–C Reductive Elimination Reactions in the Context of the Rhodium-Promoted Direct Arylation

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