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3 edition of Catalytic dehydrocoupling of group 13 - group 15 adducts found in the catalog.

Catalytic dehydrocoupling of group 13 - group 15 adducts

Cory Alan Jaska

Catalytic dehydrocoupling of group 13 - group 15 adducts

synthetic and mechanistic studies

by Cory Alan Jaska

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Published .
Written in English


About the Edition

The dehydrocoupling of primary and secondary amine-borane adducts to afford either monomeric or dimeric aminoboranes and borazines was developed using transition metal complexes as precatalysts. Mechanistic investigations performed on the dehydrocoupling of Me 2 NH*BH 3 suggested the operation of a heterogeneous process involving Rh colloids in which the first step may be an intermolecular dehydrocoupling reaction to give the linear Me 2 NH-BH 2 -NMe 2 -BH 3 , followed by a subsequent intramolecular reaction to afford the observed cyclic [Me 2 N-BH 2 ] 2 . The heterogeneity of the process was evidenced by (i) the presence of a sigmoidal kinetic curve, (ii) the observation of Rh colloids by TEM, (iii) the poisoning of the active catalyst by treatment with mercury or PPh 3 , (iv) a reduction in activity upon filtration and (v) the isolation of Rh metal as an active catalyst. A tandem catalytic dehydrocoupling-hydrogenation reaction was developed which involved the reaction of an amine-borane adduct and an unsaturated substrate using a common precatalyst. This reaction allows a stoichiometric quantity of hydrogen to be delivered for the hydrogenation reaction and operates at room temperature. Linear hybrid aminoborane-phosphinoborane chains were synthesized and were found to possess both inter- and intra-molecular proton-hydride bonding of moderate strengths. Remarkably, comparative mechanistic studies performed on the dehydrocoupling of the analogous phosphine-borane system Ph 2 PH*BH 3 suggested the operation of a homogeneous process. This fundamental difference in reactivity between amine-borane and phosphine-borane adducts is thought to arise from (i) differences in the reducing strength of the adducts, (ii) differences in the extent of dissociation of the adducts and (iii) the presence of phosphine ligation/poisoning of the active catalyst. Platinum hydride complexes with primary and secondary phosphine-borane ligands, such as trans -[PtH(PhPR*BH 3 )(PEt 3 ) 2 ] and cis -[PtH(PhPR*BH 3 )(depe)] (where R = Ph, H), were synthesized. However, further reactivity studies of these complexes did not indicate any coupling chemistry to form new P-B bonds at the metal center. The iridium hydride complex [Cp*IrH(PPhH*BH 3 )(PMe 3 )] was also synthesized, but again displayed no further reactivity when reacted with phosphine-borane adducts. Dehydrocoupling routes for the formation of platinum-phosphorus bonds from the reaction of platinum hydrides with primary and secondary phosphines and phosphine-borane adducts has been demonstrated.

Edition Notes

StatementCory Alan Jaska.
The Physical Object
Paginationxxvi, 226 leaves :
Number of Pages226
ID Numbers
Open LibraryOL20205249M
ISBN 109780494159712
OCLC/WorldCa233521790

Post-Doctoral Worker (Inorganic Polymer Chemistry), University of Bristol, UK; Supervisor: Prof. Dr. Ian Manners; Research projects in the area of the catalytic dehydrocoupling of group 13 – group 15 adducts, DFT calculations concerning metallocenophanes, mechanistic studies on polyphosphazenes. Welcome to the Manners group! Our research focuses on the development of new synthetic approaches involving ring-opening reactions, catalysis, and self-assembly and their applications in molecular chemistry, polymer and materials science, and nanoscience with a particular (but not exclusive) emphasis on exploiting the interesting features of main group and transition elements.

At present, group 13/15 compounds are already used as abrasives,[15] flame retardants,[16] high temperature ceramics[1] or as semiconducting materials in opto- and microelectronic devices.[17] Inorganic Oligomeric and Polymeric Compounds from Dehydrocoupling reactions. secondary silanes using [Cp2M] (M) group 4 metal) catalysts which are generated in situ by the reaction of the appropriate Cp2-MCl2 complex with 2 equiv of nBuLi To investigate if catalysts of this type would be active for other systems, such as group 13/ 15 adducts, we treated 1 with a catalytic (2 mol %) amount of [Cp2Ti].

  For example, the catalytic dehydrocoupling of Group 13–Group 15 Lewis acid–Lewis base adducts (e.g. 1° or 2° phosphine–boranes or amine–boranes) has been shown to yield high molecular weight polyphosphinoboranes, cyclic aminoborane species or borazines. For her post-doctoral work she joined the group of Ian Manners, also at the University of Bristol, where she worked on main group inorganic polymers, in particular catalytic dehydrocoupling reactions of group 13 group 15 adducts.


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Catalytic dehydrocoupling of group 13 - group 15 adducts by Cory Alan Jaska Download PDF EPUB FB2

Transition metal-catalyzed dehydrocoupling is a relatively new method for main group element–element bond formation, providing a facile alternative to salt metathesis processes. Lewis acid–base adducts of Groups 13 and 15 can undergo dehydrocoupling with both early and late transition metals and complexes thereof to yield rings, chains and Cited by: 7.

Transition metal-catalyzed dehydrocoupling of group group 15 Lewis acid–base adducts Article in Journal of Organometallic Chemistry (13) June with 4 Reads. Transition metal-catalyzed dehydrocoupling of group group 15 Lewis acid–base adducts.

Journal of Organometallic Chemistry, DOI: /chem Yanfeng Jiang, Heinz Berke. Dehydrocoupling of dimethylamine-borane catalysed by rhenium complexes and its application in olefin by:   Figure 7: A summary of representative catalysts and relevant catalytic cycles for the dehydrogenation and dehydrocoupling of adducts of groups 13–15 to Cited by: Transition metal-catalyzed dehydrocoupling of group group 15 Lewis acid–base adducts Timothy J.

Clark, Ian Manners Journal of Organometallic Chemistry The efficient catalytic dehydrocoupling of a range of amine−borane adducts, R′RNHBH 3 (R′ = R = Me 1a; R′ = R = i Pr 1b; R′ = Me, R = CH 2 Ph 1c) by a series of group 4 metallocene type precatalysts has been demonstrated.A reduction in catalytic activity was detected upon descending the group and also on substitution of the cyclopentadienyl (Cp) ligands with sterically bulky or Cited by: This is similar to the results of dehydrocoupling previously seen with single-site Rh I catalysts and appears to occur via intermediate group 13 hydrides, as shown by the isolation of the amido-alane [H 2 Al(μ-N i Pr 2)] 2 (7) in the formation of 4 from Al(N i Pr 2) by: The catalytic dehydrocoupling reactions of Me2NHBH3 and Ph2PHBH3 using the rhodium precatalyst [Rh(1,5-cod)(μ-Cl)]2 were found to proceed by different mechanisms: heterogeneous involving Rh(0) metal for the former case and homogeneous for the by: Catalytic dehydrocoupling of amine-borane adducts to form aminoboranes and borazines Article in Phosphorus Sulfur and Silicon and the Related Elements Sulfur() April with 11 Reads.

First published on 9th January A primary factor influencing catalytic versus stoichiometric behaviour of molecular main group species in homogeneous dehydrocoupling reactions is the redox stability of the metal centre. Thus, only in the case of redox-stable metals has catalytic behaviour so far been observed, through genuinely hydrogenic coupling (E–H + E′–H → E–E′ + H 2 Cited by:   Iridium‐Catalyzed Dehydrocoupling of Primary Amine–Borane Adducts: Group 13–Group 15 Element Bonds Replacing Carbon–Carbon Bonds in Main Group Polyolefin Analogs, Smart Inorganic Polymers, (), Formation and Catalytic Dehydrocoupling of Amine–Boranes, Angewandte Chemie,35, (), ().

First published on 10th August Dehydrocoupling reactions, i.e. reactions involving elimination of H 2 between two E–H bonds, provide a clean route to E–E bonds within the main group.

The products afforded from these reactions have applications in organic synthesis and materials chemistry, and in addition the H 2 released during these reactions can also be useful as an energy by: Transition metal-catalyzed dehydrocoupling of group group 15 Lewis acid–base adducts.

Journal of Organometallic Chemistry, DOI: /chem Timothy J. Clark, Kajin Lee, Ian Manners. Transition-Metal-Catalyzed Dehydrocoupling: A Convenient Route to Bonds between Main-Group by: The dehydrocoupling of the fluorinated secondary phosphine–borane adduct R 2 PH⋅BH 3 (R = p‐CF 3 C 6 H 4) at 60 °C is catalyzed by the rhodium complex [{Rh(μ‐Cl)(1,5‐cod)} 2] to give the four‐membered chain R 2 PH‐BH 2 ‐R 2 P‐BH 3.A mixture of the cyclic trimer [R 2 P‐BH 2] 3 and tetramer [R 2 P‐BH 2] 4 was obtained from the same reaction at a more elevated temperature.

The catalytic dehydrocoupling reaction of Me2NHBH3 with Al(NMe2)3 gives the dimer [Me2NBH2]2 and the chain [(Me2N)2BH], involving the thermally-stable AlIII hydride catalyst [{(Me2N)2BH2}2AlH].Cited by: For example, the catalytic dehydrocoupling of Group Group 15 Lewis acid-Lewis base adducts (e.g.

1degrees or 2degrees phosphine-boranes or amine boranes) has. For example, the catalytic dehydrocoupling of Group Group 15 Lewis acid-Lewis base adducts (e.g.

1degrees or 2degrees phosphine-boranes or amine boranes) has bee Cite Download full-text. Poisoning of Heterogeneous, Late Transition Metal Dehydrocoupling Catalysts by Boranes and Other Group 13 Hydrides Article in Journal of the American Chemical Society (14) May Metallocene alkyls and hydrides of group 4 show a particularly high catalytic activity in a number of dehydrocoupling reactions, including Si/Si, Ge/Ge, Si/O, Si/N and B/N reactions.

The role of some novel silyl intermediates in the dimethyltitanocene- and dimethylzirconocene-catalysed silane coupling reactions is Cited by: R2NH-BH2-NR2-BH3 (5: R = Me; 6: R = 1,4-C4H8) was developed and subsequent catalytic dehydrocoupling of these species yielded the cyclic compds.

1 and 2. The species 5 and 6 are postulated to be intermediates in the formation of 1 and 2 directly from the catalytic dehydrocoupling of the adducts R2NHBH3. Catalytic Dehydrocoupling of Group Group 15 Lewis Acid - Base Adducts: Mechanistic Studies & Synthetic Applications (P) Key: (P) =Principal Investigator, (C) =Co .Selective And Mild Synthesis Of Mono- And Diarylated Group Halides Using [Cumes]n, A Readily Available, Thermally Stable Organocopper(I) Reagent.

Jäkle .Catalytic heteronuclear-dehydrocoupling B–N bond formation The use of hydrogen as a renewable, non-toxic and clean energy B and N with respect to H within the donor–acceptor adduct H 3N - BH Group 13 Group 14 Group 15 Group 16 Group 17 B–H C–H N–H O–H F–HCited by: