scholarly journals Methanediide Formation via Hydrogen Elimination in Magnesium versus Aluminium Hydride Complexes of a Sterically Demanding Bis(iminophosphoranyl)methanediide

Inorganics ◽  
2017 ◽  
Vol 5 (2) ◽  
pp. 29 ◽  
Author(s):  
Christian Sindlinger ◽  
Samuel Lawrence ◽  
David Cordes ◽  
Alexandra Slawin ◽  
Andreas Stasch
Keyword(s):  
Hydride Complexes ◽  
Hydrogen Elimination ◽  
Sterically Demanding

scholarly journals Methanediide Formation via Hydrogen Elimination in Magnesium versus Aluminium Hydride Complexes of a Sterically Demanding Bis(iminophosphoranyl)methanediide

2017 ◽  
Author(s):  
Christian P. Sindlinger ◽  
Samuel R. Lawrence ◽  
David B. Cordes ◽  
Alexandra M. Z. Slawin ◽  
Andreas Stasch
Keyword(s):  
Diethyl Ether ◽  
Elevated Temperatures ◽  
Chemical Properties ◽  
Molecular Structures ◽  
Hydride Complexes ◽  
Hydrogen Elimination ◽  
Sterically Demanding ◽  
Central Carbon ◽  
Acidic Compounds ◽  
H2 Elimination

Substituted bis(iminophosphoranyl)methanes are CH acidic compounds that can form complexes with formally dianionic central carbon centres. The reaction of H2C(Ph2P=NDip)2 (≡ H2L), Dip = 2,6-diisopropylphenyl, with one equivalent of di-n-butylmagnesium afforded the methanide complex [HLMgnBu] 1. Treatment of complex 1 with phenylsilane in aromatic solvents at elevated temperatures afforded the methanediide complex [(LMg)2] 2 presumably via the MgH intermediate [(HLMgH)n] (n = 1 or 2). The reaction of 1 with LiAlH4 in diethyl ether yielded the AlH complex [HLAlH2] 3. Alternatively, this complex was also obtained from the reaction of H2L with AlH3∙NMe3. The molecular structures of [HLMgnBu] 1, [(LMg)2] 2, and [HLAlH2] 3 are reported. Complex 3 shows no sign of H2 elimination to a methanediide species at elevated temperatures in contrast to the facile elimination of the putative reaction intermediate [(HLMgH)n] (n = 1 or 2) to form [(LMg)2] 2. The chemical properties of complex 2 were investigated and this complex appears to be stable against coordination with strong donor molecules.

Hydrogen elimination reactivity of ruthenium pincer hydride complexes: a DFT study

2019 ◽  
Vol 43 (36) ◽  
pp. 14634-14642 ◽  
Author(s):  
Geetha S. Remya ◽  
Cherumuttathu H. Suresh
Keyword(s):  
Dft Study ◽  
Activation Barriers ◽  
Hydride Complexes ◽  
Hydrogen Elimination

The pincer effect is explained for various pincer hydride complexes, differing in the donor atoms, using activation barriers, and MESP parameters.

Regioselective Gas-Phase n-Butane Transfer Dehydrogenation via Silica-Supported Pincer-Iridium Complexes

2020 ◽  
Author(s):  
Boris Sheludko ◽  
Cristina Castro ◽  
Chaitanya Khalap ◽  
Thomas Emge ◽  
Alan Goldman ◽  
...  
Keyword(s):  
Gas Phase ◽  
Active Site ◽  
Lower Cost ◽  
Open Systems ◽  
Iridium Complexes ◽  
Terminal Olefin ◽  
Molecular Precursors ◽  
Sterically Demanding ◽  
Olefin Production ◽  
Steam Cracking

<b>Abstract:</b> The production of olefins via on-purpose dehydrogenation of alkanes allows for a more efficient, selective and lower cost alternative to processes such as steam cracking. Silica-supported pincer-iridium complexes of the form [(≡SiO-<sup>R4</sup>POCOP)Ir(CO)] (<sup>R4</sup>POCOP = κ<sup>3</sup>-C<sub>6</sub>H<sub>3</sub>-2,6-(OPR<sub>2</sub>)<sub>2</sub>) are effective for acceptorless alkane dehydrogenation, and have been shown stable up to 300 °C. However, while solution-phase analogues of such species have demonstrated high regioselectivity for terminal olefin production under transfer dehydrogenation conditions at or below 240 °C, in open systems at 300 °C, regioselectivity under acceptorless dehydrogenation conditions is consistently low. In this work, complexes <a>[(≡SiO-<i><sup>t</sup></i><sup>Bu4</sup>POCOP)Ir(CO)] </a>(<b>1</b>) and [(≡SiO-<i><sup>i</sup></i><sup>Pr4</sup>PCP)Ir(CO)] (<b>2</b>) were synthesized via immobilization of molecular precursors. These complexes were used for gas-phase butane transfer dehydrogenation using increasingly sterically demanding olefins, resulting in observed selectivities of up to 77%. The results indicate that the active site is conserved upon immobilization.

Monodentate Trialkylphosphines: Privileged Ligands in Metal-catalyzed Crosscoupling Reactions

2020 ◽  
Vol 24 (3) ◽  
pp. 231-264 ◽  
Author(s):  
Kevin H. Shaughnessy
Keyword(s):  
Transition Metal ◽  
Cross Coupling ◽  
Coupling Reactions ◽  
Cross Coupling Reactions ◽  
Aryl Bromides ◽  
Wide Range ◽  
Sterically Demanding ◽  
Transition Metal Catalyzed ◽  
Catalyzed Reactions ◽  
Metal Catalyzed

Phosphines are widely used ligands in transition metal-catalyzed reactions. Arylphosphines, such as triphenylphosphine, were among the first phosphines to show broad utility in catalysis. Beginning in the late 1990s, sterically demanding and electronrich trialkylphosphines began to receive attention as supporting ligands. These ligands were found to be particularly effective at promoting oxidative addition in cross-coupling of aryl halides. With electron-rich, sterically demanding ligands, such as tri-tertbutylphosphine, coupling of aryl bromides could be achieved at room temperature. More importantly, the less reactive, but more broadly available, aryl chlorides became accessible substrates. Tri-tert-butylphosphine has become a privileged ligand that has found application in a wide range of late transition-metal catalyzed coupling reactions. This success has led to the use of numerous monodentate trialkylphosphines in cross-coupling reactions. This review will discuss the general properties and features of monodentate trialkylphosphines and their application in cross-coupling reactions of C–X and C–H bonds.

Thermally Stable Half-Sandwich Benzhydryl Ln(II) (Ln = Sm, Yb) Complexes Supported by Sterically Demanding Carbazolyl and Fluorenyl Ligands

2019 ◽  
Vol 38 (24) ◽  
pp. 4615-4624 ◽  
Author(s):  
Alexander N. Selikhov ◽  
Andrey S. Shavyrin ◽  
Anton V. Cherkasov ◽  
Georgy K. Fukin ◽  
Alexander A. Trifonov
Keyword(s):  
Thermally Stable ◽  
Sterically Demanding ◽  
Half Sandwich

Ruthenium(II) Complexes with N-Heterocyclic Carbene-Phosphine Ligands for the N-Alkylation of Amines with Alcohols

2021 ◽  
Author(s):  
Ming Huang ◽  
Yinwu Li ◽  
Xiao-Bing Lan ◽  
Jiahao Liu ◽  
Cunyuan Zhao ◽  
...  
Keyword(s):  
Metal Hydride ◽  
Phosphine Ligands ◽  
Hydride Complexes ◽  
Borrowing Hydrogen ◽  
Hydrogen Autotransfer

Metal hydride complexes are key intermediates for N-alkylation of amines with alcohols by borrowing hydrogen/hydrogen autotransfer (BH/HA) strategy. Reactivity tuning of metal hydride complexes could adjust the dehydrogenation of alcohols...

scholarly journals Synthesis and Catalytic Reactivity of Cobalt Pincer Nitrosyl Hydride Complexes

2021 ◽  
Author(s):  
Jan Pecak ◽  
Sarah Fleissner ◽  
Luis F. Veiros ◽  
Ernst Pittenauer ◽  
Berthold Stöger ◽  
...  
Keyword(s):  
Hydride Complexes ◽  
Nitrosyl Hydride ◽  
Catalytic Reactivity

Enantiopure dimagnesium(i) and magnesium(ii) hydride complexes incorporating chiral amidinate or β-diketiminate ligands

2021 ◽  
Vol 57 (13) ◽  
pp. 1599-1602
Author(s):  
Caspar N. de Bruin-Dickason ◽  
Christopher A. Rosengarten ◽  
Glen B. Deacon ◽  
Cameron Jones
Keyword(s):  
Hydride Complexes

The first examples of enantiopure, dinuclear magnesium(i) and magnesium(ii) hydride complexes have been kinetically stabilised using bulky chiral β-diketiminate and amidinate ligands (see picture).

Cationic Strontium Hydride Complexes Supported by an NNNN-Type Macrocycle

2021 ◽  
Author(s):  
Jun Okuda ◽  
Maron Laurent ◽  
Ambre Carpentier ◽  
Thomas Paul Spaniol ◽  
Thomas Hoellerhage ◽  
...  
Keyword(s):  
Hydride Complexes ◽  
Hydride Ligand

A trinuclear strontium hydride [(Me4TACD)3Sr3(µ2-H)4(thf)][B(C6H3-3,5-Me2)4]2 (Me4TACD = 1,4,7,10-tetramethyl-tetraazacyclododecane) and a mixed calcium strontium hydride [(Me4TACD)2CaSr(µ-H)2(thf)]2+ were isolated by hydrogenolysis of cationic benzyl precursors. A solution of [(Me4TACD)2CaSr(µ-H)2(thf)][B(C6H3-3,5-Me2)4]2 shows hydride ligand...

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