Heterolysis of Dihydrogen by Nucleophilic Calcium Alkyls

Andrew Wilson, Chiara Dinoi, Michael Hill, Mary Mahon, Laurent Maron

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

β‐Diketiminato (BDI) calcium alkyl derivatives undergo hydrogenolysis with H2 to regenerate [(BDI)CaH]2, allowing the catalytic hydrogenation of a wide range of 1‐alkenes and norbornene under very mild conditions (2 bar H2, 298 K). The reactions are deduced to take place with the retention of the dimeric structures of the calcium hydrido‐alkyl and alkyl intermediates via a well‐defined sequence of Ca−H/C=C insertion and Ca−C hydrogenation events. This latter deduction is strongly supported by DFT calculations (B3PW91) performed on the 1‐hexene/H2 system, which also indicates that the hydrogenation transition states display features which discriminate them from a classical σ‐bond metathesis mechanism. In particular, NBO analysis identifies a strong second order interaction between the filled α‐methylene sp3 orbital of the n‐hexyl chain and the σ* orbital of the H2 molecule, signifying that the H−H bond is broken by what is effectively the nucleophilic displacement of hydride by the organic substituent.
LanguageEnglish
Pages15500-15504
Number of pages5
JournalAngewandte Chemie-International Edition
Volume57
Issue number47
Early online date26 Oct 2018
DOIs
StatusPublished - 19 Nov 2018

Keywords

  • calcium
  • catalysis
  • density functional theory
  • hydrogenation
  • main group chemistry

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)

Cite this

Heterolysis of Dihydrogen by Nucleophilic Calcium Alkyls. / Wilson, Andrew; Dinoi, Chiara; Hill, Michael; Mahon, Mary; Maron, Laurent.

In: Angewandte Chemie-International Edition, Vol. 57, No. 47, 19.11.2018, p. 15500-15504.

Research output: Contribution to journalArticle

@article{39e3e67f86324636bcbef67013e79c76,
title = "Heterolysis of Dihydrogen by Nucleophilic Calcium Alkyls",
abstract = "β‐Diketiminato (BDI) calcium alkyl derivatives undergo hydrogenolysis with H2 to regenerate [(BDI)CaH]2, allowing the catalytic hydrogenation of a wide range of 1‐alkenes and norbornene under very mild conditions (2 bar H2, 298 K). The reactions are deduced to take place with the retention of the dimeric structures of the calcium hydrido‐alkyl and alkyl intermediates via a well‐defined sequence of Ca−H/C=C insertion and Ca−C hydrogenation events. This latter deduction is strongly supported by DFT calculations (B3PW91) performed on the 1‐hexene/H2 system, which also indicates that the hydrogenation transition states display features which discriminate them from a classical σ‐bond metathesis mechanism. In particular, NBO analysis identifies a strong second order interaction between the filled α‐methylene sp3 orbital of the n‐hexyl chain and the σ* orbital of the H2 molecule, signifying that the H−H bond is broken by what is effectively the nucleophilic displacement of hydride by the organic substituent.",
keywords = "calcium, catalysis, density functional theory, hydrogenation, main group chemistry",
author = "Andrew Wilson and Chiara Dinoi and Michael Hill and Mary Mahon and Laurent Maron",
note = "{\circledC} 2018 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.",
year = "2018",
month = "11",
day = "19",
doi = "10.1002/anie.201809833",
language = "English",
volume = "57",
pages = "15500--15504",
journal = "Angewandte Chemie-International Edition",
issn = "1433-7851",
publisher = "WILEY-V C H VERLAG GMBH",
number = "47",

}

TY - JOUR

T1 - Heterolysis of Dihydrogen by Nucleophilic Calcium Alkyls

AU - Wilson, Andrew

AU - Dinoi, Chiara

AU - Hill, Michael

AU - Mahon, Mary

AU - Maron, Laurent

N1 - © 2018 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

PY - 2018/11/19

Y1 - 2018/11/19

N2 - β‐Diketiminato (BDI) calcium alkyl derivatives undergo hydrogenolysis with H2 to regenerate [(BDI)CaH]2, allowing the catalytic hydrogenation of a wide range of 1‐alkenes and norbornene under very mild conditions (2 bar H2, 298 K). The reactions are deduced to take place with the retention of the dimeric structures of the calcium hydrido‐alkyl and alkyl intermediates via a well‐defined sequence of Ca−H/C=C insertion and Ca−C hydrogenation events. This latter deduction is strongly supported by DFT calculations (B3PW91) performed on the 1‐hexene/H2 system, which also indicates that the hydrogenation transition states display features which discriminate them from a classical σ‐bond metathesis mechanism. In particular, NBO analysis identifies a strong second order interaction between the filled α‐methylene sp3 orbital of the n‐hexyl chain and the σ* orbital of the H2 molecule, signifying that the H−H bond is broken by what is effectively the nucleophilic displacement of hydride by the organic substituent.

AB - β‐Diketiminato (BDI) calcium alkyl derivatives undergo hydrogenolysis with H2 to regenerate [(BDI)CaH]2, allowing the catalytic hydrogenation of a wide range of 1‐alkenes and norbornene under very mild conditions (2 bar H2, 298 K). The reactions are deduced to take place with the retention of the dimeric structures of the calcium hydrido‐alkyl and alkyl intermediates via a well‐defined sequence of Ca−H/C=C insertion and Ca−C hydrogenation events. This latter deduction is strongly supported by DFT calculations (B3PW91) performed on the 1‐hexene/H2 system, which also indicates that the hydrogenation transition states display features which discriminate them from a classical σ‐bond metathesis mechanism. In particular, NBO analysis identifies a strong second order interaction between the filled α‐methylene sp3 orbital of the n‐hexyl chain and the σ* orbital of the H2 molecule, signifying that the H−H bond is broken by what is effectively the nucleophilic displacement of hydride by the organic substituent.

KW - calcium

KW - catalysis

KW - density functional theory

KW - hydrogenation

KW - main group chemistry

UR - http://www.scopus.com/inward/record.url?scp=85055530382&partnerID=8YFLogxK

U2 - 10.1002/anie.201809833

DO - 10.1002/anie.201809833

M3 - Article

VL - 57

SP - 15500

EP - 15504

JO - Angewandte Chemie-International Edition

T2 - Angewandte Chemie-International Edition

JF - Angewandte Chemie-International Edition

SN - 1433-7851

IS - 47

ER -