By the same authors

From the same journal

Activation of H-2 by halocarbonyl bis-phosphine and bis-arsine iridium(I) complexes. The use of parahydrogen induced polarisation to detect species present at low concentration and investigate their reactivity

Research output: Contribution to journalArticle

Published copy (DOI)

Author(s)

  • S K Hasnip
  • S A Colebrooke
  • C J Sleigh
  • S B Duckett
  • D R Taylor
  • G K Barlow
  • M J Taylor

Department/unit(s)

Publication details

JournalJOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS
DatePublished - 7 Mar 2002
Issue number5
Number of pages9
Pages (from-to)743-751
Original languageEnglish

Abstract

The iridium phosphine complexes Ir(CO)Cl(L)(2) [L = PPh3, PMe3, AsPh3 and PPh2Cl, and L-2 = (PPh2Cl)(PPh3)] add H-2 to form the corresponding dihydrides IrH2(CO)Cl(L)(2). These products are detected at enhanced levels of sensitivity through the H-1 NMR signatures of their hydride resonances via para-hydrogen (p-H-2) based spin state synthesis. Products corresponding to addition across both the Cl-Ir-CO and L-Ir-L axes are detected. For L = PPh3, there is a 100 fold preference for the former pathway at 295 K, while for L = AsPh3 the second product is favoured by a factor of 2.85. At elevated temperatures a third product corresponding to addition over the Cl-Ir-L axis is detected for L = AsPh3 and PPh2Cl. Under these conditions, the CO and HCl transfer products Ir(H)(3)(CO)(2)(AsPh3,), and IrH(CO)Cl-2(AsPh3), are also formed in a thermal reaction. When IrH2(CO)Cl(L)(2) is warmed or photolysed with H-2 and CO, the corresponding products are produced for L = PPh3 and PMe3. However after photolysis with H-2 alone Ir(H)(3)(CO)(L)(2) is the favoured product. Additional products detected during the photochemical studies include Ir(H)(2)(PPh3)(PPh2C5H4CO), an unusual orthometallation product containing an eta(2)-acyl ligand, and the binuclear products H(Cl)Ir(PMe3)(2)(mu-H)(mu-Cl)Ir(PMe3)(CO) and (H)(2)Ir(PMe3)(2)(mu-Cl)(2)Ir(PMe3)(CO).

    Research areas

  • STEREOSELECTIVE OXIDATIVE ADDITION, ORGANOMETALLIC REACTION-MECHANISMS, HYDROGEN INDUCED POLARIZATION, KINETIC CONTROL, NMR, DIHYDROGEN, PRODUCTS, SPECTROSCOPY, LIGAND, EXCHANGE

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