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Volumn 38, Issue 10, 1999, Pages 1401-1405

Zinc silicates: Very efficient heterogeneous catalysts for the addition of primary alcohols to alkynes and allenes

Author keywords

[No Author keywords available]

Indexed keywords

ALKYNE; ALLENE DERIVATIVE; METHANOL; SILICATE; ZINC DERIVATIVE;

EID: 0033577855     PISSN: 14337851     EISSN: None     Source Type: Journal    
DOI: 10.1002/(SICI)1521-3773(19990517)38:10<1401::AID-ANIE1401>3.0.CO;2-4     Document Type: Article
Times cited : (42)

References (57)
  • 2
    • 33747551571 scopus 로고    scopus 로고
    • Angew. Chem. Int. Ed. 1998, 37, 1416, and references therein.
    • (1998) Angew. Chem. Int. Ed. , vol.37 , pp. 1416
  • 8
    • 4544297861 scopus 로고
    • (Merck & Co.), US 5420353, 1995
    • For example as a protecting group in the synthesis of indinavir, a new HIV protease inhibitor from Merck, Sharp & Dohme: T. R. Verhoeven (Merck & Co.), US 5420353, 1995 [Chem. Abstr. 1995, 123, 314545].
    • (1995) Chem. Abstr. , vol.123 , pp. 314545
    • Verhoeven, T.R.1
  • 9
    • 33747526624 scopus 로고    scopus 로고
    • note
    • 2O) cleanly builds zinc oxide upon heating above 270°C.
  • 19
    • 33747532239 scopus 로고    scopus 로고
    • note
    • Willemite was prepared as described in reference [33d] (example 5). The observed XRD lines were identical to those in card number 37-1485 of the JCPDS-ICDD data base (1995).
  • 20
    • 33747567648 scopus 로고    scopus 로고
    • note
    • β-Zinc orthosilicate was prepared as described in reference [33d] (example 4). The observed XRD lines were identical to those in card number 14-0653 of the JCPDS-ICDD data base (1995).
  • 21
    • 33747539440 scopus 로고    scopus 로고
    • note
    • Sauconite was prepared as described in reference [33d] (example 6). The observed XRD lines were identical to those in card number 29-1393 of the JCPDS-ICDD data base (1995).
  • 22
    • 33747553052 scopus 로고    scopus 로고
    • note
    • Hemimorphite was prepared by allowing sodium silicate to react with zinc nitrate (molar ratio Zn:Si=2) in aqueous solution, which resulted in the formation of an amorphous white precipitate, and subsequently heating this suspension to 90°C for 24 hours as described in detail in reference [33d] (example 1). The observed XRD lines were identical to those in card number 5-0555 of the JCPDS-ICDD data base (1995).
  • 31
    • 33747550457 scopus 로고    scopus 로고
    • note
    • 2 and allene are isoelectronic.
  • 32
    • 33747562646 scopus 로고    scopus 로고
    • note
    • 3. This reaction is computed to occur with no activation barrier. The angle between zinc, the methoxide oxygen, and the proton-donating atom should be around 12±3° and the distance between zinc and nitrogen around 5.4±0.2 Å.
  • 33
    • 33747551133 scopus 로고    scopus 로고
    • note
    • [20]
  • 39
    • 0003841093 scopus 로고    scopus 로고
    • Molecular Simulations Inc., San Diego, USA
    • 2, Version 3.5, Molecular Simulations Inc., San Diego, USA.
    • 2, Version 3.5
  • 40
    • 33747578806 scopus 로고    scopus 로고
    • note
    • [28]
  • 50
    • 33747529126 scopus 로고    scopus 로고
    • note
    • The nuclear charges of the hydrogen link atoms have been adjusted according to the formal charge contribution of the zinc (0.5) and silicon atoms (1.0) which they replace. The link atoms have been set in the direction of the replaced atoms, with the O-H distance optimized at the DFT level. The positions of the link atoms have been kept fixed in all subsequent calculations.
  • 51
    • 33747525947 scopus 로고    scopus 로고
    • note
    • This is a very simplified view. More likely the protons will be able to distribute themselves over the available surface oxygens. The reaction will only occur when the proper silanol group is carrying a proton. In the course of this work we did not investigate the activation barriers for the proton transfers.
  • 52
    • 33747560981 scopus 로고    scopus 로고
    • note
    • A Gibbs energy of activation (ΔG*) will still exist because the activation entropy should be negative.
  • 53
    • 33747521780 scopus 로고    scopus 로고
    • note
    • -1 higher than that of methanol. A possible explanation would be that product desorption occurs through an addition-elimination mechanism.


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.