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|標題:||Os(CO)(2)(eta(2)-SC5H4N(O))(eta(2)-SC5H4N): structural evidence for the transformation of pyridine-2-thione N-oxide to pyridine-2-thiolate in osmium complexes|
|期刊/報告no：:||Journal of Organometallic Chemistry, Volume 690, Issue 2, Page(s) 441-449.|
|摘要:||The reaction Of Os-3(CO)(12) with an excess of 1-hydroxypyridine-2-thione and Me3NO gives three mononuclear osmium complexes Os(CO)(2) (eta(2) -SC5H4N(O))(2) (1), Os(CO)(2)( eta(2)-SC5H4N(O))(eta(2)-SC5H4N) (2), and Os(CO)(2)(eta(2) -SC5H4N)(2) (3). The results of single-crystal X-ray analyses reveal that complex 1 contains two O,S-chelate pyridine-2-thione N-oxide (PyOS) ligands, whereas complex 2 contains one O,S-chelate PyOS and one N,S-chelate pyridine-2-thiolate group. The unique structure of 2 provides evidence of the pathway for this transformation. When this reaction was monitored by H-1 NMR spectroscopy the triosmium complexes Os-3(CO)(10)(mu-H)( mu-eta'-S-C5H4N(O)) (4) and Os-3(CO)(9)(mu-H)(mu-eta(1): eta2-SC5H4N(O)) (5) were identified as intermediates in the formation of the mononuclear final products 1-3. The proposed pathway is further supported by the observation of several dinu-clear osmium intermediates by electrospray ionization mass spectrometry. In addition, the reaction of Os-3(CO)(12) with 1-hydroxypyridine-2-thione in the absence of Me3NO at 90degreesC generated mononuclear complex 2 as the major product along with smaller amounts of complexes 1 and 3. These results suggest that the N-oxide facilitates the decarbonylation reaction. Crystal data for 1: monoclinic, space group C2/c, a = 26.9990(5) A, b = 7.6230(7) A, c = 14.2980(13) A, beta =101.620(2)degrees, V= 2882.4(4) A(3), Z = 8. Crystal data for 2: monoclinic, space group C2/c, a = 5.7884(3) angstrom, b = 13.9667(7) angstrom, c = 17.2575(9) A, beta = 96.686(l)degrees, V= 1385.69(12) angstrom (3), Z = 4. (C) 2004 Elsevier B.V. All rights reserved.|
|Appears in Collections:||化學系所|
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