Electronic Absorption Spectra and Phosphorescence of Oxygen-Containing Molybdenum(IV) Complexes
Electronic absorption and emission spectra are reported for salts of two oxomolybdenum(IV) cations, [MoOCl(CN-t-Bu)4]+ and [MoOCl(Ph2PCH2CH2PPh2)2]+, and for the new Mo(IV) complex [trans-Mo(OCH3)2(CN-t-Bu)4]2+. All three ions show absorption bands (λmax,abs 550−570 nm; ε 45−120 M-1 cm-1) attributab...
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Published in | Inorganic chemistry Vol. 37; no. 17; pp. 4258 - 4264 |
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Main Authors | , , , |
Format | Journal Article |
Language | English |
Published |
United States
American Chemical Society
24.08.1998
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Online Access | Get full text |
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Summary: | Electronic absorption and emission spectra are reported for salts of two oxomolybdenum(IV) cations, [MoOCl(CN-t-Bu)4]+ and [MoOCl(Ph2PCH2CH2PPh2)2]+, and for the new Mo(IV) complex [trans-Mo(OCH3)2(CN-t-Bu)4]2+. All three ions show absorption bands (λmax,abs 550−570 nm; ε 45−120 M-1 cm-1) attributable to the 1A1[(d xy )2] → 1E[(d xy )1(d xz , yz )1] (C 4 v ) transition, and the last two show weak shoulders in the 700−750 nm range due to the analogous spin-forbidden (1A1 → 3E) transition. Phosphorescence (λmax,em 850−960 nm) occurs in the solid state for all three compounds at both room temperature and 77 K, and for [MoOCl(CN-t-Bu)4]+ in CH2Cl2 at room temperature. These are the first phosphorescences recorded for molybdenum(IV) complexes. [MoOCl(CN-t-Bu)4](BPh4) precipitates quickly if NaBPh4 is added to the Mo(IV) solution prepared from MoCl5 and tert-butyl isocyanide in CH3OH. However, if NaPF6 is used instead, [trans-Mo(OCH3)2(CN-t-Bu)4](PF6)2 (formed by reaction of [MoOCl(CN-t-Bu)4]+ with methanol) crystallizes over a period of ca. 24 h. The crystal structure of [trans-Mo(OCH3)2(CN-t-Bu)4](PF6)2 has been determined: C22H42F12MoN4O2P2, monoclinic; space group P21/c; a = 9.1538(8) Å, b = 15.709(2) Å, c = 13.456(2) Å; β = 103.31(1)°; Z = 2; R(F) = 0.063, R w(F) = 0.056 for 2719 reflections with I > σ(I). |
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Bibliography: | istex:DBCAF63AABF3F5182571B78890C9DA15B5B6AABC ark:/67375/TPS-DJC4050K-0 ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0020-1669 1520-510X |
DOI: | 10.1021/ic971186e |