| 11670560 |
Isovitsch RA, Beadle AS, Fronczek FR, Maverick AW: Electronic Absorption Spectra and Phosphorescence of Oxygen-Containing Molybdenum (IV) Complexes. Inorg Chem. 1998 Aug 24;37(17):4258-4264.
Electronic absorption and emission spectra are reported for salts of two oxomolybdenum (IV) cations, [MoOCl (CN-t-Bu)(4)](+) and [MoOCl (Ph (2) PCH (2) CH (2) PPh (2))(2)](+), and for the new Mo (IV) complex [trans-Mo (OCH (3))(2)(CN-t-Bu)(4)](2+). All three ions show absorption bands (lambda (max,abs) 550-570 nm; epsilon 45-120 M (-)(1) cm (-)(1)) attributable to the (1) A (1)[(d (xy)())(2)] --> (1) E [(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 ((1) A (1) --> (3) E) transition. Phosphorescence (lambda (max,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 CH (2) Cl (2) at room temperature. These are the first phosphorescences recorded for molybdenum (IV) complexes. [MoOCl (CN-t-Bu)(4)](BPh (4)) precipitates quickly if NaBPh (4) is added to the Mo (IV) solution prepared from MoCl (5) and tert-butyl isocyanide in CH (3) OH. However, if NaPF (6) is used instead, [trans-Mo (OCH (3))(2)(CN-t-Bu)(4)](PF (6))(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 (OCH (3))(2)(CN-t-Bu)(4)](PF (6))(2) has been determined: C (22) H (42) F (12) MoN (4) O (2) P (2), monoclinic; space group P2 (1)/c; a = 9.1538 (8) A, b = 15.709 (2) A, c = 13.456 (2) A; beta = 103.31 (1) degrees; Z = 2; R (F) = 0.063, R (w)(F) = 0.056 for 2719 reflections with I > sigma (I). |
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