12596-54-2Relevant articles and documents
Fluorescence spectrum of Mo2 in argon and krypton matrices
Pellin, M. J.,Foosnaes, T.,Gruen, D. M.
, p. 5547 - 5557 (1981)
The time resolved fluorescence spectra of Mo2 isolated in Ar and Kr matrices at 14 K are presented.Depending on excitation wavelength, either of two separate vibrational progressions with 475.7 (+/-4.5) cm-1 spacings can be observed in emission.Similarities between several features in the two emission spectra lead to the conclusion that the progressions arise from Mo2 trapped in two distinct sites, each characterized by its own absorption spectrum.Excitation spectra elucidate the overlapping absorption spectra of the two sites.The measured emission lifetimes are long and not single exponential.In krypton matrices, lifetimes of 0.85 msec from site and a biexponential emission decay of 0.70 and 1.94 msec from a second site are observed.In argon matrices, 2.1 msec emission decay times in one site and a triexponential decay with components of 2.1, 3.93, and 6.3 msec were measured in a second site.Phonon structure in the well resolved spectra show that the matrix coupling is different for the two matrix sites.Various empirical correlation rules are used to test the validity of ωe as well as to compare it to other experimental quantities for Mo2.These rules indicate a 1.9 Angstroem bond length for Mo2.The fluorescence lifetimes and the large spectral shift of the emission ralative to the excitation energy lead to the conclusion that the emission does not emanate from the initially excited level. Instead, the emission appears to come from one of the higher spin multiplicity levels in a dense manifold of states lying at somewhat lower energies than the 1Σu+ level coupled by laser radiation to the 1Σg+ ground state.
Preparation and structure of crystalline tetrakis(D-mandelato)dimolybdenum(II) bis(tetrahydrofuranate)
Cotton, F. Albert,Falvello, Larry R.,Murillo, Carlos A.
, p. 382 - 387 (2008/10/08)
The preparation and structural characterization of the quadruply bonded, chiral dimolybdenum complex Mo2(C8H7O3)4 are reported. Reaction of an aqueous solution of the Mo24+ unit with an aqueous solution of D-mandelic acid yielded the yellow product, which was recrystallized from a mixture of tetrahydrofuran and hexane. The crystals were found to be orthorhombic, in space group P212121, with unit cell dimensions a = 13.199 (3) ?, b = 22.302 (9) ?, c = 27.289 (6) ?, V = 8033 (7) ?3, and Z = 8. The asymmetric unit consists of two molecules of the molybdenum dimer and four uncoordinated molecules of tetrahydrofuran (THF, C4H8O). The two independent molecules are almost identical, with Mo-4Mo distances of 2.104 (1) and 2.101 (1) ?. A network of hydrogen bonds connects the extended structure. The absolute configuration has been determined and is in agreement with previous conformational analyses of mandelic acid by chemical means.
