134535-29-8Relevant academic research and scientific papers
Synthesis and electronic properties of triply bonded hexakis(fluoroalkoxy)dimolybdenum complexes. Structure of Mo2[OCMe(CF3)2]6 and investigation of the nature of the frontier orbitals in triply bonded M2X6 compounds
Gilbert, Thomas M.,Landes, Arden M.,Rogers, Robin D.
, p. 3438 - 3444 (2008/10/08)
The compound MoCl3(dme) (dme = 1,2-dimethoxyethane) was prepared in pure form and formulated as the dimeric Mo2Cl6(dme)2 (1). This material proved an excellent starting material for the metathetical syntheses of metal-metal triply bonded Mo2X6 complexes, including the hexaalkyls Mo2(CH2MMe3)6 (M = C (6), Si (7)), the hexaalkoxides Mo2(OCMe2CH2R) (R = H (2), Me (3)), and the new hexakis(fluoroalkoxide) dimers Mo2[OCMe3-x(CF3)x]6 (x = 1 (4), 2 (5)). The structure of 5 was determined by single-crystal X-ray diffraction: T = 253 K, R3 (No. 148), a = 10.894 (8) ?, c = 29.255 (9) ?, V = 3006.8 ?3, R = 0.071, Rw = 0.094, GOF = 0.50 for 747 observed reflections varying 113 parameters. The molecule exhibits disorder, some of which could be resolved, and typical Mo≡Mo (2.230 (3) ?) and Mo-O (1.88 (1) ?) bond lengths. The former observation is consistent with theoretical and experimental studies indicating that the triple bond is exclusively comprised of metal-based orbitals giving rise to a limiting σ2π4 description; the latter observation is somewhat at odds with previous suggestions that decreasing the π-donor ability of the alkoxide ligands in these systems increases the metal-oxygen distance. The electronic absorption spectra of the congeneric 2, 4, and 5 are essentially equivalent; this surprising result suggests that either the HOMO and LUMO are largely comprised of metal-based orbitals and contain little metal-ligand δ character or that these orbitals contain the same amount of ligand character and are equally affected by changes in the electronic properties of the ligands.
Synthesis and Crystal Structure of MoCl4(DME)*15-Crown-5 and MoCl4(DME) (DME = 1,2-Dimethoxyethane)
Hey-Hawkins, Evamarie,Schnering, Hans Georg von
, p. 307 - 314 (2007/10/02)
NaSi reacts with MoCl5 and 15-crown-5 in toluene with reduction of Mo(V) to Mo(IV).Work-up in DME yields MoCl4(DME)*15-crown-5 (1).MoCl4(DME) (2) is prepared more conveniently from MoCl5/DME. 1 and 2 were characterized spectroscopically and by X-ray structure determnation.Crystal data: 1, space group p212121 (No. 19), Z = 4, 2765 observed independent reflexions, R = 0.026, cell dimensions (110 K): a = 16.292(4), b = 12.884(3), c = 10,452(2) Angstroem. 2, space group I42d (No. 122), Z = 8, 558 observed independent reflexions, R = 0.037, cell dimensions (292 K): a = b = 9.562(2), c = 23.777(6) Angstroem.The MoCl4(DME) molecule of 1 and 2 forms a distorted octahedron.There are four non-coordinating 15-crown-5 molecules present in the unit cell of 1.The UV / VIS spectrum and the magnetic properties of 2 are discussed.
