title: Dioxomolybdenum(VI) complexes with ene-1,2-dithiolate ligands: synthesis, spectroscopy, and oxygen atom transfer reactivity.
abstract: New dioxomolybdenum(VI) complexes, (Et(4)N)(Ph(4)P)[Mo(VI)O(2)(S(2)C(2)(CO(2)Me)(2))(bdt)] (2) and (Et(4)N)(Ph(4)P)[Mo(VI)O(2)(S(2)C(2)(CO(2)Me)(2))(bdtCl(2))](4)(S(2)C(2)(CO(2)Me)(2) = 1,2-dicarbomethoxyethylene-1,2-ditholate, bdt = 1,2-benzenedithiolate, bdtCl(2) = 3,6-dichloro-1,2-benzenedithiolate), that possess at least one ene-1,2-dithiolate ligand were synthesized by the reaction of their mono-oxo-molybdenum(IV) derivatives, (Et(4)N)(2)[Mo(IV)O(S(2)C(2)(CO(2)Me)(2))(bdt)] (1) and (Et(4)N)(2)[Mo(IV)O(S(2)C(2)(CO(2)Me)(2))(bdtCl(2))] (3), with Me(3)NO. Additionally, the bis(ene-1,2-dithiolate)Mo(VI)O(2) complex, (Et(4)N)(Ph(4)P)[Mo(VI)O(2)(S(2)C(2)(CO(2)Me)(2))(2)] (6), was isolated. Complexes 2, 4, and 6 were characterized by elemental analysis, negative-ion ESI mass spectrometry, and IR spectroscopy. X-ray analysis of 4 and 6 revealed a Mo(VI) center that adopts a distorted octahedral geometry. Variable-temperature (1)H NMR spectra of (CD(3))(2)CO solutions of the Mo(VI)O(2) complexes indicated that the Mo centers isomerize between Delta and Lambda forms. The electronic structures of 2, 4, and 6 have been investigated by electronic absorption and resonance Raman spectroscopy and bonding calculations. The results indicate very similar electronic structures for the complexes and considerable pi-delocalization between the Mo(VI)O(2) and ene-1,2-dithiolate units. The similar oxygen atom transfer kinetics for the complexes results from their similar electronic structures.
authors.affiliation: Department of Material and Life Science, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871, Japan. sugimoto@mls.eng.osaka-u.ac.jp
authors.forename: Hideki
authors.initials: H
authors.lastname: Sugimoto
authors.forename: Susumu
authors.initials: S
authors.lastname: Tatemoto
authors.forename: Koichiro
authors.initials: K
authors.lastname: Suyama
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Miyake
authors.forename: Shinobu
authors.initials: S
authors.lastname: Itoh
authors.forename: Chao
authors.initials: C
authors.lastname: Dong
authors.forename: Jing
authors.initials: J
authors.lastname: Yang
authors.forename: Martin L
authors.initials: ML
authors.lastname: Kirk
mesh_terms: D018360:Crystallography, X-Ray; D004583:Electrons; D008024:Ligands; D008958:Models, Molecular; D008968:Molecular Conformation; D008982:Molybdenum / Q000737:chemistry*; D009942:Organometallic Compounds / Q000138:chemical synthesis* / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry*; D013057:Spectrum Analysis; D013438:Sulfhydryl Compounds / Q000737:chemistry*
chemical_list: D008024:Ligands; D009942:Organometallic Compounds; D013438:Sulfhydryl Compounds; D008982:Molybdenum; D010100:Oxygen