Reactivity of Osmium(VI) Nitrides with the Azide Ion. A New Synthetic Route to Osmium(II) Polypyridyl Complexes

Abstract

There is an extensive reactivity chemistry between trans-[Os(VI)(tpy)(Cl)(2)(N)](+) (1) (tpy = 2,2':6',2"-terpyridine) and N(3)(-). Reaction of 1 with N(3)(-) in CH(2)Cl(2) or acetone occurs by electron transfer to give trans,trans-(tpy)(Cl)(2)Os(II)(N(2))Os(II)(Cl)(2)(tpy). In CH(3)CN, trans-Os(II)(tpy)(Cl)(2)(N(2)) forms but undergoes solvolysis to give trans-Os(II)(tpy)(Cl)(2)(CH(3)CN). 1 reacts with excess N(3)(-) in CH(3)CN to give Os(III)(tpy)(Cl)(2)(5-CH(3)-tetrazolate), which has been characterized by X-ray crystallography. This is the first known Os-tetrazolato complex. 1 reacts with N(3)(-) in the presence of CS(2) to give trans-[Os(II)(tpy)(Cl)(2)(NS)](+), SCN(-), and N(2).

Mechanistic Insight into the Initiation Step of the Coupling Reaction of Oxetane or Epoxides and CO2 Catalyzed by (salen)CrX Complexes

“…PPNN 3 , PPNCN, and PPNNCO (PPN + ) (Ph 3 P) 2 N + ) were synthesized according to a published procedure. 9 Tetra-nbutylammonium bromide (Aldrich), tetra-n-butylammonium iodide (Eastman), and tetra-n-butylammonium chloride (TCI) were recrystallized from acetone/diethyl ether before use. Tetra-n-butylammonium azide (TCI) was stored in the freezer of the glovebox upon arrival.…”

Probing the localized-to-delocalized transition

“…Typically, they fail to include the multiple orbital interactions that lead to multiple transitions, assume delocalization or fail to account for time-scale differences among the vibrational and solvent modes that are coupled to electron transfer. (Demadis et al 1998a(Demadis et al ,b, 1999a. X-ray diffraction (XRD) data on the latter show that the structure is asymmetrical with DrZr(Os II -Cl)Kr(Os III -Cl)Z0.04 Å.…”

“…For this band, 3Z2600 M K1 cm K1 compared with 3Z800 M K1 cm K1 in cis-[Os(bpy) 2 (pz)Cl] C . This appears to be a non-Condon effect with coupling of the vibration to intervalence transfer across the bridge (Demadis et al 1998a(Demadis et al ,b, 1999aRocha & Shreve 2004, 2006.…”

“…An example is shown in figure 4 in the n(bpy) ring-stretching region for [(bpy) 2 ClOs(BL)OsCl(bpy) 2 ] 2C/3C/4C (BLZpz and 4,4 0 -bpy). The spectrum of [(bpy) 2 ClOs(4,4 0 -bpy)OsCl(bpy) 2 ] 3C is the sum of spectra for Os(III) and Os(II) with shifts of 5-7 cm K1 providing direct evidence for an asymmetric electronic distribution and localized oxidation states (Demadis et al 1998a(Demadis et al ,b, 1999aRocha & Shreve 2004, 2006. By contrast, the n(bpy) spectrum of [(bpy) 2 ClOs(pz)OsCl(bpy) 2 ] 3C is the average of those of Os(III) and Os(II) with bands appearing at 1316, 1423, 1450, 1465 and 1487 cm K1 .…”

“…For harmonic oscillator vibrational wave functions, the contribution to the barrier through the vZ0/vZ0 channel is exp(KS )(S v /v!). (Demadis et al 1998a(Demadis et al ,b, 1999aRocha & Shreve 2004, 2006 (Lu et al 1995).…”