Synthesis and comparative structural study of tris-chelated Sb(III), Bi(III) and Cr(III) diselenophosphinato complexes

Synthetic route to vanadium(III) dichalcogenidophosphinate complexes, V(S2PPh2)3 and V(Se2PPh2)3: A spectroscopic and structural comparative study with analogous complexes of chromium(III), Cr(E2PPh2)3 (E=S, Se)

“…These molecules have similar solubility properties as 1 and 2 and when kept under inert atmosphere they can be stored for prolonged periods both in the solid-state and in solution without observable decomposition. The solid-state IR spectra for 3 and 4 (KBr mulls) are similar to their V(III) counterparts, 1 and 2, respectively, and match previous reports, [16,18] again indicating that the IR spectra for this class of compounds is largely dominated by ligand-based vibrational modes. The UVvis spectra for 3 and 4 are generally consistent with previous reports of similar Cr(III) complexes (i. e. octahedral, d 3 centers; see structural discussion below) where several spin-allowed d!…”

“…While both the Cr(III) dithio-and diseleno-diphenylphosphinate complexes, Cr(S 2 PPh 2 ) 3 (3) and Cr(Se 2 PPh 2 ) 3 (4), have been previously reported, [16][17][18] we thought it was necessary to reproduce some of the data, especially the crystallographic data, in order to better facilitate direct structural and spectroscopic comparison to our V(III) derivatives. We also found previous reports for their preparation either employed less than desirable methods such as using hydrated Cr(III) precursors [16] or were not reproducible in our hands.…”

“…We also found previous reports for their preparation either employed less than desirable methods such as using hydrated Cr(III) precursors [16] or were not reproducible in our hands. [18] As such, we prepared 3 and 4 using similar procedures to 1 and 2, respectively; importantly we found thermolysis at~65°C for at least~48 h is critical for effective and efficient chelation of the À E 2 PPh 2 anion when using the anhydrous Cr(III) chloride salt. These modified procedures resulted in highly reproducible syntheses and dramatically increased reaction time and yield of the isolated product relative to performing the reactions at room temperature as previously reported.…”

“…These modified procedures resulted in highly reproducible syntheses and dramatically increased reaction time and yield of the isolated product relative to performing the reactions at room temperature as previously reported. [18] Upon work up of the reaction mixture, 3 crystallizes as a blue-purple solid (dichroism is observed when in solution) while 4 crystallizes as a dark green solid; both are isolated consistently in moderate to good yield. These molecules have similar solubility properties as 1 and 2 and when kept under inert atmosphere they can be stored for prolonged periods both in the solid-state and in solution without observable decomposition.…”

“…Lastly, in order to facilitate a more insightful systematic bonding analysis and comparison, we also revisited previously reported analogous chemistry of another first-row trivalent transition metal. Herein we revisit the Cr(III) analogues, Cr(E 2 PPh 2 ) 3 (E=S, Se), [16][17][18] providing more reliable synthetic procedures for their isolation, reporting solidstate molecular structures with higher resolution metrical data, and expanding on their solution-phase spectroscopic signatures.…”