Osmium(II)-Coordination Induced C–C Bond Functionalization of Bis-lawsone

Abstract

Metal-coordination-driven C–C bond functionalization without involvement of the traditional route of oxidative addition, insertion, and reductive elimination has gained immense importance. In this context, the present Communication highlights the facile ring contraction process of the deprotonated bis-lawsone (L2–) to functionalized L12– upon coordination to {Os­(bpy)2} or isomeric {Os­(pap)2} (bpy = 2,2′-bipyridine and pap = 2-phenylazopyridine) in 1–3. Further, recognition of fractional redox noninnocence of L1 in 1 + –3 + via experimental and theoretical events facilitated its inclusion in the redox noninnocent family.

Bidirectional noninnocence of hinge-like deprotonated bis-lawsone on selective ruthenium platform: a function of varying ancillary ligands

“…Herein, we demonstrated unprecedented discrete ruthenium derivatives ([1](ClO 4 ) 2 , 2, and 3) of deprotonated bis-lawsone (L 2− ) beyond the reported limited lighter metal ion (cobalt, zinc and gallium)-derived complexes, although the earlier approach with the heavier osmium ion surprisingly led to its C-C bond functionalisation (Schemes 1 and 2). 11 The salient features of this study are as follows:…”

“…However, previous attempt in this case with the osmium metal precursor {Os(bpy) 2 }(bpy = 2,2′-bipyridine) or {Os( pap) 2 }( pap = 2-phenylazopyridine) resulted in a newer set of metal-carbon bonded mononuclear complexes via the C-C bond functionalisation of L 2− on the osmium platform (Scheme 1). 11 Scheme 1 Reported metal complexes of deprotonated bis-lawsone and its functionalised form.…”

Structural and Electronic Diversity as a Function of Metal Ions and Co‐ligands in Deprotonated Epindolidione Bridged Diruthenium and Diosmium Set‐up

“…The average Os II −N(bridge) bond length (2.089(3) Å) was reasonably longer than Os II −O(bridge) (2.058(6) Å) as in 1 / 2 . The impact of π‐accepting feature (metal to ligand back‐bonding) of bpy/pap [19] was reflected in the shorter Os II −N(bpy/pap) distances (average: 2.032(4) Å/2.044(8) Å) with special reference to Os II −N(bridge) (average: 2.097(4) Å/2.088(7) Å). The appreciably longer azo distance of pap (average: 1.293(11) Å) in [ 4 ](ClO 4 ) 2 as compared to that in free pap (1.258(5) Å) [20] as well as shorter Os II −N (azo, pap, average: 1.982(8) Å) distance with respect to Os II −N (pyridine, pap, average: 2.038(8) Å) essentially contemplated (dπ)Os II →π * (azo, pap) back‐bonding [21] .…”

Tetracoordinated 15-Electron Ruthenium(I) in a Discrete Triruthenium Framework

“…(ii) Metal-dominated successive oxidations of 2 2+ extended the electronic forms of [A 2 Ru III (μ-L 1 •+ )­Ru III A 2 ] 3+ ( S = 3 / 2 ) and [A 2 Ru III (μ-L 1 •+ )­Ru IV A 2 ] 4+ ( S = 1) for 2 3+ (O1) and 2 4+ (O2), respectively. The involvements of metal and L 1 in the reductions resulted in a delocalized mixed-valent state of [A 2 Ru 2.5 (μ-L 1 )­Ru 2.5 A 2 ] + instead of a valence-localized [A 2 Ru III (μ-L 1 )­Ru II A 2 ] + ( 2 + ; S = 1 / 2 ; R1) and [A 2 Ru III (μ-L1 •– )­Ru II A 2 ] ( 2 ; S = 1; R2), which reemphasized the bidirectional noninnocence of L 1 . Mixed-valent 2 + ( S = 1 / 2 ) displayed metal-based EPR with ⟨ g ⟩/Δ g = 2.213/0.574 (Figure S10 and Table S12).…”