Structures of four types of novel high-valent manganese complexes obtained by the reactions of KMnO4 with tridentate Schiff base ligands

Synthesis and Structural Features of New Schiff Base Complexes of Mononuclear MnIV, Dinuclear CoIICoIII, and Tetranuclear CuII

“…[32] For the Mn IV complex 1, the UV/Vis spectrum reveals three absorption transitions: at 266 nm, which can be attributed to the intraligand process (πǞπ*); two lower intensive bands are observed at 346 nm (log ε = 3.70), can be assigned to the C-N imine LMCT transition, following charge-transfer O phenolate Ǟ Mn IV transition at 418 nm (log ε = 3.54), in a quasi-regular octahedral environment, in agreement with the X-ray structure proposed. [32,37,38] In the mixed-valence Co II Co III complex 2 the band observed at 398 nm (log ε = 3.36) is best described as a charge-transfer process most probably originating from a O phenolate Ǟ Co III LMCT, in agreement with the resolved X-ray structure of cobalt complex 2 (Co1-O1 and Co1-O6). No intervalence transition at lower energy was observed, thus suggesting that the valences are also localized [Co (1) III ; Co(2) II ] when 2 is dissolved in CH 3 CN solution.…”

Tripodal Trimanganese(III) Complexes of New Unsymmetrical Pentadentate Ligands Derived from 2‐(Salicylideneamino)phenol: Syntheses, Crystal Structures and Properties

“…[17] It is well known that tridentate H 2 sap derivatives usually form phenoxobridged dinuclear metal complexes. [6][7][8][9]18,20] However, when bidentate ligands such as phenanthroline are available, ternary mononuclear complexes such as [Mn(sap)L] are often reported. [11,19] In the present case, the reaction of H 3 L 1 with manganese ions corresponds to the latter because H 3 L 1 has both (sap) and bidentate coordination sites.…”

“…In the crystal packing, several intermolecular hydrogen bonds between coordinating solvents and neighbouring molecules are recognised. The distance be-tween the O(14) atom of the coordinating methanol molecule and the O (8) j atom of (L 1 ) 3-in the neighbouring molecule is 2.949(7) Å, which is regarded as a typical hydrogen bond (symmetry code j: 1 -x, -1/2 -y, 1/2 -z). As a result, the nearest intermolecular Mn···Mn distance [Mn(2)··· Mn(1) j 5.7824(15) Å] is shorter than intramolecular Mn···Mn distances.…”

“…It is known that 2-(salicylideneamino)phenol (H 2 sap) [6][7][8][9][10][11] and many other similar ONO-tridentate ligands form stable metal complexes. [12][13][14][15][16][17][18][19][20] We prepared modified ligands [H 3 L 1 : 6-hydroxy-2-(2-hydroxyphenyl)-5-(salicylideneamino)benzoxazole; H 3 L 2 : 5-(5,6-benzosalicylideneamino)-6-hydroxy-2-(2-hydroxynaphthyl)benzoxazole; H 4 LЈ: 4,6-bis(salicylideneamino)benzene-1,3-diol] and introduced ON-bidentate or ONO-tridentate coordination sites into H 2 sap (Scheme 1).…”

Aryl and 1,3-dioxoindanyl derivatives of azoles and azines (review)

“…The two modes of coordination of the ligands mentioned for complexes 25 and 31 are also characteristic of the benzoxazole complex 32 [89].…”