Two Novel Flexible Multidentate Ligands for Crystal Engineering: Syntheses, Structures, and Properties of CuII, MnII Complexes withN-[(3-Carboxyphenyl)sulfonyl]glycine andN,N′-(1,3-Phenylenedisulfonyl)bis(glycine)

Schiff Base-Based Molybdenum Complexes as Green Catalyst in the Epoxidation Reaction: A Minireview

Epoxides are class of cyclic ether and have been extensively used in petrochemicals and pharmaceuticals industries as raw materials. Due to this reasons, development of the synthetic strategy of epoxides are getting enormous interest among the research chemists. In terms of "development of the synthetic strategy", the use of a catalyst, especially, Schiff base-based complex is of potential interest due to alternative easy routes and significant advances in metal-mediated pathways giving rise to diverse degree of substrate-reagent interactions. In addition, the synthetic strategy that follows the 12 principles of green chemistry, particularly (i) reduce the use of organic solvent, especially toxic solvents, and (ii) increasing the use of catalysts to obtain selective and quick processes in terms of atom economy, are of great attention now a days. The present review encompasses the Schiff base-based molybdenum complexes as green catalyst in the epoxidation reaction. Molybdenum complexes have grown interest owing to lower cost, environmental protection and commercialization as well as its abundance in different metalloenzymes. On the other hand, molybdenum complexes speed up the O-O bond break of tert-butylhydroperoxide (TBHP); as a result, it accelerates the oxygen transfer process from TBHP to the olefin. This review mainly focused on the catalytic activity of molybdenum-based Schiff base complexes for the epoxidation reaction in water/solvent free condition.

Field-induced slow magnetic relaxation in mixed valence di- and tri-nuclear CoII-CoIII complexes

Two novel mixed valence Co^II-Co^III complexes, namely [Co^IICo^III(L1)(ab)(mb)₂(H₂O)]·dmf (1) and [CoCo^II(L2)₄(H₂O)₄]·2H₂O (2) [H₂L1 = (E)-2-((1-hydroxybutan-2-ylimino)methyl)-6-methoxyphenol, ab = 2-amino-butan-1-ol anion, mb = p-methyl benzoate, H₂L2 = 3-((2-hydroxy-3-methoxy-benzylidene)-amino)-propionic acid, and dmf = N,N-dimethyl-formamide], were synthesized and characterized by single crystal X-ray diffraction and magnetic studies at low temperature. The structure determination reveals that both complexes belong to the monoclinic system with P21/c (1) and I2/a (2) space groups. Complex 1 is a dinuclear Co^IIICo^II compound with distorted octahedral cobalt centers showing different coordination environments. In 2, a bent trinuclear CoCo^II complex, the coordination environments around the two terminal Co^III sites are alike, whereas they are different in the central Co^II ion. Alternating current/direct current (ac/dc) magnetic studies revealed that both complexes show field-induced slow magnetic relaxation. The dc magnetic susceptibility and magnetization data were analyzed with the following Hamiltonianwhere D and E are the axial and rhombic zero-field splitting (zfs) parameters, respectively, and a good agreement between experimental and simulated results was found using the parameters g_⊥ = 2.585, g_∥ = 2.437, D = +98.1 cm^-1, E/D = 0.008 and F = 8.2× 10^-5 for 1 and g_⊥ = 2.580, g_∥ = 2.580, D = +55.4 cm^-1, and E/D = 0.000 for 2.

Crystal structure of poly-[μ-1,4-bis(2-ethylbenzimidazol-1-ylmethyl)benzene-κ2 N:N′)-bis(μ3-5-hydroxyisophthalate(2–)-κ3 O,O′:O′′)dicadmium(II)] monohydrate, C64H54N8O11Cd2

C64H54Cd2N8O11, monoclinic, P21/c (No. 14), a = 10.314(2) Å, b = 18.290(4) Å, c = 16.516(6) Å, β = 113.91(2)°, V = 2848.3(13) Å3, Z = 2, R gt (F) = 0.0440, wR ref (F 2 ) = 0.0890, T = 293(2)K.

Crystal structure of 4,4′-bipyridin-1-ium 3,3′,5′-tricarboxy-[1,1′-biphenyl]-2-carboxylate, (C26H18N2O8)

C26H18N2O8, triclinic, P1̅ (No. 2), a = 10.101(5) Å, b = 10.589(6) Å, c = 10.705(6) Å, α = 93.183(8)°, β = 108.614(8)°, γ = 97.323(8)°, V = 1070.5(10) Å3, Z = 2, R gt (F) = 0.0399, wR ref (F 2 ) = 0.1027, T = 296(2) K.

Crystal structure of 4-(3-(pyridin-3-yl)-1H-1,2,4-triazol-5-yl)benzoic acid, C14H10N4O2

C14H10O2N4, monoclinic, P21/c, a = 11.750(18) Å, b = 8.194(13) Å, c = 12.91(2) Å, β = 102.306(19)°, V = 1214(3) Å3, Z = 4, R gt (F) = 0.0505, wR ref (F 2 ) = 0.1098, T = 296(2) K.

Crystal structure of catena-poly[bis(μ 2-4-(3-(pyridin-3-yl)-1H-1,2,4-triazol-5-yl)benzoato)-κ 2 N:O)copper(II)] dihydrate, C28H22N8O6Cu

C28H22O6N8Cu, Triclinic, P1̅, a = 6.826(5) Å, b = 9.040(7) Å, c = 10.930(8) Å, α = 101.068(8)°, β = 95.054(8)°, γ = 96.278(8)°, V = 653.8(9) Å3, Z = 1, R gt (F) = 0.0469, wR ref (F 2 ) = 0.1063, T = 293(2) K.