Effect of Substituents on the Crystal Structures, Optical Properties, and Catalytic Activity of Homoleptic Zn(II) and Cd(II) β-oxodithioester Complexes

Abstract

Five novel zinc­(II) and cadmium­(II) β-oxodithioester complexes, [Zn­(L1)2] (1), [Zn­(L2)2] n (2), [Zn­(L3)2] n (3) [Cd­(L1)2] n (4), [Cd­(L2)2] n (5), with β-oxodithioester ligands, where L1 = 3-(methylthio)-1-(thiophen-2-yl)-3-thioxoprop-1-en-1-olate, L2 = 3-(methylthio)-1-(pyridin-3-yl)-3-thioxoprop-1-en-1-olate, and L3 = 3-(methylthio)-1-(pyridin-4-yl)-3-thioxoprop-1-en-1-olate, were synthesized and characterized by elemental analysis, IR, UV–vis, and NMR spectroscopy (1H and 13C­{1H}). The solid-state structures of all complexes were ascertained by single-crystal X-ray crystallography. The β-oxodithioester ligands are bonded to Zn­(II)/Cd­(II) metal ions in an O∧S and N chelating/chelating–bridging fashion leading to the formation of 1D (in 2–4) and 2D (in 5) coordination polymeric structures, but complex 1 was obtained as a discrete tetrahedral molecule. Complex 4 crystallizes in the C2 chiral space group and has been studied using circular dichroism (CD) spectroscopy. The multidimensional assemblies in these complexes are stabilized by many important noncovalent C–H···π (ZnOSC3, chelate), π···π, C–H···π, and H···H interactions. The catalytic activities of 1–5 in reactions involving C–C and C–O bond formation have been studied, and the results indicated that complex 3 can be efficiently utilized as a heterogeneous bifunctional catalyst for the Knoevenagel condensation and multicomponent reactions to develop biologically important organic molecules. The luminescent properties of complexes were also studied. Interestingly, zinc complexes 1–3 showed strong lumniscent emission in the solid state, whereas cadmium complexes 4 and 5 exhibited bright luminescent emission in the solution phase. The semiconducting behavior of the complexes was studied by solid-state diffuse reflectance spectra (DRS), which showed optical band gaps in the range of 2.49–2.62 eV.

Homoleptic Ni(ii) dithiocarbamate complexes as pre-catalysts for the electrocatalytic oxygen evolution reaction

“…A variety of metal dithiolato complexes have been synthesized and used as catalysts in many catalytic reactions. [35][36][37] However, the use of transition metal complexes of dithiocarbamates as molecular electrocatalysts in water splitting reactions is rare. Despite extensive studies of the coordination chemistry of dithiolato complexes, there are few reports which describe the utilization of metal sulfides as catalytic materials obtained from the decomposition of metal dithiocarbamate complexes at high temperatures.…”

“…A variety of metal dithiolato complexes have been synthesized and used as catalysts in many catalytic reactions. 35–37…”

Dual Function of β‐Hydroxy Dithiocinnamic Esters: RAFT Agent and Ligand for Metal Complexation

“…[14,54] Interesting, but so far overlooked compounds are 𝛽-hydroxydithiocinnamic esters, which are well known for their ability to form complexes with a variety of metals including Pt, Pd, Ni, Cu, or Ru. [55][56][57][58][59][60][61][62][63][64][65] The structure differs from common CTAs based on trithiocarbonates or dithiobenzoates (Scheme 1), but the conjugation of the vinyl benzene moiety (Z-group) might still be sufficient to stabilize the intermediate radical in the RAFT process.…”

Controllable self‐assembly from homonuclear Mn (II)‐MOF to heteronuclear Mn (II)‐K(I)‐MOF by alkali‐regulation: A novel mode of structural and luminescent regulation for off–on sensing ascorbic acid

“…When the conjugated H 6 L was excited at 377 nm, the weak emission at 424 nm in blue region was observed, which can be assigned to the π!π * or n!π * electron transition within the free ligand ( Figure 4). [22] Compared with the free H 6 L, 1 and 2 exhibited wide emission bands at 442 and 404 nm under excitation at 379 and 339 nm, respectively. Both 1 and 2 result in higher emission energy than free H 6 L with red shift of 18 nm and blue shift of 20 nm, respectively ( Figure 4d).…”