Synthesis, Emission, and Electrochemical Properties of Luminescent Dinuclear Zinc(II) Chalcogenolate Complexes. Dynamic¹H NMR Studies and X-ray Crystal Structure of [(bpy)Zn₂(SC₆H₄-Cl-p)(μ-SC₆H₄-Cl-p)(μ-OAc)₂]

Abstract

A series of novel luminescent dinuclear zinc(II) diimine complexes with bridging chalcogenolate ligands have been synthesized, in which the two zinc atoms were found to exist in different coordination environment. The luminescence and electrochemical behavior of these complexes have been studied. These complexes have also been shown to exhibit dynamic fluxional behavior in solution due to an exchange of the bridging and terminal thiolate ligands. The mechanism and kinetics of which have been investigated by variable-temperature 1H NMR studies. The X-ray crystal structure of [(bpy)Zn2(SC6H4-Cl-p)(mu-SC6H4-Cl-p)(mu-OAc)2] has also been determined.

Approach toward Iron(II) Coordination Polymers Based on Chain Motifs with Thiolate or Mixed Thiolate/Carboxylate Bridges: Structures and Magnetic Properties

“…The framework structure of 2 is built from a linear trinuclear {Fe 3 S 2 (OCO) 4 } unit, where the neighboring Fe1 and Fe2 ions are triply bridged by a thiolate of 6-Hmna, a syn–syn carboxylate (torsion angles of Fe1–O1–C6–O2 = 0.03° and Fe2–O2–C6–O1 = 1.00°), and a syn–anti carboxylate group (torsion angles of Fe1–O3–C12–O4A = 4.98° and Fe2–O4A–C12–O3 = 74.97°). This type of mixed thiolate/carboxylate triple bridge has never been seen for the coordination compounds of Group 8 metals but was found only in a few cases to connect metal ions such as Cr 3+ , Mn 2+ , Zn 2+ , and Ag + . − These triply bridged {Fe 3 S 2 (OCO) 4 } trimers are held head-to-tail by two thiolates of 6-mna, leading to rod-shaped chains of {Fe 3 S 4 (OCO) 4 } n (Figure b), which are linked by the pyridinium backbones of 6-Hmna to form a layer extended along the b axis (Figure c). Each layer is also stabilized by an intralayer hydrogen-bonding scheme with approximately linear hydrogen bonds between the pillared pyridinium cations and the thiolate S atoms of the {Fe 3 S 4 (OCO) 4 } n chains (N2···S2 = 3.2788 Å; ∠N2–H1···S2 = 174.668°; Figure S5).…”

Multifunctional Zn(II) Complexes: Photophysical Properties and Catalytic Transesterification toward Biodiesel Synthesis

“…Electron withdrawing substituents decrease the electron density at the Zn­(II) center and hence decrease the nucleophilicity of Zn­(II)-bound alkoxide. In −Br substituted complex, a resonance effect of the lone pair on −Br can be expected to dominate over its negative inductive effect thus increasing the electron density at the Zn­(II) center in comparison to other electron withdrawing substituents . Based on the above arguments, a gradual decrease in the nucleophilicity of Zn­(II)-alkoxides in complexes 4A – 4D is expected in the order 4A (−OMe) > 4D (−Br) > 4B (−CH 3 ) > 4C (−COOEt), which correlates very well with their observed transesterification catalytic activities.…”

Mode of Action of Bi- and Trinuclear Zinc Hydrolases and Their Synthetic Analogues

“…No hydrolysis data is yet available for 40 . A very interesting, doubly carboxylate-bridged thiolate complex 41 has been reported by Yam et al in which the bridging and terminal thiolates readily undergo fluxional exchange . Perhaps the most interesting property of 41 is that it is luminescent .…”

“…A very interesting, doubly carboxylate-bridged thiolate complex 41 has been reported by Yam et al in which the bridging and terminal thiolates readily undergo fluxional exchange . Perhaps the most interesting property of 41 is that it is luminescent . A solution of benzhydroxamic acid, tetramethylethylenediamine, and Zn(OAc) 2 undergoes a spontaneous self-assembly to form 42 , whose solid-state structure closely resembles the hydroxamate−inhibitor complex of ApAP …”