Synthesis, Solid State, Solution and ESI‐MS Studies of Zinc(II) Cluster Complexes with a Branched Mixed Donor Thiolate Ligand

Abstract

Synthesis of the unusual spirobicyclic pentanuclear complex [Zn((ZnL)2(µ‐OH))2](ClO4)4·CH3CN·7H2O (1) (LH = N‐(2‐pyridylmethyl)‐N‐(2‐(methylthio)ethyl)‐N‐(2‐thioethyl)‐amine is described. Compound 1 was thoroughly characterized by a combination of X‐ray crystallography, XPRD, IR, variable temperature 1H NMR and ESI‐MS. The peripheral zinc ions of 1 have distorted trigonal bipyramidal coordination geometry provided by the NN′SS′ donor set of one L and a µ2‐hydroxido bridge to another peripheral zinc ion. The central zinc atom has a distorted tetrahedral Zn(SR)4 coordination environment provided by four µ2‐thiolate bridges from L. In crystalline form, the complex ions of 1 are largely insulated from contact by an elaborate hydrogen bond network involving µ2‐hydroxido bridges, perchlorate ions and all the solvent molecules. Dissociation of 1 in CD3CN solution and recombination to form other multinuclear complexes was investigated by variable temperature 1H NMR.

Homo- and Heteronuclear Group 12 Metallothionein Type B Cluster Analogs: Synthesis, Structure, 1H NMR and ESI-MS

“…Solutions with initial 1:1 ratios of Zn­(II)/ L1H consistently phase separated, possibly indicating more than one prevalent complex. Since related N x A S – ligands form complexes with general composition [Zn 3 L 4 ]­(ClO 4 ) 2 , and [Zn 5 L 4 (OH) 2 ]­(ClO 4 ) 4 ·CH 3 CN·7H 2 O in addition to aggregates of type [Zn x L x ], crystallization from alternative initial metal to ligand ratios was investigated. Vapor diffusion of ether into an acetonitrile solution containing a 3:4:4 ratio of Zn­(ClO 4 ) 2 / L1H /Et 3 N produced fine needles of [Zn 3 ( L1 ) 3 ]­(ClO 4 ) 3 ·4CH 3 CN ( 2 ·4CH 3 CN) in low yield, which lost solvent extremely rapidly upon removal of the mother liquor.…”

“…In contrast, Cd 3 S 3 rings with S–Cd–S and Cd–S–Cd bond angles ranging from 101.96° to 118.0° and 93.5° to 118.4°, respectively, have been observed for cluster anions with an adamantyl Cd 4 S 6 core. − To the best of our knowledge, the only nonproteinaceous structurally characterized trinuclear Cd­(II) thiolate complexes have four bridging thiolates. The two with [3.1.1]­bicyclic Cd 3 S 4 cores have six-membered metallacycles with a half chair conformation. , The one with a defective cubane core has a chair conformation six-membered metallacycle with expanded S–Cd–S angles (100.4°–116.6°) and contracted Cd–S–Cd angles (100.4°–116.6°) compared to 1 …”

“…Similarly, although both 1 and 2 had three unique ligand environments in the solid state, intact M 3 S 3 aggregates would be expected to have a single 1 H NMR ligand environment following solution relaxation processes. While dissociation of multinuclear metal ion complexes to smaller complexes is mathematically predictable with dilution, other studies suggest tridentate and tetradentate N,S ligands can remain bound to group 12 metal ions over the concentration range used. , …”

Crystal structure and Hirshfeld surface analysis of cyclo-tetrabromido-1κ2 Br,3κ2 Br-tetrakis(μ2-2-{[(pyridin-2-yl)methyl]amino}ethane-1-thiolato-κ3 N,S:S)tetramercury(II)

“…For many years, we and others have been interested in the structures of group 12 coordination compounds including an aminoethanethiolate moiety (Hu et al, 2020;Hallinger et al, 2017;Akhtar et al, 2015;Bharara et al, 2006a,b;Fleischer et al, 2006;Viehweg et al, 2010;Brand & Vahrenkamp, 1995;Avdeef et al, 1992;Tuntulani et al, 1992;Kaptein et al, 1987). Single-crystal X-ray diffraction is critical to the characterization of group 12 aminoethanethiolate complexes since the nuclearity of complexes with 1:1 metal-to-ligand ratio can vary with the identity of ancillary ligands and counter-ions (Brennan et al, 2022;Lai et al, 2013;Brand & Vahrenkamp, 1995) and complexes with novel ring structures have been produced (Ritz et al, 2019;Viehweg et al, 2010).…”