Versatile N₂S₂nickel-dithiolates as mono- and bridging bidentate, S-donor ligands to gold(i)

Abstract

Development of square planar cis-dithiolate nickel complexes as metallo S-donor ligands focuses on the synthesis and structures of gold(I) heterometallic clusters derived from assemblage with three NiN2S2 complexes: Ni(bme-daco), Ni(bme-dach) and Ni(ema)(2-) (bme-daco = (bismercaptoethanediazacyclooctane); bme-dach = bismercaptoethanediazacycloheptane; and ema = N,N'-ethylenebis-2-mercaptoacetamide). With Ph3PAuCl as the gold source, examples of simple S-aurolation retaining the PPh3 on Au(+) were obtained for [{Ni(bme-daco)}AuPPh3](+)Cl(-) and [{Ni(ema)}2Au4(PPh3)4], where the latter complex demonstrated unsupported aurophilic interactions between [{Ni(ema)}Au2(PPh3)2] units in its X-ray crystal structure (Au-Au = 3.054 and 3.127 Å). Three compounds containing fully-supported digold units with Au-Au distances in the aurophilic range of 3.11 to 3.13 Å were found as stair-step structures in which planar NiN2S2 step treads are connected by planar S2Au2S2 risers at ca. 90°: [{Ni(bme-daco)}2Au2](2+)(Cl(-))2; [{Ni(bme-dach)}2Au2](2+)(Cl(-))2; and (Et4N(+))2[{Ni(ema)}2Au2](2-). Electrochemical data from cyclic voltammograms demonstrated a positive shift in Ni(II/I) couples for the [{NiN2S2}xAuy] complexes as compared to the NiN2S2 precursors and a ca. 700 mV decrease in communication between multiple NiN2S2 units as compared to [{NiN2S2}2Ni](2+) analogues in slant chair conformation. The analogy between NiN2S2 metallodithiolate ligands and diphosphine ligands holds here as in other examples of inorganic and organometallic complexes.

Strong-Acid-Templated Construction of a Metallosupramolecular Architecture: Reversible Ammonia Adsorption in Aqueous Media in a Single-Crystal-to-Single-Crystal Conversion Manner

“… , In these complexes, Au I and Ni II centers are bridged by thiolate S atoms from d -pen. Similar Ni–S–Au structures have been widely observed in gold­(I)–nickel­(II) complexes having square-planar or octahedral nickel­(II) dithiolate species. − …”

Digermylene Oxide Stabilized Group 11 Metal Iodide Complexes

“…The Au···Au distance between the two gold atoms (3.1562(8) Å) is less than the sum of their van der Waals radii (3.3 Å) and indicates the presence of an aurophilic interaction . This interaction between the two gold atoms can be classified as a semisupported aurophilic interaction . The Ge–Au–I bond angles (172.87(5) and 174.68(6)°) suggest that this moiety is almost linear.…”

A matrix of heterobimetallic complexes for interrogation of hydrogen evolution reaction electrocatalysts

“…The tetrahedral geometry about each Fe(NO) 2 unit is thus completed by two thiolates from different NiN 2 S 2 metalloligands, thus generating an abbreviated paddlewheel, or propeller type, complex seen in examples of nickel–gold tetrametallic complexes. 41 Likewise, the molecular structure of [Ni 2 –Fe] + demonstrates that one Fe(NO) 2 unit bridges two NiN 2 S 2 metalloligands, each acting as a monodentate ligand. As shown in the [Ni 2 –Fe] + structure, Fig.…”