Diverse silver(i) coordination chemistry with cyclic selenourea ligands

Abstract

The coordination chemistry of two selenourea ligands (SeIMes and SeIPr) towards silver(i) triflate and silver(i) nitrate was investigated. Two aggregation modes were observed in the solid state, strongly influenced by the size of the aromatic substituents on the ligand. With mesityl groups, selenium-bridged bimetallic motifs [AgX(SeIMes)] were obtained, while for the bulkier diisopropylphenyl groups ion-separated species of formulae [Ag(SeIPr)][X] were obtained. Recrystallization of [Ag(NO)(SeIMes)] from hot methanol resulted in the formation of a unique coordination polymer featuring three silver environments. Characterization of the complexes by NMR spectroscopy and mass spectrometry suggested all complexes adopt the ionic aggregation mode in methanol solution.

Unexpected reactions of NHC*—CuI and —AgI bromides with potassium thio- or selenocyanate

“…However, since together with the information above only a schematic drawing of the surrounding of the Cu II atom was given, we cannot establish structural details of the anion in [Cu(NH 3 ) 2 Ag(SCN) 3 ] with any degree of certainty. The Ag-Se distances in (2) fall well within the region reported for similar compounds (Perras et al, 2018;Nahra et al, 2018). Remarkably, at least for the neutral compounds, the distances do not depend on whether the coordination number around the silver is 3 or 4: In N,N-dimesitylselenoimidazolesilver nitrate, the Ag-Se bond lengths range from 2.65 to 2.68 Å for the four-coordinate atom and from 2.63 to 2.71 for the three-coordinate atom (Perras et al, 2018).…”

Coinage metal complexes of selenoureas derived from N-heterocyclic carbenes

“…, and [Ag(µ-X)(4)]2 (X = OTf, NO3). 43 These results strongly suggest that the coordination environment of the silver centres is highly sensitive to the substitution pattern of the ligand and to the nature of the silver counterion. In order to study these coordination patterns and to consequently correlate results with those from investigations with other coinage metals (i.e.…”

“…The dimeric structure of [Ag(μ-Cl)(4)]2 is in direct agreement with that reported by Ritch on the reaction of 4 with AgNO3 and AgOTf. 43 The dicoordinated structure [Ag(1)2]Cl deviates somewhat from the expected structure; since it was concluded on the basis of DOSY experiments that this species is most likely mono-coordinated in solution, one might expect the X-ray structure to be either the monomeric form [AgCl(1)] or the rearranged structure [Ag(1)2][AgCl2], by analogy to the work reported here with copper, and previous investigations with gold and silver. This slight difference in coordination could be a direct consequence of the crystallisation method/system; the insolubility of AgCl and its high lattice energy could be a significant driving force in the elimination of AgCl from [Ag (1)2][AgCl2] during crystallisation in this particular solvent combination.…”

“…Each silver centre has two smaller angles and one larger angle; Se1-Ag1-Se2, Se1-Ag1-Se5, Se4-Ag2-Se5, and Se4-Ag2-Se3 are in the range 108 -116°, while Se2-Ag1-Se5 and Se3-Ag2-Se5 are 134. 43(3) and 135.72(3), respectively. A search of the CSD revealed no other structures of this type.…”

Synthesis, characterization, and catalytic activity of half‐sandwich ruthenium complexes with pyridine/phenylene bridged NHC = E (NHC = N‐heterocyclic carbene, E = S, Se) ligands

“…[ 18–23 ] Modification of the NHC = E precursors and bridging groups allows chemists to fine‐tune the sterics, electronic properties, solubility, and catalytic activities of the metal complex. [ 24–28 ]…”