Skip to main content

An in-depth examination of the properties and behaviour of Au(III)-based [AuX2(CN)2]- (X = Cl, Br, I) as a coordination polymer building block

Resource type
Thesis type
(Thesis) Ph.D.
Date created
This thesis primarily focuses on the synthesis and characterization of [AuX2(CN)2]- (X = Cl, Br, I), a square planar Au(III)-based compound, and its use as a coordination polymer building block. K+, nBu4N+ and PPN+ salts of [AuX2(CN)2]- and the Au(I/III)-based double salts K3[Au(CN)2]2[AuBr2(CN)2]-H2O and K5[Au(CN)2]4[AuI2(CN)2]-2H2O were prepared and structurally characterized. All compounds exhibited many structure-defining weak interactions such as X-X, Au-X (X = Br, I) and Au(I)-Au(I) interactions, as well as a rare Au(I)-Au(III) interaction with an intermolecular distance of 3.58 A; no Cl-Cl interactions were observed. [AuX2(CN)2]- was introduced to solutions containing a variety of divalent metals (Mn, Fe, Co, Ni, Cu, Zn, Pb) and ancillary N-donating chelating ligands such as 1,10-phenanthroline or bridging ligands such as 4,4'-bipyridine. In most cases, an ionic material resulted, containing a metal cation coordinatively saturated by ligand and an unbound [AuX2(CN)2]- (X = Cl, Br) anion. In some cases, [AuX2(CN)2]- did bind, but in a pendant, non bridging fashion. With ethylenediamine and 4,4'-bipyridine ligands, and Ni(II) and Co(II) or Zn(II), respectively, an [AuBr2(CN)2]--bridged coordination polymer resulted; no [AuCl2(CN)2]--bridged materials were observed with added ancillary ligands. In the absence of ancillary ligand, several [AuX2(CN)2]--bridged (X = Cl, Br) formed; all reactions involving [AuI2(CN)2]- resulted in decomposition of the [AuI2(CN)2]- molecule. Exposing [AuX2(CN)2]- to temperatures above 80 C or UV light resulted in the reductive elimination of halogen, yielding [Au(CN)2]-. Kinetics (thermal and photochemical) studies revealed pseudo first-order rate kinetics with. Heating some [AuBr2(CN)2]--containing coordination polymers to 125 C converted them to analogous [Au(CN)2]--containing materials. The ligand-free Cu[AuX2(CN)2]2 materials exhibited a vapochromic response when exposed to H2O, DMF, DMSO, pyridine, 1,4-dioxane and ethyleneglycol; they also exhibited distinct IR and Raman vCN patterns. Using Raman analysis, these vCN patterns can be effectively used to detect and identify between DMF, DMSO and pyridine. A series of Cu(I) and Ag(I)-based coordination polymer materials containing bridging [AuX2(CN)2]-, [Au(CN)4]- and [Au(CN)2]- were synthesized and characterized. M[Au(CN)4] (M = Cu, Ag) exhibit negative thermal expansion with expansion coefficients between -11e-6 and -24e-6 K-1. M[Au(CN)2] are isomorphous to known AuCN, and exhibit turquoise (Ag) and red (Cu) emission. Incorporating pyridine, THT, PPh3 and Me2S in the Cu(I)/[Au(CN)2]- reaction yielded materials with distinct emissive properties; Cu(SMe2)[Au(CN)2] emits white light. Thus, Cu[Au(CN)2] shows potential as a sensor for P- or S-donor solvents.
Copyright statement
Copyright is held by the author.
The author granted permission for the file to be printed and for the text to be copied and pasted.
Scholarly level
Supervisor or Senior Supervisor
Thesis advisor: Leznoff, Daniel B.
Member of collection
Download file Size
etd8871_JOvens.pdf 112.99 MB

Views & downloads - as of June 2023

Views: 7
Downloads: 0