Author : Sang Ho Lim
Publisher :
ISBN 13 : 9781267240613
Total Pages : pages
Book Rating : 4.2/5 (46 download)
Book Synopsis Structural Diversity and Luminescence Studies of Two-coordinate and Three-coordinate Gold(I) Complexes by : Sang Ho Lim
Download or read book Structural Diversity and Luminescence Studies of Two-coordinate and Three-coordinate Gold(I) Complexes written by Sang Ho Lim and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Structural and spectroscopic studies of a number of two-coordinate and three-coordinate gold(I) compounds have been conducted. These studies were undertaken in order to examine various influences one aurophilic interactions, where aurophilicity is generally defined as a non-covalent, weakly attractive interaction between two gold atoms and to investigate other interesting photo-physical properties such as luminescence and vapochromism. Two- and three-coordinate gold(I) complexes discussed here, displayed structural diversity, a variety of aurophilic interactions, and interesting luminescence or vapoluminescence properties. Simple mixing of the labile complex (tht)AuBr with dppe in either dichloromethane or acetone results in the formation of a colorless product with a green luminescence that can be crystallized from a variety of solvents to produce three distinct types of colorless crystals, each of which is a solvate.: type A, orange luminescent solvates of the dimer Au2(dppe)2Br2(Au2([mu]-dppe)2 Br22(OSMe2), Au2([mu]-dppe)2Br22(OCMe2), Au2([mu]-dppe)2Br22(CH2Cl2), Au2([mu]-dppe)2Br22(HC(O)NMe2)); type B, green luminescent solvates of the same dimer (Au2 ([mu]-dppe)2Br2(NCMe) and Au2([mu]-dppe)2Br20.5(C4H10O); and type C, orange luminescent solvates of a polymer ({Au([mu]-dppe)Br}n 0.5(C4H10O) and {Au([mu]-dppe)Br}n(CH2C2). Some crystals of types A are solvoluminescent. Exposure of type A crystals of Au2([mu]-dppe)2Br22(OCMe2) or Au2([mu]-dppe)2Br22(CH2Cl2) to air or vacuum results in the loss of the orange luminescence and the formation of new green luminescent crystals. Solutions containing the components Au+, dppe (dppe is bis-(diphenylphosphino)ethane), and I- in a 1:1:1 ratio can produce five different types of crystals: type 1, orange luminescent solvates of the dimer Au2(dppe)2I2 (isostructural crystals of Au2([mu]-dppe)2I22(OSMe2), Au2([mu]-dppe)2I22(OCMe2)-[alpha], and Au2([mu]-dppe)2I22(CH2Cl2)); type 2, yellow-green luminescent solvates of the same dimer (isostructural crystals of Au2([mu]-dppe)2I22(OCMe2)-[beta]) and Au2([mu]-dppe)2I22(HC(O)NMe2)-polymorph-1); type 3, a yellow luminescent solvate containing two different molecules of the dimer Au2(dppe)2I2(Au2([mu]-dppe)2I22(HC(O)NMe2)-polymorph-2); type 4, orange luminescent crystals of the iodide-bridged dimer Au2([mu]-dppe) 2([mu]-I)2 ; and type 5, orange emitting crystals of polymeric Au2([mu]-dppe)2I22(CHCl3). Simple reactions of gold(I) with PnP, where PnP is PPh2(CH2)[n] PPh2 with n=3-6, produced seven crystalline dimers from molecules of the type, Au2([mu]-P[n]P)2X2 , where, X is bromide or iodide. The molecules show accordion-like structures (n=3, 4 for bromide and n=3, 4, and 6 for iodide) and hinge-like structures (n=5 for both bromide and iodide), which is the first three-coordinate gold complexes with non-centro symmetry. The range of Au···Au separations of these compounds are remarkably longer than other related compounds. Solutions containing the components Au+, dpae (dpae is 1,2 bis-(diphenylarsine)ethane), and X- (X is Cl, Br, or I) in a 2:1:2 ratio can produce two different forms: colorless blocks and colorless needles. Crystallographic studies of these crystals show that they are polymorphs with different motifs: polymorph [alpha] that form discrete dimers, and polymorph [beta] that assemble into polymeric chains. Cationic [Au2([mu]-dpae)2](PF6)22CHCl3 and [Au2([mu]-dpae)2](AsF6)22(CHCl3) have been also obtained from the similar reaction of either [alpha]-[Au2([mu]-dpae)X2] or [beta]-[Au2([mu]-dpae)2X2], but, with excess of KPF6 and NaAsF6. Crystallographic studies have revealed that these crystals are isostructural with close but, slightly different Au separations.
