The new palladium complexes with NHC and phosphine ligands, cis-PdCl 2 (L 2 )(PPh 3 ) (2), cis-PdBr 2 (L 2 )(PPh 3 ) (3), and cis-PdCl 2 (L 3 )(PPh 3 ) (4) were prepared following a general protocol of a one pot reaction between PdCl 2 (COD), PPh 3 , and the ligand precursors LH 3 Y (Y=Cl, Br, BF 4 ) (L 2 = 1,3-dibenzylimidazolin-2-ylidene; L 3 =1,3-dibenzylimidazol-2-ylidene). The cis-PdCl 2 (L 3 )(PCy 3 ) complex (5) was prepared by the ligand substitution reaction between 4 and PCy 3 . The palladium complexes with NHC and pyridine complexes, trans-PdCl 2 (L)(py) (6: L = L 2 ; 7: L = L 3 ) were obtained by heating a mixture of PdCl 2 (COD) and LH 3 BF 4 in pyridine. A similar reaction condition using CH 3 CN as solvent with KO t Bu as base afforded cis-PdCl 2 (L 3 ) 2 (8). Complexes 2-8 were successfully characterized by X-ray crystallographic studies, among which, intriguingly, two polymorphs of 8 were obtained. Thermogravimetric analysis showed that the cis-PdX 2 (NHC)(PR 3 ) complexes are more thermally stable than the trans-PdCl 2 (NHC)(py) complexes. Together with the known cis-PdCl 2 (L 1 )(PCy 3 ) (1) (L 1 =1-benzyl-3-(N-phenylacetamido)imidazol-2-ylidene), they were screened for the direct arylation reaction between aryl halides and alkynes. The result indicate that the carbene/phosphine complexes 1-5 are superior precatalysts than 6-8 with higher activities than the commonly-used system of Pd(OAc) 2 /2PPh 3 .

No abstract

The city is a continuous process that constantly changes and evolves. The process leads to changes in urban fabric, street blocks, the building size, etc. Therefore, the study in the vicissitude of urban fabric can allow better understanding of the developing contexts of a place. Tainan City was the political and economic center of Taiwan. The axis of the old town used to be the major port for old river transportation. However; the transportation methods and the city itself changed throughout time, and commercial businesses had to relocated. Today, the focus of the axis area is on cultural preservation. Traditional urban morphology focus on the spatial characteristics composed of different levels. However, this method lacked driving force for the evolution of the structure and the operational relationship in space. In this study, urban morphology will be used to observe settlement and essential space patterns of business. In addition, the study will go deep into investigating about the process of conformation, the space network hidden behind the fabrics and how urban context could be influenced. This study will investigate the structural transformation of Tainan's urban developmental process. The investigation will sort out the foundational background of the city from 17th century to the 21st century and analyze the context of the era. This study will investigate the urban fabric at different levels, and come up with strategies on how the structure of commercial aspects could be effectively modified.

No abstract