It is well known that various transition elements can form M···H hydrogen bonds. However, for gold, there has been limited decisive experimental evidence of such attractive interactions. Herein we demonstrate an example of spectroscopically identified hydrogen bonding interaction of C–H units to Au atoms in divalent hexagold clusters ([Au6]2+) decorated by diphosphine ligands. X-ray crystallography reveals substantially short Au–H/Au–C distances to indicate the presence of attractive interactions involving unfunctionalized C–H moieties. Solution 1H and 13C NMR signals of the C–H units appear at considerably downfield regions, indicating the hydrogen-bond character of the interactions. The Au···H interactions are critically involved in the ligand-cluster interactions to affect the stability of the cluster framework. This work demonstrates the uniqueness and potential of partially oxidised Au cluster moieties to participate in non-covalent interaction with various organic functionalities, which would expand the scope of gold clusters.

Addition reactions O 0060 Rh-N-Heterocyclic Carbene (NHC) Complex-Catalyzed Addition of Phenylboronic Acid to N-Sulfonyl and N-PhosphinoylAldimines. -(ABU BAKAR, M.; SUZUKI*, Y.; SATO, M.; Chem. Pharm. Bull. 56 (2008) 7, 973-976; Sch. Pharm.

Chattogram is the second most populated city in Bangladesh. This port city faces a serious threat mainly due to the lack of safe drinking water. This study was conducted for determining drinking water quality of groundwater sources in Chattogram city. The study was performed in the BCSIR laboratory, Chattogram. It was carried out for a period of six months from 1st July, 2018 to 31th December, 2018. Total six water samples were collected from three different locations (Baluchora, C&B colony and Khulshi area). Each sampling location consists of two separate sampling points. Physicochemical parameters of the collected samples like Temperature, pH, Electrical Conductivity (EC), Total dissolved solid (TDS), Hardness, Turbidity and concentration of Cl, As, Mn, Fe, Pb, Cr and Cd were examined. Microbial parameters like Total Coliform (TC) were also measured. All the analyzed parameters compared with BSTI and WHO drinking water quality standards to understand the overall ground water quality status of the study area. The results reveal that water samples in almost all locations were contaminated with microbial contamination and that the range of physico-chemical parameters was not adequate for consumption. Preliminary treatments like boiling, filtering etc are required before using groundwater for drinking and the necessary measures must be taken for a safe alternative source of drinking water.