An external oxidant-free oxidative coupling for aromatic C-H thiolation by visible-light photoredox cobalt-catalysis has been developed. Various substrates could afford benzothiazoles in good to excellent yields, and only H2 is generated as a side product. When catalytic TBAOH was used as the base, not only 2-aryl but also 2-alkylbenzothiazoles could be obtained through this novel dehydrogenative coupling reaction. This method could be scaled up and applied to the synthesis of biologically active molecules bearing benzothiazole structural scaffolds (potent antitumor agents). Furthermore, the unexpected oxidation byproduct amides, which are often generated in oxidative cyclization of thiobenzanilides, can be completely avoided. Mechanistic studies showed that the H2 originates from the substrates. The kinetic studies indicate that the interaction between the cobalt catalyst and proton might be involved in the rate-limiting process.

Many of the largest rivers on the planet emanate from the Tibetan Plateau and the Himalayas (Fig. 1a), fed by glacial and snow melting and monsoon rainfall. Nearly 25% of the global population reside in the vast agrarian societies in the Yellow, Yangtze, Mekong, Irrawaddy, Ganges, Brahmaputra, and Indus river basins, each of which is subject to periods of widespread and long-lived flooding. Flooding remains the greatest cause of death and destruction in the developing world, leading to catastrophic loss of life and property. While almost every government in Asia has made substantial progress over the past two decades in saving the lives of victims of slow-onset flood disasters, such events remain relentlessly impoverishing. In India alone, an average 6 million hectares ( A new ensemble flood prediction scheme, with skill to 10 to 15 days, allowed people along the Brahmaputra to evacuate well in advance of floods in 2007/08.

Reliable water supply from the Ganges and Brahmaputra is of critical importance to the sustainability of the agricultural societies of India and Bangladesh. But, the flow in both basins is highly variable on time-scales ranging from days to years, creating challenges for the optimization of agricultural practices, water resource management and disaster mitigation. The following questions are addressed. Is intraseasonal monsoon variability related to the subseasonal variability of river flow? Do variations in the large-scale tropical sea-surface temperature (SST) located both regionally and remotely promote seasonal and interannual variations of river discharge? And, if these relationships do exist, are they determinable with sufficient lead-times to allow useful predictions for user communities in South Asia? We examine these questions using 50 years of daily river discharge data for both rivers calculated at the points where they enter Bangladesh, and with SST data in the Indo-Pacific region. We also examine the question of determining the impact of man-made dams, diversions and barrages on the data record, especially that of the Ganges. A comparison of discharge prior to 1974 (the time of the construction of the largest barrage) shows no statistical difference that cannot be explained by basin-wide rainfall distributions. Changes that do occur are restricted to the dry-season months.Subseasonal river discharge is found to be strongly tied to the monsoon intraseasonal cycle resulting in a near-inphase timing of Ganges and Brahmaputra discharge. A basin isochrone analysis is used to couple stream-flow variability and intraseasonal precipitation during the different phases of the intraseasonal cycle. On longer time-scales, statistically significant correlations are found between mean monthly equatorial Pacific SST and the boreal summer Ganges discharge with lead times of 2-3 months. These relationships are tied to El Niño-Southern Oscillation (ENSO) oscillations in addition to SST variability in the southwest and northwest Pacific that also seems to be related to ENSO. The Brahmaputra discharge, on the other hand, shows somewhat weaker relationships with tropical SST. Strong lagged correlation relationships are found with SST in the Bay of Bengal but these are the result of very warm SSTs and exceptional Brahmaputra discharge during the summer of 1998. When this year is removed from the time series, relationships with SST anomalies weaken everywhere except in the northwest Pacific for the June discharge and in areas of the central Pacific straddling the Equator for the July discharge. In addition, the northwest Pacific relationship changes polarity for June and July discharges. Although the relationships are weaker than those found for the Ganges, they are persistent from month to month and suggest that two different and sequential factors influence Brahmaputra river flow.

Light, polymer, action: A set of water‐soluble poly(acrylic acid) catalysts PAA‐g‐Fe2S2 containing {Fe2S2}, an [FeFe]‐hydrogenase active‐site mimic, is synthesized. This system, combined with CdSe quantum dots and ascorbic acid, has an exceptional turnover number and initial turnover frequency (27 135 and 3.6 s−1) for the photocatalytic production of H2 in water, which is the highest efficiency to date for [FeFe]‐hydrogenase mimics.