Recent changes in atmospheric input and primary productivity in the north Indian Ocean

Global oceanic regions are rapidly changing in terms of their temperature, oxygen, heat content, salinity and biogeochemistry. Since the biogeochemistry of the oceans is important and pivotal for global food production, and a major part of the world population relies on marine resources for their daily life and livelihood, it is imperative to monitor and find the spatio-temporal changes in the primary productivity of oceans. Here, we estimate the changes in Chlorophyll-a (Chl-a) and Net Primary Productivity (NPP) in the north Indian Ocean (NIO) basins of Bay of Bengal and Arabian Sea for the period 1998–2019. We find a substantial reduction of NPP in NIO since 1998 (−0.048 mg m−3 day−1 yr−1) and the increase in sea surface temperature (SST) (+0.02 °C yr−1) is the primary driver of this change. Furthermore, there is a significant (10–20%) change in the air mass or dust transport to NIO from the period Decade 1 (1998–2008) to Decade 2 (2009–2019). This change in air mass trajectories has also altered NPP in both basins through the changes in nutrient input and associated biogeochemistry. Henceforth, this study cautions the changes in primary productivity of NIO, and suggests regular assessments and continuous monitoring of the physical and biological processes from a perspective of food security and ecosystem dynamics

Synthesis, structure, electrochemistry and ROMP-activity of new ferrocenyl analog of Grubbs’ metathesis catalyst

Treatment of [(PCy3)2Cl2Ru=CH–Ph] (I) with vinylferrocene 1 and 1-ferrocenyl-1,3-butadiene 2 yielded solid products. These new complexes were characterized by 1H NMR, 31P NMR and 13C NMR spectroscopy. X-ray crystal structures of both the complexes have been solved. The crystal structure of II confirmed the assigned structure and revealed existence of two sets of intermolecular C–H–Cl(M) type interactions, viz. (Ru)Cl–H–C(ferrocene) and (Ru)Cl–H–CHCl2. The air-stable, dark solid II is an efficient catalyst for ring-opening metathesis polymerization (ROMP) of cyclopentene, norbornene and cycloocta-1,5-diene. Electrochemical behavior of the complexes clearly reflects electronic communication between two metal centers.© Elsevie

A highly ordered mesostructured material containing regularly distributed phenols: preparation and characterization at a molecular level through ultra-fast magic angle spinning proton NMR spectroscopy

Highly ordered organic-inorganic mesostructured material containing regularly distributed phenols is synthesized by combining a direct synthesis of the functional material and a protection-deprotection strategy and characterized at a molecular level through ultra-fast magic angle spinning proton NMR spectroscopy

Cooperative Two-Photon Absorption Enhancement via Through-Space Interactions in Covalent Multichromophoric Compounds

Space invaders: A series of multichromophores (from dimers to dendritic 24-mers) is synthesized, spectroscopically characterized, and theoretically modeled. Enhancement of the two-photon absorption response depends on the number and distribution of chromophoric subunits (see picture, red) and increases with their proximity. The exciton model indicates purely electrostatic interactions

Well-Defined Silica-Supported Mo-Alkylidene Catalyst Precursors Containing One OR Substituent: Methods of Preparation and Structure-Reactivity Relationship in Alkene Metathesis

The monosiloxy surface complexes [( SiO)Mo( NAr)(=CHC-Me(2)R')(OR)] (R' = Me or Ph: OR = OtBu, OCMe(CF(3))(2) or OAr) are obtained by grafting onto SiO(2-(700)) either symmetric Mo-alkylidene derivatives [Mo( NAr)(=CHCMe(2)R')(OR)(2)] Or asymmetric derivatives, that is, with two different pendant ligands, one amido and one alkoxy/aryloxy, [Mo( NAr)(=CHCMe(2)R')(OR)(NC(6)H(8))]. ne formation of these complexes was confirmed by mass-balance analysis, and infrared (IR) and NMR spectroscopies. These systems are highly efficient catalyst precursors for the metathesis of acyclic alkenes; the best results were seen when OR = OCMe-(CF(3))(2). Nevertheless, they display poor performances in ring-closing metathesis, possibly due to the rigidity of the metal center (as evidenced by NMR spectroscopy), which therefore slows the rate of the metathesis