02205nas a2200289 4500008004100000022001400041245008700055210006900142260000800211300001100219490000800230520126600238653001601504653001301520653003101533653001701564653003601581653003301617100002001650700002101670700002001691700002101711700001801732700001701750700003101767856011701798 2020 eng d a0927-775700aDual responsive cellulose microspheres with high solid-state fluorescence emission0 aDual responsive cellulose microspheres with high solidstate fluo cAPR a1245100 v5913 a

Materials that respond to multiple stimuli such as magnetic field and light are attractive for security and medical diagnostic applications. One of the major challenges in dual functional microspheres is that the presence of magnetic nanoparticles can quench fluorescence emission. Also, there is a probability of solid-state quenching due to the proximity of the fluorophore. We report here a facile approach to prepare cellulose microspheres with high solid-state fluorescence using 40 % tetrabutylammonium hydroxide (TBAH). The fluorescence quenching effect due to the presence of Fe3O4 nanoparticles and solid-state quenching due to aggregation of fluorophore was systematically investigated. Microspheres with the detectable magnetic response and fluorescence quantum yield as high as 0.57 (FMB 414) was obtained by optimizing the reaction conditions. Such a high quantum yield has not been reported before for dual stimuli-responsive fluorescent microspheres. The magnetic and fluorescent properties were found to be durable even after multiple washing cycles. These dual responsive cellulose microspheres can be added as security features to authenticate documents such as passports, degree certificates, currency notes, financial documents etc.

10aFluorescent10aMagnetic10aMicrocrystalline cellulose10amicrospheres10aStimuli responsive microspheres10aTetrabutylammonium hydroxide1 aYadav, Prashant1 aPrajitha, K., P.1 aDhaware, Vinita1 aSubramani, Mohan1 aJoy, Pattayil1 aAsha, S., K.1 aShanmuganathan, Kadhiravan uhttps://library.ncl.res.in/content/dual-responsive-cellulose-microspheres-high-solid-state-fluorescence-emission02899nas a2200157 4500008004100000245005900041210005800100260004400158490000900202520236600211100001702577700001702594700001802611700002102629856009102650 2020 eng d00aMagnetism in bimetallic NiII-CoII coordination polymer0 aMagnetism in bimetallic NiIICoII coordination polymer bAmerican Institute of Physics Inc.cNOV0 v22653 a

Co-BDC ([Co2(OH)2BDC], H2BDC = 1,4-benzenedicarboxylic acid) is known to possess metamagnetism originating from the antiparallel spins and high magneto crystalline anisotropy of Co(II).1 Herein, we have introduced a bimetallic concept by incorporating Ni(II) along with Co(II) in the same coordination polymer to modulate the magneto crystalline anisotropy in the lattice which in turn, affects the overall magnetic response of the coordination polymer. The Curie-Weiss equation fit suggested antiparallel arrangement of the spins (θ ≈ -62.5 K) of Ni(II) and Co(II) arranged in alternate fashion. The cusp in magnetization was observed at 7 K (Tc) with a significant coercive field of ∼750 Oe at 5 K.

1 aGupta, Kriti1 aDadwal, Arun1 aJoy, Pattayil1 aBallav, Nirmalya uhttps://library.ncl.res.in/content/magnetism-bimetallic-niii-coii-coordination-polymer