02165nas a2200253 4500008004100000022001400041245008400055210006900139260000800208300001500216490000700231520135000238653001601588653001701604653001101621653001701632100002201649700002201671700002601693700002101719700002801740700003001768856011301798 2022 eng d a1861-472800aCoordination flexibility aided CO2-specific gating in an iron isonicotinate MOF0 aCoordination flexibility aided CO2specific gating in an iron iso cFEB ae2021013050 v173 a

Coordination flexibility assisted porosity has been introduced into an Iron-isonicotinate metal-organic framework (MOF), (Fe(4-PyC)(2) . (OH). The framework showed CO2-specific gate opening behavior, which gets tuned as a function of temperature and pressure. The MOF ` s physisorptive porosity towards CO2, CH4, and N-2 was investigated; it adsorbed only CO2 via a gate opening phenomenon. The isonicotinate, representing a borderline soft base, is bound to the hard Fe3+ centre through monodentate carboxylate and pyridyl nitrogen. This moderately weak binding enables isonicotinate to spin like a spindle under the CO2 pressure opening the gate for a sharp increase in CO2 uptake at 333 mmHg (At 298 K, the CO2 uptake increases from 0.70 to 1.57 mmol/g). We investigated the MOF ` s potential for CO2/N-2 and CO2/CH4 gas separation aided by this gating. IAST model reveals that the CO2/N-2 selectivity jumps from 325 to 3131 when the gate opens, while the CO2/CH4 selectivity increases three times. Interestingly, this Fe-isonicotinate MOF did not follow the trend set by our earlier reported Hard-Soft Gate Control (established for isostructural M2+-isonicotinate MOFs (M=Mg, Mn)). However, we account for this discrepancy using the different oxidation state of metals confirmed by X-ray photoelectron spectroscopy and magnetism.

10aCO2 capture10aflexible MOF10agating10aIsonicotinic1 aSingh, Himan, Dev1 aNandi, Shyamapada1 aChakraborty, Debanjan1 aSingh, Kirandeep1 aVinod, Chathakudath, P.1 aVaidhyanathan, Ramanathan uhttps://library.ncl.res.in/content/coordination-flexibility-aided-co2-specific-gating-iron-isonicotinate-mof01928nas a2200229 4500008004100000022001400041245008600055210006900141260000800210300001600218490000700234520116200241100002001403700002501423700002301448700001901471700002701490700002701517700002101544700001801565856011501583 2022 eng d a0020-166900aFirst-row transition metal complexes of a phosphine-silylene- based hybrid ligand0 aFirstrow transition metal complexes of a phosphinesilylene based cAUG a13330-133410 v613 a

We have prepared two new silylene-phosphine-based hybrid ligands Si{N(R)C6H4(PPh2)}{PhC((NBu)-Bu-t)(2)} [R = TMS {trimethylsilyl} (1) and TBDMS {tert-butyldimethylsilyl} (2)], which possess two donor sites. Furthermore, the treatment of the bidentate ligand 1 with base metal halides {FeBr2, CoBr2, NiCl(2)middotdme [nickel chloride(II) ethylene glycol dimethyl ether]} and 2 with NiBr(2)middotdme [nickel bromide(II) ethylene glycol dimethyl ether] afforded four-coordinate six-membered metal complexes 3-6, respectively, which feature coordination from both Si(II) and P(III) sites. Subsequently, complexes 3 [(FeBr2)Si{N(SiMe3)C6H4(PPh2)}{PhC((NBu)-Bu-t)(2)}], 4 [(CoBr2)Si{N(SiMe3)C6H4(PPh2)}{PhC((NBu)-Bu-t)(2)}], 5 [(NiCl2)Si{N(SiMe3)C6H4(PPh2)}{PhC((NBu)-Bu-t)(2)}], and 6 [(NiBr2)Si{N((SiBuMe2)-Bu-t)C6H4(PPh2)}{PhC((NBu)-Bu-t)(2)}] are studied for their redox and magnetic properties with the help of UV-vis spectroscopy, cyclic voltammetry, SQUID magnetometry, and theoretical calculations. Complexes 3-6 were found to display a paramagnetic behavior. All the compounds are well established by single-crystal X-ray diffraction studies.

1 aAkhtar, Ruksana1 aKaulage, Sandeep, H.1 aSangole, Mayur, P.1 aTothadi, Srinu1 aParvathy, Parameswaran1 aParameswaran, Pattiyil1 aSingh, Kirandeep1 aKhan, Shabana uhttps://library.ncl.res.in/content/first-row-transition-metal-complexes-phosphine-silylene-based-hybrid-ligand02192nas a2200217 4500008004100000022001400041245012900055210007000184260000800254300001400262490000700276520142900283100001601712700001901728700001501747700001901762700001801781700002101799700002101820856013301841 2024 eng d a0020-166900aIntertwining of localized (d) and delocalized (π) spins in magnetically frustrated two-dimensional metal-organic frameworks0 aIntertwining of localized d and delocalized π spins in magnetica cFEB a3675-36810 v633 a

Two-dimensional metal-organic frameworks (2D MOFs) are emerging as a new class of multifunctional materials for diversified applications, although magnetic properties have not been widely explored. The metal ions and organic ligands in some of the 2D MOFs are arranged in the well-known Kagome lattice, leading to geometric spin frustration. Hence, such systems could be the potential candidates to exhibit an exotic quantum spin liquid (QSL) state, as was observed in Cu-3(HHTP)(2) (HHTP = hexahydroxytriphenylene), with no magnetic transition down to 38 mK. Hereto, we have investigated the spin intertwining in a bimetallic 2D MOF system, M-3(HHTP)(2) (M = Cu/Zn)(,) arising from the localized (d-electron) and delocalized (pi-electron) S = 1/2 spins from the Cu(II) ions and the HHTP radicals, respectively. The origin of the spin frustration (down to 5K) was critically examined by varying the metal composition in bimetallic systems, CuxZn3-x(HHTP)(2) (x = 1, 1.5, 2), containing both S = 1/2 and S = 0 spins. Additionally, to gain a deeper understanding, we studied the spin interaction in the pristine Zn-3(HHTP)(2) system containing only S = 0 Zn(II) ions. In view of the quantitative estimate of the localized and delocalized spins, the d-pi spin correlation appears essential in understanding the unusual magnetic and/or other physical properties of such hybrid organic-inorganic 2D crystalline solids

1 aUgale, Ajay1 aNinawe, Pranay1 aJain, Anil1 aSangole, Mayur1 aMandal, Rimpa1 aSingh, Kirandeep1 aBallav, Nirmalya uhttps://library.ncl.res.in/content/intertwining-localized-d-and-delocalized-%CF%80-spins-magnetically-frustrated-two-dimensional02272nas a2200289 4500008004100000022001400041245009400055210006900149260000900218490000700227520134800234653003101582653002001613653002701633653001601660653002101676100001901697700001501716700001901731700001501750700001601765700002101781700002101802700002101823700002101844856011701865 2024 eng d a0947-653900aRobust spin liquidity in 2D metal-organic framework Cu3 (HHTP)2 with S=1/2 kagome lattice0 aRobust spin liquidity in 2D metalorganic framework Cu3 HHTP2 wit cJAN 0 v303 a

On one hand electron or hole doping of quantum spin liquid (QSL) may unlock high-temperature superconductivity and on the other hand it can disrupt the spin liquidity, giving rise to a magnetically ordered ground state. Recently, a 2D MOF, Cu-3(HHTP)(2) (HHTP - 2,3,6,7,10,11-hexahydroxytriphenylene), containing Cu(II) S = 1/2 frustrated spins in the Kagome lattice is emerging as a promising QSL candidate. Herein, we present an elegant in situ redox-chemistry strategy of anchoring Cu-3(HHTP)(2) crystallites onto diamagnetic reduced graphene oxide (rGO) sheets, resulting in the formation of electron-doped Cu-3(HHTP)(2)-rGO composite which exhibited a characteristic semiconducting behavior (5 K to 300 K) with high electrical conductivity of 70 S . m(-1) and a carrier density of similar to 1.1 x 10(18) cm(-3) at 300 K. Remarkably, no magnetic transition in the Cu-3(HHTP)(2)-rGO composite was observed down to 1.5 K endorsing the robust spin liquidity of the 2D MOF Cu-3(HHTP)(2). Specific heat capacity measurements led to the estimation of the residual entropy values of 28 % and 34 % of the theoretically expected value for the pristine Cu-3(HHTP)(2) and Cu-3(HHTP)(2)-rGO composite, establishing the presence of strong quantum fluctuations down to 1.5 K (two times smaller than the value of the exchange interaction J).

10a2D Metal-organic Framework10aElectron doping10aReduced graphene oxide10aSpin Liquid10aSpin-frustration1 aNinawe, Pranay1 aJain, Anil1 aSangole, Mayur1 aAnas, Mohd1 aUgale, Ajay1 aMalik, Vivek, K.1 aYusuf, Seikh, M.1 aSingh, Kirandeep1 aBallav, Nirmalya uhttps://library.ncl.res.in/content/robust-spin-liquidity-2d-metal-organic-framework-cu3-hhtp2-s12-kagome-lattice02167nas a2200289 4500008004100000022001400041245005500055210005200110260000800162490000700170520133100177653002301508653002401531653001901555653001101574653002201585100002001607700001901627700001501646700002301661700002401684700002101708700001701729700002401746700001901770856008801789 2024 eng d a0947-653900aTridentate NacNac tames T-shaped nickel(I) radical0 aTridentate NacNac tames Tshaped nickelI radical cFEB0 v303 a

The reaction of a nickel(II) chloride complex containing a tridentate beta-diketiminato ligand with a picolyl group [2,6-iPr2-C6H3NC(Me)CHC(Me)NH(CH2py)]Ni(II)Cl (1)] with KSi(SiMe3)3 conveniently afforded a nickel(I) radical with a T-shaped geometry (2). The compound's metalloradical nature was confirmed through electron paramagnetic resonance (EPR) studies and its reaction with TEMPO, resulting in the formation of a highly unusual three-membered nickeloxaziridine complex (3). When reacted with disulfide and diselenide, the S-S and Se-Se bonds were cleaved, and a coupled product was formed through carbon atom of the pyridine-imine group. The nickel(I) radical activates dihydrogen at room temperature and atmospheric pressure to give the monomeric nickel hydride. A thermally stable, T-shaped, nickel(I) radical was straightforward obtained by reduction of a tridentate nacnac nickel(II) chloride with KSi(TMS)3. The metalloradical character of the compound was demonstrated by the formation of a highly unusual nickeloxaziridine complex upon addition of TEMPO. The Ni(I) species displays a rich chemistry towards activation S-S, and Se-Se bond leading to unusual C-C coupled product as well as dihydrogen activation at room temperature and atmospheric pressure to generate monomeric nickel hydride.+image

10aC-C Bond formation10aHydrogen Activation10aMetalloradical10aNickel10aTridentate nacnac1 aPahar, Sanjukta1 aSharma, Vishal1 aRaj, Vipin1 aSangole, Mayur, P.1 aGeorge, Christy, P.1 aSingh, Kirandeep1 aVanka, Kumar1 aGonnade, Rajesh, G.1 aSen, Sakya, S. uhttps://library.ncl.res.in/content/tridentate-nacnac-tames-t-shaped-nickeli-radical04907nas a2200229 4500008004100000245007800041210007000119260000800189490000600197520417400203100001804377700001904395700002204414700001704436700001704453700001704470700001604487700002104503700002204524700002104546856011004567 2024 eng d00aUnconventional hole doping of S = ½ kagome antiferromagnet CoCu3(OH)6Cl20 aUnconventional hole doping of S ½ kagome antiferromagnet CoCu3OH cSEP0 v33 a

Geometrically perfect S = ½ kagome lattices with frustrated magnetism are typically electrical insulators. Electron or hole doping is predicted to induce an exotic conducting state including superconductivity. Herein, an unconventional strategy of doping an S = ½ kagome lattice CoCu3(OH)6Cl2 is adopted – a structural analogue of a well-known quantum spin liquid (QSL) candidate herbertsmithite (ZnCu3(OH)6Cl2) – by integrating it with reduced graphene oxide (rGO) via in situ redox chemistry. Such an integration drastically enhances the electrical conductivity, resulting in the transformation of an insulator to a semiconductor, corroborating the respective density of states obtained from the density functional theory calculations. Estimation of the magnetic moments, data on the Hall-effect measurements, Bader charge analysis, and photoemission signals, altogether provide a bold signature of remote hole doping in CoCu3(OH)6Cl2 by rGO. The remote doping provides an alternative to the site doping approach to impart exotic electronic properties in spin liquid candidates, specifically, the generation of topological states like Dirac metal is envisioned.

1 aMandal, Rimpa1 aNinawe, Pranay1 aAnanthram, K., S.1 aMhase, Akash1 aGupta, Kriti1 aSaha, Sauvik1 aUgale, Ajay1 aSingh, Kirandeep1 aTarafder, Kartick1 aBallav, Nirmalya uhttps://library.ncl.res.in/content/unconventional-hole-doping-s-%C2%BD-kagome-antiferromagnet-cocu3oh6cl200799nas a2200241 4500008004100000022001400041245008900055210006900144260000900213300001600222490000700238100001700245700002100262700002500283700001600308700001900324700001900343700001700362700001700379700002100396700001900417856012100436 2024 eng d a1477-922600aUnprecedented C-F bond cleavage in perfluoronaphthalene during cobaltocene reduction0 aUnprecedented CF bond cleavage in perfluoronaphthalene during co cNOV  a17789-177930 v531 aKundu, Gargi1 aPramanik, Debjit1 aDash, Soumya, Ranjan1 aKumar, Ravi1 aSangole, Mayur1 aTothadi, Srinu1 aGhosh, Aryya1 aVanka, Kumar1 aSingh, Kirandeep1 aSen, Sakya, S. uhttps://library.ncl.res.in/content/unprecedented-c-f-bond-cleavage-perfluoronaphthalene-during-cobaltocene-reduction01467nas a2200205 4500008004100000022001400041245005900055210005800114260000800172300001100180490000800191520084600199100001901045700001901064700002301083700002101106700002101127700002201148856009101170 2024 eng d a2469-995000aUnveiling different structural orderings in Fe5-xGeTe20 aUnveiling different structural orderings in Fe5xGeTe2 cAUG a0751190 v1103 a

We investigate the metallic van der Waals itinerant ferromagnet Fe5-xGeTe2 5 - x GeTe 2 with atomic scale, spatially resolved low-temperature scanning tunneling microscopy (STM), and spectroscopy (STS). STM images unveil / / a new structural order 2a a x 1a a along with the known order 3a a x 3a a manifesting as nonuniform domains. STS shows spatial and energy resolved local density of states that reveal the crucial influence of Fe(1) site occupancy on the system's electronic interactions. Our magnetization measurements show magnetic anomalies at lower temperatures and identify a Curie temperature (Tc) c ) surpassing room temperature. Collectively, our results elucidate the intricate nature of Fe5-xGeTe2 5 - x GeTe 2 and underscore its potential for tunability of spintronics and high-temperature magnetic applications.

1 aWalve, Vaibhav1 aParakh, Piyush1 aRajput, Umashankar1 aMhase, Akash, S.1 aSingh, Kirandeep1 aDeshpande, Aparna uhttps://library.ncl.res.in/content/unveiling-different-structural-orderings-fe5-xgete202424nas a2200265 4500008004100000022001400041245012000055210006900175260000800244300001100252490000800263520154000271653002201811653001801833653001801851653001601869653001701885653002601902100002001928700002101948700001901969700001901988700002602007856012502033 2025 eng d a0921-452600aInfluence of ionic radius on structural, optical and multiferroic properties of RMnO3 [R= Y, Er, Yb] hexamanganites0 aInfluence of ionic radius on structural optical and multiferroic cOCT a4174960 v7143 a

The crystalline samples of YMnO3, ErMnO3, and YbMnO3 were synthesized by a conventional solid-state reaction technique. The single-phase hexagonal structure with the P63cm space group was verified by X-ray diffraction (XRD) study. Morphological studies show that the grains are uniform and closely packed, and that the grain size increases as the ionic radii of the rare-earth ions decrease of rare earth ions and the samples are in the stoichiometry. From the Diffused Reflectance Spectroscopy study, narrow optical band gap is observed for all the samples. Magnetic phase transitions, corresponding to the antiferromagnetic ordering, were detected for all samples. The Neel temperature was found to increase with the decrease of the ionic radii of A site element in RMnO3 (Y, Er, and Yb) samples. Ferroelectric hysteresis loops at room temperature as a function of applied electric fields reveal the leaky behaviour. The dielectric constant and dielectric loss tangent variation across different frequencies are also explored for these samples. A summary and discussion of the structural, optical, magnetic and ferroelectric properties, underlying physical mechanisms, the role of the rare earth ions, and the complex interactions in hexagonal manganites, are presented in this paper. This work emphasizes how systematic variation of A-site ionic radii influences the multiferroic properties of RMnO3, gaining thorough insights into structure-property relationships that are essential to design multifunctional materials.

10aAntiferromagnetic10aferroelectric10aMultiferroics10aPerovskites10aPhotovoltaic10aRecombination centers1 aInchara, D., R.1 aSingh, Kirandeep1 aSangole, Mayur1 aMurari, M., S.1 aDaivajna, Mamatha, D. uhttps://library.ncl.res.in/content/influence-ionic-radius-structural-optical-and-multiferroic-properties-rmno3-r-y-er-yb02220nas a2200289 4500008004100000245011500041210006900156260000800225300000900233490000700242520124100249100002501490700002301515700002601538700001701564700002301581700002101604700002901625700002801654700001701682700002101699700002101720700002401741700002001765700002201785856012301807 2026 eng d00aSmallest acyclic tricationic molecule containing a Bis(phosphine)-stabilized low-valent triantimony-based Unit0 aSmallest acyclic tricationic molecule containing a Bisphosphines cMAR a26970 v173 a

Element-element bonded multiply charged cationic species are well known as dimers or small cyclic oligomers in the condensed phase. However, the smallest acyclic version, a trinuclear unit possessing greater than a monocationic charge, has remained elusive. Here we introduce a bis(phosphine) supported low valent triantimony-based tricationic compound as a new entrant in this field. Structural elucidation and electronic understanding reveal a W-shaped tricationic unit comprising of a three-center four-electron sigma-bonded triantimony moiety that is terminally capped by bis(phosphine) ligands, with the central antimony atom having two lone pairs of electrons. The unique counter trianion [Sb(O)2(OTf)4]3- (OTf = CF3SO3) possesses reactive polar Sb delta+-O delta- bonds, the structure of which is determined from single crystal X-ray diffraction analysis. The ensemble of reactive molecular fragments found in this highly charged antimony-based compound makes it thermally unstable. Nonetheless, this fully characterized fleeting species shows a diverse reactivity profile, advancing the isolation of various novel antimony compounds, including the formation of a distinct low-valent antimony-cobalt carbonyl cluster.

1 aMukherjee, Nilanjana1 aPeerless, Benjamin1 aNadurata, Vincent, L.1 aKumar, Vikas1 aSangole, Mayur, P.1 aSingh, Kirandeep1 aWiedemann, Haakon, T. A.1 aKay, Christopher, W. M.1 aKruk, Robert1 aWeigend, Florian1 aDehnen, Stefanie1 aGonnade, Rajesh, G.1 aYildiz, Cem, B.1 aMajumdar, Moumita uhttps://library.ncl.res.in/content/smallest-acyclic-tricationic-molecule-containing-bisphosphine-stabilized-low-valent