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Ninawe P, Jain A, Sangole M, Anas M, Ugale A, Malik VK, Yusuf SM, Singh K, Ballav N. Robust Spin Liquidity in 2D Metal-Organic Framework Cu 3 (HHTP) 2 with S= 1 / 2 Kagome Lattice. Chemistry 2024; 30:e202303718. [PMID: 37955413 DOI: 10.1002/chem.202303718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 11/13/2023] [Accepted: 11/13/2023] [Indexed: 11/14/2023]
Abstract
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, Cu3 (HHTP)2 (HHTP - 2,3,6,7,10,11-hexahydroxytriphenylene), containing Cu(II) S=1 / 2 ${{ 1/2 }}$ 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 Cu3 (HHTP)2 crystallites onto diamagnetic reduced graphene oxide (rGO) sheets, resulting in the formation of electron-doped Cu3 (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 ~1.1×1018 cm-3 at 300 K. Remarkably, no magnetic transition in the Cu3 (HHTP)2 -rGO composite was observed down to 1.5 K endorsing the robust spin liquidity of the 2D MOF Cu3 (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 Cu3 (HHTP)2 and Cu3 (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).
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Affiliation(s)
- Pranay Ninawe
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune, 411008, India
| | - Anil Jain
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai, 400085, India
- Homi Bhabha National Institute Anushakti Nagar, Mumbai, 400091, India
| | - Mayur Sangole
- Physical and Materials Chemistry Division, National Chemical Laboratory, Pune, 411008, India
| | - Mohd Anas
- Department of Physics, Indian Institute of Technology, Roorkee, 247667, India
| | - Ajay Ugale
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune, 411008, India
| | - Vivek K Malik
- Department of Physics, Indian Institute of Technology, Roorkee, 247667, India
| | - Seikh M Yusuf
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai, 400085, India
- Homi Bhabha National Institute Anushakti Nagar, Mumbai, 400091, India
| | - Kirandeep Singh
- Physical and Materials Chemistry Division, National Chemical Laboratory, Pune, 411008, India
| | - Nirmalya Ballav
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune, 411008, India
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Ninawe P, Gupta K, Ballav N. Chemically Integrating a 2D Metal-Organic Framework with 2D Functionalized Graphene. Inorg Chem 2021; 60:19079-19085. [PMID: 34851108 DOI: 10.1021/acs.inorgchem.1c02910] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Two-dimensional metal-organic frameworks (2D MOFs) are the next-generation 2D crystalline solids. Integrating 2D MOFs with conventional 2D materials like graphene is promising for a variety of applications, including energy or gas storage, catalysis, and sensing. However, unraveling the importance of chemical interaction over an additive effect is essential. Here, we present an unconventional chemistry to integrate a Cu-based 2D MOF, Cu-HHTP (HHTP = 2,3,6,7,10,11-hexahydroxytriphenylene), with 2D functionalized graphene, reduced graphene oxide (rGO), by an in situ oxidation-reduction reaction. Combined Raman spectroscopy, electron spin resonance (ESR) spectroscopy, and X-ray photoelectron spectroscopy (XPS) measurements along with structural analysis evidenced the chemical interaction between Cu-HHTP and rGO, which was subsequently assigned to be the key for the manifestation of significantly modified physical properties. Of particular mention is the conversion of an n-type crystalline solid to a p-type crystalline solid upon the chemical integration of Cu-HHTP with rGO, as revealed by Seebeck coefficient. More importantly, the thermoelectric power factor exhibited an increasing trend with increasing temperature, unlike an opposite trend observed due to an additive effect. The results anticipate the ability of a redox reaction to chemically integrate other 2D MOFs with rGO and show how an in situ synthesis can trigger chemical interaction between two distinctive 2D materials.
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Affiliation(s)
- Pranay Ninawe
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune 411008, India
| | - Kriti Gupta
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune 411008, India
| | - Nirmalya Ballav
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune 411008, India
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Influence of Carboxylic Modification Using Polyacrylic Acid on Characteristics of Fe3O4 Nanoparticles with Cluster Structure. Processes (Basel) 2021. [DOI: 10.3390/pr9101795] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Fe3O4 nanoparticles with cluster structure are superparamagnetic particles with applicability in various high-tech fields. In this study, the influence of surface modification with polyacrylic acid (PAA), a polymeric precursor, on the characteristics of Fe3O4 nanoparticles was investigated. The particles were synthesized by the polyol method and surface modified with various amounts of PAA. The surficial, structural, optical, and magnetic properties of the PAA-modified Fe3O4 nanoparticles were analyzed, confirming that negatively charged carboxyl groups were formed on the particle surface, and the particle dispersibility was enhanced by surface modification. This arises from an increase in the electrostatic repulsive force due to the surface functional groups. Functionalization promoted dissociation of the cluster particles, which became more pronounced as the PAA content increased. The optical parameters changed with the PAA content. Analysis of the magnetic properties showed that the saturation magnetization decreased as the PAA content increased. Overall, PAA modification induces structural changes of the Fe3O4 nanoparticles that enhance the dispersibility and influence the characteristics of the particles.
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Gupta K, Dadwal A, Jha PK, Jain A, Yusuf SM, Joy PA, Ballav N. Exploring Magnetic XY Behavior in a Quasi-2D Anisotropic Triangular Lattice of Cu(II) by Functionalized Graphene. Inorg Chem 2020; 59:6214-6219. [PMID: 32302106 DOI: 10.1021/acs.inorgchem.0c00315] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Study on magnetism in two-dimensional (2D) spin-lattices is advancing rapidly. In this work, phase-pure botallackite (Bo) (Cu2(OH)3Br), a quasi-2D S = 1/2 anisotropic triangular spin-lattice is stabilized over 2D reduced graphene oxide (rGO) nanosheets via simple oxidation-reduction reaction chemistry. In comparison to polycrystalline Bo, such an anchoring resulted in the oriented growth of Bo crystallites in the Bo-rGO system. The Bo-rGO nanocomposite was found to be magnetically active with a Néel transition at ∼8.9 K, crossing over to possible XY anisotropy at ∼5 K-as revealed by complementary dc and ac susceptibility measurements-an unprecedented observation in the field assigned to an interfacial effect. This work demonstrates the potential usage of nonmagnetic 2D functionalized graphene to significantly modulate the magnetic properties of 2D spin-lattices.
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Affiliation(s)
- Kriti Gupta
- Department of Chemistry, Indian Institute of Science Education and Research, Pune 411008, India
| | - Arun Dadwal
- Physical and Materials Chemistry Division, National Chemical Laboratory, Pune 411008, India
| | - Plawan Kumar Jha
- Department of Chemistry, Indian Institute of Science Education and Research, Pune 411008, India
| | - Anil Jain
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400085, India.,Homi Bhabha National Institute, Anushakti Nagar, Mumbai 400094, India
| | - S M Yusuf
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400085, India.,Homi Bhabha National Institute, Anushakti Nagar, Mumbai 400094, India
| | - Pattayil A Joy
- Physical and Materials Chemistry Division, National Chemical Laboratory, Pune 411008, India
| | - Nirmalya Ballav
- Department of Chemistry, Indian Institute of Science Education and Research, Pune 411008, India
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