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Sarkar M, Boomishankar R. Mapping the Assembly of Neutral Tetrahedral Cages Tethered by Oximido Linkers and Their Guest Encapsulation Studies. Inorg Chem 2023; 62:1855-1863. [PMID: 35623320 DOI: 10.1021/acs.inorgchem.2c01178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
A primary criterion for the design of polyhedral metal-organic cages is the requirement of geometrically matched pairs of metal ions and ligand moieties. However, understanding the pathway it takes to reach the final polyhedral structure can provide more insights into the self-assembly process and improved design strategies. In this regard, we report two neutral tetrahedral cages with the formulas {[Pd3(NiPr)3PO]4(L1)6} (1-TD) and {[Pd3(NiPr)3PO]4(L2)6} (2-TD) starting from the acetate-bridged cluster {[Pd3(NiPr)3PO]2(OAc)2(OH)}2·2(CH3)2SO (HEXA-Pd) and the respective oxamide precursors (L1H2: [C2(NH2)2O2]) and (L2H2: (C2(NHMe)2O2]). When subtle variations in the reaction conditions were made, two new tetrameric Pd12 assemblies, {[Pd3(NiPr)3PO]4(L1)2(OAc)4(OMe)4} (1-TM) and {[Pd3(NiPr)3PO]4(L2)2(OAc)4(OMe)4} (2-TM), were obtained from the same precursors. Detailed investigations using NMR, mass spectrometry, X-ray crystallography, and computational studies indicate that the macrocyclic complexes 1-TM and 2-TM are the reaction intermediates involved in the formation of the tetrahedral cages 1-TD and 2-TD, respectively. Moreover, the tetrahedral cages 1-TD and 2-TD exhibited intrinsic cavities of volume ∼85 Å3. Guest encapsulation studies revealed that the cage 1-TD can encapsulate a wide range of guest molecules such as CH2Cl2, CHCl3, CCl4, C6H6, and C6H5F. Interestingly, 1-TD was shown to exhibit a preferential binding of C6H5F and C6H6 over other halogenated guest molecules, as determined from NMR titrations and computational studies.
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Affiliation(s)
- Meghamala Sarkar
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune, Dr. Homi Bhabha Road, Pune 411008, India
| | - Ramamoorthy Boomishankar
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune, Dr. Homi Bhabha Road, Pune 411008, India.,Centre for Energy Science, Indian Institute of Science Education and Research (IISER), Pune, Dr. Homi Bhabha Road, Pune 411008, India
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Marolf DM, Johnstone JE, Touchton HA, Nesterov VN, Powell CB, Powell GL. Diosmium carbonyl sawhorse complexes containing a ferrocenedicarboxylato ligand. J COORD CHEM 2022. [DOI: 10.1080/00958972.2022.2145960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
- David M. Marolf
- Department of Chemistry & Biochemistry, Abilene Christian University, Abilene, TX, USA
| | - James E. Johnstone
- Department of Chemistry & Biochemistry, Abilene Christian University, Abilene, TX, USA
| | - Henry A. Touchton
- Department of Chemistry & Biochemistry, Abilene Christian University, Abilene, TX, USA
| | | | - Cynthia B. Powell
- Department of Chemistry & Biochemistry, Abilene Christian University, Abilene, TX, USA
| | - Gregory L. Powell
- Department of Chemistry & Biochemistry, Abilene Christian University, Abilene, TX, USA
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Sarkar M, Rajasekar P, Jose C, Boomishankar R. Polyanionic Imido-P(V) Ligands: From Transition Metal Complexes to Coordination Driven Self-Assemblies. CHEM REC 2021; 22:e202100281. [PMID: 34962082 DOI: 10.1002/tcr.202100281] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 12/03/2021] [Indexed: 11/11/2022]
Abstract
The chemistry of the imido-anions of the main group elements has been studied for more than three decades. The imido (NR)- group is isoelectronic to the oxo (=O) group and can coordinate with metal ions through its lone pairs of electrons. The polyimido-P(V) anions are well explored as they resemble the phosphorus oxo moieties such as H3 PO4 , H2 PO4 - , HPO4 2- and PO4 3- species. These imido anions are typically generated using strong main group organometallic reagents such as n BuLi, Et2 Zn, Me3 Al and n Bu2 Mg, etc. As a result, their coordination chemistry has been restricted to reactions in anhydrous aprotic solvents for a few main group metal ions. This account presents our findings on using certain soft transition metal such Ag(I) and Pd (II) for isolating these imido-P(V) anions as their corresponding self-assembled clusters and cages. Using the various salts of Ag(I) ions in reaction with 2-pyridyl (2 Py) functionalized phosphonium salts and phosphoric triamides, we obtained the mono- and dianionic form of these imido ligands {[P(N2 Py)2 (NH2 Py)2 ]- , [P(N2 Py)2 (NH2 Py)]- , [PO(N2 Py)(NH2 Py)2 ]2- } and derived interesting examples of tri, penta, hepta and octanuclear Ag(I) clusters. Interestingly, by using the salts of Pd (II) ions, the elusive imido-phosphate trianions of the type [(RN)3 PO]3- (R=t Bu, c Hex, i Pr) were generated in a facile one pot reaction as their corresponding tri- and hexanuclear clusters of the type {Pd3 [(NR)3 PO](OAc)3 }n (n=1 or 2). These trianions acts as a cis-coordinated hexadentate ligand for a trinuclear Pd (II) cluster and serve as the polyhedral building units for constructing hitherto unknown family of neutral cages in tetrahedral {Pd3 [(Ni Pr)3 PO]4 (L)6 } and cubic {Pd3 [(Ni Pr)3 PO]8 (L)12 } structures in the presence of suitable linker ligands (L2- ). These cages show interesting host-guest chemistry and post-assembly reactions. Remarkably, by employing chiral tris(imido)phosphate trianions, enantiopure chiral cages of the type [(Pd3 X*)4 (L)6 ], ([X*]3- =RRR- or SSS-[PO(N(*CH(CH3 )Ph)3 ]3- ), were synthesized and used for the chiral-recognition and enantio-separation of small racemic guest molecules. Some of these chiral cages were also shown to exhibit polyradical framework structures. In future, these and other similar types of cages are envisioned as potential molecular vessels for performing the reactions in their confined environment. The enantiomeric cages can be probed for asymmetric catalysis and the separation of a range of small chiral molecules.
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Affiliation(s)
- Meghamala Sarkar
- Department of Chemistry, Indian Institute of Science Education and Research, Pune, Dr. Homi Bhabha Road, Pune, 411008, India
| | - Prabhakaran Rajasekar
- Department of Chemistry, Indian Institute of Science Education and Research, Pune, Dr. Homi Bhabha Road, Pune, 411008, India
| | - Cavya Jose
- Department of Chemistry, Indian Institute of Science Education and Research, Pune, Dr. Homi Bhabha Road, Pune, 411008, India
| | - Ramamoorthy Boomishankar
- Department of Chemistry, Indian Institute of Science Education and Research, Pune, Dr. Homi Bhabha Road, Pune, 411008, India.,Centre for Energy Science, Indian Institute of Science Education and Research, Pune, Dr. Homi Bhabha Road, Pune, 411008, India
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Rajasekar P, Swain A, Rajaraman G, Boomishankar R. Enantiopure Polyradical Tetrahedral Pd 12 L 6 Cages. Chemistry 2021; 27:10012-10015. [PMID: 33978271 DOI: 10.1002/chem.202101239] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Indexed: 11/08/2022]
Abstract
The synthesis of cages with a polyradical framework remains a challenging task. Herein is reported an enantiomeric pair of quinoid-bridged polyradical tetrahedral palladium(II) cages that are stabilized by an unusual dianionic diradical form (dhbq..2- ). These cages have been characterized by electron paramagnetic resonance and UV-visible spectroscopy, squid magnetometry and mass spectrometry. Single-crystal-derived X-ray investigations of the iso-structural cages built on fluoranilate linkers confirm the tetrahedral structure of the obtained radical cages. Theoretical calculations showed that the diradical state of the dhbq anions is more stable than the usual monoradical state. A weak ferromagnetic exchange between adjacent radical centers was observed in DFT studies.
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Affiliation(s)
- Prabhakaran Rajasekar
- Department of Chemistry, Indian Institute of Science Education and Research Pune, Pune, 411008, India
| | - Abinash Swain
- Department of Chemistry, Indian Institute of Technology, Bombay, Mumbai, 400076, India
| | - Gopalan Rajaraman
- Department of Chemistry, Indian Institute of Technology, Bombay, Mumbai, 400076, India
| | - Ramamoorthy Boomishankar
- Department of Chemistry, Indian Institute of Science Education and Research Pune, Pune, 411008, India.,Centre for Energy Science, Indian Institute of Science Education and Research Pune, Dr. Homi Bhabha Road, Pune, 411008, India
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Abstract
Metal-organic polyhedra are a member of metal-organic materials, and are together with metal-organic frameworks utilized as emerging porous platforms for numerous applications in energy- and bio-related sciences. However, metal-organic polyhedra have been significantly underexplored, unlike their metal-organic framework counterparts. In this review, we will cover the topologies and the classification of metal-organic polyhedra and share several suggestions, which might be useful to synthetic chemists regarding the future directions in this rapid-growing field.
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Affiliation(s)
- Soochan Lee
- Department of Chemistry, Ulsan National Institute of Science and Technology, UNIST-gil 50, Ulsan 44919, Republic of Korea.
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Affiliation(s)
- Aeri J. Gosselin
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
| | - Casey A. Rowland
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
| | - Eric D. Bloch
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
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Yadav A, Sarkar M, Subrahmanyam S, Chaudhary A, Hey-Hawkins E, Boomishankar R. Anilate Tethered Neutral Tetrahedral Pd(II) Cages Exhibiting Selective Encapsulation of Xylenes and Mesitylene. Chemistry 2020; 26:4209-4213. [PMID: 31916272 DOI: 10.1002/chem.201905852] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2019] [Indexed: 01/25/2023]
Abstract
The design of porous materials for the recognition of multiple hydrocarbons is highly desirable for the energy-efficient separation and recognition of chemical feedstock. Herein, three new iso-structural porous discrete metal-organic cages of formula {[Pd3 (NiPr)3 PO]4 (R-AN)6 } (R-AN=anilate linkers) for the selective recognition of substituted aromatic hydrocarbons are reported. The tetrahedral cages 1, 2, and 3 containing anilate, chloranilate, and bromanilate linkers exhibited selective encapsulation of mesitylene, o-xylene, and p-xylene, respectively, over other analogous aromatic hydrocarbons. These selective encapsulations were driven by the variations in the portal diameters present at each of these cages and their interactions with the hydrocarbon guests. These observations are supported by mass spectrometry, NMR studies, and theoretical binding-energy calculations.
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Affiliation(s)
- Ashok Yadav
- Department of Chemistry, Indian Institute of Science Education and Research Pune, Dr. Homi Bhabha Road, Pune, 411008, India
| | - Meghamala Sarkar
- Department of Chemistry, Indian Institute of Science Education and Research Pune, Dr. Homi Bhabha Road, Pune, 411008, India
| | - Sappati Subrahmanyam
- Department of Chemistry, Indian Institute of Science Education and Research Pune, Dr. Homi Bhabha Road, Pune, 411008, India
| | - Atul Chaudhary
- Department of Chemistry, Indian Institute of Science Education and Research Pune, Dr. Homi Bhabha Road, Pune, 411008, India
| | - Evamarie Hey-Hawkins
- Institut für Anorganische Chemie, Fakultät für Chemie und Mineralogie, Universität Leipzig, 04103, Leipzig, Germany
| | - Ramamoorthy Boomishankar
- Department of Chemistry, Indian Institute of Science Education and Research Pune, Dr. Homi Bhabha Road, Pune, 411008, India.,Centre of Energy Science, Indian Institute of Science Education and Research Pune, Dr. Homi Bhabha Road, Pune, 411008, India
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Rajasekar P, Pandey S, Paithankar H, Chugh J, Steiner A, Boomishankar R. Imido-P(v) trianion supported enantiopure neutral tetrahedral Pd(ii) cages. Chem Commun (Camb) 2018; 54:1873-1876. [PMID: 29389000 DOI: 10.1039/c8cc00207j] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Charge-neutral chiral hosts are attractive due to their ability to recognize a wide range of guest functionalities and support enantioselective processes. However, reports on such charge-neutral cages are very scarce in the literature. Here, we report an enantiomeric pair of tetrahedral Pd(ii) cages built from chiral tris(imido)phosphate trianions and oxalate linkers, which exhibit enantioselective separation capabilities for epichlorohydrin, β-butyrolactone, and 3-methyl- and 3-ethyl cyclopentanone.
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Affiliation(s)
- Prabhakaran Rajasekar
- Department of Chemistry, Indian Institute of Science Education and Research (IISER) Pune, Dr HomiBhabha Road, Pune - 411008, India.
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Yadav A, Gupta AK, Steiner A, Boomishankar R. Mapping the Assembly of Metal-Organic Cages into Complex Coordination Networks. Chemistry 2017; 23:18296-18302. [PMID: 29076576 DOI: 10.1002/chem.201704585] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Indexed: 11/09/2022]
Abstract
Structural transformations of supramolecular assemblies play an important role in the synthesis of complex metal-organic materials. Nonetheless, often little is known of the assembly pathways that lead to the final product. This work describes the conversion of cubic metal-organic polyhedra to connected-cage networks of varying topologies. The neutral cubic cage assembly of formula {Pd3 [PO(NiPr)3 ]}8 (PZDC)12 has been synthesized from {Pd3 [(NiPr)3 PO](OAc)2 (OH)}2 ⋅2 (CH3 )2 SO and 2,5-pyrazenedicarboxilic acid (PZDC-2H). This 42-component self-assembly is the largest known among the neutral cages with PdII ions. The cage contains twenty-four vacant carboxylate O-sites at the PZDC ligands that are available for further coordination. Post-assembly reactions of the cubic cage with FeII and ZnII ions produced cage-connected networks of dia and qtz topologies, respectively. During these reactions, the discrete cubic cage transforms into a network of tetrahedral cages that are bridged by the 3D metal ions. The robustness of the [Pd3 {[PO(NiPr)3 }]3+ molecular building units made it possible to map the post-assembly reactions in detail, which revealed a variety of intermediate 1D and 2D cage networks. Such step-by-step mapping of the transformation of discrete cages to cage-connected frameworks is unprecedented in the chemistry of coordination driven assemblies.
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Affiliation(s)
- Ashok Yadav
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune Dr. Homi Bhabha Road, Pune, 411008, India
| | - Arvind K Gupta
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune Dr. Homi Bhabha Road, Pune, 411008, India
| | - Alexander Steiner
- Department of Chemistry, University of Liverpool, Crown Street, Liverpool, L69 7ZD, UK
| | - Ramamoorthy Boomishankar
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune Dr. Homi Bhabha Road, Pune, 411008, India.,Centre for Energy Science, Indian Institute of Science Education and Research (IISER), Pune Dr. Homi Bhabha Road, Pune, 411008, India
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Gupta AK, Reddy SAD, Rajasekar P, Prakash P, Boomishankar R. Chloro-Bridged Hexanuclear Pd(II) Clusters Supported by cis
-Blocking Tris(imido)phosphate Trianions. ChemistrySelect 2017. [DOI: 10.1002/slct.201701770] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Arvind K. Gupta
- Department of Chemistry; Indian Institute of Science Education and Research (IISER), Pune; Dr. Homi Bhabha Road Pune - 411008 India
| | - Shada Arun Dixith Reddy
- Department of Chemistry; Indian Institute of Science Education and Research (IISER), Pune; Dr. Homi Bhabha Road Pune - 411008 India
| | - Prabhakaran Rajasekar
- Department of Chemistry; Indian Institute of Science Education and Research (IISER), Pune; Dr. Homi Bhabha Road Pune - 411008 India
| | - Prabhat Prakash
- Department of Chemistry; Indian Institute of Science Education and Research (IISER), Pune; Dr. Homi Bhabha Road Pune - 411008 India
| | - Ramamoorthy Boomishankar
- Department of Chemistry; Indian Institute of Science Education and Research (IISER), Pune; Dr. Homi Bhabha Road Pune - 411008 India
- Centre for Energy Sciences; Indian Institute of Science Education and Research (IISER), Pune; Dr. Homi Bhabha Road Pune - 411008 India
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Boomishankar R, Srivastava AK. Functional metal-organic molecules and materials derived from rigid and flexible P-N scaffolds. PHOSPHORUS SULFUR 2016. [DOI: 10.1080/10426507.2015.1128919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- Ramamoorthy Boomishankar
- Department of Chemistry, Indian Institute of Science Education and Research (IISER) Pune, Pune, India
| | - Anant Kumar Srivastava
- Department of Chemistry, Indian Institute of Science Education and Research (IISER) Pune, Pune, India
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