Main Group Metal Complexes as Molecular Materials

Abhishek Mishra and Ramesh K. Metre

Research Snippets

Nanomaterials have overpowered the electronic and advanced material industry in past few decades because of their uncountable properties originating from the smaller size and low band gap.1 More recently, coordination complexes of transition and lanthanide metal ions were explored as molecular materials in electronic devices.2,3 These organometallic molecular complexes are considered as potential candidates for electronic and electrical devices in recent time due to their discrete size, controllable design, and ease of handling. Literature shows numerous example of organometallic complexes successfully used as molecular materials in various devices such as OLEDs (organic light emitting devices)4, molecular switches5, molecular wires6, memristive devices7, dye sensitized solar cells8, etc.

However, intriguing research is still underway for developing new strategies and molecular architectures for these advanced functional molecular materials. Organometallic complexes of main group metals have, with their recently reported properties, been considered as promising molecular materials. Main group organometallic complexes have proven their suitability for being molecular materials in terms of their solution processable synthesis, versatile design, solubility, flexibility, stability, and ease of processing etc. Recent literature reports on “the rearrangement of NHC to abnormal NHC by an organotin sulphide cation9, a photon up-conversion of IR light into a broad white light spectrum using [(RdelocSn)4S6] (Rdeloc = 4–(CH2=CH)–C6H4)10, an interesting Zn metal trapping phenomenon by functionalizing the organotin sulfide cage11, and a molecular precursor based on Zn/Sn/S ternary complex for CZTS (Cu2ZnSnS4) i.e., a potential material for thin film solar cells12”, provides further evidence of their wide range of interesting properties.

Recently, we have reported a tetranuclear monoorganotin sulfide cage [(RSnIV)4(μ-S)6]·2CHCl3·4H2O (1) (R = 2-phenylazophenyl) exploiting the intramolecular N→Sn coordination. The complex 1 is further explored as active material for the fabrication of solution-processable resistive memory switching device. The current-voltage (I-V) characteristics of the device showed an excellent memory behaviour with low write voltage i.e., -1.4 V. The device also displayed a good ON/OFF ratio of 103 with retention time of 10000s. The complex 1 is the first organotin complex to exhibit the memristive behaviour.13 On the other hand, we reported another hydroxido-bridged dinuclear monoorganostannoxane [(RSnIV)2(μ-OH)(μ-OMe)Cl4]·CH3OH (R = 2-phenylazophenyl) (2) which was explored as active material for NDR (negative differential resistance) device. The I−V characteristic studies performed on the device made using 2 found to exhibit excellent NDR behavior in the region of 1.5−2.5 V.14

Ramesh K. Metre


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11. Geringer, E.; Leusmann, E.; Tambornino, F.; Gerhard, M.; Koch, M.; Dehnen, S. Chem. Commun. 2020, 56, 4769-4772.
12. Fuhrmann, D.; Dietrich, S.; Krautscheid, H. Inorg. Chem. 2017, 56, 13123–13131.
13. Mishra, A.; Betal, A.; Pal, N.; Kumar, R.; Lama, P.; Sahu, S.; Metre, R. K. ACS Appl. Electron. Mater. 2020, 2, 220−229
14. Mishra, A.; Betal, A.; Kumar, R.; Lama, P.; Sahu, S.; Metre, R. K. ACS Appl. Electron. Mater. 2021, 3, 203−210

About the Authors

Abhishek Mishra,
PhD Student,
Department of Chemistry

Dr. Ramesh K. Metre,
Assistant Professor,
Department of Chemistry