Two different series of manganese(I) tricarbonyl complexes containing phosphine‐based (1–5) and 4′‐substituted 2,2′:6′,2″‐terpyridine‐based ligands (6–10) have been synthesized in order to study their CO‐releasing ability and to investigate their anticancer activity. All the synthesized complexes (1–10) have been fully characterized using standard spectroscopic and analytical techniques. Further 5, 7, and 9 have also been characterized by single‐crystal X‐ray diffraction studies. Although both the sets of ligands are π‐acceptors, they tend to change the Mn—CO bond strength upon complexation, thus affecting the CO release. Photoactivation of 1–5 and 6–10 has been achieved using 365 nm UV irradiation and low intensity visible light, respectively. The MnCO bond strength has been examined using the density functional theory (DFT) and time‐dependent DFT (TD‐DFT) calculations. In order to find the therapeutic viability of the visible light activated complexes, their cytotoxicity has been investigated both in the dark and under irradiation. The MTT (3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyl tetrazolium bromide) assay reveals the potential application of some of the synthesized complexes especially towards the lung cancer cells in the dark condition.

Chemists have long been pursuing the aim of synthesising practically viable low temperature catalysts with high stability, activity and selectivity towards the generation of ammonia under less expensive reaction conditions by using H 2 and N 2 . In this regard, we have used molybdenum bound nitrogen-doped graphene as a catalyst in the present computational investigation. We developed a new concept of the Frustrated Lewis Pair [AH] + [BH] À (FLP-H 2 ), which can be used as a source of hydrogen to functionalise the coordinated dinitrogen into ammonia. Furthermore, the utilisation of FLP-H 2 can prevent the competition in binding of N 2 and H 2 with Mo centre and enable the product formation. Our computed thermodynamic and kinetic barriers clearly reveal that the molybdenum bound nitrogen-doped graphene can be used as a catalyst to activate and functionalise the dinitrogen. In the proposed catalytic cycle, H + and H À can be added in an alternate manner using the FLP-H 2 source to yield NH 3 and NH 2 NH 2 . Some thermodynamically viable penta-coordinated [M] H intermediates have also been identified in the current study. K E Y W O R D SDFT (density functional theory), dinitrogen, FLP (frustrated Lewis pair), molybdenum, nitrogen-doped graphene | INTRODUCTIONChemists are still grappling with the formation of ammonia at low temperature and pressure of 1 atm. Dinitrogen is difficult to activate because of its inert nature. [1][2][3][4][5][6][7][8][9][10][11][12][13] Several investigations have been conducted in recent years to develop a suitable catalyst for the activation and functionalization of dinitrogen. Every year, more than 100 million tonnes of ammonia are used in a variety of applications. The Haber-Bosch process for producing ammonia is commonly utilised, and it involves extreme experimental conditions such as high temperature and high pressure. [14][15][16] On the other hand, the biological conversion of atmospheric dinitrogen to ammonia occurs due to the activity of nitrogenase enzyme at ambient reaction conditions. [17][18][19][20][21][22][23] This study is dedicated to Prof. Dr. Gajapathy Dasaratharam, Muthurangam Government Arts College, Vellore, TN, India, on the occasion of his 75th birthday celebration.

Ammonia is an indispensable component for the development of human society due to its widespread applications and because it is an excellent source of energy. Chemists are looking for a viable catalyst for the activation of N2 molecule to subsequently synthesize ammonia. In this theoretical work, we have used [Co(N2)(RPNP)] (R = tBu, tBuPNP = 2,5‐bis(di‐tert‐butylphosphinomethyl)pyrrolide) complex and ruthenium coordinated by nitrogen‐doped graphene (NDG) as catalysts. To limit the competitive binding of N2 and H2 to the metal centre, we have utilized the concept of Frustrated Lewis Pair [AH]+[BH]− (FLP‐H2), which can act as a co‐catalyst. It can be utilized to functionalize the coordinated N2 into NH3 and hydrazine. According to the calculated thermodynamic and kinetic barriers, we have observed that the [Co(N2)(RPNP)] and ruthenium coordinated by NDG can be used as catalysts to activate N2. The alternative addition of H+ and H− to metal coordinated N2 molecule using the FLP‐H2 source is proposed in the catalytic cycle to generate NH3 and NH2NH2. The current investigation also reveals some thermodynamically feasible hexa‐ and penta‐coordinated metal‐hydride bond formation.

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Synthesis of NH3 and NH2NH2 from dinitrogen using Os‐triamidoamine (1N) and Os‐triamdiophosphine (1P) complexes as catalysts under ambient reaction conditions is investigated. In this current study, we used the FLP‐H2 as a co‐catalyst since it releases H+ and H−, which when added to the dinitrogen complex yields the desired products with realizable energy barriers. The proposed catalytic cycle for this process produces NH3 and N2H4 under viable conditions. A comparison of the computed energies of the structures involved in the catalytic cycle of both the complexes reveals that the [Os{(NHCH2CH2)3P}] catalyst shows better result for ammonia formation than the [Os{(NHCH2CH2)3N}] catalyst. This study paves a new path in the usage of these osmium metal complexes as catalysts for nitrogen reduction reactions (NRRs) in future.