The use of molecular spin state as a quantum of information for storage, sensing and computing has generated considerable interest in the context of next-generation data storage and communication devices 1, 2 , opening avenues for developing multifunctional molecular spintronics 3 . Such ideas have been researched extensively, using singlemolecule magnets 4, 5 and molecules with a metal ion 6 or nitrogen vacancy 7 as localized spin-carrying centres for storage and for realizing logic operations 8 . However, the electronic coupling between the spin centres of these molecules is rather weak, which makes construction of quantum memory registers a challenging task 9 . In this regard, delocalized carbon-based radical species with unpaired spin, such as phenalenyl 10 , have shown promise. These phenalenyl moieties, which can be regarded as graphene fragments, are formed by the fusion of three benzene rings and belong to the class of open-shell systems. The spin structure of these molecules responds to external stimuli 11, 12 (such as light, and electric and magnetic fields), which provides novel schemes for performing spin memory and logic operations. Here we construct a molecular device using such molecules as templates to engineer interfacial spin transfer resulting from hybridization and magnetic exchange interaction with the surface of a ferromagnet; the device shows an unexpected interfacial magnetoresistance of more than 20 per cent near room temperature. Moreover, we successfully demonstrate the formation of a nanoscale magnetic molecule with a well-defined magnetic hysteresis on ferromagnetic surfaces. Owing to strong magnetic coupling with the ferromagnet, such independent switching of an adsorbed magnetic molecule has been unsuccessful with single-molecule magnets 13 . Our findings suggest the use of chemically amenable phenalenyl-based molecules as a viable and scalable platform for building molecular-scale quantum spin memory and processors for technological development.The diversity and flexibility of molecular synthesis has given researchers ample freedom to design functional molecules for spintronics. These include molecular magnets 14 , spinfilter molecules 15 , spin-crossover molecules 16 , molecular batteries 17 , molecular conductors 10 , molecular switches 12 , and spacer layers for organic spin valves 18 and magnetic tunnel junctions 19,20 . Using such synthetic techniques, we have designed a neutral planar phenalenyl-based molecule, zinc methyl phenalenyl (ZMP, C 14 H 10 O 2 Zn; see Fig. 1a and Methods), that has no net spin. When these molecules are grown on a ferromagnetic surface, interface spin transfer causes a hybridized organometallic supramolecular magnetic layer to develop, which shows a large magnetic anisotropy and spin-filter properties 21 . This interface layer creates a spin-dependent resistance and gives rise to an interface magnetoresistance (IMR) effect.

The catalytic dehydrogenative coupling of alcohols and amines to form aldimines represents an environmentally benign methodology in organic chemistry. This has been accomplished in recent years mainly with precious-metal-based catalysts. We present the dehydrogenative coupling of alcohols and amines to form imines and H2 that is catalyzed, for the first time, by a complex of the earth-abundant Mn. Detailed mechanistic study was carried out with the aid of NMR spectroscopy, intermediate isolation, and X-ray analysis.

Homogeneous catalysis of organic transformations by metal complexes has been mostly based on complexes of noble metals. In recent years, tremendous progress has been made in the field of base-metal catalysis, mostly with pincer-type complexes, such as iron, cobalt, nickel, and manganese pincer systems. Particularly impressive is the explosive growth in the catalysis by Mn-based pincer complexes, the first such complexes being reported as recently as 2016. This review covers recent progress in the field of homogeneously catalyzed reactions using pincer-type complexes of cobalt and manganese. Various reactions are described, including acceptorless dehydrogenation, hydrogenation, dehydrogenative coupling, hydrogen borrowing, hydrogen transfer, H–X additions, C–C coupling, alkene polymerization and N2 fixation, including their scope and brief mechanistic comments.

The catalytic hydrogenation of nitriles to primary amines represents an atom-efficient and environmentally benign reduction methodology in organic chemistry. This has been accomplished in recent years mainly with precious-metal-based catalysts, with a single exception. Here we report the first homogeneous Co-catalyzed hydrogenation of nitriles to primary amines. Several (hetero)aromatic, benzylic, and aliphatic nitriles undergo hydrogenation to the corresponding primary amines in good to excellent yields under the reaction conditions.

The odd alternant hydrocarbon phenalenyl (PLY) can exist in three different forms, a closed-shell cation, an open-shell radical, and a closed-shell anion, using its nonbonding molecular orbital (NBMO). The chemistry of PLY-based molecules began more than five decades ago, and so far, the progress has mainly involved the open-shell neutral radical state. Over the last two decades, we have witnessed the evolution of a range of PLY-based radicals generating an array of multifunctional materials. However, it has been admitted that the practical applications of PLY radicals are greatly challenged by the low stability of the open-shell (radical) state. Recently, we took a different route to establish the utility of these PLY molecules using the closed-shell cationic state. In such a design, the closed-shell unit of PLY can readily accept free electrons, stabilizing in its NBMO upon generation of the open-shell state of the molecule. Thus, one can synthetically avoid the unstable open-shell state but still take advantage of this state by in situ generating the radical through external electron transfer or spin injection into the empty NBMO. It is worth noting that such approaches using closed-shell phenalenyl have been missing in the literature. This Account focuses on our recent developments using the closed-shell cationic state of the PLY molecule and its application in broad multidisciplinary areas spanning from catalysis to spin electronics. We describe how this concept has been utilized to develop a variety of homogeneous catalysts. For example, this concept was used in designing an iron(III) PLY-based electrocatalyst for a single-compartment HO fuel cell, which delivered the best electrocatalytic activity among previously reported iron complexes, organometallic catalysts for various homogeneous organic transformations (hydroamination and polymerization), an organic Lewis acid catalyst for the ring opening of epoxides, and transition-metal-free C-H functionalization catalysts. Moreover, this concept of using the empty NBMO present in the closed-shell cationic state of the PLY moiety to capture electron(s) was further extended to an entirely different area of spin electronics to design a PLY-based spin-memory device, which worked by a spin-filtration mechanism using an organozinc compound based on a PLY backbone deposited over a ferromagnetic substrate. In this Account, we summarize our recent efforts to understand how this unexplored closed-shell state of the phenalenyl molecule, which has been known for over five decades, can be utilized in devising an array of materials that not only are important from an organometallic chemistry or organic chemistry point of view but also provide new understanding for device physics.