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Using periodic DFT calculations, we have established the mechanism of the unusual cooperative adsorption of CO gas in an Fe-bistriazolate MOF observed previously. The binding of one CO molecule to FeII triggers structural alteration of the neighbouring Fe centres, reducing the steric energy penalty and aiding cooperative adsorption. This is similar to the entatic state concept proposed for metalloenzymes, and offers novel strategies for selective gas adsorption. [ABSTRACT FROM AUTHOR]

Historically in India as elsewhere in the world, there has been a deep-rooted cultural antipathy to persons with disabilities, wherein they have been portrayed as medical anomalies, helpless victims and a lifelong burden for family and society. In recent years, research surrounding the intersection of disability, sexuality and gender and its importance in the lives of those who are in the centre of it has been gaining recognition. Representation of persons with disability in disability scholarships would provide an opportunity to view the world through their lens. Life narratives in this case, have the potential of bringing forth the 'personal', which helps in understanding a community objectively and empathetically, which is essential for synchronous functioning in a diverse society. The primary material for this paper includes the narratives and first-hand accounts of persons with disability in India in an edited book titled Skin Stories (2019) wherein the disabled individual is the subject of enquiry. These narratives shed light on a different discourse of sexuality for the disabled individual. We find an active desiring sexual subject in these narratives, in contrast to the passive and objectified view of disabled lives. The methodology for this study-discourse analysis through a critical theoretical framework - would enable an in-depth understanding of the sociocultural, historical, and political context of these narratives. Through my study, I have tried to explore the intersection of disability, gender and sexuality in the lives of persons with disability in India. and shed light on the diminished social, economic, political, cultural and interpersonal rights of the people from the disabled community, and enable one to think critically not only about disability but also other historical marginalized groups. [ABSTRACT FROM AUTHOR]

The coordinatively unsaturated chromium(II)‐based Cr3[(Cr4Cl)3(BTT)8]2 (Cr−BTT; BTT3−=1,3,5‐benzenetristetrazolate) metal–organic framework (MOF) has been shown to exhibit exceptional selectivity towards adsorption of O2 over N2/H2. Using periodic density functional theory (DFT) calculations, we attempted to decipher the origin of this puzzling selectivity. By computing and analyzing the magnetic exchange coupling, binding energies, the partial density of states (pDOS), and adsorption isotherms for the pristine and gas‐bound MOFs [(Cr4(X)4Cl)3(BTT)8]3− (X=O2, N2, and H2), we unequivocally established the role of spin states and spin coupling in controlling the gas selectivity. The computed geometries and gas adsorption isotherms are consistent with the earlier experiments. The binding of O2 to the MOF follows an electron‐transfer mechanism resulting in a CrIII superoxo species (O2.−) with a very strong antiferromagnetic coupling between the two centers, whereas N2/H2 are found to weakly interact with the metal center and hence only slightly perturb the associated coupling constants. Although the gas‐bound and unbound MOFs have an S=0 ground state (GS), the nature of spin the configurations and the associated magnetic exchanges are dramatically different. The binding energy and the number of oxygen molecules that can favorably bind to the Cr center were found to vary with respect to the spin state, with a significant energy margin (47.6 kJ mol−1). This study offers a hitherto unknown strategy of using spin state/spin couplings to control gas adsorption selectivity in MOFs. [ABSTRACT FROM AUTHOR]

The reaction of MnCl2·4H2O, H8L (2,2′-bis-p-tBu-calix[4]arene) and NEt3 in a dmf/MeOH solvent mixture results in the formation of a mixed valent decametallic cluster of formula [Mn II6 Mn III4 (L)2(μ3-OH)4(μ-OH)4(MeOH)4(dmf)4(MeCN)2]·MeCN (3). Complex 3 crystallises in the monoclinic space group P21/n with the asymmetric unit comprising half of the compound. Structure solution reveals that the bis-calix[4]arene ligands are arranged such that one TBC[4] moiety in each has undergone inversion in order to accommodate a [Mn III4 Mn II6 ] metallic skeleton that describes three vertex-sharing [Mn III2 Mn II2 ] butterflies. The structure is closely related to the species [Mn III6 Mn II4 (L)2(μ3-O)2(μ3-OH)2(μ-OMe)4(H2O)4(dmf)8]·4dmf (4), the major difference being the oxidation level of the Mn ions in the core of the compound. DFT calculations on the full structures reveal that replacing the MnIII ions in 4 for MnII ions in 3 results in a significant decrease in the magnitude of some antiferromagnetic exchange contributions, a switch from ferromagnetic to antiferromagnetic in others, and the loss of significant spin frustration. [ABSTRACT FROM AUTHOR]

Invited for the cover of this issue are Sourav Pal, Gopalan Rajaraman and co-workers at the Indian Institute of Technology Bombay, the Bhabha Atomic Research Centre and the Indian Institute of Science Education and Research. The image depicts how a mixture of atmospheric gases such as CO 2 , H 2 , N 2 and O 2 can be selectively separated using a Cr metal-organic framework where spin state and spin coupling play a crucial role. Read the full text of the article at 10.1002/chem.202104526., (© 2022 Wiley-VCH GmbH.)

The reaction of MnCl 2 ·4H 2 O, H 8 L (2,2'-bis- p - t Bu-calix[4]arene) and NEt 3 in a dmf/MeOH solvent mixture results in the formation of a mixed valent decametallic cluster of formula [MnII6MnIII4(L) 2 (μ 3 -OH) 4 (μ-OH) 4 (MeOH) 4 (dmf) 4 (MeCN) 2 ]·MeCN (3). Complex 3 crystallises in the monoclinic space group P 2 1 / n with the asymmetric unit comprising half of the compound. Structure solution reveals that the bis-calix[4]arene ligands are arranged such that one TBC[4] moiety in each has undergone inversion in order to accommodate a [MnIII4MnII6] metallic skeleton that describes three vertex-sharing [MnIII2MnII2] butterflies. The structure is closely related to the species [MnIII6MnII4(L) 2 (μ 3 -O) 2 (μ 3 -OH) 2 (μ-OMe) 4 (H 2 O) 4 (dmf) 8 ]·4dmf (4), the major difference being the oxidation level of the Mn ions in the core of the compound. DFT calculations on the full structures reveal that replacing the Mn III ions in 4 for Mn II ions in 3 results in a significant decrease in the magnitude of some antiferromagnetic exchange contributions, a switch from ferromagnetic to antiferromagnetic in others, and the loss of significant spin frustration.

Ab initio calculations performed in two three-coordinate complexes [Mn{N(SiMe 3 ) 2 } 3 ] ( 1 ) and [K(18-crown-6) (Et 2 O) 2 ][Cr{N(SiMe 3 ) 2 } 3 ] ( 2 ) reveal record-high magnetic anisotropy with the D values -64 and -15 cm -1 , respectively, enlisting d 4 ions back in the race for single-ion magnets. A detailed spin-vibrational analysis performed of 1 and 2 suggests dominance under barrier relaxation due to the flexible coordination spheres around the metal ion. Furthermore, several in silico models were constructed by varying the nature of donor atoms based on the X-ray structure of 1 and 2 , unveiling much larger anisotropy and robust single-ion magnet (SIM) characteristics for some of the models offering design clues for low-coordinate transition-metal SIMs.

Among various applications that are proposed for {3d-4f} clusters, magnetic refrigeration based on the principle of the magnetocaloric effect (MCE) is gaining attention in recent years due to the substantially large MCE values reported for these types of molecules. While various factors play a role in controlling the MCE values, understanding the structural parameters that control the magnetic exchange play a vital role in the development of novel molecules possessing attractive MCE characteristics. In this regard, theoretical tools based on density functional methods are indispensable. In this work, we have employed density functional methods to study the magnetic properties of six {Mn III Gd III } clusters. This comprises a trinuclear complex {Mn III 2 Gd III }, [Mn 2 GdO(Piv) 2 (dmem) 2 (NO 3 ) 3 ] (dmem = 2-{[2-(dimethylamino)ethyl]methylamino}ethanol) ( 1 ), along with four tetranuclear {Mn III 2 Gd III 2 } complexes, [Mn 2 Gd 2 O 2 (Piv) 8 (HO 2 CCMe 3 ) 2 (MeOH) 2 ] (Piv = 2,2-dimethylpropanoic acid) ( 2 ), [Mn 2 Gd 2 O 2 (Piv) 8 (HO 2 CCMe 3 ) 4 ] ( 3 ), [Mn 2 Gd 2 (OH) 2 (O 2 CPh) 4 (NO 3 ) 2 (teaH) 2 ] (tea = triethanolamine) ( 4 ), and [Mn 2 Gd 2 (O)(Piv) 2 (hep) 4 (NO 3 ) 4 ] (hep = 2-(2-hydroxyethyl)pyridine) ( 5 ), and a single-chain compound containing the {Mn III 2 Gd III 2 } core, [Mn 2 Ln 2 (OH)(OMe)(hmp) 4 (NO 3 ) 4 (O 3 SC 6 H 4 CH 3 ) 2 ] n (hmp = 2-hydroxymethylpyridine) ( 6 ). Here we have evaluated the exchange interactions between Mn III and Gd III ions and Mn III ···Mn III ions in trinuclear as well as tetranuclear complexes. Our DFT-computed exchange interaction ( J ) values reproduce the experimental susceptibility data well, offering confidence in the estimated J values. Our calculations yield a diverse set of J values among these complexes ranging from weak ferromagnetic to moderate antiferromagnetic {Mn III ···Gd III } coupling. Using orbital overlap and NBO analysis, we have explored the mechanism of magnetic coupling and deciphered the origin of diverse J values noted among these complexes. Particularly, the importance of Jahn-Teller axes of the Mn III ions and its orientation with respect to the nature of coupling is established using the qualitative mechanism derived. The {Mn III ···Mn III } coupling in all complexes are estimated to be antiferromagnetic, and the consequence of this on the {Mn III ···Gd III } J values and how this influences the ground-state S values are discussed in detail. Further, we have developed magneto-structural correlations to evaluate the importance of structural parameters that control the {Mn III ···Gd III } coupling. Our results reveal that Mn-O-Gd bond angles and Mn-O-Gd-O dihedral angles hold the key to the sign and magnitude of the {Mn III ···Gd III } J values. Further on, utilizing the computed J values, we have estimated the MCE values for these complexes and offer insight into how these two factors are correlated. To this end, our study reveals that the incorporation of anisotropic Mn III ions in the cluster aggregation could lead to respectable MCE values if a suitable ligand design that offers a way to control the direction of the Jahn-Teller axes of Mn III ions is presented.