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An efficient and mild reaction protocol for the decarbonylation of isocyanates has been developed using catalytic amounts of Lewis acidic boranes. The electronic nature (electron withdrawing, electron neutral, and electron donating) and the position of the substituents (ortho/meta/para) bound to isocyanate controls the chain length and composition of the products formed in the reaction. Detailed DFT studies were undertaken to account for the formation of the mono/di‐carboxamidation products and benzoxazolone compounds. [ABSTRACT FROM AUTHOR]

Cocrystallization of the dithiadiazolyl (DTDA) radicals p‐XC6F4CNSSN (X=F, Cl, Br, I, CN) with TEMPO afforded the 2 : 1 cocrystals [p‐XC6F4CNSSN]2[TEMPO] (1–5) whose structures all reflect a common S4⋅⋅⋅O supramolecular motif. The nature of this interaction was probed by DFT calculations (M06/aug‐cc‐pVDZ) on 1 which revealed that the enthalpy of formation of the [C6F5CNSSN]2[TEMPO] supramolecular motif from [C6F5CNSSN]2 and TEMPO is substantial (−54.0 kJ mol−1). Electronic structure calculations revealed a TEMPO‐based doublet S=1/2 configuration as the ground state with limited spin density on the DTDA rings (2.4 %). The corresponding spin quartet state is +78.9 kJ mol−1 higher in energy. An atoms‐in‐molecules analysis reveals four bond critical points (BCPs) between the TEMPO O and the DTDA S atoms as well as additional BCPs between selected DTDA S atoms and methyl H atoms of the TEMPO molecule. Herein, the structures of 2–5 are considered within the context of a hierarchical view of competing and complementary intermolecular interactions; in particular, the established supramolecular CN⋅⋅⋅S−S synthon is sacrificed in order to form the new S4⋅⋅⋅O interaction. [ABSTRACT FROM AUTHOR]

Reactions of 1,10‐phenanthroline (phen) and 2‐(3,4‐dichlorophenyl)acetic acid (dcaH) with Mn(CO3) (M = LiI, NaI and MgII; n = 1 and 2) in MeOH yield the mononuclear lithium complex aqua[2‐(3,4‐dichlorophenyl)acetato‐κO](1,10‐phenanthroline‐κ2N,N′)lithium(I), [Li(C8H5Cl2O2)(C12H8N2)(H2O)] or [Li(dca)(phen)(H2O)] (1), the dinuclear sodium complex di‐μ‐aqua‐bis{[2‐(3,4‐dichlorophenyl)acetato‐κO](1,10‐phenanthroline‐κ2N,N′)sodium(I)}, [Na2(C8H5Cl2O2)2(C12H8N2)2(H2O)2] or [Na2(dca)2(phen)2(H2O)2] (2), and the one‐dimensional chain magnesium complex catena‐poly[[[diaqua(1,10‐phenanthroline‐κ2N,N′)magnesium]‐μ‐2‐(3,4‐dichlorophenyl)acetato‐κ2O:O′] 2‐(3,4‐dichlorophenyl)acetate monohydrate], {[Mg(C8H5Cl2O2)(C12H8N2)(H2O)2](C8H5Cl2O2)·H2O}n or {[Mg(dca)(phen)(H2O)2](dca)·H2O}n (3). In these complexes, phen binds via an N,N′‐chelate pocket, while the deprotonated dca− ligands coordinate either in a monodentate (in 1 and 2) or bidentate (in 3) fashion. The remaining coordination sites around the metal ions are occupied by water molecules in all three complexes. Complex 1 crystallizes in the triclinic space group P with one molecule in the asymmetric unit. The Li+ ion adopts a four‐coordinated distorted seesaw geometry comprising an [N2O2] donor set. Complex 2 crystallizes in the triclinic space group P with half a molecule in the asymmetric unit, in which the Na+ ion adopts a five‐coordinated distorted spherical square‐pyramidal geometry, with an [N2O3] donor set. Complex 3 crystallizes in the orthorhombic space group P212121, with one Mg2+ ion, one phen ligand, two dca− ligands and three water molecules in the asymmetric unit. Both dcaH ligands are deprotonated, however, one dca− anion is not coordinated, whereas the second dca− anion coordinates in a bidentate fashion bridging two Mg2+ ions, resulting in a one‐dimensional chain structure for 3. The Mg2+ ion adopts a distorted octahedral geometry, with an [N2O4] donor set. Complexes 1–3 were evaluated against urease and α‐glucosidase enzymes for their inhibition potential and were found to be inactive. Reactions of 1,10‐phenanthroline (phen) and 2‐(3,4‐dichlorophenyl)acetic acid (dcaH) with Mn(CO3) (M = LiI, NaI and MgII; n = 1 and 2) in MeOH yield the mononuclear lithium complex, the dinuclear sodium complex and the one‐dimensional chain magnesium complex. In these complexes, phen binds via an N,N′‐chelate pocket, while the deprotonated dca− ligands coordinate either in a monodentate or bidentate fashion. [ABSTRACT FROM AUTHOR]

Formation of radical–radical cocrystals is an important step towards the design of organic ferrimagnets. We describe a simple approach to generate radical–radical cocrystals through the identification and implementation of well‐defined supramolecular synthons which favor cocrystallization over phase separation. In the current paper we implement the structure‐directing interactions of the E−E bond (E=S, Se) of dithiadiazolyl (DTDA) and diselenadiazolyl (DSDA) radicals to form close contacts to electronegative groups. This is exemplified through the preparation and structural characterization of three sets of radical cocrystals; the 2:2 cocrystal [PhCNSSN]2[MBDTA]2 (4) [MBDTA=methyl benzodithiazolyl] and the 2:1 cocrystals [C6F5CNEEN]2[TEMPO] (E=S, 5; E=Se, 6). In 4 the two types of radical are linked via bifurcated inter‐dimer δ+S⋅⋅⋅Nδ− interactions whereas 5 and 6 exhibit a set of five‐centre δ+E⋅⋅⋅Oδ− contacts (E=S, Se). SOMO wrestling: Cocrystallization of radicals requires different open‐shell molecules to interact with each other rather than themselves. This process can be driven by careful selection of favorable electrostatic interactions between molecules. [ABSTRACT FROM AUTHOR]

We show that the αi and βj parameters developed by Hunter to describe the hydrogen‐bond donor and acceptor properties of particular functional groups can be successfully applied to understand favourable intermolecular interactions between molecules containing heavier p‐block elements, notwithstanding the increasing dispersion terms associated with these elements. Although dispersion is an important contribution to the dimerisation enthalpy of dithiadiazolyls, we show that many aspects of the crystal packing of dimers can successfully be interpreted through such an electrostatic analysis. This approach is exemplified through analysis of the crystal structures of a series of fluoro‐ and trifluoromethyl‐substituted 1,2,3,5‐dithiadiazolyl radicals. Comparison of fluoro‐ and trifluoromethyl‐substituted aryl dithiadiazolyls reveals that the trifluoromethyl group has a pronounced electron‐withdrawing effect, enhancing the electrostatic contribution, but also adding steric bulk. The possible intermolecular interactions between these molecules are close in energy, resulting in structural diversity and at least one case of polymorphism. Despite neglecting the significant favourable dimerisation enthalpy in the analysis of the electrostatic potential, this approach provides a very clear rationalisation of many aspects of the observed crystal structures.|||||| [ABSTRACT FROM AUTHOR]

A new tetrathiafulvalene (TTF) donor covalently appended with a 1,5-diisopropylverdazyl radical through a cross-conjugated pyridyl linker ( 3) has been prepared and characterised. Reaction of 3 with tetracyanoquinonedimethane (TCNQ) afforded the 2:1 charge-transfer complex ( 3)2 ⋅TCNQ ( 4), in which the IR and structural data are consistent with 0.25 e− charge transfer from the TTF donor (D) to the TCNQ acceptor (A). The TTF and TCNQ molecules adopt a mixed-stack D⋅⋅⋅D⋅⋅⋅A arrangement that does not facilitate conduction. A solution EPR spectrum of 4 comprises a broad featureless singlet, which is consistent with the presence of a TCNQ radical anion. Theoretical studies were performed to probe the exchange interactions within selected fragments of 4 with and without charge transfer. In the absence of charge transfer, DFT calculations reveal weak antiferromagnetic exchange between verdazyl radicals within the ( 3)2 monoradical unit. However, partial oxidation of the dimer ( 3)2 to the diradical cation leads to an S= [ABSTRACT FROM AUTHOR]

1,3,7,8-Tetraphenyl-4,8-dihydro-1 H-imidazolo[4,5 g][1,2,4]benzotriazin-4-yl ( 5), 8-(4-bromophenyl)-1,3,7-triphenyl-4,8-dihydro-1 H-imidazolo[4,5 g][1,2,4]benzotriazin-4-yl ( 6), and 8-(4-methoxyphenyl)-1,3,7-triphenyl-4,8-dihydro-1 H-imidazolo[4,5 g][1,2,4]benzotriazin-4-yl ( 7) were characterized by using X-ray diffraction crystallography, variable-temperature magnetic susceptibility studies, and DFT calculations. Radicals 5- 7 pack in 1 D π stacks made of radical pairs with alternate short and long interplanar distances. The magnetic susceptibility ( χ vs. T) of radicals 5 and 6 exhibit broad maxima at (50±2) and (50±4) K, respectively, and are interpreted in terms of an alternating antiferromagnetic Heisenberg linear chain model with average exchange-interaction values of J=−31.3 and −35.4 cm−1 ( gsolid=2.0030 and 2.0028) and an alternation parameter a=0.15 and 0.38 for 5 and 6, respectively. However, radical 7 forms 1 D columns of radical pairs with alternating distances; one of the interplanar distances is significantly longer than the other, which decreases the magnetic dimensionality and leads to discrete dimers with a ferromagnetic exchange interaction between the radicals (2 J=23.6 cm−1, 2 zJ′=−2.8 cm−1, gsolid=2.0028). Magnetic exchange-coupling interactions in 1,2,4-benzotriazinyl radicals are sensitive to the degree of slippage and inter-radical separation, and such subtle changes in structure alter the fine balance between ferro- and antiferromagnetic interactions. [ABSTRACT FROM AUTHOR]

Attempts to coordinate neutral ligands to low oxidation state indium centers are often hindered by disproportionation pathways that produce elemental indium and higher oxidation state species. In contrast, we find that reactions of the salt, InOTf (OTf=trifluoromethanesulfonate), with α-diimine ligands yielded intensely colored compounds with no evidence of decomposition. X-ray structural analysis of InOTf ⋅MesDABMe (MesDABMe= N, N-dimesityl-2,3-dimethyl-diazabutadiene; 1) reveals a discrete molecular compound with a pyramidal coordination environment at the indium center, consistent with the presence of a stereochemically active lone pair of electrons on indium and a neutral diazabutadiene chelate ligand. The use of the less-electron-rich MesDABH ligand (MesDABH= N, N-dimesityl-diazabutadiene) engenders dramatically different reactivity and produces a metallopolymer (InOTf ⋅MesDABH)∞ ( 2) linked via CC and InIn bonds. The difference in reactivity is rationalized by cyclic voltammetry and DFT studies that suggest more facile electron transfer from InI to the MesDABH and bis(aryl)acenaphthenequinonediimine (BIAN) ligands. Solution EPR spectroscopy indicates the presence of non-interacting ligand-based radicals in solution, whereas solid-state EPR studies reflect the presence of a thermally accessible spin triplet consistent with reversible CC bond cleavage. [ABSTRACT FROM AUTHOR]

7-(4-Fluorophenyl) and 7-phenyl-substituted 1,3-diphenyl-1,4-dihydro-1,2,4-benzotriazin-4-yl radicals were characterized by X-ray diffraction analysis and variable-temperature magnetic susceptibility studies. The radicals pack in 1D π stacks of equally spaced slipped radicals with interplanar distances of 3.59 and 3.67 Å and longitudinal angles of 40.97 and 43.47°, respectively. Magnetic-susceptibility studies showed that both radicals exhibit antiferromagnetic interactions. Fitting the magnetic data revealed that the behavior is consistent with 1D regular linear antiferromagnetic chain with J=−12.9 cm−1, zJ′=−0.4 cm−1, g=2.0069 and J=−11.8 cm−1, zJ′=−6.5 cm−1, g=2.0071, respectively. Magnetic-exchange interactions in benzotriazinyl radicals are sensitive to the degree of slippage, and inter-radical separation and subtle changes in structure alter the fine balance between ferro- and antiferromagnetic interactions. [ABSTRACT FROM AUTHOR]

The structure of the canted antiferromagnet β- p-NCC6F4CNSSN ( 1) was determined from synchrotron powder-diffraction studies in the pressure range 0-21.6 kbar. Radical 1 crystallizes in the orthorhombic space group Fdd2, but undergoes an asymmetric contraction of the unit-cell size with increasing pressure. At the molecular level, this contraction of the unit cell is simultaneously accommodated by: 1) an increase in twist angle between aryl and heterocyclic rings; and 2) a shortening of the intermolecular S ⋅⋅⋅N contacts, which propagate the magnetic-exchange pathway. DFT calculations based on the structures in this pressure range revealed an increase in the magnetic-exchange interaction ( J) with increasing pressure, and an excellent correlation was observed between J and the magnetic-ordering temperature, which increased from 36 K at ambient pressure up to 70 K at 16 kbar. [ABSTRACT FROM AUTHOR]

X-ray studies show that 1,3-diphenyl-7-(thien-2-yl)-1,4-dihydro-1,2,4-benzotriazin-4-yl ( 6) adopts a distorted, slipped π-stacked structure of centrosymmetric dimers with alternate short and long interplanar distances (3.48 and 3.52 Å). Cyclic voltammograms of 7-(thien-2-yl)benzotriazin-4-yl 6 show two fully reversible waves that correspond to the −1/0 and 0/+1 processes. EPR and DFT studies on radical 6 indicate that the spin density is mainly delocalized over the triazinyl fragment. Magnetic susceptibility measurements show that radical 6 obeys Curie-Weiss behavior in the 5-300 K region with C=0.378 emu K mol−1 and θ=+4.72 K, which is consistent with ferromagnetic interactions between S=1/2 radicals. Fitting the magnetic susceptibility revealed the behavior is consistent with an alternating ferromagnetic chain ( g=2.0071, J1=+7.12 cm−1, J2=+1.28 cm−1). [ABSTRACT FROM AUTHOR]

SOMO Wrestling Molecules of C6F5CNSSN and TEMPO radicals tangle on the Dohyō. In their Communication on page 1371, J. M. Rawson and co‐workers implement favorable electrostatic contacts to drive cocrystal formation between different radicals. The concept is exemplified through the preparation and structural characterization of three sets of radical cocrystals: the 2:2 cocrystal [PhCNSSN]2[MBDTA]2 and the 2:1 cocrystals [C6F5CNEEN]2[TEMPO] (E=S, Se). [ABSTRACT FROM AUTHOR]

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The cover picture shows a 2:1 charge transfer complex formed from a tetrathiafulvalene (TTF)–pyridylverdazyldiradical cation and tetracyanoquinonedimethane (TCNQ) which crystallizes in a mixed‐stack arrangement. These building blocks show promise for the development of spintronic devices where the spin of the electrons as well as their charge can be used to process information. More details can be found in the Full Paper by Melanie Pilkington et al. on page 1624 in Issue 11, 2015 (DOI: 10.1002/cplu.201500309). [ABSTRACT FROM AUTHOR]