Search

Inclusion of the dithiadiazolyl and diselenadiazolyl radicals PhCNEEN (E = S, Se) into the porous framework, Al(bdc)(OH) [MIL-53(Al); bdc = 1,4-benzenedicarboxylate] was achieved by vacuum sublimation. PXRD studies reveal the inclusion complexes adopt the orthorhombic space group Imma. Variable temperature PXRD studies coupled with thermal analysis reveal that for PhCNSSN@MIL-53(Al), radical elimination from the pores at elevated temperatures is accompanied by an opening of the pore channels. Radicals can also be extracted from the framework using an appropriate solvent. Oxidation of the radical guest within the host framework has been achieved with Cl2 or Br2 and led to complete radical oxidation (based on EPR studies) whereas the milder oxidant I2 leads to incomplete oxidation. [ABSTRACT FROM AUTHOR]

Reaction of the methyl-benzodithiazolyl radical (MBDTA) with M(hfac)2 complexes (M = Mn, Co, Zn) affords the complexes M(hfac)2(MBDTA)2. Strong antiferromagnetic exchange interactions are observed between M(II) ions and the two S = 1/2 radicals (M = Mn, Co), whereas weak antiferromagnetic interactions are observed between radicals when using the diamagnetic Zn(II) ion. Strong intermolecular exchange coupling is also evident in Mn(hfac)2(MBDTA)2 and attributed to π*–π* contacts between MBDTA radicals which are absent for the Co and Zn derivatives. [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]

Reaction of benzo-1,2,3-dithiazolyl, 1 , with Pt(PPh 3 ) 4 has been shown to produce the aminothiolate complex (amt)Pt(PPh 3 ) 2 [amt = HNC 6 H 4 S], via oxidative addition of 1 to Pt(PPh 3 ) 2 followed by S-abstraction by PPh 3 . Semi-empirical calculations (AM1 and EHT) have been used to probe the oxidative addition step of this reaction. These studies clearly reveal that close approach of 1 to Pt(PR 3 ) 2 induces electron transfer from Pt(PR 3 ) 2 to 1 with concomitant ring opening at the S--N bond and coordination to the metal centre. The SOMO of this complex retains the π* character of the dithiazolyl ring. [ABSTRACT FROM AUTHOR]

The 2c-2e- P-P bonded dimers [(CH)2(NR)2P]2 dissociate in solution to give the persistent new 7p radicals [(CH)2(NR)2P]·, which are isoelectronic with the well known S/N thiazolyl radicals. [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]

Focuses on small molecule fixation by CF3C6H3FCNSSN sulfur-nitrogen radical. Influence of sublimation under oxygen on the development of dithiatetrazocine.

1-Phenyl-3-trifluoromethyl-l,4-dihydrobenzo[e][1,2,4]triazin-4-yl is the first example of a hydrazyl radical that shows a reversible sharp spin transition fully completed within 5(1) K. The nominally first-order transition takes place at ca. 58(2) K and proceeds via subtle changes of intra- and interstack interactions between two similar structural phases. The low-temperature phase (5—60 K) is diamagnetic and has a singlet ground state (2Jexp= -166.8 cm-1, gsolid = 2.0042, ρ = 0.2%) stemming from a multicenter two-electron interaction. The high-temperature phase (60—300 K) is paramagnetic as a result of noninteracting S = 1/2 spins arising from weakly bound dimers. [ABSTRACT FROM AUTHOR]

Abstract: Dithiazolyl radicals with π-stacking motifs have attracted particular interest because of their ability to exhibit spin-switching between diamagnetic distorted π-stacks and paramagnetic regular π-stacked structures through a solid state phase transition. Previous studies indicate that inclusion of electronegative heteroatoms into the backbone favours lamellar structures. This methodology has been extended to the synthesis and characterisation of the title compound, 4′-cyanobenzo-1,3,2-dithiazolyl (4-NCBDTA). Its electronic structure is probed through DFT calculations, cyclic voltammetry and EPR spectroscopy and its crystal structure determined by X-ray powder diffraction at room temperature. Variable temperature SQUID magnetometry reveals that 4-NCBDTA undergoes two phase transitions, each exhibiting bistability; a high temperature phase transition occurs at room temperature (T C↓ =291K, T C↑ =304K, ΔT =13K); whilst the low temperature phase transition occurs below liquid nitrogen temperatures (T C↓ =37K, T C↑ =28K;ΔT =9K). [Copyright &y& Elsevier]

Abstract: A general three-step synthesis to a range of benzo-fused-1,3,2-dithiazolylium salts bearing both electron-withdrawing (CN) and electron-donating (Me) groups is described. This methodology has also been extended to pyridyl derivatives and offers a potential route to a diversity of 1,3,2-dithiazolylium rings and their corresponding 1,3,2-dithiazolyl free radicals. The key steps in the reaction are treatment of a substituted 1,2,-dichlorobenzene with two equivalents of [ t BuS]Na, followed by chlorination to yield the corresponding bis(sulfenyl chloride). Subsequent ring closure with Me3SiN3 yields the target 1,3,2-dithiazolylium ring system in good yield. The preparation and crystal structures of 3′-methyl-benzo-1,3,2-dithiazolylium chloride and 3′-methyl-benzo-1,3,2-dithiazolyl are described and the electronic properties of the radical examined through EPR spectroscopy, DFT calculations and variable temperature magnetic susceptibility measurements. [Copyright &y& Elsevier]

The 2c-2e- P-P bonded dimers [(CH)2(NR)2P]2 dissociate in solution to give the persistent new 7p radicals [(CH)2(NR)2P]·, which are isoelectronic with the well known S/N thiazolyl radicals. [ABSTRACT FROM AUTHOR]

The incorporation of the electronegative cyano group into the structure of the title dithiazolyl radical 1 induces a lamellar packing motif that favors spin-transition behavior. Variable-temperature magnetic studies on 1 reveal a reversible phase transition at 250 K between a diamagnetic low-temperature phase and a paramagnetic high-temperature phase. X-ray crystal structures at 180(2) and 300(2) K reveal that both phases crystallize in the space group P21/c, with the phase transition associated with a doubling of the crystallographic a axis. The concomitant change in magnetic properties is associated with a change from a paramagnetic regular stack of radicals and a diamagnetic distorted π stack in which an energy gap opens up at the Fermi level corresponding to a Peierls-like transition. [ABSTRACT FROM AUTHOR]

Reduction of the radical-cation [·NSSNC—-CNSNS][AsF6] with ferrocene affords the novel biradical ·NSNSC-CNSSN· containing both 1,2,3,5- and 1,3,2,4-isomeric dithiadiazolyl rings. Biradicals form centrosymmetric dimmers with π∗-π∗ interactions between different isometric rings. Biradical ·NSNSC-CNSSN· is diamagnetic in the solid state (C = 0.00035, TIP=6.5 × 10-5 emu/Oe·mol); however, an increase in paramagnetism was observed upon grinding (C = 0.003, TIP = 4.2 × 10-4 emu/Oe·mol). [ABSTRACT FROM AUTHOR]