Isolable Bis-BN-Based Analogues of Müller's Hydrocarbon

Müller's hydrocarbon and its analogues are classical examples of Kekulé diradicaloids and have gained great attention.However,because of their high reactivities,their isolation and structural characterizations are still challenging.Herein,we report the isolation of two bis-BN-based analogues of Müller's hydrocarbon (1 and 2) as crystalline solids in moderate yields.Experimental results and theoretical studies demonstrated that compound 1 possessing the terminal 1,3,2-diazaboryl groups is an open-shell singlet diradicaloid,which is in contrast to the closed-shell singlet ground states of the bis-BN-based analogues of Thiele's and Chichibabin's hydrocarbons with the same terminal groups,illustrating the strong influence of the central linkers on the ground state.Additionally,the replacement of the terminal 1,3,2-diazaboryl groups in 1 with the bis(2,4,6-triisopropylphenyl)boryl groups affords 2 with higher diradical character and a smaller singlet-triplet energy gap.

Novel 1,2,3-triazole-based compounds： Iodo effect on their gelation behavior and cation response

Two new series of 1,2,3-triazole derivatives, with and without iodo substitution, were synthesized and their gelation properties were measured. It was found that the iodo substitution at position 5 of triazole ring could greatly enhance the gelation ability. Scanning electron microscopy and X-ray diffraction reveal that the structures of the organogels from iodo and hydrogenous gelators are totally different, lodo gels are selectively responsive to the stimuli of Hg2＋, whereas hydrogenous gels can respond to Hg2＋ and Cu2＋. Moreover, the reversible gel-sol transition of hydrogenous gels can be controlled by redox reaction or tuned with suitable chemicals. The single crystal analysis of reference compound （C2） suggests that there are intermolecular and intramolecular non-classical hydrogen bonding interactions but no π-π interaction in hydrogenous gelator. The great difference between the two series of compounds results from the iodo effect and implies the existence of halogen bonding interaction in the iodo compounds.

Crystalline Germanium-Dipyrromethene Radicals:from a Delocalized Neutral to a Localized Cation

Both dipyrromethene complexes and radicals of heavier main group elements have been of high interest.However,cationic germanium radicals and dipyrromethene-based radicals of heavier main group elements are still escaped to be isolated.Herein,we report the isolation and full characterization of a neutral Ge(I)-masked dipyrromethene-based radical 3 and the first cationic Ge(III)-centered radical 5^(·+)as stable crystalline solids.3 behaves as a germanium(I)radical in its reaction with diphenyl disulfide to form the Ge-S bond,although X-ray crystallographic,EPR spectroscopic,computational studies revealed that the unpaired electron of 3 is mainly delocalized over the C_(9)N_(2)Ge backbone and the allylic radical character is also significant in 3.In contrast to 3,the spin density of 5^(·+)is mainly localized at the Ge center with minor contribution from the dipyrromethene ligand.Moreover,reduction of 5^(·+)with potassium graphite quantitatively regenerates 5,illustrating a reversible one-electron redox pair.