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.

Effect of organic materials on the chemical properties of saline soil in the Yellow River Delta of China

A 180-day incubation experiment was con- ducted to investigate the effect of different organic materials on the chemical properties of coastal soil with high salinity and relatively low pH. Four organic materials （three kinds of plant residues： straw, composted straw, and fresh reed; and one kind of poultry manure： chicken manure） were applied at a ratio of 15 g·kg^-1 to samples of costal saline soil from the Yellow River Delta of China. The results showed that the soil pH and exchangeable sodium percentage （ESP） decreased, whereas soil cation exchangeable capacity （CEC） and macronutrient concen- trations increased, regardless of the type of organic material used. All treatments showed a remarkable increase in soil soluble organic carbon （SOC） during the 180-day incubation. The peak values of SOC in descend- ing order were chicken manure, reed, composted straw, straw, and control soil. At the end of incubation, the highest level of SOC occurred in the straw-amended soil, followed by composted straw, reed, and chicken manure- amended soils. Soil respiration rate and available nitrogen were significantly influenced by the type of material used. Although reed-amended soil had a relatively high SOC and respiration rate, the ESP was reduced the least. Consider- ing the possible risk of heavy metals caused by chicken manure, it is proposed that straw and composted straw are the more efficient materials to use for reclaiming costal saline soil and improving the availability of macronu- trients.

Luminescence tuning of Ce^3+,Pr^3+activated(Y,Gd)AGG system by band gap engineering and energy transfer

Tuning of phosphor luminescence properties,including the emission energy/intensity and thermal stability,is an important way to develop superior luminescent materials for diverse applications.In this work,we discuss the effect of band gap engineering and energy transfer on the luminescence properties of Ce^3+or Pr^3+doped(Y,Gd)AGG systems,and analyze the underlying reasons for their different phenomena.By using VUV-UV excitation spectra and constructing VRBE schemes,the changes of host band structure,5 d excited level energies and emission thermal stability of Ce^3+and Pr^3+with the incorporation of Gd^3+ions were studied.In addition,the energy transfer dynamics was also investigated in terms of the luminescence decay curves.This work demonstrates a way to tune phosphor luminescence properties by combining band gap engineering and energy transfer tailoring and provides an inspiring discussion on the different results of Ce^3+doping on the Ce^3+and Pr^3+emissions.

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.

Brualdi-type inclusion sets of Z-eigenvalues and l^k,s-singular values for tensors

We give a Brualdi-type Z-eigenvalue inclusion set of tensors,and prove that it is tighter than the inclusion set given by G.Wang,G.L.Zhou,and L.Caccetta[Discrete Contin.Dyn.Syst.Ser.B,2017,22:187–198]in a special case.We also give an inclusion set for l^k,s-singular values of rectangular tensors.

Further Results on the Drazin Inverse of Tensors via Einstein Product

In this paper,we give further results on the Drazin inverse of tensors via the Einstein product.We give a limit formula for the Drazin inverse of tensors.By using this formula,the representations for the Drazin inverse of several block tensor are obtained.Further,we give the Drazin inverse of the sum of two tensors based on the representation for the Drazin inverse of,a block tensor.