Amino-Acid-Induced Circular Polarized Luminescence in One-Dimensional Manganese(II) Halide Hybrid.

Circular polarized luminescence (CPL)-active materials attract great attentions owing to their widely applications in 3D optical displays and encrypted transmission. Inspired by the strategies adopted in perovskite based CPL materials, herein, CPL-active hybrids (D)- and (L)-(tert-butyl prolinate)MnCl3 were successfully prepared by assembling chiral D/L tert-butyl prolinate with manganese (II) chloride. Single crystal structures show the as-formed hybrids possess one-dimensional (1D) structure containing linear chains of face-sharing MnCl6 octahedral surrounded by prolinate cations. The 1D Mn(II) hybrids display strong red emission peaked at 646 nm with PLQY of 67.1 % and 57.2 % for d-type and l-type, respectively, representing the highest PLQY for 1D MnII hybrids. Interestingly, the 1D Mn(II) hybrids exhibit prominent circular dichroism (CD) signals and remarkable CPL activity with the dissymmetry factor g of 6.1*10-3 and -6.3*10-3 from 550 to 800 nm for (D)- and (L)-(tert-butyl prolinate)MnCl3 , respectively, owing to the existence of chiral cations. It is worthy noted the obtained g represents the highest value for non-lead organic-inorganic hybrids.

Highly Phosphorescent Dimers of PtAu2 Complexes and the Use in Solution-Processed OLEDs.

Two asymmetric PtAu2 complexes having HC≡CC6H4C≡CH (1,4-diethynylbenzene) or HC≡CCarbC≡CH (2,7-diethynyl-9-(2,3,5,6-tetrafluorophenyl)-9H-carbazole) and the corresponding bis(acetylide)-linked Pt2Au4 complexes are prepared and characterized. The structures of PtAu2 complexes 1 and 3 together with Pt2Au4 complex 2 are determined by X-ray crystallography. Relative to PtAu2 complexes, bis(acetylide)-linked Pt2Au4 complexes not only display a distinct red shift of the emission but also provide a much higher phosphorescent efficiency. Utilizing highly emissive Pt2Au4 complexes as phosphorescent dopants, high-efficiency solution-processed OLEDs are obtained with peak current efficiency of 75.9 cd A-1 and external quantum efficiency of 19.0% at luminance of 336 cd m-2 and voltage of 5.2 V. When two PtAu2 moieties are linked by a bis(acetylide) ligand, the corresponding Pt2Au4 complexes show a much improved electroluminescent performance compared with that of asymmetric PtAu2 complexes.

From homonuclear to heteronuclear: a viable strategy to promote and modulate phosphorescence.

Numerous mononuclear platinum(ii) complexes are non-emissive or weakly emissive under ambient conditions, but the corresponding Pt-M (M = Cu(i), Ag(i), Au(i), etc.) heteronuclear assemblies could become intensely luminescent because of the inhibition of non-radiative relaxation and the promotion of intersystem crossing from singlet to triplet state through Pt-M intermetallic interactions. To this end, the fabrication of specifically structured Pt-M complexes by the use of slightly luminescent homonuclear Pt(ii) precursors provides a promising approach to switching on phosphorescence as well as modulating emission energy and colour. This feature article is aimed at providing some typical examples for attaining highly phosphorescent Pt-M heteronuclear complexes using homonuclear Pt(ii) precursors, focusing on the assembly strategy, the correlation of emissive properties to the structures, and the application of phosphorescence in sensing and light-emitting devices.

[Expression of mosquitocidal Cyt1Aa toxin from Bacillus thuringiensis subsp. israelensis in Asticcacaulis excentricus].

Asticcacaulis excentricus, who lives in upper-layer waters providing food resource to the mosquito larvae and has been proven to be a successful host to produce the mosquitocidal binary toxins or Cry11Aa toxin from Bacilli (Liu et al., 1996, Nat Biotech 14: 343; Armengol, et al. , 2005, Curr Microbiol 51: 430), was developed to express cyt1Aa gene from Bacillus thuringiensis subsp. israelensis (Bti). Two A. excentricus transformants were constructed with the attempt of producing CytlAa alone and alongside with Cry11Aa, repectively. Detection of expressed Cry11Aa and CytlAa proteins by immunoblot in the recombinant A. excentricus clones showed that either cry11Aa or cyt1Aa was expressed well solely but not simultaneously although both restriction analyses of plasmid DNA and DNA sequencing showed that the transformed plasmid was identical to scheme. To investigate the reason why the recombinant A. excentricus harboring both genes and their ribosome binding site (RBS) sequences expressed only Cry11Aa, the total RNA of A. excentricus cells was extracted and revealed three-band pattern in which all RNA molecule weights are not greater than 16S RNA of Escherichia coli by formamide agarose gel electrophoresis, indicating that different RNA systems within these two Gram-negative strains required distinguishingly organised constructs to express multiple foreign genes. It is hypothesized that an extra promoter upstream of RBS sequence is required to express cyt1Aa in the cry11Aa-cyt1Aa tandom plasmid.

Single nucleotide deletion of cqm1 gene results in the development of resistance to Bacillus sphaericus in Culex quinquefasciatus.

The entomopathogen Bacillus sphaericus is one of the most effective biolarvicides used to control the Culex species of mosquito. The appearance of resistance in mosquitoes to this bacterium, however, remains a threat to its continuous use in integrated mosquito control programs. Previous work showed that the resistance to B. sphaericus in Culex colonies was associated with the absence of the 60-kDa binary toxin receptor (Cpm1/Cqm1), an alpha-glucosidase present in the larval midgut microvilli. In this work, we studied the molecular basis of the resistance developed by Culex quinquefasciatus to B. sphaericus C3-41. The cqm1 genes were cloned from susceptible (CqSL) and resistant (CqRL/C3-41) colonies, respectively. The sequence of the cDNA and genomic DNA derived from CqRL/C3-41 colony differed from that of CqSL one by a one-nucleotide deletion which resulted in a premature stop codon, leading to production of a truncated protein. Recombinant Cqm1S from the CqSL colony expressed in Escherichia coli specifically bound to the Bin toxin and had α-glucosidase activity, whereas the Cqm1R from the CqRL/C3-41 colony, with a deletion of three quarters of the receptor's C-terminal lost its α-glucosidase activity and could not bind to the binary toxin. Immunoblotting experiments showed that Cqm1 was undetectable in CqRL/C3-41 larvae, although the gene was correctly transcribed. Thus, the cqm1R represents a new allele in C. quinquefasciatus that confers resistance to B. sphaericus.

Toxicity of Bacillus sphaericus LP1-G against susceptible and resistant Culex quinquefasciatus and the cloning of the mosquitocidal toxin gene.

Bacillus sphaericus LP1-G, belonging to flagellar serotype H3, has been found to have moderate toxicity against two resistant Culex quinquefasciatus colonies (RLCq1 and RLCq2) and the susceptible contrast (SLCq). With an aim of screening mosquitocidal acting factor, a partial genome library was prepared from a partial HindIII digest of the total DNA from Bacillus sphaericus LP1-G. Two thousand twenty Escherichia coli clones were screened for toxicity against susceptible SLCq, and a toxic clone, designated E-UL68, was chosen for further study. The recombinant E-UL68 performed toxicity against both susceptible and two resistant colonies, having the same level of toxicity as that of wide-type strain LP1-G. Sequence analysis revealed that the inserted fragment was composed of 3876 nucleotides and contained a complete gene, whose sequence was identical to that of the mtx gene from B. sphaericus SSII-1. Because the binary toxin produced during sporulation of strain LP1-G has no activity against the target mosquitoes, this indicates that the Mtx toxin or other active factors might perhaps be responsible for the toxicity of LP1-G against different colonies of mosquito larvae.