Two new transition-metal coordination polymers,{[Cd(oba)(L)_(2)]·H_(2)O}_n(1)and[Cd(4-nph)(L)_(2)]_n(2)(H_(2)oba=4,4'-oxydibenzoic acid,4-H_(2)nph=4-nitrophthalic acid,L=2,2'-biimidazole),were successfully synthesized under hydrothermal conditions and characterized structurally by IR spectroscopy,elemental analyses,single-crystal X-ray diffraction,powder X-ray diffraction,and thermogravimetric analysis.The results of single-crystal X-ray diffraction show that complex 1 presents a 1D zigzag chain structure and further extends to a 2D network through N—H…O hydrogen bonds andπ-πstacking interactions.Meanwhile,complex 2 has a zero-dimensional structure and also extends to form a 2D network through N—H…O hydrogen bonds andπ-πstacking interactions.In addition,both 1and 2 exhibited luminescent properties in the solid state.Furthermore,quantum chemical calculations were carried out on the"molecular fragments"extracted from the crystal structures of 1 and 2 using the PBE0/LANL2DZ method constructed by the Gaussian 16 program.The calculated values signify a significant covalent interaction between the coordination atoms and the Cd(Ⅱ)ions.CCDC:2332173,1;2332176,2.
Microplastics and heavy metal contamination poses major threats to soil function and food security;however,their synergistic effects remain largely unclear.This study investigated the effects of single or combined addition of polyethylene(PE)microplastic(1%w/w)and cadmium(Cd;1.5 and 5 mg kg–1)on functional microbial communities in the wheat rhizosphere soil.We observed that the biomass of wheat increased by 142.44%under high doses of Cd addition.The bacterial alpha diversity in wheat bulk soil reduced by 37.34%–37.83%with the combined addition of microplastic and Cd.The addition of microplastic reduced the relative abundance of Proteus involved in nitrogen fixation by 19.93%,while the relative abundance of Proteus and Actinobacteria involved in nitrogen cycling increased with the increase of Cd concentration,increasing by 27.96%–37.37%and 51.14%–55.04%,respectively.FAPROTAX analysis revealed that increasing Cd concentration promoted the abundance of functional bacterial communities involved in nitrification/denitrification and nitrate/nitrite respiration in rhizosphere soil.A FunGuild analysis showed that the synergy of PE-microplastics and Cd increased the abundance of saprophytic fungi,suggesting an enhanced degradation function.Our findings provide new knowledge on the effects of microplastics and heavy metals on soil microorganisms and functional microbial communities in agricultural soil.
Jianhong JiYingying ZhongMouliang XiaoXianting WangZhi’e HuMianjin ZhanJina DingZhenke ZhuTida Ge
