Bis[dieth­yl(hy­droxy)ammonium] benzene-1,4-dicarboxyl­ate

In the centrosymmetric title compound, 2C4H12NO+·C8H4O4 2−, two N,N-dieth­yl(hy­droxy)ammonium cations are linked to a benzene-1,4-dicarboxyl­ate dianion by a combination of O—H⋯O and N—H⋯O hydrogen bonds, which can be described in graph-set terminology as R 2 2(7). The crystal structure is further stabilized by C—H⋯O hydrogen bonds, leading to the fomation of a ribbon-like network

Poly[diaqua­bis(μ2-5-carb­oxy-2-propyl-1H-imidazole-4-carboxyl­ato-κ3 N 3,O 4:O 5)lead(II)]

In the title complex, [Pb(C8H9N2O4)2(H2O)2]n, the eight-coordinate PbII atom lies on a twofold rotation axis and adopts a slightly distorted square-anti­prismatic N2O6 coordination geometry. The ligand donor atoms are the tertiary N atoms of the imidazole rings and the carboxyl­ate O atoms of two chelating 5-carb­oxy-2-propyl-1H-imidazole-4-carboxyl­ate ligands, the carb­oxy O atoms of two additional imidazole ligands and two water O atoms. The carb­oxy O and the N,O-chelate systems also link adjacent PbII atoms, forming a two-dimensional layer structure, with four individual PbII atoms located at the corners of a square. These layers are further inter­connected by an extensive array of O—H⋯O and N—H⋯O hydrogen bonds into a three-dimensional network

Establishing the first hidden-charm pentaquark with strangeness

We study the $P_{cs}(4459)^0$ recently observed by LHCb using the method of QCD sum rules. Our results support its interpretation as the $\bar D^* \Xi_c$ hadronic molecular state of either $J^P=1/2^-$ or $3/2^-$. Within the hadronic molecular picture, the three LHCb experiments observing $P_c$ and $P_{cs}$ states~\cite{lhcb,Aaij:2015tga,Aaij:2019vzc} can be well understood as a whole. This strongly supports the existence of hadronic molecules, whose studies can significantly improve our understanding on the construction of the subatomic world. To verify this picture, we propose to further investigate the $P_{cs}(4459)^0$ to examine whether it can be separated into two states, and to search for the $\bar D \Xi_c$ molecular state of $J^P=1/2^-$.Comment: 5 pages, 2 figure, 1 table, revised versio