Reactions of silver(I) salts with the isomeric pyridyl amide ligands methyl-4-(pyridin-2-ylcarbamoyl)benzoate (L 1 ), methyl-4-(pyridin-3-ylcarbamoyl)benzoate (L 2 ) and methyl-4-(pyridin-4-ylcarbamoyl)benzoate (L 3 ) and the pyrimidyl amide ligand methyl-4-(pyrimidin-2-ylcarbamoyl)benzoate (L 4 ) afforded the complexes Ag 4 (L 1 ) 4 (NO 3 ) 4 9), which were structurally characterized by X-ray crystallography. The L 1 -L 3 ligands in 1-6 adopt monodentate bonding modes, which coordinate to the metal centers through the pyridyl nitrogen atoms, whereas the L 4 ligands of 7-9 adopt a bidentate mode, featuring chelation through one pyrimidyl nitrogen atom and the amide oxygen atom. All nine complexes adopt discrete structures with 1 being tetranuclear and 2-9 being mononuclear. Moreover, Ag … Ag short contacts, p … p stacking interactions and/or Ag … O interactions are found in these complexes which extend the dimensionalities of the structures. The changes of the donor atom positions and counteranions significantly affect the supramolecular structures of these complexes and the L 1 -L 4 ligands are sufficiently flexible to adopt the cis and/or trans conformations.

Construction of N,N′-di(3-pyridyl)adipoamide-based Zn(II) and Cd(II) coordination networks by tuning the isomeric effect of polycarboxylate ligands †

No abstract

Two three-dimensional (3D) coordination networks, [Co 3 (1,4-BDC)3(L 1 )] N (L 1 ¼ N,N 0 -bis(3-pyridinyl)-1,4-benzenedicarboxamide; 1,4-H 2 BDC ¼ 1,4-benzenedicarboxylic acid), 1, and [K 2 Co 3 (L 2 ) 4 ] N (H 2 L 2 ¼ 5-acetamidoisophthalic acid), 2, have been synthesized by hydrothermal reactions and characterized by single crystal X-ray crystallography. Complex 1 consists of linear trinuclear Co(II) centers, which are linked by the 1,4-BDC À and L 1 ligands to form a rare (1 + 3) self-catenated 3D net with the new (3 6 ,4 10 ,5 11 ,6) topology, and complex 2 reveals a 3p-3d heterometallic coordination network based on linear trinuclear Co(II) and dinuclear K(I) centers bridged by the m 6 -L 2 ligands, forming a 4,4,8-connected trinodal net with the new (4 14 $6 10 $8 4 )(4 2 $6 4 )(4 4 $6 2 ) topology. The linear trinuclear Co(II) centers in 1 adopt the square pyramidal-octahedral-square pyramidal geometries, whereas those in 2 are tetrahedral-octahedral-tetrahedral. Both of the complexes exhibit paramagnetism that is consistent with the Curie-Weiss law between 60 and 300 K. The effective magnetic moments (hm eff i) of both complexes are larger than the estimated value of 6.71 m B /f.u., revealing the spin-orbit couplings that are invoked by the different distorted geometries of the linear trinuclear Co(II) centers. The dinuclear K(I) centers in 2 weaken the magnetic coupling, and reduce the antiferromagnetic ordering at 6 K.

Two measurement systems, one being comprised of three HPGe detectors and the other being a 4π measurement system of the assembly of 10 sets of scintillation detectors, were compared for their measurement performance in operations of radioactive waste drum radioactivity measurement and clearance and release operation of decommissioning. The system features of the former were high costs, capable of identifying radionuclides, a measurement time of about 1000 sec. The system features of the latter were high sensibility, capable of identifying hotspots, a measurement time of about 100 sec. Various comparisons were made for the differences of the two systems on reference drums, whole-drum homogeneous and non-homogeneous metal drums and non-metal drums, whole-drums of different filling rates. The aim was to compare the differences of the two measurement systems in measuring radioactivity of critical radionuclides of 137 Cs, 54 Mn and 60 Co.