Dimethyl­bis­(pyrazine-2-carboxyl­ato-κ²N¹,O)tin(IV)

In the title compound, [Sn(CH₃)₂(C₅H₃N₂O₂)₂], the Sn^IV atom is twice N,O-chelated by two pyrazine-2-carboxyl­ate ligands. The distorted six-coordination is completed by two tin-bound methyl C atoms. The C₂N₂O₂ donor set defines a skewed trapezoidal–bipyramidal geometry. Inter­molecular π–π inter­actions between the pyrazine rings [centroid–centroid distance = 3.8112 (13) Å] are observed.

cis-(2,2′-Bipyridine-κ²N,N′)bis­(isonicotinamide-κN¹)palladium(II) bis­(hexa­fluoridophosphate)

In the title salt, [Pd(C₁₀H₈N₂)(C₆H₆NO)₂](PF₆)₂, the Pd^II atom is in a slightly distorted square-planar coordination environment by N atoms derived from two 4-pyridine­carboxamide ligands, in a cis disposition, and a chelating 2,2′-bipyridine mol­ecule. The monodentate ligands are nearly orthogonal to each other [dihedral angle = 85.7 (5)°] and to the PdN₄ plane [dihedral angles = 79.3 (3) and 78.7 (3)°]. The amide O atoms lie to opposite sides of the PdN₄ plane. The most notable feature of the crystal packing is a linear supra­molecular chain orientated approximately along [310] and formed via 16-membered {...HNCO}₄ motifs. These are connected into a three-dimensional network by amide–H...O, F inter­actions. Both PF₆⁻ anions are disordered over two positions of equal occupancy in respect of the F atoms.

A second polymorph of 2,4,6-tris­(3,5-dimethyl-1H-pyrazol-1-yl)-1,3,5-triazine

The mol­ecule of the title compound, C₁₈H₂₁N₉, is nearly planar, with the three pyrazole rings aligned at 2.40 (5), 9.27 (5) and 9.71 (5)° with respect to the triazine ring. The triazine ring is planar (r.m.s. deviation = 0.005 Å), the distortion from a hexa­gonal arrangement arising from the angles at the N [112.4 (1)-113.1 (1)°] and C [127.1 (1)-127.6 (1)°] atoms deviating from 120°. The crystal studied was an inversion twin.