cis-Bis(2,2′-bipyrimidine-κ²N¹,N^1′)di­iodidomanganese(II)

The asymmetric unit of the title complex, [MnI₂(C₈H₆N₄)₂], contains one half of a neutral Mn^II complex, with the entire molecule completed by the application of twofold symmetry. The Mn^II ion is six-coordinated in a distorted octa­hedral environment defined by four N atoms of the two chelating 2,2′-bipyrimidine (bpym) ligands and two I⁻ anions in a cis-N₄I₂ coordination geometry. The dihedral angle between the least-squares planes of the two bpym ligands (r.m.s deviation for all non-H atoms = 0.063 Å) is 85.04 (6)°. In the crystal, complex mol­ecules are connected by C—H...N and C—H...I hydrogen bonds, forming a three-dimensional network. Mol­ecules are stacked in columns along the a axis. Along the c axis, successive mol­ecules stack in the opposite directions.

cis-Dichloridobis(di-2-pyridyl­amine-κ²N,N′)manganese(II)

In the title complex, [MnCl₂(C₁₀H₉N₃)₂], the Mn^II ion is six-coordinated in a considerably distorted cis-N₄Cl₂ octa­hedral environment defined by four N atoms of two chelating di-2-pyridyl­amine (dpa) ligands and two Cl⁻ anions. In the crystal, the dpa ligands are not planar, the dihedral angles between the two pyridine rings being 29.3 (2) and 30.9 (2)°. The complex mol­ecules are stacked in columns along the c axis and are connected by inter­molecular N—H...Cl hydrogen bonds, forming a three-dimensional network. Weak inter- and intra­molecular π–π inter­actions are present between the pyridine rings, the shortest centroid—centroid distance being 4.406 (3) Å.

trans-Bis(acridine-κN)dichloridopalladium(II)

In the title complex, [PdCl₂(C₁₃H₉N)₂], the Pd^II ion is four-coordinated in an essentially square-planar environment by two N atoms from two acridine ligands and two Cl⁻ anions. The Pd atom is located on an inversion centre, and thus the asymmetric unit contains one half of the complex and the PdN₂Cl₂ unit is exactly planar. The dihedral angle between the PdN₂Cl₂ unit and the acridine ligand is 84.66 (6)°. In the crystal, the complex mol­ecules are stacked in columns along the a axis connected by C—H...Cl hydrogen bonds, forming chains along [110]. In the columns, numerous inter­molecular π–π inter­actions between the six-membered rings are present, the shortest ring centroid–centroid distance being 3.722 (4) Å.

Acridin-10-ium 6-carb­oxy­pyridine-2-carboxyl­ate

The title compound, C₁₃H₁₀N⁺·C₇H₄NO₄⁻, consists of a protonated acridinium cation and a 6-carb­oxy­pyridine-2-carboxyl­ate monoanion. The carboxyl­ate group of the anion appears to be delocalized on the basis of the nearly equivalent C—O bond lengths. In the crystal, the anions are connected by strong O—H...O hydrogen bonds, forming chains along the b axis. The acridinium cations are linked to the anionic chains by strong N—H...O hydrogen bonds between the carboxyl­ate group of the anion and the N—H group of the cation. Along the b axis, successive chains stack in opposite directions. Weak inter­molecular C—H...O hydrogen bonds further stabilize the crystal structure.