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Nine salts of the antifolate drugs trimethoprim and pyrimethamine, namely, trimethoprimium [or 2,4‐diamino‐5‐(3,4,5‐trimethoxybenzyl)pyrimidin‐1‐ium] 2,5‐dichlorothiophene‐3‐carboxylate monohydrate (TMPDCTPC, 1:1), C14H19N4O3+·C5HCl2O2S−, (I), trimethoprimium 3‐bromothiophene‐2‐carboxylate monohydrate, (TMPBTPC, 1:1:1), C14H19N4O3+·C5H2BrO2S−·H2O, (II), trimethoprimium 3‐chlorothiophene‐2‐carboxylate monohydrate (TMPCTPC, 1:1:1), C14H19N4O3+·C5H2ClO2S−·H2O, (III), trimethoprimium 5‐methylthiophene‐2‐carboxylate monohydrate (TMPMTPC, 1:1:1), C14H19N4O3+·C6H5O2S−·H2O, (IV), trimethoprimium anthracene‐9‐carboxylate sesquihydrate (TMPAC, 2:2:3), C14H19N4O3+·C15H9O2−·1.5H2O, (V), pyrimethaminium [or 2,4‐diamino‐5‐(4‐chlorophenyl)‐6‐ethylpyrimidin‐1‐ium] 2,5‐dichlorothiophene‐3‐carboxylate (PMNDCTPC, 1:1), C12H14ClN4+·C5HCl2O2S−, (VI), pyrimethaminium 5‐bromothiophene‐2‐carboxylate (PMNBTPC, 1:1), C12H14ClN4+·C5H2BrO2S−, (VII), pyrimethaminium anthracene‐9‐carboxylate ethanol monosolvate monohydrate (PMNAC, 1:1:1:1), C12H14ClN4+·C15H9O2−·C2H5OH·H2O, (VIII), and bis(pyrimethaminium) naphthalene‐1,5‐disulfonate (PMNNSA, 2:1), 2C12H14ClN4+·C10H6O6S22−, (IX), have been prepared and characterized by single‐crystal X‐ray diffraction. In all the crystal structures, the pyrimidine N1 atom is protonated. In salts (I)–(III) and (VI)–(IX), the 2‐aminopyrimidinium cation interacts with the corresponding anion via a pair of N—H…O hydrogen bonds, generating the robust R22(8) supramolecular heterosynthon. In salt (IV), instead of forming the R22(8) heterosynthon, the carboxylate group bridges two pyrimidinium cations via N—H…O hydrogen bonds. In salt (V), one of the carboxylate O atoms bridges the N1—H group and a 2‐amino H atom of the pyrimidinium cation to form a smaller R21(6) ring instead of the R22(8) ring. In salt (IX), the sulfonate O atoms mimic the role of carboxylate O atoms in forming an R22(8) ring motif. In salts (II)–(IX), the pyrimidinium cation forms base pairs via a pair of N—H…N hydrogen bonds, generating a ring motif [R22(8) homosynthon]. Compounds (II) and (III) are isomorphous. The quadruple DDAA (D = hydrogen‐bond donor and A = hydrogen‐bond acceptor) array is observed in (I). In salts (II)–(IV) and (VI)–(IX), quadruple DADA arrays are present. In salts (VI) and (VII), both DADA and DDAA arrays co‐exist. The crystal structures are further stabilized by π–π stacking interactions [in (I), (V) and (VII)–(IX)], C—H…π interactions [in (IV)–(V) and (VII)–(IX)], C—Br…π interactions [in (II)] and C—Cl…π interactions [in (I), (III) and (VI)]. Cl…O and Cl…Cl halogen‐bond interactions are present in (I) and (VI), with distances and angles of 3.0020 (18) and 3.5159 (16) Å, and 165.56 (10) and 154.81 (11)°, respectively. [ABSTRACT FROM AUTHOR]

Aminopyrimidine derivatives are biologically important as they are components of nucleic acids and drugs. The crystals of two new salts, namely cytosinium 6‐chloronicotinate monohydrate, C4H6N3O+·C6H3ClNO2−·H2O, (I), and 5‐bromo‐6‐methylisocytosinium hydrogen sulfate (or 2‐amino‐5‐bromo‐4‐oxo‐6‐methylpyrimidinium hydrogen sulfate), C5H7BrN3O+·HSO4−, (II), have been prepared and characterized by single‐crystal X‐ray diffraction. The pyrimidine ring of both compounds is protonated at the imine N atom. In hydrated salt (I), the primary R22(8) ring motif (supramolecular heterosynthon) is formed via a pair of N—H…O(carboxylate) hydrogen bonds. The cations, anions and water molecule are hydrogen bonded through N—H…O, N—H…N, O—H…O and C—H…O hydrogen bonds, forming R22(8), R32(7) and R55(21) motifs, leading to a hydrogen‐bonded supramolecular sheet structure. The supramolecular double sheet structure is formed via water–carboxylate O—H…O hydrogen bonds and π–π interactions between the anions and the cations. In salt (II), the hydrogen sulfate ions are linked via O—H…O hydrogen bonds to generate zigzag chains. The aminopyrimidinium cations are embedded between these zigzag chains. Each hydrogen sulfate ion bridges two cations via pairs of N—H…O hydrogen bonds and vice versa, generating two R22(8) ring motifs (supramolecular heterosynthon). The cations also interact with one another via halogen–halogen (Br…Br) and halogen–oxygen (Br…O) interactions. [ABSTRACT FROM AUTHOR]

Copper(II) bis(4,4,4-trifluoro-1-phenylbutane-1,3-dionate) complexes with pyridin-2-one (pyon), 3-hydroxypyridine (hpy) and 3-hydroxypyridin-2-one (hpyon) were prepared and the solid-state structures of (pyridin-2-one-κ O)bis(4,4,4-trifluoro-3-oxo-1-phenylbutan-1-olato-κ2 O, O′)copper(II), [Cu(C10H6F3O2)2(C5H5NO)] or [Cu(tfpb-κ2 O, O′)2(pyon-κ O)], (I), bis(pyridin-3-ol-κ O)bis(4,4,4-trifluoro-3-oxo-1-phenylbutan-1-olato-κ2 O, O′)copper(II), [Cu(C10H6F3O2)2(C5H5NO)2] or [Cu(tfpb-κ2 O, O′)2(hpy-κ O)2], (II), and bis(3-hydroxypyridin-2-one-κ O)bis(4,4,4-trifluoro-3-oxo-1-phenylbutan-1-olato-κ2 O, O′)copper(II), [Cu(C10H6F3O2)2(C5H5NO2)2] or [Cu(tfpb-κ2 O, O′)2(hpyon-κ O)2], (III), were determined by single-crystal X-ray analysis. The coordination of the metal centre is square pyramidal and displays a rare example of a mutual cis arrangement of the β-diketonate ligands in (I) and a trans-octahedral arrangement in (II) and (III). Complex (II) presents the first crystallographic evidence of κ O-monodentate hpy ligation to the transition metal enabling the pyridine N atom to participate in a two-dimensional hydrogen-bonded network through O-H...N interactions, forming a graph-set motif R22(7) through a C-H...O interaction. Complex (III) presents the first crystallographic evidence of monodentate coordination of the neutral hpyon ligand to a metal centre and a two-dimensional hydrogen-bonded network is formed through N-H...O interactions facilitated by C-H...O interactions, forming the graph-set motifs R22(8) and R22(7). [ABSTRACT FROM AUTHOR]

In the salt trimethoprimium ferrocenecarboxylate [systematic name: 2,4-diamino-5-(3,4,5-trimethoxybenzyl)pyrimidin-1-ium ferrocene-1-carboxylate], (C14H19N4O3)[Fe(C5H5)(C6H4O2)], (I), of the antibacterial compound trimethoprim, the carboxylate group interacts with the protonated aminopyrimidine group of trimethoprim via two N-H...O hydrogen bonds, generating a robust R22(8) ring motif (heterosynthon). However, in the cocrystal 4-amino-5-chloro-2,6-dimethylpyrimidine-ferrocene-1-carboxylic acid (1/1), [Fe(C5H5)(C6H5O2)]·C6H8ClN3, (II), the carboxyl-aminopyrimidine interaction [ R22(8) motif] is absent. The carboxyl group interacts with the pyrimidine ring via a single O-H...N hydrogen bond. The pyrimidine rings, however, form base pairs via a pair of N-H...N hydrogen bonds, generating an R22(8) supramolecular homosynthon. In salt (I), the unsubstituted cyclopentadienyl ring is disordered over two positions, with a refined site-occupation ratio of 0.573 (10):0.427 (10). In this study, the two five-membered cyclopentadienyl (Cp) rings of ferrocene are in a staggered conformation, as is evident from the C... Cg... Cg...C pseudo-torsion angles, which are in the range 36.13-37.53° for (I) and 22.58-23.46° for (II). Regarding the Cp ring of the minor component in salt (I), the geometry of the ferrocene ring is in an eclipsed conformation, as is evident from the C... Cg... Cg...C pseudo-torsion angles, which are in the range 79.26-80.94°. Both crystal structures are further stabilized by weak π-π interactions. [ABSTRACT FROM AUTHOR]

The coordination chemistry of mixed-ligand complexes continues to be an active area of research since these compounds have a wide range of applications. Many coordination polymers and metal-organic framworks are emerging as novel functional materials. Aminopyrimidine and its derivatives are flexible ligands with versatile binding and coordination modes which have been proven to be useful in the construction of organic-inorganic hybrid materials and coordination polymers. Thiophenecarboxylic acid, its derivatives and their complexes exhibit pharmacological properties. Cobalt(II) and copper(II) complexes of thiophenecarboxylate have many biological applications, for example, as antifungal and antitumor agents. Two new cobalt(II) and copper(II) complexes incorporating thiophene-2-carboxylate (2-TPC) and 2-amino-4,6-dimethoxypyrimidine (OMP) ligands have been synthesized and characterized by X-ray diffraction studies, namely (2-amino-4,6-dimethoxypyrimidine-κ N)aquachlorido(thiophene-2-carboxylato-κ O)cobalt(II) monohydrate, [Co(C5H3O2S)Cl(C6H9N3O2)(H2O)]·H2O, (I), and catena-poly[copper(II)-tetrakis(μ-thiophene-2-carboxylato-κ2 O: O′)-copper(II)-(μ-2-amino-4,6-dimethoxypyrimidine-κ2 N1: N3)], [Cu2(C5H3O2S)4(C6H9N3O2)] n, (II). In (I), the CoII ion has a distorted tetrahedral coordination environment involving one O atom from a monodentate 2-TPC ligand, one N atom from an OMP ligand, one chloride ligand and one O atom of a water molecule. An additional water molecule is present in the asymmetric unit. The amino group of the coordinated OMP molecule and the coordinated carboxylate O atom of the 2-TPC ligand form an interligand N-H...O hydrogen bond, generating an S(6) ring motif. The pyrimidine molecules also form a base pair [ R22(8) motif] via a pair of N-H...N hydrogen bonds. These interactions, together with O-H...O and O-H...Cl hydrogen bonds and π-π stacking interactions, generate a three-dimensional supramolecular architecture. The one-dimensional coordination polymer (II) contains the classical paddle-wheel [Cu2(CH3COO)4(H2O)2] unit, where each carboxylate group of four 2-TPC ligands bridges two square-pyramidally coordinated CuII ions and the apically coordinated OMP ligands bridge the dinuclear copper units. Each dinuclear copper unit has a crystallographic inversion centre, whereas the bridging OMP ligand has crystallographic twofold symmetry. The one-dimensional polymeric chains self-assemble via N-H...O, π-π and C-H...π interactions, generating a three-dimensional supramolecular architecture. [ABSTRACT FROM AUTHOR]

Two novel cocrystals of the N(7)-H tautomeric form of N6-benzoyladenine (BA), namely N6-benzoyladenine-3-hydroxypyridinium-2-carboxylate (3HPA) (1/1), C12H9N5O·C6H5NO3, (I), and N6-benzoyladenine-DL-tartaric acid (TA) (1/1), C12H9N5O·C4H6O6, (II), are reported. In both cocrystals, the N6-benzoyladenine molecule exists as the N(7)-H tautomer, and this tautomeric form is stabilized by intramolecular N-H...O hydrogen bonding between the benzoyl C=O group and the N(7)-H hydrogen on the Hoogsteen site of the purine ring, forming an S(7) motif. The dihedral angle between the adenine and phenyl planes is 0.94 (8)° in (I) and 9.77 (8)° in (II). In (I), the Watson-Crick face of BA (N6-H and N1; purine numbering) interacts with the carboxylate and phenol groups of 3HPA through N-H...O and O-H...N hydrogen bonds, generating a ring-motif heterosynthon [graph set R22(6)]. However, in (II), the Hoogsteen face of BA (benzoyl O atom and N7; purine numbering) interacts with TA (hydroxy and carbonyl O atoms) through N-H...O and O-H...O hydrogen bonds, generating a different heterosynthon [graph set R22(4)]. Both crystal structures are further stabilized by π-π stacking interactions. [ABSTRACT FROM AUTHOR]