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Two series of a total of ten cocrystals involving 4‐amino‐5‐chloro‐2,6‐dimethylpyrimidine with various carboxylic acids have been prepared and characterized by single‐crystal X‐ray diffraction. The pyrimidine unit used for the cocrystals offers two ring N atoms (positions N1 and N3) as proton‐accepting sites. Depending upon the site of protonation, two types of cations are possible [Rajam et al. (2017). Acta Cryst. C73, 862–868]. In a parallel arrangement, two series of cocrystals are possible depending upon the hydrogen bonding of the carboxyl group with position N1 or N3. In one series of cocrystals, i.e. 4‐amino‐5‐chloro‐2,6‐dimethylpyrimidine–3‐bromothiophene‐2‐carboxylic acid (1/1), 1, 4‐amino‐5‐chloro‐2,6‐dimethylpyrimidine–5‐chlorothiophene‐2‐carboxylic acid (1/1), 2, 4‐amino‐5‐chloro‐2,6‐dimethylpyrimidine–2,4‐dichlorobenzoic acid (1/1), 3, and 4‐amino‐5‐chloro‐2,6‐dimethylpyrimidine–2‐aminobenzoic acid (1/1), 4, the carboxyl hydroxy group (–OH) is hydrogen bonded to position N1 (O—H…N1) of the corresponding pyrimidine unit (single point supramolecular synthon). The inversion‐related stacked pyrimidines are doubly bridged by the carboxyl groups via N—H…O and O—H…N hydrogen bonds to form a large cage‐like tetrameric unit with an R42(20) graph‐set ring motif. These tetrameric units are further connected via base pairing through a pair of N—H…N hydrogen bonds, generating R22(8) motifs (supramolecular homosynthon). In the other series of cocrystals, i.e. 4‐amino‐5‐chloro‐2,6‐dimethylpyrimidine–5‐methylthiophene‐2‐carboxylic acid (1/1), 5, 4‐amino‐5‐chloro‐2,6‐dimethylpyrimidine–benzoic acid (1/1), 6, 4‐amino‐5‐chloro‐2,6‐dimethylpyrimidine–2‐methylbenzoic acid (1/1), 7, 4‐amino‐5‐chloro‐2,6‐dimethylpyrimidine–3‐methylbenzoic acid (1/1), 8, 4‐amino‐5‐chloro‐2,6‐dimethylpyrimidine–4‐methylbenzoic acid (1/1), 9, and 4‐amino‐5‐chloro‐2,6‐dimethylpyrimidine–4‐aminobenzoic acid (1/1), 10, the carboxyl group interacts with position N3 and the adjacent 4‐amino group of the corresponding pyrimidine ring via O—H…N and N—H…O hydrogen bonds to generate the robust R22(8) supramolecular heterosynthon. These heterosynthons are further connected by N—H…N hydrogen‐bond interactions in a linear fashion to form a chain‐like arrangement. In cocrystal 1, a Br…Br halogen bond is present, in cocrystals 2 and 3, Cl…Cl halogen bonds are present, and in cocrystals 5, 6 and 7, Cl…O halogen bonds are present. In all of the ten cocrystals, π–π stacking interactions are observed. [ABSTRACT FROM AUTHOR]

The crystals of two new salts, 2,6-diamino-4-chloropyrimidin-1-ium 5-chlorosalicylate, C4H6ClN4 +.C7H4ClO3 -, (I), and bis(2,6-diamino-4-chloropyrimidin-1- ium) naphthalene-1,5-di-sulfonate, 2C4H6ClN4 +.C10H6O6S2 2-, (II), have been synthesized and characterized by single-crystal X-ray diffraction. In both compounds, the N atom of the pyrimidine group in between the amino substituents is protonated and the pyrimidinium cation forms a pair of N-- H. . .O hydrogen bonds with the carboxylate/sulfonate ion, leading to a robust R2 2(8) motif (supramolecular heterosynthon). In compound (I), a selfcomplementary base pairing involving the other pyrimidinium ring nitrogen atom and one of the amino groups via a pair of N--H. . .N hydrogen bonds [R2 ²(8) homosynthon] is also present. In compound (II), the crystallographic inversion centre coincides with the inversion centre of the naphthalene-1,5- disulfonate ion and all the sulfonate O atoms are hydrogen-bond acceptors, generating fused-ring motifs and a quadruple DDAA array. A halogen-bond (Cl. . .Cl) interaction is present in (I) with a distance and angle of 3.3505 (12) Å and 151.37 (10)°, respectively. In addition, a C--Cl. . .π interaction and a π-π interaction in (I) and a π-π interaction in (II) further stabilize these crystal structures. [ABSTRACT FROM AUTHOR]

The design of a pharmaceutical cocrystal is based on the identification of specific hydrogen-bond donor and acceptor groups in active pharmaceutical ingredients (APIs) in order to choose a `complementary interacting' molecule that can act as an efficient coformer. 5-Fluorouracil (5FU) is a pyrimidine derivative with two N-H donors and C=O acceptors and shows a diversity of hydrogen-bonding motifs. Two 1:1 cocrystals of 5-fluorouracil (5FU), namely 5-fluorouracil-4-methylbenzoic acid (5FU-MBA), C4H3FN2O2·C8H8O2, (I), and 5-fluorouracil-3-nitrobenzoic acid (5FU-NBA), C4H3FN2O2·C7H5NO4, (II), have been prepared and characterized by single-crystal X-ray diffraction. In (I), the MBA molecules form carboxylic acid dimers [ R22(8) homosynthon]. Similarly, the 5FU molecules form two types of base pair via a pair of N-H...O hydrogen bonds [ R22(8) homosynthon]. In (II), 5FU interacts with the carboxylic acid group of NBA via N-H...O and O-H...O hydrogen bonds, generating an R22(8) ring motif (heterosynthon). Furthermore, the 5FU molecules form base pairs [ R22(8) homosynthon] via N-H...O hydrogen bonds. Both of the crystal structures are stabilized by C-H...F interactions. [ABSTRACT FROM AUTHOR]

The asymmetric unit of the title co-crystal, C12H9N5O·C7H6O3, contains one molecule of N6-benzoyladenine (BA) and one molecule of 4-hydroxybenzoic acid (HBA). The N6-benzoyladenine (BA) has an N(7)--H tautomeric form with nonprotonated N-1 and N-3 atoms. This tautomeric form is stabilized by a typical intramolecular N--H⋯O hydrogen bond between the carbonyl (C＝O) group and the N(7)--H hydrogen on the Hoogsteen face of the purine ring, forming a graph-set S(7) ring motif. The primary robust R²2(8) ring motif is formed in the Watson-Crick face via N--H⋯O and O--H⋯N hydrogen bonds (involving N1, N6--H and the carboxyl group of HBA).Weak interactions, such as, C--H⋯π and π-π are also observed in this crystal structure. [ABSTRACT FROM AUTHOR]

In the crystal structure of the title compound, 5-fluorocytosinium picrate, C4H5FN3O+·C6H2N3O7-, one N heteroatom of the 5-fluorocytosine (5FC) ring is protonated. The 5FC ring forms a dihedral angle of 19.97 (11)° with the ring of the picrate (PA-) anion. In the crystal, the 5FC+ cation interacts with the PA- anion through three-centre N--H⋯O hydrogen bonds, forming two conjoined rings having R2¹(6) and R1²(6) motifs, and is extended by N--H⋯O hydrogen bonds and C--H⋯O interactions into a two-dimensional sheet structure lying parallel to (001). Also present in the crystal structure are weak C--F⋯π interactions. [ABSTRACT FROM AUTHOR]

In the title salt, C6H9ClN3+·C6H3O4S-, the cations and anions are linked via O-H⋯O and N-H⋯O hydrogen bonds, forming R66(37) ring motifs that are inter?connected with each other, producing sheets. Separate parallel inversion-related sheets are linked through N-H⋯N and [pi]-[pi] stacking inter?actions [centroid-centroid distance = 3.5414 (13) Å], forming double layers parallel to (101). Weak C-H⋯O and C-H⋯S hydrogen bonds, as well as C-H⋯π inter?actions, connect the double layers into a three-dimensional network. [ABSTRACT FROM AUTHOR]

The asymmetric unit of the title co-crystal, C12H9N5O0.5C6H10O4, consists of one molecule of N6-benzoyladenine (BA) and one half-molecule of adipic acid (AA), the other half being generated by inversion symmetry. The dihedral angle between the adenine and phenyl ring planes is 26.71 (7)°. The N6-benzoyladenine molecule crystallizes in the N(7)--H tautomeric form with three non-pro tonated N atoms. This tautomeric form is stabilized by intramolecular N--H⋯O hydrogen bonding between the carbonyl (CO) group and the N(7)--H hydrogen atom on the Hoogsteen face of the purine ring, forming an S(7) ring motif. The two carboxyl groups of adipic acid interact with the Watson-Crick face of the BA molecules through O--H⋯N and N--H⋯O hydrogen bonds, generating an R2²(8) ring motif. The latter units are linked by N--H⋯N hydrogen bonds, forming layers parallel to (105. A weak C--H⋯O hydrogen bond is also present, linking adipic acid molecules in neighbouring layers, enclosing R²2(10) ring motifs and forming a three-dimensional structure. C=O⋯π and C--H⋯π interactions are also present in the structure. [ABSTRACT FROM AUTHOR]

The asymmetric unit of the title compound, 4C4H4FN3O•C3H6N6, comprises of two independent 5-fluoro-cytosine (5FC) molecules (A and B) and one half-molecule of melamine (M). The other half of the melamine molecule is generated by a twofold axis. 5FC molecules A and B are linked through two different homosynthons [R2² (8) ring motif]; one is formed via a pair of N--H⋯O hydrogen bonds and the second via a pair of N--H⋯N hydrogen bonds. In addition to this pairing, the O atoms of 5FC molecules A and B inter-act with the N2 amino group on both sides of the melamine molecule, forming a DDAA array of quadruple hydrogen bonds and generating a supramolecular pattern. The 5FC (molecules A and B) and two melamine molecules interact via N--H⋯O, N--H⋯N and N--H⋯O, N--H⋯N, C--H⋯F hydrogen bonds forming R66(24) and R44(15) ring motifs. The crystal structure is further strengthened by C--H⋯F, C--F⋯π and π--π stacking interactions. [ABSTRACT FROM AUTHOR]

Background The usage of polynuclear metal clusters as secondary building units (SBU's) in designing of metal organic frameworks (MOF's) is a field of current interest. These metal clusters have attracted a great deal of attention not only due to their interesting structural topologies but also due to promising physical and chemical properties. In this regard various d,f block (transition and lanthanide) metal clusters have been widely investigated so far. Less attention is paid to construction of heavy p-block Pb(II) clusters. Results Two mixed ligand Pb(II) clusters have been synthesized with bipy(2,2'-Bipyridine), phen(1,10-Phenanthroline), quin (8-Hydroxy quinolinate) and 5-tpc (5-chloro thiophene 2- carboxylate). They have been characterized by elemental analysis, IR, TGA and X-ray crystallography. X-ray diffraction analysis reveals that the complexes [Pb4(quin)4(bipy)2(5- tpc)4] (1) and [Pb4(quin) 4(phen) 2(5-tpc)4] (2) are tetranuclear. The complexes show a slight variation in unit cell parameters, due to the replacement of bipy and the phen ligands. Both complexes contain two types of Pb(II) ions which differ in the coordination geometry around the Pb(II) ion. Conclusions In both complexes the four lead ions Pb1,Pb2, Pb1i and Pb2i lie on the same plane bridged by the 5-tpc anions. Pb1 and Pb2 of both complexes contain a 5-tpc and quin coordinated in a bidentate chelating bridging fashion. In addition the Pb2 and Pb2i ions alone contain a bipy and phen in a bidentate chelating fashion in (1) and (2) respectively. An additional notable feature in both of these complexes are the bridging ability of the quin oxygen which forms a network of coordination bonds in between the four Pb(II) ions. In both complexes the individual units are self-assembled by C-H---Cl/C-H---S hydrogen bonding interactions to generate 2-D aggregates. [ABSTRACT FROM AUTHOR]

The article describes the crystal structures of the compounds hemi(4,4'-bipyridinium) tris(5-chiorothiophene-2-carboxylato)dioxidouranate(VI) monohydrate and hemi[4,4'-(ethane-l,2-diyl)dipyridin-ium] tris(5-chlorothiophene-2-carboxylato)dioxidouranate(VI) monohydrate. The metal centres are connected by classical O--H-.O and N--H.O hydrogen bonds involving the coordinated ligands, the diprotonated organic linker cation and water molecules. The crystal structures are further supported by weak C--H.O and π-π stacking interactions.

In the crystal structure of the title compound, 2C6H9N3 C8H6O4, terephthalic acid has a crystallographic inversion centre and the dimethylpyrimidine molecule shows approximate non-crystallographic mirror and twofold rotation symmetry. The inversion-related pyrimidine molecules form a base pair [R2 2(8) ring motif] via a pair of NH⋯N hydrogen bonds. The carboxyl groups of terephthalic acid link the base pairs via OH⋯N and NH⋯O hydrogen bonds [R2 2(8) motif] to generate a supramolecular ribbon. [ABSTRACT FROM AUTHOR]

In the title complex, [Ni(NCS)2(H2O)4]·4C6H9N3·2H2O, the nickel(II) ion occupies an inversion centre and is octahedrally coordinated by two N-bonded thio­cyanate ions and four water mol­ecules. The two distinct 2-amino-4,6-di­methyl­pyrimidine mol­ecules adopt distinct base-pairing dimerization patterns via different pairs of N—H⋯N bonds. They are also hydrogen bonded to the coordinated and uncoordinated water mol­ecules and thio­cyanate ions through O—H⋯O, O—H⋯S(thio­cyanate) and N—H⋯N(thio­cyanate) hydrogen bonds. [ABSTRACT FROM AUTHOR]

In the title compound, 2,4-di­amino-5-(3,4,5-tri­methoxy­benzyl)­pyrimidinium hydrogen malonate, C14H19N4O3+·C3H3O4−, the trimethoprim mol­ecule is protonated at one of the pyrimidine N atoms. The carboxyl­ate group of the hydrogen malonate ion accepts a pair of N—H⋯O hydrogen bonds from an adjacent trimethoprim mol­ecule, which is similar to the carboxyl­ate–trimethoprim cation interaction present in the complex of di­hydro­folate reductase with trimethoprim. An O atom of the carboxyl group forms an intramolecular O—H⋯O hydrogen bond with the carboxyl­ate group, leading to a folded conformation for the hydrogen malonate ion. Each hydrogen malonate ion bridges two di­amino­pyrimidine cations, via N—H⋯O and C—H⋯N hydrogen bonds, leading to a supramolecular ribbon made up of alternating cations and anions. Two such inversion-related ribbons are cross-linked by (amino)N—H⋯O(methoxy) hydrogen bonds, (pyrimidine)C—H⋯O(methoxy) hydrogen bonds and π–π stacking involving the benzene planes. [ABSTRACT FROM AUTHOR]

In the title compound, C4H7N4O2+·SO42−·H2O, the asymmetric unit contains two amino­pyrimidinium cations, a sulfate anion and a water mol­ecule. These species are connected by N—H⋯O and O—H⋯O hydrogen bonds, resulting in a three-dimensional network. [ABSTRACT FROM AUTHOR]

In the crystal structure of the title compound, C6H10N3+·Br−·C6H9N3·H2O, the asymmetric unit contains a 2-amino-4,6-di­methyl­pyrimidinium cation, a Br− anion, a neutral 2-amino-4,6-di­methyl­pyrimidine mol­ecule and a water mol­ecule. Each neutral base molecule is paired with another inversion-related molecule through N—H⋯N hydrogen bonds to form dimers, and these are linked to one another through water-mediated hydrogen bonds, generating a supramolecular ribbon. The cations also pair with one another through N—H⋯N hydrogen bonds. The cation pairs are stacked on top of the neutral pairs. The Br− anion also takes part in hydrogen bonding (N/O—H⋯Br). [ABSTRACT FROM AUTHOR]

Investigates the conformation and hydrogen-bonding patterns of N[sup 6]-furfuryladenine hydrochloride. Adenine moiety existing as the N3-protonated N7-H tautomer; Orientation of the N6 substituent distal to the imidazole ring of the adenine base; Dihedral angle between the adenine plane and the furfuryl ring plane.

The titled dinuclear uranyl complex, U2O18N4H2·2(C5H7N2) 2(H2O) was crystallised in Monoclinic (C2/c) space group with the cell parameters a = 18.0728(3) b = 10.6896(3) c = 13.9068(3)Å, α = γ = 90.00° β = 103.988(2)°. In the structure, the U(VI) atom is eight coordinated with slightly distorted hexagonal bipyramidal geometry around the U(VI) ion. Two oxide ligands in the axial positions and four oxygen atoms from two bidentate nitrate ligands and two oxygen atoms from two hydroxy groups in the equatorial plane form the coordination sphere around the uranium atom. The two hydroxy groups act as bridging ligands between the uranyl ions generating a dinuclear unit having an inversion centre. The coordinated and non coordinated nitrate O atoms, axial uranyl O atoms, bridged hydroxy O atom, the non coordinated 2-aminopyridinium ion and the lattice water molecule play a vital role in assembling the three-dimensional structure via an extensive network of intermolecular O–H···O, N–H···O and C–H···O hydrogen bonds and aromatic π–π stacking interaction. The U(VI) atom is eight coordinated with slightly distorted hexagonal bipyramidal geometry. The three-dimensional structure is built through extensive network of intermolecular O–H···O, N–H···O, C–H···O hydrogen bonds and aromatic π–π stacking interaction. [ABSTRACT FROM AUTHOR]

In the title compound, C10H12O3N3S+·Cl−, 4-amino- N-(5-methyl-3-isoxazolyl)benzenesulfonamide is protonated on the amine N atom which is connected to the benzene ring. The geometry around the S atom is considerably distorted from ideal tetrahedral geometry. The crystal packing is stabilized by intermolecular N—H...N, N—H...Cl, N—H...O and C—H...O hydrogen bonds. [ABSTRACT FROM AUTHOR]

In the title cocrystal, C9H9N5·C6H8O2, the asymmetric unit contains one 2,4-diamino-6-phenyl-1,3,5-triazine molecule and a sorbic acid molecule. The triazine molecules are base-paired [with a graph set of R22(8)] on either side via N—H...N hydrogen bonds, forming a supramolecular ribbon along the c axis. Each triazine molecule interacts with the carboxyl group of a sorbic acid molecule via N—H...O and O—H...N hydrogen bonds, generating R22(8) motifs. The supramolecular ribbons are interlinked by N—H...O hydrogen bonds involving the 2-amino group of the triazine molecules and the carboxyl O atom of the sorbic acid molecule. [ABSTRACT FROM AUTHOR]

In the title compound, C4H6N4O·C7H5NO4, there are two types of base-pairing motifs, one involving a pair of N—H...N hydrogen bonds and the other involving a pair of N—H...O hydrogen bonds. These paired molecules are further linked by N—H...O hydrogen bonds to generate DADA and DDAA ( D = donor and A = acceptor) arrays leading to a supramolecular sheet. [ABSTRACT FROM AUTHOR]

In the title compound, C12H14ClN4+·C6H4NO2−·H2O, the pyrimethamine molecule is protonated at one of the pyrimidine N atoms. The protonated N atom and 2-amino group of the cation interact with an adjacent nicotinate anion through a pair of N—H...O hydrogen bonds [graph set R22(8)]. The cation, anion and water molecule form a hydrogen-bonded ring motif with graph-set notation R42(8). The crystal structure is further stabilized by N—H...O and O—H...O hydrogen bonds and π–π interactions [centroid–centroid distance = 3.637 (6) Å]. [ABSTRACT FROM AUTHOR]

In 2,4-diamino-5-( p-chlorophenyl)-6-ethylpyrimidinium hydrogen adipate, C12H14ClN4+·C6H9O4−, the protonated pyrimethamine cation interacts with the carboxylate group of the adipate ion through N—H...O hydrogen bonds, forming a cyclic hydrogen-bonded R22(8) motif. The carboxyl and carboxylate groups of the adipate ions are linked through O—H...O hydrogen bonds in a head-to-tail fashion, forming a chain. Anions and cations are further connected by an extensive network of N—H...O hydrogen bonds. [ABSTRACT FROM AUTHOR]

In the crystal structure of the title compound [systematic name: 2,4-diamino-5-(4-chlorophenyl)-6-ethylpyrimidin-1-ium 3,5-dinitrobenzoate], C12H14ClN4+·C7H3N2O6−, the pyrimethamine molecule is protonated at one of the pyrimidine N atoms. The carboxylate group of the 3,5-dinitrobenzoate anion forms double hydrogen bonds of type N—H...O, resulting in a fork-like interaction with the protonated diaminopyrimidine rings [graph-set notation R22(8)]. This motif self-assembles through a DDAA array of quadruple hydrogen bonds. The crystal structure is also stabilized by C—H...O hydrogen bonds. [ABSTRACT FROM AUTHOR]

The title compound [systematic name: 2,4-diamino-5-(4-chlorophenyl)-6-ethylpyrimdinium tetrafluoroborate], C12H14ClN4+·BF4−, is isomorphous with pyrimethamine perchlorate. The pyrimethamine (PMN) molecule is protonated at one of the pyrimidine N atoms. The protonated N atom and 2-amino group of the PMN cation interact with the tetrafluoroborate anion through a pair of N—H...F hydrogen bonds [graph set R22(8)]. The inversion-related PMN cations are linked through a pair of N—H...N hydrogen bonds. In addition to the base pairing, the F atoms bridge the 2-amino and 4-amino groups on either side of the paired bases, resulting in a complementary DADA array. [ABSTRACT FROM AUTHOR]

In the title molecular salt, C12H10N5O+·NO3-, the adenine unit has an N9-protonated N(7)--H tautomeric form with non-protonated N¹ and N³ atoms. The dihedral angle between the adenine ring system and the phenyl ring is 51.10(10)°. The typical intra­molecular N7--H···O hydrogen bond with an S(7) graph-set motif is also present. The benzoyl­adeninium cations also form base pairs through N--H···O and C--H···N hydrogen bonds involving the Watson-Crick face of the adenine ring and the C and O atoms of the benzoyl ring of an adjacent cation, forming a supra­molecular ribbon with R2²(9) rings. Benzoyl­adeninum cations are also bridged by one of the oxygen atoms of the nitrate anion, which acts as a double acceptor, forming a pair of N--HH···O hydrogen bonds to generate a second ribbon motif. These ribbons together with p-p stacking inter­actions between the phenyl ring and the five- and six-membered adenine rings of adjacent mol­ecules generate a three-dimensional supra­molecular architecture. [ABSTRACT FROM AUTHOR]

Three salts, namely 2-amino-4,6-dimethylpyrimidin-1-ium thiobarbiturate trihydrate (I), 2-amino-4,6-dimethoxypyrimidin-1-ium thiobarbiturate dihydrate (II) and 2,4-diamino-5-(3′,4′,5′-trimethoxybenzyl)pyrimidin-1-ium thiobarbiturate (III), were synthesized and characterized by IR and X-ray diffraction techniques. The primary interaction between the acid and base happens via N-H...O hydrogen bonds in (II) and (III), and via water-mediated N-H...O W and O W-H W...S in (I). The water molecules present in compound (I) form a (H2O)12 water cluster via water-water interactions. In all three compounds (I)-(III), thiobarbiturate anions form self-complementary pairs with a robust R22(8) motif via a pair of N-H...O/N-H...S hydrogen bonds. They mimic the nucleobase base pairs by utilizing the same groups (thymine/uracil uses N3-H and C4=O8 groups during the formation of Watson-Crick and Hoogsteen base pairs with adenine). Compound (I) forms a water-mediated base pair through N-H...O W hydrogen bonds and forms an R42(12) motif. The formation of N-H...S hydrogen bonds, water-mediated base pairs and water-water interactions in these crystal systems offers scope for these systems to be considered as a model in the study of hydration of nucleobases and water-mediated nucleobase base pairs in macromolecules. [ABSTRACT FROM AUTHOR]

Abstract: Interesting hydrogen-bonded supramolecular patterns have been achieved by hexafluorosilicate anion in the crystal structures of bis(thiabendazole) hexafluorosilicate dihydrate 1 and bis(pyrimethamine) hexafluorosilicate 2. In compound 1, the nitrogen atom of the benzimidazole ring rather than that of the thiazole ring is protonated. Water molecule is hydrogen-bonded with SiF6 2− anion through O–H⋯F hydrogen bonds to form a twelve membered cyclic hydrogen-bonded cluster. This cluster is self-organized to form a supramolecular chain. In the crystal structure of compound 2, the asymmetric unit contains two crystallographically independent protonated pyrimethamine (PMN) cations and a hexafluorosilicate SiF6 2− anion. The combination N–H⋯F and N–H⋯N hydrogen bonds results in the formation of complementary DADA (D and A represent donor and acceptor, respectively) array motif. It confirms that DADA array motif is a robust synthon in the crystal structures of diaminopyrimidine salts. [Copyright &y& Elsevier]

N-benzyladeninium nitrate, ( 1), CHN NO crystallizes in P2/ c, with a = 15.0035(13), b = 5.3788(5), c = 16.8954(13) Å, β = 107.331(6)°, Z = 4 and N-benzyladeninium 3-hydroxy picolinate, ( 2), CHN CHNO, crystallizes in P1, with a = 8.3017(4), b = 14.6170(7), c = 14.7909 (8) Å, α = 78.801 (4), β = 81.979 (4),γ = 88.849 (4)°, Z = 4. In both the salts, the cation exists as N(7)H tautomer with protonation at the N atom. The dihedral angle of 76.64 (16)° for ( 1), 67.91(12)° for (cation A) and 68.27 (13)° for (cation B) in ( 2), between the adenine plane and phenyl ring plane, the distal orientation of the N6 substituent with respect to the imidazole ring and the free N1 position, make these benzyladeninium cations meet all the requirements necessary for cytokinin activity. The crystal structures are stabilized by N-H···N, N-H···O, C-H···O hydrogen bonds and C-H···π stacking interaction between symmetry related benzyladenine molecule. Graphical Abstract: Supramolecular architectures in the crystal structures of N-Benzyladeninium nitrate and N-Benzyladeninium 3-hydroxy picolinate salts. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

The article presents a paper about hydrogen-bonded supramolecular motifs in 2-amino-4,6-dimethoxypyrimidinium picrate and pyrimethaminium picrate dimethyl sulfoxide solvate. It mentions the use of picric acid as an acidic ligand to form salts with polar biomolecules through specific electrostatic or hydrogen-bonding interactions. According to one study, hydrogen bonding plays an important role in molecular recognition and crystal engineering research.

The title compound, [Sr(C9H5INO4S2)2(H2O)2]·H2O, is isomorphous with the corresponding calcium complex of ferron (8-hydroxy-7-iodo­quinoline-5-sulfonic acid). The asymmetric unit consists of one SrII ion, two organic ligands, two coordinated water mol­ecules and one uncoordinated water mol­ecule. The SrII ion has a pentagonal–bipyramidal coordination geometry made up of O atoms of three different sulfonate groups, deprotonated quinolinol O atoms of two different oxine rings and two water mol­ecules. In the ligands of type I, two O atoms of the sulfonate group are involved in coordination, whereas in type II ligands, only one O atom is involved. Ligands of type I are stacked on top of one another, each pair of adjacent members of the stack being related by an inversion centre. Ligands of type II are also stacked in a similar manner. These molecular stacks are cross-linked by Sr—O(sulfonate) and Sr—O(quinolinol) bonds, leading to an extended framework. This architecture is further stabilized by a number of O—H⋯O and N—H⋯O hydrogen bonds. [ABSTRACT FROM AUTHOR]

Polymorphs of 2-amino-4,6-dimethoxypyrimidine [ADMP (1)], 2,4-diamino-6-methyl-1,3,5-triazine [DAMT ( 2 )], 2,4-diamino-6-phenyl-1,3,5-triazine [DAPT ( 3 )] and a solvate of DAPT with DMF solvent, [DAPT·DMF ( 4 )] were obtained either during a systematic screening using various solvents or by serendipity. These polymorphs and solvates were then characterized using single crystal X-ray diffraction technique and their structural and supramolecular aspects are analyzed. The supramolecular architecture of compounds ( 1 – 4 ) are predominantly hydrogen bonded via N–H⋯N base pairs. These base pairs are formed either between crystallographically independent molecules in the lattice or between symmetry related molecules. The molecular self assembly process involved in 2 , 3 and 4 , facilitates the formation of some base pair motifs with graph-set of R 2 2 (8) and a rare non-complementary base pair motif with graph-set R 2 2 (10). The other interesting supramolecular patterns and non-covalent interactions which lead to the formation of new forms are discussed in detail. [ABSTRACT FROM AUTHOR]