Bildung siliciumorganischer Verbindungen. LXI. Die Kristall- und MolekülStruktur des 1,1,3,3,5,5,7,7-Octamethyl-1,3,5,7-tetrasila-cyclooctans Si4C12H32

Formation of Organosilicon Compounds. LXI. Crystal and Molecular Structure of 1.1.3.3.5.5.7.7-Octamethyl-1.3.5.7-tetrasila-cyclooctane Si₄C₁₂H₃₂ Octamethyl-tetrasila-cyclooctan Si₄C₁₂H₃₂ crystallizes in the monoclinic space group C2 with a = 17.807, b = 6.121, c = 10.856 Å, β = 126.09° und 2 molecules in the unit cell. The molecule has a C₂-conformation which deviates slightly from C_2v symmetry. The mean Si? C bond length is 1.879 ± 0.011 Å. The mean Si? CH₂ bond length is greater than the Si? CH₃ bond length (1.897(15) Å and 1.861(10) Å respectively).     

rac‐1‐Phenyl­ethyl­ammonium carboxy­methyl­phospho­nate(1–): hydrogen‐bonded anion sheets with pendent cations

In the title compound, C₈H₁₂N⁺·C₂H₄O₅P⁻, the anions are linked by two O—H⋯O hydrogen bonds [H⋯O both 1.75 Å, O⋯O = 2.5781 (15) and 2.5834 (15) Å, and O—H⋯O = 169 and 176°] into sheets built from alternating (8) and (32) rings. Each cation is linked to an anion sheet by three N—H⋯O hydrogen bonds [H⋯O = 1.88–2.04 Å, N⋯O = 2.7603 (16)–2.9334 (17) Å and N—H⋯O = 162–166°], such that all the cations pendent from one face of the sheet are of the R configuration, while all those pendent from the opposite face are of the S configuration.     

Flavonoids of inflorescences of Calendula officinalis

By column chromatography on polyamide sorbent, the inflorescences of pot marigold calendula have yielded eight substances of flavonoid nature: two aglycons — quercetin (C₁₅H₁₀O₇, mp 309–311°C) and isorhamnetin (C₁₆H₁₂O₇, mp 314–316°C); six glycosides, of which three have been identified as isoquercetin (C₂₁H₂₀O₁₂, [α] _D ²⁰ ?36° in methanol, mp 218–220°C), isorhamnetin 3-O-β-D-glucoside (C₂₂H₂₂O₁₂, [α] _D ²⁰ ?59° in dimethylformamide, mp 193–195°C), narcissin (C₂₈H₃₂O₁₆, [α] _D ²¹ ?28° in dimethylformamide, mp 180–182°C), and three substances that have proved to be new and have been called calendoflaside (C₂₈H₃₂O₁₅, [α] _D ²¹ ?85° in methanol, mp 192–195°C; calendoflavoside (C₂₈H₃₂O₁₆, [α] _D ²⁰ ?106° in methanol, mp 189–192°C), and calendoflavobioside (c₂₇H₃₀O₁₆, [α] _D ²⁰ ?105° in methanol, mp 194–197°C).     

Cyclopentadecanone 2,4‐dinitrophenylhydrazone

In the title compound, C₂₁H₃₂N₄O₄, no disorder is present in the 15‐membered hydrocarbon ring, which exists in an unsymmetrical quinquangular [12345] conformation. The 2,4‐dinitrophenylhydrazone group is approximately perpendicular to the C₁₅ ring, with a dihedral angle of 84.66 (1)° between their best planes.     

Hydrothermal Synthesis,Crystal Structure,and Catalytic Performance of Four Organic–Inorganic Hybrids Based on Polyoxometalates and O/N-Containing Groups

Four new network organic–inorganic hybrid supramolecular compounds [PW₁₂O₄₀](C₂H₄N₃)₃·6H₂O (1), [PMo₁₂O₄₀](C₂H₄N₃)₃·6H₂O (2), [H₄SiW₁₂O₄₀]₈[C₆NO₂H₄]₄[C₆NO₂H₅]₁₆[C₅NH₆]₄·39H₂O (3) and [H₃VW₁₂O₄₀] (C₆H₆NO₂)₂(CHO₂)₂·4H₂O (4) composed by keggin type heteropolyanion and O/N-containing organic groups of 1H-1,2,4-Triazole or 2,3-Pyridinedicarboxylic acid have been successfully synthesized by hydrothermally method, and characterized by infrared spectrum (IR), thermogravimetric–differentialthermal analysis (TG–DTA), cyclic voltammetry (CV) and single crystal X-ray diffraction (XRD). Compounds 1–4 exhibit three dimensional supramolecular network via hydrogen bonds and/or π–π stacking interactions. These compounds exhibit good thermal stability and catalytic ability. They are active for catalytic oxidation of methanol in a continuous-flow fixed-bed micro-reactor, when the initial concentration of methanol is 2.5 g m^?3 in air and flow rate is 10 mL min^?1, the corresponding elimination rates of methanol are 65% (125 °C), 85% (125 °C), 94% (150 °C), and 80% (125 °C), respectively.     

Trigonal–planar silver coordination in (3,5‐di­nitro­benzoato)­bis­(tri­phenyl­phosphine)­silver(I)

The three‐coordinate Ag atom in the title compound, [Ag(C₇H₃N₂O₆)(C₁₈H₁₅P)₂], shows trigonal–planar coordination [P—Ag—P = 147.1 (1)° and Σ_Ag = 359.0 (3)°]. Adjacent mol­ecules are linked through the O atoms of adjacent nitro groups [Ag?O = 3.205 (3) and 3.302 (4) Å] into a zigzag chain running parallel to the c axis.     

Crystal structures of 3/4-pyridyl-based thiosemicarbazones and related Cu and Ni coordination compounds

In this investigation, the crystal structures of the thio-ligands 3-formylpyridine 4-phenylthiosemicarbazone (C₁₃H₁₂N₄S, 1 ) and 4-benzoylpyridine 4-ethylthiosemicarbazone (C₁₅H₁₆N₄S, 2 ), and of two new coordination compounds, chlorido(3-formylpyridine 4-phenylthiosemicarbazone-κS)bis(triphenylphosphane-κP)copper(I) acetonitrile monosolvate, [CuCl(C₁₃H₁₂N₄S)(C₁₈H₁₅P)₂]·CH₃CN, 3 , and bis(3-formylpyridine 4-ethylthiosemicarbazonato-κ²N¹,S)nickel(II), [Ni(C₉H₁₁N₄S)₂], 4 , are reported. In complex 3 , the thio-ligand coordinates in a neutral form to the Cu atom through its S-donor atom, and in complex 4 , the anionic thio-ligand chelates to the Ni atom through N- and S-donor atoms. The geometry of complex 3 is distorted tetrahedral [bond angles 99.70 (5)–123.23 (5)°], with the P—Cu—P bond angle being the largest, while that of complex 4 is square planar, with trans-S—Ni—S and N—Ni—N bond angles of 180°.     

Bulk cyclopolymerization of 1,2:5,6‐diepithio‐3,4‐di‐O‐methyl‐1,2:5,6‐tetradeoxy‐D‐mannitol with quaternary ammonium salts leading to gel‐free thiosugar polymer

The bulk cyclopolymerization of diepisulfide, 1,2:5,6‐diepithio‐3,4‐di‐O‐methyl‐1,2:5,6‐tetradeoxy‐D ‐mannitol ( 1 ), was studied using R₄N⁺Br^? (R = ? CH₃, C₂H₅, C₃H₇, C₄H₉, and C₇H₁₅) and (C₄H₉)₄N⁺X^? (X = Cl, I, NO₃, and ClO₄) as the initiators. All the bulk polymerizations of 1 using quaternary tetraalkylammonium salts at 90 °C proceeded without gelation even at high conversion to produce gel‐free polymers consisting of 2,5‐anhydro‐1,5‐dithio‐D ‐glucitol (I) as the major cyclic repeating unit along with 1,5‐anhydro‐2,5‐dithio‐D ‐mannitol (II) and the desulfurized acyclic unit (III) as the minor units. The polymerization rate and molar fraction of the I unit increased with the increasing alkyl chain length of the tetraalkylammonium cation and the increasing nucleophilicity of the counteranion. Tetrabutylammonium chloride exhibited the highest catalytic activity and the highest stereoselectivity, that is, the thiosugar polymer with I:II:III = 81:15:4 and a number‐average molecular weight of 31.9 × 10³ was obtained in 85% yield for a polymerization time of 0.5 h. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 965–970, 2002     

Über die Schichtstruktur von Cu2(H2O)4[C4H4N2][C6H2(COO)4]·2H2O

The Layered Structure of Cu₂(H₂O)₄[C₄H₄N₂][C₆H₂(COO)₄]·2H₂O Triclinic single crystals of Cu₂(H₂O)₄[C₄H₄N₂][C₆H₂(COO)₄]·2H₂O have been grown in an aqueous silica gel. Space group (Nr. 2), a = 723.94(7) pm, b = 813.38(14) pm, c = 931.0(2) pm, α = 74.24(2)°, β = 79.24(2)°, γ = 65.451(10)°, V = 0.47819(14) nm³, Z = 1. Cu²⁺ is coordinated in a distorted, octahedral manner by two water molecules, three oxygen atoms of the pyromellitate anions and one nitrogen atom of pyrazine (Cu—O 194.1(2)–229.3(3) pm; Cu–N 202.0(2) pm). The connection of Cu²⁺ and [C₆H₂(COO)₄)]^4? yields infinite strands, which are linked by pyrazine molecules to form a two‐dimensional coordination polymer. Thermogravimetric analysis in air showed that the dehydrated compound was stable between 175 and 248 °C. Further heating yielded CuO.     

Hydro­gen bonding in substituted nitro­anilines: isolated nets in 1,3‐­diamino‐4‐nitrobenzene and continuously interwoven nets in 3,5‐­dinitro­aniline

Molecules of 1,3‐diamino‐4‐nitrobenzene, C₆H₇N₃O₂, are linked by N—H?O hydrogen bonds [N?O 2.964 (2) and 3.021 (2) Å; N—H?O 155 and 149°] into (4,4) nets. In 3,5‐di­nitro­aniline, C₆H₅N₃O₄, where Z′ = 2, the mol­ecules are linked by three N—H?O hydrogen bonds [N?O 3.344 (2)–3.433 (2) Å and N—H?O 150–167°] into deeply puckered nets, each of which is interwoven with its two immediate neighbours.     

The design of novel metronidazole benzoate structures: exploring stoichiometric diversity

The use of supramolecular synthons as a strategy to control crystalline structure is a crucial factor in developing new solid forms with physicochemical properties optimized by design. However, to achieve this objective, it is necessary to understand the intermolecular interactions in the context of crystal packing. The feasibility of a given synthon depends on its flexibility to combine the drug with a variety of coformers. In the present work, the imidazole–hydroxy synthon is investigated using as the target molecule benzoylmetronidazole [BZMD; systematic name 2‐(2‐methyl‐5‐nitro‐1H‐imidazol‐1‐yl)ethyl benzoate], whose imidazole group seems to be a suitable acceptor for hydrogen bonds. Thus, coformers with carboxylic acid and phenol groups were chosen. According to the availability of binding sites presented in the coformer, and considering the proposed synthon and hydrogen‐bond complementarity as major factors, different drug–coformer stoichiometric ratios were explored (1:1, 2:1 and 3:1). Thirteen new solid forms (two salts and eleven cocrystals) were produced, namely BZMD–benzoic acid (1/1), C₁₃H₁₃N₃O₄·C₇H₆O₂, BZMD–β‐naphthol (1/1), C₁₃H₁₃N₃O₄·C₁₀H₈O, BZMD–4‐methoxybenzoic acid (1/1), C₁₃H₁₃N₃O₄·C₈H₈O₃, BZMD–3,5‐dinitrobenzoic acid (1/1), C₁₃H₁₃N₃O₄·C₇H₄N₂O₆, BZMD–3‐aminobenzoic acid (1/1), C₁₃H₁₃N₃O₄·C₇H₇NO₂, BZMD–salicylic acid (1/1), C₁₃H₁₃N₃O₄·C₇H₆O₃, BZMD–maleic acid (1/1) {as the salt 1‐[2‐(benzoyloxy)ethyl]‐2‐methyl‐5‐nitro‐1H‐imidazol‐3‐ium 3‐carboxyprop‐2‐enoate}, C₁₃H₁₄N₃O₄⁺·C₄H₃O₄^?, BZMD–isophthalic acid (1/1), C₁₃H₁₃N₃O₄·C₈H₆O4, BZMD–resorcinol (2/1), 2C₁₃H₁₃N₃O₄·C₆H₆O₂, BZMD–fumaric acid (2/1), C₁₃H₁₃N₃O₄·0.5C₄H₄O₄, BZMD–malonic acid (2/1), 2C₁₃H₁₃N₃O₄·C₃H₂O₄, BZMD–2,6‐dihydroxybenzoic acid (1/1) {as the salt 1‐[2‐(benzoyloxy)ethyl]‐2‐methyl‐5‐nitro‐1H‐imidazol‐3‐ium 2,6‐dihydroxybenzoate}, C₁₃H₁₄N₃O₄⁺·C₇H₅O₄^?, and BZMD–3,5‐dihydroxybenzoic acid (3/1), 3C₁₃H₁₃N₃O₄·C₇H₆O₄, and their crystalline structures elucidated, confirming the robustness of the selected synthon.     

Lactones ofFerula gigantea

The following substances have been isolated from an acetone extract ofFerula gigantea B. Fedtsch.: a coumarin — umbelliferone, C₉H₆O₂, mp 230–233°C; and sesquiterpene lactones — talassin A, C₂₅H₃₀O₇, mp 188–191°C; malaphyllinin, C₂₄H₂₄O₇, mp 231–235°C; malaphyll, C₂₉H₃₂O₉, mp 212–213°C; and malaphyllin, C₂₆H₂₈O₉, mp 216–218°C. Structures have been proposed for three new sesquiterpene lactones on the basis of an analysis of their spectral characteristics.     

Three rotational isomers of se-methyl N,N-di-isopropyldiselenocarbamate and the sulphur analogue found in low temperature 1H NMR spectra

Variable temperature ¹H NMR spectra of Se-methyl N,N-di-isopropyldiselenocarbamate, CH₃SeC(Se)N (C₃H₇-i)₂, in CS₂ have indicated that internal rotations around both the carbamate C? N and isopropyl–nitrogen bonds are restricted below ?40°C; the compound exists as three rotational isomers with respect to the isopropyl-nitrogen bond with mol ratios of approximately 0·54:0·31 :0·15. The corresponding dithiocarbamate, CH₃SC(S)N(C₃H₇-i)₂, has also been found to exist as three isomers with ratios of about 0·71:0·27:0·02 under similar conditions. Possible conformations of both carbamate esters are proposed, together with the assignments of each proton signal.     

Kristallstruktur des Molybdän(V)‐Imido‐Komplexes [MoCl3(NtBu)(H2NtBu)]2 · 1/2 C7H8

Crystal Structure of the Molybdenum(V) Complex [MoCl₃(N^tBu)(H₂N^tBu)]₂ · ¹/₂ C₇H₈ Green moisture sensitive single crystals of [MoCl₃(N^tBu)(H₂N^tBu)]₂ ( 1 · ¹/₂ C₇H₈) have been prepared from molybdenum pentachloride with Me₂Si(HN^tBu)₂ in toluene solution; they were suitable for a crystal structure determination. 1 · ¹/₂ C₇H₈: Space group P 1, Z = 2, lattice dimensions at –83 °C: a = 696.9(1), b = 1470.9(2), c = 1579.0(2) pm, α = 96.673(13)°, β = 92.014(14)°, γ = 94.852(14)°, R = 0.0321. 1 forms centrosymmetric molecules in which the molybdenum atoms are linked by two μ‐Cl‐bridges with MoCl bond lengths of 245.7 and 270.2 pm in average of the two crystallographically independent individuals. The longer MoCl bond is in trans‐position to the nitrogen atom of the imido ligand (MoN distance 169.0 pm, MoNC bond angle 167.0° in average).     

Trimerisierung von Dicyanamid-Ionen C2N3– im Festkörper – Synthesen,Kristallstrukturen und Eigenschaften von NaCs2(C2N3)3 und Na3C6N9 · 3 H2O

Trimerization of Dicyanamide Ions C₂N₃^– in the Solid – Syntheses, Crystal Structures, and Properties of NaCs₂(C₂N₃)₃ und Na₃C₆N₉ · 3 H₂O The Tricyanomelaminate Na₃C₆N₉ · 3 H₂O is obtained by heating NaC₂N₃ to 500 °C and subsequent crystallization from water. According to the single-crystal structure determination (Na₃C₆N₉ · 3 H₂O: P62c; a = 1023.53(8), c = 650.85(15) pm, Z = 2, R1 = 0.0276, wR2 = 0.0710) in the solid cyclic C₆N₉^3– ions occur. Partial ion exchange and crystallization from water yields anhydrous NaCs₂(C₂N₃)₃. The X-ray structure determination (NaCs₂(C₂N₃)₃: P6₃/m, a = 700.01(4), c = 1449.29(7) pm, Z = 2, R1 = 0.0173, wR2 = 0.0432) reveals C₂N₃^– ions in the solid. Calorimetric investigations and detailed IR spectroscopy of NaC₂N₃, Na₃C₆N₉, Na₃C₆N₉ · 3 H₂O, as well as NaCs₂(C₂N₃)₃ reveal in combination with the structure analyses that NaC₂N₃ transforms to Na₃C₆N₉ above 380 °C by trimerization of the C₂N₃^– ions in the solid. Above 180 °C the hydrate Na₃C₆N₉ · 3 H₂O reversibly dehydrates.     

Synthesis,crystal structure,and catalytic performance of two 3-D supramolecular compounds: (C7N2H7)3(C7N2H6) · PMo12O40 · 2H2O and (C7N2H7)3(C7N2H6)2 · AsMo12O40 · 3H2O

Two organic–inorganic compounds based on Keggin building blocks have been synthesized by hydrothermal methods, (C₇N₂H₇)₃(C₇N₂H₆)?·?PMo₁₂O_40?·?2H₂O (1) and (C₇N₂H₇)₃(C₇N₂H₆)_2?·?AsMo₁₂O_40?·?3H₂O (2) (C₇N₂H₆?=?benzimidazole). Single-crystal X-ray analysis revealed that 1 crystallized in the triclinic system, P-1 space group with a?=?9.8980(4)?Å, b?=?11.2893(4)?Å, c?=?25.8933(9)?Å, α?=?93.307(2)°, β?=?90.630(2)°, γ?=?108.330(2)°, V?=?2740.68(18)?ų, Z?=?2, R ₁(F)?=?0.0740, ωR ₂(F ²)?=?0.1511, and S?=?1.037; 2 crystallized in the triclinic system, P-1 space group with a?=?12.3353(4)?Å, b?=?13.2649(4)?Å, c?=?20.2878(6)?Å, α?=?95.6630(10)°, β?=?100.1720(10)°, γ?=?99.3940(10)°, V?=?3195.72(17)?ų, Z?=?2, R ₁(F)?= 0.0329, ωR₂ (F ²)?=?0.1236, and S?=?1.088. The two compounds show a layer framework constructed from Keggin-polyoxoanion clusters and benzimidazole via hydrogen bonds and π–π stacking interactions, resulting in a 3-D supramolecular network. Both have high catalytic activity for oxidation of methanol. When the initial concentration of the methanol is 5.37?g?m^?3 in air and the flow velocity is 4.51?mL?min^?1, methanol is completely eliminated at 150°C for 1 (160°C for 2).     

The trans influence of the pyridine ligand on ruthenium(II)–porphyrin–carbene complexes

In the two ruthenium(II)–porphyrin–carbene complexes ­(di­benzoyl­carbenyl‐κC)(pyridine‐κN)(5,10,15,20‐tetra‐p‐tolyl­porphyrinato‐κ⁴N)­ruthenium(II), [Ru(C₁₅H₁₀O₂)(C₅H₅N)(C₄₈H₃₆N₄)], (I), and (pyridine‐κN)(5,10,15,20‐tetra‐p‐tolyl­porphyrinato‐κ⁴N)[bis(3‐tri­fluoro­methyl­phenyl)­carbenyl‐κC]­ruthenium(II), [Ru(C₁₅H₈F₆)(C₅H₅N)(C₄₈H₃₆N₄)], (II), the pyridine ligand coordinates to the octahedral Ru atom trans with respect to the carbene ligand. The C(carbene)—Ru—N(pyridine) bonds in (I) coincide with a crystallographic twofold axis. The Ru—C bond lengths of 1.877 (8) and 1.868 (3) Å in (I) and (II), respectively, are slightly longer than those of other ruthenium(II)–porphyrin–carbene complexes, owing to the trans influence of the pyridine ligands.     

Thermal stability of fullerene amines host-guest crystals

Fullerences C₆₀ with adamantane (C₁₀H₁₆), hexamethylotetramine (HMT, C₆H₁₂N₄) or 1,4-diazabicyclooctane (DABCO, C₆H₁₂N₂) crystallize, at the relative concentration C₆₀/guest=2/1, in the pseudotetragonal lattice in which C₆₀ retains almost the same positions as in pure fullerides. The ‘guest’ molecules occupy the octahedral interstitial sites. The mixed crystals which exhibit interesting physical properties are thermally unstable. The decomposition starts at 40–50°C.     

Two Light-Metal Dihydrogenisocyanurate Hydrates Linked by Diagonal Relationship: Syntheses,Crystal Structures,and Vibrational Spectra of Li[H2N3C3O3]·1.75 H2O and Mg[H2N3C3O3]2·8 H2O

Single-crystalline materials of Li[H₂N₃C₃O₃] · 1.75 H₂O and Mg[H₂N₃C₃O₃]₂ · 8 H₂O were obtained by dissolving stoichiometric amounts of the respective carbonates with cyanuric acid in boiling water followed by gentle evaporation of excess water after cooling to room temperature. Even though both of these compounds crystallize in the triclinic space group P1 according to X-ray structure analyses of their colorless and transparent single crystals, they adopt two new different structure types. Li[H₂N₃C₃O₃] · 1.75 H₂O exhibits the unit-cell parameters a = 884.71(6) pm, b = 905.12(7) pm, c = 964.38(7) pm, α = 67.847(2)°, β = 62.904(2)° and γ = 68.565(2)° (Z = 4), whereas the lattice parameters for Mg[H₂N₃C₃O₃]₂ · 8 H₂O are a = 691.95(5) pm, b = 1055.06(8) pm, c = 1183.87(9) pm, α = 85.652(2)°, β = 83.439(2)° and γ = 79.814(2)° (Z = 2). In both cases, the singly deprotonated isocyanuric acid forms monovalent anions consisting of cyclic [H₂N₃C₃O₃]^– units, which are arranged in ribbons typical for most hitherto known monobasic isocyanurate hydrates. The structures are governed by the oxophilic strength of the respective cation which means that they fulfil their oxophilic coordination requirements either solely with water molecules ([Mg(OH₂)₆]²⁺ for Mg²⁺) or with crystal water and one or two direct coordinative contacts to carbonyl oxygen atoms (O_(cy)) of [H₂N₃C₃O₃]^– anions ([(Li(OH₂)_2–3(O_(cy)1–2]⁺ for Li⁺). In both structures occur dominant hydrogen bonds N–H ··· O within the anionic [H₂N₃C₃O₃]^– ribbons as well as hydrogen bonds O–H ··· O between these ribbons and the hydrated Li⁺ and Mg²⁺ cations.     

Cocrystals of 6‐methyl‐2‐thiouracil: presence of the acceptor–donor–acceptor/donor–acceptor–donor synthon

The results of seven cocrystallization experiments of the antithyroid drug 6‐methyl‐2‐thiouracil (MTU), C₅H₆N₂OS, with 2,4‐diaminopyrimidine, 2,4,6‐triaminopyrimidine and 6‐amino‐3H‐isocytosine (viz. 2,6‐diamino‐3H‐pyrimidin‐4‐one) are reported. MTU features an ADA (A = acceptor and D = donor) hydrogen‐bonding site, while the three coformers show complementary DAD hydrogen‐bonding sites and therefore should be capable of forming an ADA/DAD N—H...O/N—H...N/N—H...S synthon with MTU. The experiments yielded one cocrystal and six cocrystal solvates, namely 6‐methyl‐2‐thiouracil–2,4‐diaminopyrimidine–1‐methylpyrrolidin‐2‐one (1/1/2), C₅H₆N₂OS·C₄H₆N₄·2C₅H₉NO, (I), 6‐methyl‐2‐thiouracil–2,4‐diaminopyrimidine (1/1), C₅H₆N₂OS·C₄H₆N₄, (II), 6‐methyl‐2‐thiouracil–2,4‐diaminopyrimidine–N,N‐dimethylacetamide (2/1/2), 2C₅H₆N₂OS·C₄H₆N₄·2C₄H₉NO, (III), 6‐methyl‐2‐thiouracil–2,4‐diaminopyrimidine–N,N‐dimethylformamide (2/1/2), C₅H₆N₂OS·0.5C₄H₆N₄·C₃H₇NO, (IV), 2,4,6‐triaminopyrimidinium 6‐methyl‐2‐thiouracilate–6‐methyl‐2‐thiouracil–N,N‐dimethylformamide (1/1/2), C₄H₈N₅⁺·C₅H₅N₂OS⁻·C₅H₆N₂OS·2C₃H₇NO, (V), 6‐methyl‐2‐thiouracil–6‐amino‐3H‐isocytosine–N,N‐dimethylformamide (1/1/1), C₅H₆N₂OS·C₄H₆N₄O·C₃H₇NO, (VI), and 6‐methyl‐2‐thiouracil–6‐amino‐3H‐isocytosine–dimethyl sulfoxide (1/1/1), C₅H₆N₂OS·C₄H₆N₄O·C₂H₆OS, (VII). Whereas in cocrystal (I) an R₂²(8) interaction similar to the Watson–Crick adenine/uracil base pair is formed and a two‐dimensional hydrogen‐bonding network is observed, the cocrystals (II)–(VII) contain the triply hydrogen‐bonded ADA/DAD N—H...O/N—H...N/N—H...S synthon and show a one‐dimensional hydrogen‐bonding network. Although 2,4‐diaminopyrimidine possesses only one DAD hydrogen‐bonding site, it is, due to orientational disorder, triply connected to two MTU molecules in (III) and (IV).