Ternary Cocrystals Research Articles

Trimesic Acid as a Building Block for Ternary and Quaternary Salts and Salt Cocrystals.

In the field of cocrystals, the synthon-based design of two-component crystals is well established and the interest is now shifting toward higher order cocrystals as the next challenge. Carboxylic acids form a robust synthon with pyridyl coformers and interact with 2-aminopyrimidines through a pair of strong, charge-assisted hydrogen bonds. In this work we describe the formation of higher order salts and salt cocrystals of trimesic acid using 2,4-diaminopyrimidine (pyrimethamine, trimethoprim) and pyridyl (4,4'-bipyridine, 1,2-di(4-pyridyl)ethylene, 1,3-di(4-pyridyl)propane, 4-phenylpyridine) coformers. We report the single crystal structures of five binary, eight ternary and three quaternary systems with the compositions AB, A2B, A3B, A2BC, A3BC, A2BC1.5, ABC1.5, A1 2A2B, ABC1C,2 A2BC1C2 0.5, and A1A2BC where A is a 2,4-diaminopyrimidine cation, B is the mono-, di- or trianion of trimesic acid and C is a pyridine. We also show that the ternary and quaternary salts and salt cocrystals can be prepared in bulk quantities by liquid-assisted grinding.

Ternary π-π Stacking Complexes by Allosteric Regulation in Multilayer Nanographenes.

Construction of π-π stacking supramolecular complexes with more than two different components is challenging due to the weak and directionless nature of dispersion interactions. Here, we report ternary complexes of a ditopic nanographene tetraimide (1), α-substituted phthalocyanine (Pc), and polyaromatic hydrocarbons (PAHs) in solution and the crystalline state via allosteric regulation. Binding of one Pc gives rise to significant distortion and conformational changes in 1 that in turn lead to the inhibition of the second binding of Pc. The conformational changes associated with first binding allowed an allosteric binding of a third component (PAHs) to form ternary complexes in solution. 1H NMR titration revealed moderately high thermodynamic stability for the ternary complexes in CDCl3. Competition between allosterically regulated ternary complexes ([Pc·1·PAH]) and 1:2 stoichiometric binary complexes of 1 with PAHs ([PAH·1·PAH]) was elucidated. Further, the selective formation of ternary complexes in solution led to the generation of ternary cocrystals from a 1:1:1 mixture of three components in solution. Our work shows that large π-conjugated nanographenes designed with allosteric recognition sites allow the construction of multilayer ternary complexes in solution and the solid state even with dispersive π-π interactions.

Effect of the Functional Group Position in Coformers on Ternary Cocrystals: A Case of Sulfamoylbenzoic Acids

Effect of the Functional Group Position in Coformers on Ternary Cocrystals: A Case of Sulfamoylbenzoic Acids

Integrating Molecular Motions in Ternary Cocrystals for NIR‐II Photothermal Conversion

Organic photothermal conversion materials hold immense promise for various applications owing to their structural flexibility. Recent research has focused on enhancing near‐infrared (NIR) absorption and mitigating radiative transition processes. In this study, we have developed a viable approach to the design of photothermal conversion materials through the construction of ternary organic cocrystals, by introducing a third component as a molecular blocker and motion unit into a binary donor–acceptor system. Superstructural and photophysical properties of the ternary cocrystals were characterized using various spectroscopic techniques. The role of the molecular blocker in radical stabilization and photothermal conversion were demonstrated. Intriguingly, the motions of the entire pyrene molecules in the cocrystal have been observed by variable temperature single‐crystal X‐ray diffraction results. The excellent performance of ternary cocrystal as a photothermal material was validated through efficient NIR‐II photothermal and solar‐driven water evaporation experiments. The efficiency of water evaporation reached 88.7 %, with a corresponding evaporation rate of 1.29 kg m−2 h−1, representing excellent performance among pure organic small molecular photothermal conversion materials. Our research underscores the introduction of molecular blockers and motion units to stabilize radicals and produce outstanding photothermal conversion materials, offering new pathways for developing efficient and stable photothermal conversion materials.

Integrating Molecular Motions in Ternary Cocrystals for NIR-II Photothermal Conversion.

Organic photothermal conversion materials hold immense promise for various applications owing to their structural flexibility. Recent research has focused on enhancing near-infrared (NIR) absorption and mitigating radiative transition processes. In this study, we have developed a viable approach to the design of photothermal conversion materials through the construction of ternary organic cocrystals, by introducing a third component as a molecular blocker and motion unit into a binary donor-acceptor system. Superstructural and photophysical properties of the ternary cocrystals were characterized using various spectroscopic techniques. The role of the molecular blocker in radical stabilization and photothermal conversion was demonstrated. Intriguingly, the motions of the entire pyrene molecules in the cocrystal have been observed by the results of variable temperature single-crystal X-ray diffraction. The excellent performance of the ternary cocrystal as a photothermal material was validated through efficient NIR-II photothermal and solar-driven water evaporation experiments. The efficiency of water evaporation reached 88.7 %, with a corresponding evaporation rate of 1.29 kg m-2 h-1, representing excellent performance among pure organic small molecular photothermal conversion materials. Our research underscores the introduction of molecular blockers and motion units to stabilize radicals and produce outstanding photothermal conversion materials, offering new pathways for developing efficient and stable photothermal conversion materials.

Rational Design of the Carbamazepine Ternary Cocrystals

Rational Design of the Carbamazepine Ternary Cocrystals

Ternary Cocrystal with Long‐Lived Charge‐Transfer State for Efficient Light Conversion Applications

AbstractCharge‐transfer (CT) cocrystals have attracted continuous interest for their promising optical and optoelectronic applications. To improve the performance of this class of material, a CT cocrystal with long‐lived CT excitons is highly desired. Herein, the development of a pyrene‐doped trans‐1,2‐diphenylethylene‐1,2,4,5‐tetracyanobenzene ternary cocrystal (named P‐TS‐TC) is reported. Compared to the undoped binary cocrystals (without pyrene), P‐TS‐TC exhibits a two times longer CT exciton lifetime (≈60.2 ns), and thus 8.8‐ and 16.6‐times improvement in photocurrent response and photocatalytic H2 evolution activity. By using transient photoluminescence spectroscopy, it is uncovered that the absorbed photon energy in P‐TS‐TC is localized to a lower energy CT state through an efficient energy transfer process (≈389.8 ps) between two co‐existing CT states. The CT exciton lifetime is prolonged due to the weakened CT coupling strength, as a result of the enlarged donor‐acceptor distance and the change of geometric structure. The result is expected to inspire the design of cocrystals with manipulatable CT exciton properties and to promote the potential application of multi‐component CT cocrystals.

Comparison of mechanochemical methods in the synthesis of binaphthol-benzoquinone based cocrystals.

Mechanochemical methods either under neat or liquid assisted conditions have proven to be successful in making cocrystals. In this paper we compare the outcome of cocrystallization using two different mechanochemical methods, ball milling (BM) and resonant acoustic mixing (RAM), with solution crystallization. Racemic binaphthol and benzoquinone based binary and ternary cocrystals were investigated by BM and RAM. Both mechanochemical methods were successful in making the binary and ternary cocrystals that have been observed in solid state and solution. It is shown that the type of mechanochemical force imparted to the sample is very different between BM and RAM and this in turn leads to different cocrystallization outcomes. Thus, different mechanochemical methods should not be treated as the same and care must be taken when choosing a mechanochemical method for a particular application.

Thermodynamic stability relationship of ternary and binary cocrystals of isoniazid: why pH and coformer concentration matter

We explained the thermodynamic behavior of ternary and binary cocrystals of isoniazid, identifying conditions where solution-mediated transformations may take place.

Cocrystallization-Driven Double-Optimized Stratagem toward Directional Self-Assembly for the First Ternary Salt Cocrystal of Cardiotonic Drug Milrinone with Different Phenolic Acids Exhibits Optimal In Vitro/Vivo Biopharmaceutical Peculiarities.

The current research leverages the structural features and property superiorities along with benefits in protecting cardiovascular system of gallic acid (GLC) and gentisic acid (HGA) to optimize in vitro/vivo peculiarities of cardiotonic drug milrinone (MIL) through developing a stratagem of cocrystallization-driven double-optimized ternary salt cocrystal. This strategy assembles MIL ternary salt cocrystal by shaping a cocrystallization moiety relying on noncovalent interplays with GLC to obtain permeability advancement and molding a salt segment via the salification of proton transfer between HGA and MIL molecules to facilitate solubility enhancement. While the ameliorative in vitro properties further modulate the in vivo pharmacokinetic behaviors, thus fulfilling a dual optimization of MIL's biopharmaceutical characteristics on both in vitro and in vivo aspects. Along this line, the first MIL ternary salt cocrystal, viz., [HMIL+-GA-]-MIL-GLC-H2O (denoted as MTSC hereinafter), has been satisfactorily constructed and precisely structurally identified by diversified techniques. The single-crystal X-ray diffraction experiment validates that a molecular salt [HMIL+-GA-] species cocrystallizes with one neutral MIL, two GLC, and five solvent water molecules, among which the organic constituents compose laminated hydrogen bond networks, and then are self-assembled by water molecules to a 3D supramolecular structure. The unique structural feature and stacking pattern of MTSC make both the permeability and solubility be respectively enhanced by 9.69 times and 5.17- to 6.03-fold compared with the parent drug per se. The experimental outcomes are powerfully supported by associated calculations based on density functional theory. Intriguingly, these optimal in vitro physicochemical natures of MTSC have been potently converted into strengths of in vivo pharmacokinetics, showcasing the elevated drug plasma concentration, elongated half-life, alongside advanced bioavailability. Consequently, this presentation not just contributes a brand-new crystalline form with utility values, but ushers in a new dimension of ternary salt cocrystals for improving in vitro/vivo limitations of poor drug bioavailability.

Precise Tuning Near‐Infrared Photothermal Conversion of Ternary Cocrystals via Supramolecular Interactions

Effective utilization of solar energy through cocrystal strategy is still a considerable challenge. Herein, the ternary cocrystal strategy is subtly applied to broaden the absorption of cocrystals, resulting in an efficient solar photothermal conversion (PTC). Specifically, the donors of triphenylene (T) and perylene (P) and guest molecules anthracene (AT), pyrene (PY), and perylene (P) are self‐assembled with 7,7,8,8‐tetracyanoquinodimethane (TCNQ) to obtain five ternary cocrystals (AT‐T‐TCNQ, PY‐T‐T‐TCNQ, AT‐P‐TCNQ, PY‐P‐TCNQ, and P‐P‐TCNQ). The PTC of ternary cocrystals can be regulated by changing the number of benzene rings of donor and guest molecules, which may be attributed to the π–π and C–H···π intermolecular interactions. Femtosecond transient absorption and excited‐state theoretical calculations confirm that the intense π–π stacking interactions facilitate the light‐harvesting capability, while the weak C–H···π interactions are conducive to molecular stacking loosening and thus facilitate the rotation of C(C ≡ N)2, which promotes nonradiative transition to achieve the efficient PTC. As expected, the PTC efficiencies of AT‐T‐TCNQ, PY‐T‐TCNQ, AT‐P‐TCNQ, PY‐P‐TCNQ, and P‐P‐TCNQ are 59.62%, 63.07%, 81.72%, 79.06%, and 87.72%, respectively, under 808 nm irradiation. Due to the P‐P‐TCNQ having excellent near‐infrared PTC efficiency, it is applied in a solar‐driven interfacial heating evaporation system, gaining a decent evaporation efficiency (83.1%).

Ketoprofen, lysine and gabapentin co-crystal magnifies synergistic efficacy and tolerability of the constituent drugs: Pre-clinical evidences towards an innovative therapeutic approach for neuroinflammatory pain

Chronic pain is an enormous public health concern, and its treatment is still an unmet medical need. Starting from data highlighting the promising effects of some nonsteroidal anti-inflammatory drugs in combination with gabapentin in pain treatment, we sought to combine ketoprofen lysine salt (KLS) and gabapentin to obtain an effective multimodal therapeutic approach for chronic pain. Using relevant in vitro models, we first demonstrated that KLS and gabapentin have supra-additive effects in modulating key pathways in neuropathic pain and gastric mucosal damage. To leverage these supra-additive effects, we then chemically combined the two drugs via co-crystallization to yield a new compound, a ternary drug-drug co-crystal of ketoprofen, lysine and gabapentin (KLS-GABA co-crystal). Physicochemical, biodistribution and pharmacokinetic studies showed that within the co-crystal, ketoprofen reaches an increased gastrointestinal solubility and permeability, as well as a higher systemic exposure in vivo compared to KLS alone or in combination with gabapentin, while both the constituent drugs have increased central nervous system permeation. These unique characteristics led to striking, synergistic anti-nociceptive and anti-inflammatory effects of KLS-GABA co-crystal, as well as significantly reduced spinal neuroinflammation, in translational inflammatory and neuropathic pain rat models, suggesting that the synergistic therapeutic effects of the constituent drugs are further boosted by the co-crystallization. Notably, while strengthening the therapeutic effects of ketoprofen, KLS-GABA co-crystal showed remarkable gastrointestinal tolerability in both inflammatory and chronic neuropathic pain rat models. In conclusion, these results allow us to propose KLS-GABA co-crystal as a new drug candidate with high potential clinical benefit–to–risk ratio for chronic pain treatment.

Organic Binary and Ternary Cocrystal Engineering Based on Halogen Bonding Aimed at Room-Temperature Phosphorescence.

Recently, there has been intense interest in pure organic room-temperature phosphorescence (ORTP) from cocrystals composed of 1,4-diiodotetrafluorobenzene (DITFB) and a variety of polycyclic aromatic hydrocarbons (PAHs) or their derivatives. To expand the possibility of halogen bonding-based cocrystals, the relationship between the crystal packing motifs and ORTP characteristics in binary cocrystals composed of DITFB and PAHs of phenanthrene (Phen), chrysene (Chry), and pyrene (Pyr), respectively, is investigated. The σ-hole···π and π-hole···π interactions determine not only the crystal packing motifs but also photoluminescence quantum yields (PLQYs). The Phen-DITFB and Chry-DITFB binary cocrystals withσ-hole···πinteractions show higher PLQY compared with the Pyr-DITFB binary cocrystal with π-hole···πinteraction. Further, to clarify the effect of crystal structures on PLQY, ternary cocrystals are prepared by partially doping Pyr into Phen-DITFB. The crystal packing motif of the ternary cocrystal originates from a Phen-DITFB cocrystal with σ-hole···π interaction, and some of the Phen sites are randomly replaced with Pyr molecules. The ORTP emission is derived from Pyr. The maximum PLQY is >20% due to suppressing nonradiative decay by changing the crystal packing motif.

Vibrational spectroscopic detection and analysis of isoniazid-nicotinamide-succinic acid ternary cocrystal

In this paper, binary and ternary cocrystals in the ternary cocrystal system of isoniazid-nicotinamide-succinic acid were prepared by solvent evaporation and grinding methods. All of them were characterized by terahertz time-domain spectroscopy (THz-TDS), confirming that the cocrystals could be obtained by the above two methods. In addition, to investigate the formation of hydrogen bonds and their influence in cocrystal, several possible forms of hydrogen bond in cocrystal were simulated by density functional theory (DFT). The simulated result was in good agreement with the experimental result, indicating that the hydrogen bonds in cocrystal were the carboxyl groups on both side of succinic acid forming a pyridine N-carboxylic acid heterosynthon with pyridine N of isoniazid or nicotinamide respectively. Meanwhile, the vibrational modes of the cocrystal were analyzed to investigate the effect of hydrogen bond to the molecules. To further understand the formation process of ternary cocrystal in this system, Raman spectroscopy was used to analyze the cocrystal samples with different time of grinding. Process information of cocrystal formation were obtained by analyzing the changes of the characteristic peaks in the corresponding Raman spectra. These results provide a wealth of information and a unique approach to the analysis of both structures and intermolecular interactions shown within ternary cocrystal.

Elucidating mechanochemical reactivity of a ternary halogen-bonded cocrystal system by computational and calorimetric studies.

Discovery of a halogen-bonded ternary cocrystal of 1,3,5-trifluoro-2,4,6-triiodobenzene with pyrazine and triphenylphosphine sulfide has revealed a complex landscape of multicomponent phases, all achievable by mechanochemical interconversion. The observed solid-state reaction pathways were explained by periodic density-functional calculations and comprehensive intermolecular interaction analysis, supported by dissolution calorimetry measurements.

Synthetic Strategies toward Higher Cocrystals of Some Resorcinols

Higher cocrystal synthesis depends on precise strategic approaches. A total of 32 stoichiometric ternary and quaternary cocrystals based on resorcinol derivatives were achieved using structural inequivalence and shape–size mimicry approaches and are reported here. Along with 28 binary precursors that were also obtained, these 60 cocrystals serve to generalize synthetic strategies toward these ends. A number of large synthon Aufbau modules (LSAMs) were designed depending on the substitution pattern in the resorcinol. The LSAMs from 5-substituted resorcinol were found to be useful in designing higher cocrystals. The construction of a stoichiometric quaternary cocrystal without the “special” compound 2,3,5,6-tetramethylpyrazine has been finally secured.

The strange case of metal coordination in disubstituted-biquinolines: competition between ligands and formation of a hybrid organic/inorganic Cu(II)/Cu(I) ternary cocrystal

The synthesis of a new Cu(II) derivative, [(biq-OH)CuCl2], (4,4-bis(hydroxymethyl)-2,2-biquinoline (biq-OH)), and its reaction with potassium tropolonate (KTrop) is herein reported and the surprising results are discussed. Due to the steric requirements of the biq moiety, the tetrahedral geometry adopted by [(biq-OH)CuCl2] derivative makes it an unstable species, causing an overall rearrangement after reaction with KTrop, with competition between ligands and reduction of the copper ion. Indeed, a heteroleptic Cu(II) complex, [(biq-OH)Cu(Trop)Cl], and a ternary cocrystal, {[Cu(Trop)2][Cu(biq-OH)2]Cl}(biq-OH), in which homoleptic Cu(II) and Cu(I) species coexist, could be isolated from the reaction mixture and characterized. Single crystal X-ray analysis of both the biq-OH ligand and the ternary cocrystal {[Cu(Trop)2][Cu(biq-OH)2]Cl}(biq-OH) are reported and a deep analysis of the intermolecular interactions of their supramolecular assemblies in the solid crystalline state, conducted by Hirshfeld surface and contact enrichment tools, are thus reported.

Playing with Isostructurality from Binary Cocrystals to Ternary Cocrystal Solvates of Quercetin: Tuning Colors of Pigment

Playing with Isostructurality from Binary Cocrystals to Ternary Cocrystal Solvates of Quercetin: Tuning Colors of Pigment

Synthesis of Ternary Cocrystals, Salts, and Hydrates of Acefylline with Enhanced Dissolution and High Permeability

Synthesis of Ternary Cocrystals, Salts, and Hydrates of Acefylline with Enhanced Dissolution and High Permeability

Formation of Salts and Molecular Ionic Cocrystals of Fluoroquinolones and α,ω-Dicarboxylic Acids.

The cocrystallization of the fluoroquinolones ciprofloxacin (cip), norfloxacin (nor), and enrofloxacin (enro) with the α,ω-dicarboxylic acids glutaric acid (glu), adipic acid (adi), pimelic acid (pim), suberic acid (sub), azeliac acid (az), and sebacic acid (seb) resulted in 27 new molecular salts and ternary molecular ionic cocrystals of compositions A+B–, A2+B2–, A2+B2–B, and A+B–A. Depending on the solvent, different stoichiomorphs, solvates, or polymorphs were obtained. All salts and cocrystals contain the robust R2NH2+...–OOC or R3NH+...–OOC synthon but have different supramolecular ring motifs. Moderate solubility enhancements over the parent fluoroquinolones were observed. Salts in the ratio of 1:1 and 2:1 were also prepared by ball-milling. The milled sample nor/az (1:1) was shown to gel the GRAS (generally recognized as safe) solvent propylene glycol, and enro/sub (1:1) was shown to gel both propylene glycol and water. Dynamic rheology measurements confirmed that nor/az and enro/sub behave like viscoelastic materials and supramolecular gels.