Phenylacetic acid co-crystals with acridine, caffeine, isonicotinamide and nicotinamide: Crystal structures, thermal analysis, FTIR spectroscopy and Hirshfeld surface analysis

Energetics of carboxylic acid–pyridine heterosynthon revisited: A computational study of intermolecular hydrogen bond domination on phenylacetic acid–nicotinamide cocrystals

Carboxylic acid–pyridine heterosynthon (CPHS) is one of the most common synthons found in cocrystal packing. Phenylacetic acid (PYC)–nicotinamide (NIC) (PYCNIC) cocrystals were used as a computational model to assess the most important factor in the emergence of the synthon. Geometry optimization was carried out on every possible two molecules of PYC–NIC conformation based on B3LYP-D3BJ/6-311G (d,p). Various energetic parameters, including total energy, interaction energy, and hydrogen bond energy, were used to compare the existing conformation to the putative conformation. The conformation with CPHS has −53.87 kJ mol−1 of single intermolecular hydrogen bond energy (EHB), which is the strongest of all. It turns out that there is no other parameter better than EHB to describe the superiority of CPHS in PYCNIC.

Raman and Terahertz Spectroscopic Characterization of Solid-state Cocrystal Formation within Specific Active Pharmaceutical Ingredients

Cocrystallization of specific active pharmaceutical ingredients (APIs) in the solid-state phase is becoming a feasible way to improve their corresponding physicochemical properties and ultimate bioavailability without making and breaking any covalent bonds within them. Many recent reports deal with the characterization and analysis topics of pharmaceutical APIs-based cocrystals. In this mini-review, we will focus on the recent steady-state and time-dependent spectroscopic investigation into the cocrystallization of specific APIs based on both Raman and emerging terahertz spectroscopy in pharmaceutical fields. Distinctive spectral, structural and also kinetic information of pharmaceutical APIs-based cocrystals are obtained and discussed, which would highlight the potential of vibrational spectroscopy as an attractive technique for various drug research and development during cocrystallization of specific APIs.

Crystal structure of ethyl-5-formyl-3,4-dimethylpyrrole-2-carboxylate — N-(5-ethoxycarbonyl-3,4-dimethylpyrrole)-2-methylene-5-nitrobenzene-1,2-diamine (1:1), C26H31N5O7

C26H31N5O7, monoclinic, P21/n (no. 14), a = 7.0353(5) Å, b = 15.1943(8) Å, c = 24.8536(13) Å, β = 92.314(4)°, V = 2654.6(3) Å3, Z = 4, R gt(F) = 0.0535, wR ref(F 2) = 0.1615, T = 296(2) K.

Crystal structure of ethyl 5-formyl-3,4-dimethylpyrrole-2-carboxylate–1-(propan-2-ylidene)thiosemicarbazide (1/1), C14H22N4O3S

C13H17N3OS, triclinic, P1̄ (no. 2), a = 6.9906(9) Å, b = 8.0075(11) Å, c = 16.057(2) Å, α = 81.822(2)°, β = 89.151(2)°, γ = 70.735(2)°, V = 839.4(2) Å3, Z = 2, R gt(F) = 0.0444, wR ref(F 2) = 0.1299, T = 296(2) K.