Molecular structures of ten ionic hydrogen bond-mediated anhydrous tert-butylammonium salts from different carboxylic acids

Cocrystallization of the simplest bulky organic amine, tert-butylamine (L), with a series of organic acids got a whole of 10 anhydrous salts with the compositions: tert-butylammonium 2-(4-chlorophenoxy)-2-methylpropionate [(HL)(+) center dot (cpmppa(-)), cpmppa(-)= 2-(4-chlorophenoxy)-2-methylpropionate] (1), bis(tert-butylammonium) dibenzoyl-l-tartarate [(HL+)(2) center dot (dbztat)(2-), (dbztat)(2-) = dibenzoyl-l-tartarate] (2), tert-butylammonium pyrazinecarboxylate [(HL+)center dot(pyrca)(-), pyrca = pyrazinecarboxylate] (3), tertbutylammonium 2-(4-chlorobenzoyl)benzoate [(HL+)center dot (cbzbz)(-), cbzbz = 2-(4-chlorobenzoyl)benzoate] (4), tert-butylammonium 3-methylsalicylate [(HL+)center dot(3-msal)(-), 3-msal = 3-methylsalicylate] (5), tert-butylammonium 4-methylsalicylate [(HL+)center dot (4-msal)(-), 4-msal = 3-methylsalicylate] (6), tertbutylammonium 2-chloro-4-nitrobenzoate [(HL+)center dot(cnba)(-), cnba = 2-chloro-4-nitrobenzoate] (7), tertbutylammonium 4-bromo-3,5-dimethoxy benzoate [(HL+)center dot (bdmbza)(-), bdmbza = 4-bromo-3,5-dimethoxy benzoate] (8), tert-butylammonium 3,5-diiodosalicylate [(HL+)center dot (didsal)(-), didsal = 3,5-diiodosalicylate] (9) and tert-butylammonium 3,5,6-trichlorosalicylate [(HL+)center dot(tcsal)(-), tcsal =3,5,6-trichlorosalicylate] (10). The salts have been featured by XRD, IR and EA, the melting points were also gauged. Their structural and supramolecular aspects are analyzed in detail; all compounds are ionic with H-transferring to the tert-butylamine. The result unveils that among the whole investigated crystals the NH2 units in L are protonated when the acids are deprotonated and the crystal packing is interpreted via the strong charge-assisted N-H center dot center dot center dot O H-bond from the NH3+ and the CO2-. Apart from the N-H center dot center dot center dot O H-bond, the O-H center dot center dot center dot O H-bonds were also found at 5, 6, 9 and 10. 3, 9 and 10 had the additional N-H center dot center dot center dot N, N-H center dot center dot center dot I and N-H center dot center dot center dot Cl H-bonds, respectively. Deep analysis of the crystal packing uncovered that a different set of additional O center dot center dot center dot O, Cl center dot center dot center dot Cl, Cl center dot center dot center dot O, Br center dot center dot center dot O, I center dot center dot center dot I, CH3 center dot center dot center dot C, CH3 center dot center dot center dot CH, CH3 center dot center dot center dot CH3, CH center dot center dot center dot O/CH3 center dot center dot center dot O, CH3 center dot center dot center dot Cl and CH3 center dot center dot center dot pcontacts contribute to the stabilization and expansion of the total structures. For the synergism of the various nonbonding forces these structures had the homo/hetero supramolecular synthons. Some classical synthons of R-2(2)(8), R-4(2)(8), R-4(3)(10) and R-4(4)(12), commonly contained in solids of organic acids with amine, were present in these hydrogen bonding nets. (C) 2021 Elsevier B.V. All rights reserved.