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) + ·(cpmppa − ), cpmppa − =2-(4-chlorophenoxy)-2-methylpropionate] (1) , bis(tert‑butylammonium) dibenzoyl- l -tartarate [(HL + ) 2 ·(dbztat) 2− , (dbztat) 2-  = dibenzoyl- l -tartarate] (2) , tert‑butylammonium pyrazinecarboxylate [(HL + )·(pyrca) − , pyrca = pyrazinecarboxylate] (3) , tert‑butylammonium 2-(4-chlorobenzoyl)benzoate [(HL + )·(cbzbz) − , cbzbz = 2-(4-chlorobenzoyl)benzoate] (4) , tert‑butylammonium 3-methylsalicylate [(HL + )·(3-msal) − , 3-msal = 3-methylsalicylate] (5) , tert‑butylammonium 4-methylsalicylate [(HL + )·(4-msal) − , 4-msal = 3-methylsalicylate] (6) , tert‑butylammonium 2‑chloro-4-nitrobenzoate [(HL + )·(cnba) − , cnba = 2‑chloro-4-nitrobenzoate] (7) , tert‑butylammonium 4‑bromo-3,5-dimethoxy benzoate [(HL + )·(bdmbza) − , bdmbza = 4‑bromo-3,5-dimethoxy benzoate] (8) , tert‑butylammonium 3,5-diiodosalicylate [(HL + )·(didsal) − , didsal = 3,5-diiodosalicylate] (9) and tert‑butylammonium 3,5,6-trichlorosalicylate [(HL + )·(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 NH 2 units in L are protonated when the acids are deprotonated and the crystal packing is interpreted via the strong charge-assisted N H⋯O H-bond from the NH 3 + and the CO 2 − . Apart from the N H⋯O H-bond, the O H···O H-bonds were also found at 5, 6, 9 and 10. 3, 9 and 10 had the additional N H⋯N, N H···I and N H···Cl H-bonds, respectively. Deep analysis of the crystal packing uncovered that a different set of additional O···O, Cl···Cl, Cl···O, Br···O, I···I, CH 3 ···C, CH 3 ···CH, CH 3 ···CH 3 , CH···O/CH 3 ···O, CH 3 ···Cl and CH 3 ···π contacts 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.