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The structure of bis(4-trimethylammoniumbenzoate) hydroiodide hydrate 1 has been studied by X-ray diffraction, B3LYP/6–311G(d,p) calculations, FTIR, Raman and NMR spectroscopic techniques. The crystal is polar in monoclinic space group Cc. Two 4-trimethylammoniumbenzoate moieties are joined by a short and asymmetric hydrogen bond of 2.45(2) Å. Water molecules are gradually released from the structure, causing shifts in the position of iodine anions, which induces their disorder. The water molecule interacts with 4-trimethylammoniumbenzoate moiety and iodide anion via two O(3)–H(1)⋯O(1) and O(3)–H(2)⋯I(1) hydrogen bonds of lengths 2.70(3) and 3.51(1) Å. Hydrogen bonds in theoretically predicted structures of 2 and 3 (in vacuum), and 4 , 5 (in DMSO) optimized by the B3LYP/6-311G(d,p) approach are slightly longer than in crystal 1 . The FTIR spectrum of 1 shows a broad and intense absorption in the 1500–400 cm −1 region, typical of short hydrogen bonds assigned to the ν as (OHO) + γ (OHO) vibrations. The correlations between the experimental 13 C and 1 H chemical shifts ( δ exp ) of the investigated compound in DMSO and the GIAO/B3LYP/6-311G(d,p) magnetic isotropic shielding constants ( σ calc ) calculated by using the screening solvation model (COSMO) are linear, δ exp = a + b σ calc , and they well reproduce the experimental chemical shifts. [ABSTRACT FROM AUTHOR]

The 1:2 complex of 1,4-dimethylpiperazine mono-betaine (MBPZ) with squaric acid (H2SQ) has been characterised by single-crystal X-ray analysis, FTIR and NMR spectroscopies, and by DFT calculations. The crystals are monoclinic, space groupP21/c. Two MBPZ cations and four hydrogen squarate anions (HSQ− ) are linked by strong O(1)–H…O(13) (2.525(4) Å), O(14)–H…O(21) (2.511(4) Å) and N(4)–H…O(23) (2.607(3) Å) hydrogen bonds into a cyclamer. In turn, the cyclamers are linked into a helixthrough two O(24)–H…O(11) hydrogen bonds of 2.516(4) Å. The piperazinium ring has a chair conformation with N(4)–CH3and N(1)–CH2COOH substituents in the equatorial positions, and N(1)–CH3in the axial position. The FTIR spectrum is consistent with the crystal data. Two models of the 1:2 complex of MBPZ with H2SQ have been optimised at the B3LYP/6-311++G(d,p) level of theory and have been used to calculate harmonic IR frequencies. One of the models (2) is dominated by electrostatic attraction between NH(4)+and HSQ− , whereas in the other (3) squaric acid interacts with a zwitterionic MBPZ through the O–H…O and O–H…N hydrogen bonds. [ABSTRACT FROM PUBLISHER]

A novel anhydrous 1:1 and 2:1 complexes of quinoline betaine (QB) with perchloric acid have been prepared and their structures determined by X-ray diffraction. The 1:1 complex betaine is protonated and the carboxylate group forms a hydrogen bond with the ClO4 ion: O⋯O distance is 2.820(3) A˚. In the 2:1 complex, the carboxylate group of a pair of QB molecules are bridged by a proton to form dimeric cation in non-planar configuration, [(QB)2H]+, featuring a very strong hydrogen bond of the length 2.453(3) A˚. The FTIR spectrum of the 1:1 complex shows a strong absorption at ca. 3100 cm−1 due to the νOH vibration. Broad and intense absorption in the 1500–400 cm−1 region in the spectrum of the 2:1 complex is typical for the very short hydrogen bonds. B3LYP calculations predict slightly shorter hydrogen bonds with different orientation of the ring vs. COOH group than these observed in crystals. [Copyright &y& Elsevier]

A novel and unique crystalline three-component complex was formed of 2-(1-piperidine)ethanol, p -hydroxybenzoic acid and water at the ratio 1:1:1. Its structure has been determined by single-crystal X-ray diffraction. This is an example of a hydrogen-bonded interaction between amino alcohol and benzoic acid molecules. Water acts as a bridge between molecules. The molecules are linked through medium-strong OH⋯O hydrogen bonds from 2.665(6) to 2.813(6) Å and NH⋯O one 2.744(5) Å in length. The molecular structure of 2-(1-piperidinium)ethanol p -hydroxybenzoate hydrate has been characterized by FTIR and Raman spectra and optimized at the B3LYP/6−311++G(d,p) level of theory. The potential energy distributions (PED) have been used to assign the vibrational spectra. Charge delocalization was analyzed using the natural bond orbital (NBO) methods. [ABSTRACT FROM AUTHOR]

The 1:1 complex of piperidine-4-carboxylic acid (isonipecotic acid, P4C) with 2,6-dichloro-4-nitrophenol (DCNP), has been investigated by single-crystal X-ray analysis, Raman and FTIR spectroscopy and theoretical calculations. The hydrogen-bonded-ion-pair complex is observed in the crystalline state with the O⋯H⋯OOC hydrogen bond of 2.453(16) Å. FTIR spectrum shows a broad absorption in the 1600–400 cm −1 region characteristic of very short OHO hydrogen bond, broken by the Evans holes. The complexes are joined through N H⋯O into a H-bonding network. The N H⋯O mode appears as a broad band in the range of 3100–2000 cm −1 . In the structure optimized at the B3LYP/6–311 + +G(d,p) level of theory the proton is transferred from DCNP to P4C, and molecules are joined through the O⋯HOOC hydrogen bond of 2.640 Å. The experimental and theoretical infrared spectra are discussed. Detail interpretation of the vibrational spectra has been carried out with the use of computed Potential Energy Distribution (PED). [ABSTRACT FROM AUTHOR]

( R / S )-Piperidine-3-carboxylic acid (P3C, nipecotic acid) forms a stable 1:1 hydrogen-bonded complex with 2,6-dichloro-4-nitrophenol (DCNP). Both, in crystal and in the optimized theoretically structure by the B3LYP/6-311 + +G(d,p) approach the proton is transferred from DCNP to P3C. The ( R ) and ( S )-stereoisomersic complexes of piperidinium-3-carboxylic acid 2,6-dichloro-4-nitrophenolate, P3C + H·DCNP − , aggregate into centrosymmetric cyclic dimers through the COOH⋯O − and N + H⋯ONO hydrogen bonds of 2.57(1) and 3.06(1) Å, respectively, which in turn are linked into a ladder-type cyclamer through the C H⋯Cl hydrogen bonds of 3.71(1) Å. The title compound is characterized by single-crystal X-ray analysis, Raman and FTIR spectroscopies. The structures of the complexes of the ratio 1:1 (monomer), 2:2 (dimer) and 4:4 (cyclamer) of P3C + H·DCNP − units are optimized by the B3LYP/6-311 + + G(d,p) approach and compared with the solid-state experimental structure. Detail interpretation of the vibrational spectra has been carried out by computing Potential Energy Distribution (PED). Charge delocalization has been analyzed using the Natural Bond Orbital (NBO) method. [ABSTRACT FROM AUTHOR]

Abstract: The 2:2 hydrogen-bonded complex between Kemp’s triacid (KTA) and 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene (MTBD) has been synthesised and studied by X-ray and FT-IR methods. The crystals of KTA–MTBD are orthorhombic, space group is Pbca with a= 15.3435(9)Å, b =13.0764(7)Å, c= 21.2403(14)Å, and Z =8. In the solid state two protonated MTBD and two deprotonated KTA molecules form a hydrogen-bonded dimer. The dimer structure is stabilised by two OH⋯O− middle strength and two N+H⋯Otermolecular hydrogen bonds as well as by two OO− very strong intramolecular hydrogen bonds. The existence of these three types of hydrogen bonds is well visible in the FT-IR spectrum of the complex and is discussed in detail. [ABSTRACT FROM AUTHOR]

Abstract: Structure of the 2:2 complex of cyclic oxaalkyl diamide of o-phthalic acid (CPhDA) with sodium perchlorate is studied by X-ray diffraction, ESI-MS, FT-IR, 1H and 13C NMR as well as PM5 semiempirical methods. The crystal space group is P2 1 /n with a =8.599(1)Å, b =14.802(2)Å, c =13.988(2)Å, β= 93.37(1)° and Z =4. In the dimeric crystal structure each sodium cation is coordinated by oxygen atoms of two CPhDA molecules. The ESI-MS measurements have proved that in the gas phase the 2:2 (or 1:1) as well as 2:1 complexes are formed. In the acetonitrile solution the equilibrium between the 2:2 and 1:1 complexes is found. The structures of the 2:2, 1:1 and 2:1 complexes of CPhDA with sodium cation are visualized using the PM5 method and discussed in detail. [Copyright &y& Elsevier]

Abstract: Cyclic diamide of o-phthalic acid (CPhDA) was synthesised in the reaction between phtalic anhydride and 1,2-bis(2-aminoethoxy)ethane in high dilution conditions and its ability to form the 1:1 and 2:1 complexes with Li+ cations was detected by ESI mass spectrometry. The 1:1 complex was obtained in the solid state and studied by X-ray diffraction, FT-IR, NMR and PM5 semiempirical methods. The structure of 1:1 complex was also studied in acetonitrile. It was found that the structures of 1:1 complex are different in the solid and in solution. [Copyright &y& Elsevier]

Abstract: The 2:2 hydrogen-bonded complex between Kemp’s triacid (KTA) and 1,1,3,3-tetramethylguanidine (TMG) has been synthesised and studied by X-ray diffraction and by FT-IR spectroscopy. Cocrystals of KTA–TMG belong to the monoclinic system and crystallize in the space group is P2 1 with a =10.5017(3)Å, b =7.9504(3)Å, c =11.8910(4)Å, β =104.004(4)° and Z =2. The ring of the KTA monoanion molecule exhibits a chair conformation with all three carboxylic groups in the axial positions and all three methyl groups in the equatorial positions. In the crystal of the complex, cooperative systems involving inter- and intra-molecular hydrogen bonds are formed. In the solid state two protonated TMG molecules and two deprotonated KTA molecules form a dimer in which three-dimensional hydrogen-bonded networks are found. [Copyright &y& Elsevier]

Abstract: Crystal structure of monensin A rubidium salt dihydrate, [Rb(C36H61O11)·2H2O], has been studied by X-ray diffraction, FT-IR spectroscopy and PM5 semiempirical methods. The crystal space group is P212121 with a =12.6153(7), b =16.4841(10), c =19.4840(12) and Z =4. The Rb–O bond lengths are between 2.788(7) and 2.901(6)Å. The carboxyl group of monensin A is deprotonated and engaged in two intramolecular O(11)–H···O(1) of 2.52(1)Å and O(10)–H···O(2) of 2.60(1)Å hydrogen bonds with hydroxyl groups, accompanied with formation of a pseudo-cyclic structure. This structure is stabilised by the coordination of the Rb+ cation by oxygen atoms. Two water molecules are involved in the weak intermolecular hydrogen bond between the different species forming a supramolecule. The IR spectrum of the crystal is consistent with the results obtained by the X-ray study and provides spectroscopic evidence for the complex formation. The calculated structure and the structural parameters of the monensin A rubidium salt are comparable with those determined by the X-ray study. [Copyright &y& Elsevier]

Abstract 2-(Quinuclidinium)-alkanocarboxylates co-crystallize with 2,6-dichloro-4-nitrophenol at the ratios 1:1 and 1:2 depending on the alkyl-chain lengths. The obtained complexes have been characterized by single-crystal X-ray diffraction, UV–vis, FTIR and NMR spectroscopy. The compounds 2-(quinuclidinium)-acetate and 2-(quinuclidinium)-propionate form complexes with 2,6-dichloro-4-nitrophenol at the stoichiometric ratio 1:2, while 2-(quinuclidinium)-butyrate and 2-(quinuclidinium)-valerate at ratio 1:1. Three crystal structures of compounds of these series were determined, but no single crystals of sufficient quality could be obtained of the 2-(quinuclidinium)-butyrate complex. The B3LYP/6-311++G(d,p) approach has been used to determine structures of their isolated molecules and to interpret the IR and UV–vis spectra. Diagrams of the HOMO and LUMO of molecules have been obtained. Graphical abstract Image 1 Highlights • Quiniclidinium-alkanocarboxylates form H B complexes with 2,6-dichloro-4-nitrophenol. • Lower homologues form molecular complexes at the 1:2 ratio. • Longer homologues form proton transfer 1:1 complexes. • Molecular structures were solved by X-ray diffraction and optimized by DFT methods. • UV–vis, FTIR and NMR spectra were measured. [ABSTRACT FROM AUTHOR]

The molecular structure of 1,2-di(3-hydroxymethylpyridinium)ethane dibromide ( 1 ) has been characterized by X-ray diffraction, B3LYP/6-311++G(d,p) calculations, FTIR, Raman and NMR spectra. The crystals are monoclinic, space group C2/c . 1,2-Di(3-hydroxymethylpyridinium)ethane dication and hydrogen-bonded bromide anions in crystals are located at the inversion center. The both CH 2 OH groups are engaged in two equal length hydrogen bonds with bromide anions. Two structures ( 2 ) and ( 3 ) were optimized at the B3LYP/6-311++G(d,p) level of theory. The optimized complex ( 2) resembles the crystal structure, while complex ( 3 ) is preferred energetically. The O⋯Br − hydrogen bonds distances are: 3.289(2) Å in crystals ( 1 ), but in the optimized structures ( 2 ) and ( 3 ) they are 3.303 Å and 3.461 Å, respectively. The investigated complex is additionally stabilized by the N + ⋯Br − electrostatic attractions. The potential energy distributions (PED) were used for the assignments of IR and Raman frequencies in the experimental and calculated spectra of the title compound. The FTIR spectrum of ( 1 ) is consistent with the X-ray results. Interpretation of the 1 H and 13 C NMR spectra in DMSO- d 6 has been based on 2D experiments. The calculated GIAO/B3LYP/6-311++G(d,p) magnetic shielding constants have been used to predict 1 H and 13 C chemical shifts for the optimized structures of ( 2 ) and ( 3 ). [ABSTRACT FROM AUTHOR]

The 1:2 complex ( 1 ) of dimethylphenyl betaine (DMPB) with two molecules of 2,6-dichloro-4-nitro-phenol (DCNP) was prepared and characterized by X-ray diffraction, B3LYP/6-311++G(d,p) and B3LYP-D3/6-311++G(d,p)calculations, FTIR and NMR spectroscopies. The crystal is monoclinic, space group P 2 1 / c with Z = 4. The protons at the oxygen atoms of phenols are bonded to each oxygen atoms of the DMPB carboxylate group by two nonequivalent H-bonds with the O H⋯O distances of 2.473(5) and 2.688(4) Å. Both H-bonds in the optimized structures 2 (in vacuum), 3 (in DMSO solution) and dispersion-correlated functional (D3) 4 (in vacuum) are comparable and are slightly shorter than O(6) H(O6)⋯O(2) in the crystal. The FTIR spectrum of 1 shows a broad absorption in the 3400–2000 cm −1 region corresponding to a longer hydrogen bond and a broad absorption in the 1800–500 cm −1 region caused by the shorter H-bond. The relations between the experimental 13 C and 1 H chemical shifts ( δ exp ) of the investigated compound 1 in DMSO solution and GIAO/B3LYP/6-311++G(d,p) magnetic isotropic shielding constants ( σ calc ) obtained by using the screening solvation model (COSMO) for 3 are linear and reproduce well the experimental chemical shifts described by the equation: δ exp = a + b σ calc . [ABSTRACT FROM AUTHOR]

Abstract: Two new complexes of the ionophore antibiotic Lasalocid acid (LAS) with phenylamine (PhA) and butylamine (BuA) were synthesized and their molecular structures were studied using single crystal X-ray diffraction and spectroscopic methods. In the solid state both amines are protonated and all protons are hydrogen bonded to etheric, hydroxyl and carboxylic oxygen atoms of the LAS anion. In chloroform solutions the structure observed in the crystal of LAS–BuA complex is preserved and an equilibrium between the LAS–PhA complex and dissociated Lasalocid acid and phenylamine is observed. In vitro antimicrobial tests of the complexes showed a significant activity towards some strains of Gram-positive bacteria. For the first time Lasalocid acid and its complexes with amines were tested in vitro for cytotoxic activity against human cancer cell lines: A-549 (lung), MCF-7 (breast), HT-29 (colon) and mouse cancer cell line P-388 (leukemia). We found that LAS and its complexes are strong cytotoxic agents towards all tested cell lines. The cytostatic activity of the compounds studied is greater than that of cisplatin, indicating that Lasalocid and its complexes are promising candidates for new anticancer drugs. [Copyright &y& Elsevier]

Abstract: For the first time the structure of the complex formed between N-allylamide of monensin A (M-AM2) and divalent cation (Sr2+) has been studied by X-ray crystallography and FT-IR spectroscopy. The crystal structure of this complex contains one Sr2+ cation coordinated by six O atoms of M-AM2 molecule, one oxygen atom of the perchlorate anion and the nitrogen atom of the acetonitrile molecule. The M-AM2 molecule is additionally tied by an intramolecular hydrogen-bonded chain [O(3)H⋯O(9)H⋯O(10)H⋯O(1)e crystal data, FT-IR spectra and semiempirical calculations show that the oxygen atom of the amide group is not involved in the coordination of the Sr2+ cation. In the gas phase the formation of two types of (M-AM2+Sr)2+ and (M-AM2+Sr+ClO4)+ complexes is detected using ESI mass spectrometry and their structures are visualized by PM5 semiempirical calculations. [Copyright &y& Elsevier]

Abstract: A complex between a new N-phenylamide of monensin A (M-AM1) and sodium chloride has been synthesised and studied by X-ray diffraction and FT-IR spectroscopy. The crystal structure of the complex between M-AM1 and sodium chloride with acetonitrile was examined using X-ray diffraction and discussed in detail. Its structure is stabilised by coordination of the Na+ cation with oxygen atoms. The Na–O bond lengths are between 2.382(2) and 2.562(2)Å. The chloride anion is involved in a weak intermolecular hydrogen bond between different species forming a supramolecule. The ESI-MS spectra indicate that the amide forms stable complexes of exclusively 1:1 stoichiometry with Na+ cations. The FT-IR spectrum of the crystal is consistent with the results obtained by the X-ray study and provides spectroscopic evidence for the complex formation. Due to its specific structural properties N-phenylamide of monensin A efficiently binds sodium chloride. The result of the PM5 semiempirical calculation is in agreement with the spectroscopic data and allows visualisation of the structure of the M-AM1–Na+ complex. The new amide of monensin A has been additionally tested in view of its antimicrobial properties. It shows great activity towards some strains of Gram-positive bacteria (MIC=6.25–12.5μg/ml). [Copyright &y& Elsevier]

Abstract: A new lasalocid 1-naphthylmethyl ester (NAFA) has been synthesised and studied by X-ray, 1H NMR, 13C NMR, FT-IR, UV–vis, fluorescence as well as by PM5 semiempirical methods. The crystals of NAFA belong to the monoclinic system with the space group P2 1 with a =13.4251(5)Å, b =17.1064(7)Å, c =18.5454(7)Å, β =98.924(4)° and Z =4. Two conformers of NAFA have been observed for two symmetry-independent molecules in different crystal environments. The molecular conformation of NAFA is partially stabilized by three intramolecular hydrogen bonds, in which the keto group is not involved. The FT-IR spectrum of NAFA in chloroform indicates that in this solvent the equilibrium between two structures of NAFA is realized. In one of the structures, the keto group is hydrogen bonded while in the other one this group is not involved in any hydrogen bond. The two structures of NAFA are discussed in detail. The new ester which has been additionally tested for its antimicrobial properties shows a certain activity against Gram-positive bacteria, however no activity against Gram-negative bacteria and Candida. [Copyright &y& Elsevier]