The structures of 2-hydroxy-5-methylbenzoic acid and dimorphs of 2,5-dihydroxybenzoic acid

Haisa, M.; Kashino, Setsuo; Hanada, Shiori; Tanaka, K.; Okazaki, Susumu; Shibagaki, Makoto

doi:10.1107/s0567740882006189

Cited by 55 publications

(50 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…An intramolecular hydrogen bond is formed between the carboxylic O(1) and the 2-hydroxy group. The geometry of the hydrogen bond is close to those found in 2-hydroxy-5-methylbenzoic acid and 2,5-dihydroxybenzoic acid (Haisa, Kashino, Hanada, Tanaka, Okazaki & Shibagaki, 1982) and salicyclic acid (Bacon & Jude, 1973). The two crystallographically independent molecules, A and B, are almost identical, except for the direction of the carboxylic plane relative to the benzene ring.…”

Section: Gdomdtrie Au Niveau Des Groupements Carbonylesmentioning

confidence: 48%

The structure of 3,5-dichloro-2-hydroxy-4-methoxy-6-n-propylbenzoic acid (differanisole A), C11H12Cl2O4

Iimura¹,

Sakurai²,

Asahi³

et al. 1984

Acta Crystallogr C

View full text Add to dashboard Cite

ylic groups. There is an intramolecular hydrogen bond between a carboxylic oxygen and the adjacent hydroxy group. The crystal structure consists of centrosymmetric dimers linked by hydrogen bonds. Introduction.To clarify the molecular mechanisms of cell differentiation and development, and to make use of differentiation-inducing substances for the medical treatment of cancer and muscular dystrophy etc., we have studied the endogenous and the exogenous differentiation-inducing substances of animal cells.

show abstract

Section: Gdomdtrie Au Niveau Des Groupements Carbonylesmentioning

confidence: 48%

The structure of 3,5-dichloro-2-hydroxy-4-methoxy-6-n-propylbenzoic acid (differanisole A), C11H12Cl2O4

Iimura¹,

Sakurai²,

Asahi³

et al. 1984

Acta Crystallogr C

View full text Add to dashboard Cite

show abstract

“…In the solidstate, carboxylic acids form centrosymmetric dimers, linked by hydrogen bonds between carboxylic groups (as illustrated in the inset of Figure 2a). In 2,5-DHB, dimers are stacked to form columns, which are held together by hydrogen bonds involving hydroxylic groups in position 5 to form sheets [29]. This particular organization explains the shifts observed in the solidstate experiments (compared with liquid state NMR data), in particular for signals of carboxylic (C7) and both phenol carbons (C2 and C5), which are characteristic of the strong intra-and intermolecular hydrogen bonds in the crystal.…”

Section: Solid-state Nmrmentioning

confidence: 65%

Solid state nuclear magnetic resonance as a tool to explore solvent-free MALDI samples

Pizzala

Barrère

Mazarin

et al. 2009

J. Am. Soc. Mass Spectrom.

View full text Add to dashboard Cite

Solid-state Nuclear magnetic resonance (NMR) was used here to explore structural characteristics of samples to be subjected to matrix-assisted laser desorption/ionization (MALDI) and prepared without the use of any solvent. The analytical systems scrutinized in NMR were mixtures of a 2,5-dihydroxybenzoic acid (2,5-DHB) matrix and caesium fluoride (CsF), used as the cationization agent in synthetic polymer MALDI mass analysis, at different molar ratios (1:1, 5:1, and 10:1). Complementary information could be obtained from 13 C, 133 Cs, and 19 F NMR spectra. Grinding the matrix together with the salt in the solid state was shown to induce a strong modification in the molecular organization within the MALDI sample. The evidenced mechano-induced reactions allow strong interactions between the matrix and the cation, up to the formation of a salt, and only occur in the presence of some water molecules. Addition of a poly(ethylene oxide) polymer as the analyte did not further modify the observed molecular organizations. Although relative matrix and salt concentrations in the scrutinized samples were unusual for MALDI analysis, mass spectra of good quality could be obtained and revealed that cation attachment on polymers during the MALDI process is not a matrix-independent event since a lower ionization efficiency was obtained from highly organized solid samples, mostly consisting of 2,5-DHB caesium salt species. (J Am Soc Mass Spectrom 2009, 20, 1906 -1911) © 2009 American Society for Mass Spectrometry M atrix-assisted laser desorption/ionization (MALDI) is widely used as an efficient ionization method to characterize synthetic polymers by time-of-flight mass spectrometry (TOF MS) [1,2]. A key point in the success of a MALDI-MS analysis is sample preparation, that is, proper matrix and cation selection as well as solid-state organization. The matrix actually plays multiple roles in the MALDI process and should accordingly present specific properties. Some criteria are clearly defined, such as a strong absorptivity at the employed laser wavelength or good vacuum stability, while other requirements, such as a good miscibility of the matrix with the analyte in the solid state, are not easily related to physico-chemical parameters of the matrix. As a result, prediction for the optimal matrix-polymer system is still not possible and sample preparation methods are usually developed from published protocols that were shown to work for a given polymeric system [3]. In particular, solvent-free MALDI was recently proposed as an alternative to the conventional dried droplet method [4,5].Despite MALDI being a widely used technique, mechanisms underlying this desorption/ionization process are still not fully understood. To investigate the MALDI process, many studies have focused on sample morphology using different imaging experiments. Sample heterogeneity and distribution of molecules within the MALDI solid sample have been explored using microscopy techniques, such as optical microscopy [6,7], scanning electron microscopy [8 -...

show abstract

“…Contrary to the sinapinic acid large crystal, no specific cleavage planes exist for the 2,5-DHB crystals with typical dimensions of 5 ϫ 0.15 ϫ 0.15 mm 3 and thus, natural surfaces were used for this study. The longer dimension was in the [010] direction [11,12]. It should be noted that the procedures published in the literature for obtaining these crystals [12,13] were unsuccessful.…”

Section: 5-dhb Single Crystalsmentioning

confidence: 99%

Irradiation effects in MALDI, ablation, ion production, and surface modifications. Part II: 2,5-dihydroxybenzoic acid monocrystals

Fournier

Marinach

Tabet

et al. 2003

J. Am. Soc. Mass Spectrom.

View full text Add to dashboard Cite

Irradiation effects at low and high laser fluence on 2,5-dihydroxybenzoic acid large crystals were investigated. Contrary to what was observed for matrices as cinnamic acid derivatives, no chemical degradation of matrix is evidenced and continuous ablation as well as ion production resulted of extended irradiation in all the fluence range corresponding to classical matrix-assisted laser desorption /ionization. Ripples are formed on the base of the crater for a limited number of laser shots under moderate fluence. For extended irradiation, conical shape craters are formed with the axis of the crater oriented along the incident direction of the laser beam. A study of the craters showed that ablation through the ablated volume slowly varied with the laser fluence when a strong increase of ion production (matrix and analyte) was recorded. Ablation volume was found to vary non-linearly with the number of laser shots. On a same spot, the ablated volume and the ion production were measured as a function of the laser energy. With an increasing laser energy (or fluence), the ablated volume slowly increases when the ion production strongly increases. This gives evidence of a decoupling between ablation and ionization. is now a powerful method to produce ions of large molecules and its coupling with mass spectrometry (MS) provides a major analytical tool, particularly in proteomic studies and synthetic polymers characterization. To date, many of the methodologies developed for MALDI have been empirically determined. Indeed, the mechanisms involved in the ion production are very complex and cannot be experimentally studied in detail in all the time range of elementary processes. Briefly, these mechanisms involve ablation of molecules and aggregates from a solid state, the expansion of a plume from a very dense state to a very dilute gas. Ionization processes are likely involved in all the steps of the ablation and expansion. In addition, it is still difficult to predict for a small molecule absorbing at the laser wavelength whether it will be an effective or an inefficient matrix for the analysis of a given analyte. Some recent reviews gave an overview of the common ideas on these ionization mechanisms [2, 3] involving specific chemical reaction, ion-molecule reaction [2] or proton transfer in aggregates [3,4]. Generally, the mechanisms in MALDI are studied in two different ways. One deals with the ablation phenomenon mainly by molecular dynamics simulation [5,6] at very short scale (Ͻ Ͻ1 ns) and experimentally on the plume expansion [7] at medium and long-time scale (a few s to a few tens of s). The second deals with the ions produced by MALDI at the time scale of the ion time-of-flight, the role of the laser parameters [8], the target preparations and the nature of analyte ions. This subject occupies most publications in this field.In this article, we will focus on the relationship between the ablated volume and the analyte ion production and on the irradiation effects using large 2,5-dihydroxybenzoic acid single crystals...

show abstract

The structures of 2-hydroxy-5-methylbenzoic acid and dimorphs of 2,5-dihydroxybenzoic acid

Cited by 55 publications

References 4 publications

The structure of 3,5-dichloro-2-hydroxy-4-methoxy-6-n-propylbenzoic acid (differanisole A), C11H12Cl2O4

The structure of 3,5-dichloro-2-hydroxy-4-methoxy-6-n-propylbenzoic acid (differanisole A), C11H12Cl2O4

Solid state nuclear magnetic resonance as a tool to explore solvent-free MALDI samples

Irradiation effects in MALDI, ablation, ion production, and surface modifications. Part II: 2,5-dihydroxybenzoic acid monocrystals

Contact Info

Product

Resources

About