Infrared, X-ray and microscopic studies on the room temperature structure of anhydrous lead (II) n-alkanoates

Ellis, Henry A.; White, Nicole A.S.; Taylor, Richard A.; Maragh, Paul T.

doi:10.1016/j.molstruc.2004.12.006

Cited by 25 publications

(37 citation statements)

References 15 publications

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“…[39][40][41][42] The distinction between these classes is supported by the observation of differences in IR spectra and X-ray diffraction patterns of short-and long-chain carboxylates. 43 Differences in packing have also been noted for copper octanoate and copper decanoate. 44,45 Oleic acid is a precursor to azelaic acid in dried oils, 14 so lead oleate's NMR parameters provide important information on a potential intermediate in the reactions that may lead to soap formation.…”

Section: Resultsmentioning

confidence: 95%

Nuclear Magnetic Resonance Spectra and ²⁰⁷Pb Chemical-Shift Tensors of Lead Carboxylates Relevant to Soap Formation in Oil Paintings

et al. 2014

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Soap formation in traditional oil paintings occurs when heavy-metal-containing pigments, such as lead white, 2PbCO3·Pb(OH)2, and lead tin yellow type I, Pb2SnO4, react with fatty acids in the binding medium. These soaps may form aggregates that can be 100-200 μm in diameter, which swell and protrude through the paint surface, resulting in the degradation of the paint film and damage to the integrity of the artwork. The factors that trigger soap formation and the mechanism(s) of the process are not yet well understood. To elucidate these issues, chemical and structural information is necessary, which can be obtained using solid-state (207)Pb and (13)C nuclear magnetic resonance (NMR). In this article, we report (207)Pb and (13)C solid-state NMR spectra and (207)Pb chemical-shift tensors of lead carboxylates implicated in soap formation: lead stearate, lead palmitate, and lead azelate, in addition to lead oleate and lead heptanoate for comparison. The (13)C cross polarization with magic-angle spinning (MAS) spectra of these lead carboxylates show resonance doubling for the carbons closest to the lead, indicating two different conformations of the fatty acid chains in the asymmetric unit. The (207)Pb NMR spectra, from which tensors were determined, were obtained with direct excitation and spin-temperature alternation, with and without MAS, and with the wide band uniform rate smooth truncation Carr-Purcell-Meiboom-Gill pulse sequence. The results of these experiments show that the local coordination environment of lead azelate is different from lead palmitate and lead stearate and could thus be distinguished from these in a paint film displaying soap formation. In addition, comparing the (207)Pb NMR chemical-shift tensors of the lead carboxylates studied shows that crystal packing of the acyl chains may be a factor in determining the coordination environment around the lead.

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Section: Resultsmentioning

confidence: 95%

Nuclear Magnetic Resonance Spectra and ²⁰⁷Pb Chemical-Shift Tensors of Lead Carboxylates Relevant to Soap Formation in Oil Paintings

et al. 2014

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“…It was found that for bivalent metal cation coordination ability, Δν weakens in the order of monodentate, bridging/ionic bidentate to chelating bidentate form (Ellis et al 2005; Ohe et al 1999). The larger band shift for the complex indicates a larger unsymmetrical interaction between the metal ion and the carboxylate group.…”

Section: Resultsmentioning

confidence: 99%

Synthesis and characterization of silver nanoparticles from (bis)alkylamine silver carboxylate precursors

Uznański¹,

Zakrzewska²,

Favier³

et al. 2017

J Nanopart Res

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A comparative study of amine and silver carboxylate adducts [R1COOAg-2(R2NH2)] (R1 = 1, 7, 11; R2 = 8, 12) as a key intermediate in NPs synthesis is carried out via differential scanning calorimetry, solid-state FT-infrared spectroscopy, 13C CP MAS NMR, powder X-ray diffraction and X-ray photoelectron spectroscopy, and various solution NMR spectroscopies (1H and 13C NMR, pulsed field gradient spin-echo NMR, and ROESY). It is proposed that carboxyl moieties in the presence of amine ligands are bound to silver ions via chelating bidentate type of coordination as opposed to bridging bidentate coordination of pure silver carboxylates resulting from the formation of dimeric units. All complexes are packed as lamellar bilayer structures. Silver carboxylate/amine complexes show one first-order melting transition. The evidence presented in this study shows that phase behavior of monovalent metal carboxylates are controlled, mainly, by head group bonding. In solution, insoluble silver salt is stabilized by amine molecules which exist in dynamic equilibrium. Using (bis)amine-silver carboxylate complex as precursor, silver nanoparticles were fabricated. During high-temperature thermolysis, the (bis)amine-carboxylate adduct decomposes to produce silver nanoparticles of small size. NPs are stabilized by strongly interacting carboxylate and trace amounts of amine derived from the silver precursor interacting with carboxylic acid. A corresponding aliphatic amide obtained from silver precursor at high-temperature reaction conditions is not taking part in the stabilization. Combining NMR techniques with FTIR, it was possible to follow an original stabilization mechanism. Graphical abstractThe synthesis of a series (bis)alkylamine silver(I) carboxylate complexes in nonpolar solvents were carried out and fully characterized both in the solid and solution. Carboxyl moieties in the presence of amine ligands are bound to silver ions via chelating bidentate type of coordination. The complexes form layered structures which thermally decompose forming nanoparticles stabilized only by aliphatic carboxylates.

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“…There are differences in the low-frequency region, as well, where bands are quite sensitive to the alkyl chain packing. 48 In the C6, C7, and C8 carboxylates, a peak assigned to a CH 2 rocking mode appears around 720 cm −1 . 51 In C9, C10, C11, C16 and C18 carboxylates, this region contains multiple features, consistent with the IR results of Mesubi et al who found a singlet for lead carboxylates of C6 and C8 but a doublet for C10, C12, C14, and C16 carboxylates.…”

Section: Nmr Spectroscopymentioning

confidence: 97%

“…On the other hand, from infrared and X-ray studies at room temperature, Ellis et al conclude that this transition occurs between C12 and C14. 48 Based on the number of intermediate liquid crystalline phases detected by differential thermal analysis (DTA), Adeosun and Sime place the transition between C8 and C12, with C10 exhibiting an intermediate behavior. 49 In these experiments, 48,49 only the members of the series having even numbers of carbons were investigated.…”

Section: Nmr Spectroscopymentioning

confidence: 99%

Coordination geometry of lead carboxylates – spectroscopic and crystallographic evidence

et al. 2015

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Despite their versatility, only a few single-crystal X-ray structures of lead carboxylates exist, due to difficulties with solubility. In particular, the structures of long-chain metal carboxylates have not been reported. The lone electron pair in Pb(ii) can be stereochemically active or inactive, leading to two types of coordination geometries commonly referred to as hemidirected and holodirected structures, respectively. We report (13)C and (207)Pb solid-state NMR and infrared spectra for a series of lead carboxylates, ranging from lead hexanoate (C6) to lead hexadecanoate (C18). The lead carboxylates based on consistent NMR parameters can be divided in two groups, shorter-chain (C6, C7, and C8) and longer-chain (C9, C10, C11, C12, C14, C16, and C18) carboxylates. This dichotomy suggests two modes of packing in these solids, one for the short-chain lead carboxylates and one for long-chain lead carboxylates. The consistency of the (13)C and (207)Pb NMR parameters, as well as the IR data, in each group suggests that each motif represents a structure characteristic of each subgroup. We also report the single-crystal X-ray diffraction structure of lead nonanoate (C9), the first single-crystal structure to have been reported for the longer-chain subgroup. Taken together the evidence suggests that the coordination geometry of C6-C8 lead carboxylates is hemidirected, and that of C9-C14, C16 and C18 lead carboxylates is holodirected.

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Infrared, X-ray and microscopic studies on the room temperature structure of anhydrous lead (II) n-alkanoates

Cited by 25 publications

References 15 publications

Nuclear Magnetic Resonance Spectra and ²⁰⁷Pb Chemical-Shift Tensors of Lead Carboxylates Relevant to Soap Formation in Oil Paintings

Nuclear Magnetic Resonance Spectra and ²⁰⁷Pb Chemical-Shift Tensors of Lead Carboxylates Relevant to Soap Formation in Oil Paintings

Synthesis and characterization of silver nanoparticles from (bis)alkylamine silver carboxylate precursors

Coordination geometry of lead carboxylates – spectroscopic and crystallographic evidence

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Infrared, X-ray and microscopic studies on the room temperature structure of anhydrous lead (II) n-alkanoates

Cited by 25 publications

References 15 publications

Nuclear Magnetic Resonance Spectra and 207Pb Chemical-Shift Tensors of Lead Carboxylates Relevant to Soap Formation in Oil Paintings

Nuclear Magnetic Resonance Spectra and 207Pb Chemical-Shift Tensors of Lead Carboxylates Relevant to Soap Formation in Oil Paintings

Synthesis and characterization of silver nanoparticles from (bis)alkylamine silver carboxylate precursors

Coordination geometry of lead carboxylates – spectroscopic and crystallographic evidence

Contact Info

Product

Resources

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Nuclear Magnetic Resonance Spectra and ²⁰⁷Pb Chemical-Shift Tensors of Lead Carboxylates Relevant to Soap Formation in Oil Paintings

Nuclear Magnetic Resonance Spectra and ²⁰⁷Pb Chemical-Shift Tensors of Lead Carboxylates Relevant to Soap Formation in Oil Paintings