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Scope Catechin-rich green tea extract (GTE) limits inflammation in nonalcoholic steatohepatitis (NASH) consistent with a Toll-like receptor 4 (TLR4)-dependent mechanism. Our hypothesis was that GTE supplementation during NASH would shift the hepatic metabolome similar to that attributed to the loss-of-TLR4 signaling. Methods and results Wild-type (WT) and loss-of-function TLR4-mutant (TLR4mut ) mice were fed a high-fat diet containing 0% or 2% GTE for 8 weeks prior to performing untargeted mass spectrometry-based metabolomics on liver tissue. The loss-of-TLR4 signaling and GTE shifted the hepatic metabolome away from that of WT mice. However, relatively few metabolites were altered by GTE in WT mice to the same extent as the loss-of-TLR4 signaling in TLR4mut mice. GTE increased acetyl-CoA precursors and spermidine to a greater extent than the loss-of-TLR4 signaling. Select metabolites associated with thiol metabolism were similarly affected by GTE and the loss-of-TLR4 signaling. Glycerophospholipid catabolites were decreased by GTE, but were unaffected in TLR4mut mice. Conversely, the loss-of-TLR4 signaling but not GTE increased several bile acid metabolites. Conclusion GTE limitedly alters the hepatic metabolome consistent with a TLR4-dependent mechanism. This suggests that the anti-inflammatory activities of GTE and loss-of-TLR4 signaling that regulate hepatic metabolism to abrogate NASH are likely due to distinct mechanisms. This article is protected by copyright. All rights reserved.

People with HIV (PWH) are at increased risk for atherosclerotic cardiovascular disease (ASCVD). Proportions of vascular homing monocytes are enriched in PWH; however, little is known regarding monocyte-derived macrophages (MDMs) that may drive atherosclerosis in this population. We isolated PBMCs from people with and without HIV, and cultured these cells for 5 days in medium containing autologous serum to generate MDMs. Differential gene expression (DGE) analysis of MDMs from PWH identified broad alterations in innate immune signaling (IL-1β, TLR expression, PPAR βδ) and lipid processing (LXR/RXR, ACPP, SREBP1). Transcriptional changes aligned with the functional capabilities of these cells. Expression of activation markers and innate immune receptors (CD163, TLR4, and CD300e) was altered on MDMs from PWH, and these cells produced more TNFα, reactive oxygen species (ROS), and matrix metalloproteinases (MMPs) than did cells from people without HIV. MDMs from PWH also had greater lipid accumulation and uptake of oxidized LDL. PWH had increased serum levels of free fatty acids (FFAs) and ceramides, with enrichment of saturated FAs and a reduction in polyunsaturated FAs. Levels of lipid classes and species that are associated with CVD correlated with unique DGE signatures and altered metabolic pathway activation in MDMs from PWH. Here, we show that MDMs from PWH display a pro-atherogenic phenotype; they readily form foam cells, have altered transcriptional profiles, and produce mediators that likely contribute to accelerated ASCVD., Author summary People with HIV (PWH) are at greater risk for developing cardiovascular disease (CVD) than the general public, but the mechanisms underlying this increased risk are poorly understood. Macrophages play key roles in the pathogenesis of atherosclerosis, and are potential targets for therapeutic intervention. Here, we investigate phenotypic and functional abnormalities in monocyte-derived macrophages (MDMs) isolated from PWH that may drive CVD risk in this population. MDMs were differentiated in the presence of autologous serum, enabling us to explore the contributions of serum components (lipids, inflammatory cytokines, microbial products) as drivers of altered MDM function. We link serum levels of inflammatory biomarkers and CVD-associated lipid species to MDM activation. Our study provides new insight into drivers of pro-atherogenic MDM phenotype in PWH, and identifies directions for future study and potential intervention strategies to mitigate CVD risk.

BACKGROUND: Nonvitamin A apocarotenoids occur in foods. Some function as retinoic acid receptor antagonists in vitro, though it is unclear if apocarotenoids are absorbed or accumulate to levels needed to elicit biological function. OBJECTIVE: The aim of this study was to quantify carotenoids and apocarotenoids (β-apo-8′-, -10′-, -12′-, and -14′-carotenal, apo-6′-, -8′-, -10′-, -12′-, and -14′-lycopenal, retinal, acycloretinal, β-apo-13-carotenone, and apo-13-lycopenone) in human plasma after controlled consumption of carotenoid-rich tomato juices. DESIGN: Healthy subjects (n = 35) consumed a low-carotenoid diet for 2 wk, then consumed 360 mL of high-β-carotene tomato juice (30.4 mg of β-carotene, 34.5 μg total β-apocarotenoids/d), high-lycopene tomato juice (42.5 mg of lycopene, 119.2 μg total apolycopenoids/d), or a carotenoid-free control (cucumber juice) per day for 4 wk. Plasma was sampled at baseline (after washout) and after 2 and 4 wk, and analyzed for carotenoids and apocarotenoids using high-pressure liquid chromatography (HPLC) and HPLC-tandem mass spectrometry, respectively. The methods used to analyze the apocarotenoids had limits of detection of ∼ 100 pmol/L. RESULTS: Apocarotenoids are present in tomato juices at 0.1–0.5% of the parent carotenoids. Plasma lycopene and β-carotene increased (P

Background: HIV infection and antiretroviral therapy (ART) have both been linked to dyslipidemia and increased cardiovascular disease (CVD) risk. Alterations in the composition of saturated (SaFA), monounsaturated (MUFA), and polyunsaturated (PUFA) fatty acids are related to inflammation and CVD progression in HIV-uninfected (HIV-) populations. The relationships among the lipidome and markers of monocyte and immune activation in HIV-infected (HIV+) individuals are not well understood. Methods: Concentrations of serum lipids and their fatty acid composition were measured by direct infusion-tandem mass spectrometry in samples from 20 ART-treated HIV+ individuals and 20 HIV- individuals. Results: HIV+ individuals had increased levels of free fatty acids (FFAs) with enrichment of SaFAs, including palmitic acid (16:0) and stearic acid (18:0), and these levels were directly associated with markers of monocyte (CD40, HLA-DR, TLR4, CD36) and serum inflammation (LBP, CRP). PUFA levels were reduced significantly in HIV+ individuals, and many individual PUFA species levels were inversely related to markers of monocyte activation, such as tissue factor, TLR4, CD69, and SR-A. Also in HIV+ individuals, the composition of lysophosphatidylcholine (LPC) was enriched for SaFAs; LPC species containing SaFAs were directly associated with IL-6 levels and monocyte activation. We similarly observed direct relationships between levels of SaFAs and inflammation in HIV uninfected individuals. Further, SaFA exposure altered monocyte subset phenotypes and inflammatory cytokine production in vitro. Conclusions: The lipidome is altered in ART-treated HIV infection, and may contribute to inflammation and CVD progression. Detailed lipidomic analyses may better assess CVD risk in both HIV+ and HIV- individuals than does traditional lipid profiling.

The carotenoid lycopene is a bioactive component of tomatoes and is hypothesized to reduce risk of several chronic diseases, such as prostate cancer. The metabolism of lycopene is only beginning to be understood and some studies suggest that metabolites of lycopene may be partially responsible for bioactivity associated with the parent compound. The detection and characterization of these compounds in vivo is an important step in understanding lycopene bioactivity. The metabolism of lycopene likely involves both chemical and enzymatic oxidation. While numerous lycopene metabolites have been proposed, few have actually been identified in vivo following lycopene intake. Here, LC-QTOF-MS was used along with 13C-labeling to investigate the post-prandial oxidative metabolism of lycopene in human plasma. Previously reported aldehyde cleavage products were not detected, but a lycopene 1,2-epoxide was identified as a new candidate oxidative metabolite.

Background Phytoene is a tomato carotenoid that may contribute to the apparent health benefits of tomato consumption. Although phytoene is a less prominent tomato carotenoid than lycopene, it is a major carotenoid in various human tissues. Phytoene distribution to plasma lipoproteins and tissues differs from lycopene, suggesting the kinetics of phytoene and lycopene differ. Objective The objective of this study was to characterize the kinetic parameters of phytoene absorption, distribution, and excretion in adults, to better understand why biodistribution of phytoene differs from lycopene. Methods Four adults (2 males, 2 females) maintained a controlled phytoene diet (1-5 mg/d) for 42 d. On day 14, each consumed 3.2 mg (13)C-phytoene, produced using tomato cell suspension culture technology. Blood samples were collected at 0, 1-15, 17, 21, and 24 h and 2, 3, 4, 7, 10, 14, 17, 21, and 28 d after (13)C-phytoene consumption. Plasma-unlabeled and plasma-labeled phytoene concentrations were determined using ultra-HPLC-quadrupole time-of-flight-mass spectrometry, and data were fit to a 7-compartment carotenoid kinetic model using WinSAAM 3.0.7 software. Results Subjects were compliant with a controlled phytoene diet, consuming a mean ± SE of 2.5 ± 0.6 mg/d, resulting in a plasma unlabeled phytoene concentration of 71 ± 14 nmol/L. A maximal plasma (13)C-phytoene concentration of 55.6 ± 5.9 nM was achieved 19.8 ± 9.2 h after consumption, and the plasma half-life was 2.3 ± 0.2 d. Compared with previous results for lycopene, phytoene bioavailability was nearly double at 58% ± 19%, the clearance rate from chylomicrons was slower, and the rates of deposition into and utilization by the slow turnover tissue compartment were nearly 3 times greater. Conclusions Although only differing from lycopene by 4 double bonds, phytoene exhibits markedly different kinetic characteristics in human plasma, providing insight into metabolic processes contributing to phytoene enrichment in plasma and tissues compared with lycopene. This trial was registered at clinicaltrials.gov as NCT01692340.

Background: Lycopene, which is a red carotenoid in tomatoes, has been hypothesized to mediate disease-preventive effects associated with tomato consumption. Lycopene is consumed primarily as the all-trans geometric isomer in foods, whereas human plasma and tissues show greater proportions of cis isomers. Objective: With the use of compartmental modeling and stable isotope technology, we determined whether endogenous all-trans-to-cis-lycopene isomerization or isomeric-bioavailability differences underlie the greater proportion of lycopene cis isomers in human tissues than in tomato foods. Design: Healthy men (n = 4) and women (n = 4) consumed 13C-lycopene (10.2 mg; 82% all-trans and 18% cis), and plasma was collected over 28 d. Unlabeled and 13C-labeled total lycopene and lycopene-isomer plasma concentrations, which were measured with the use of high-performance liquid chromatography–mass spectrometry, were fit to a 7-compartment model. Results: Subjects absorbed a mean ± SEM of 23% ± 6% of the lycopene. The proportion of plasma cis-13C-lycopene isomers increased over time, and all-trans had a shorter half-life than that of cis isomers (5.3 ± 0.3 and 8.8 ± 0.6 d, respectively; P < 0.001) and an earlier time to reach maximal plasma concentration than that of cis isomers (28 ± 7 and 48 ± 9 h, respectively). A compartmental model that allowed for interindividual differences in cis- and all-trans-lycopene bioavailability and endogenous trans-to-cis-lycopene isomerization was predictive of plasma 13C and unlabeled cis- and all-trans-lycopene concentrations. Although the bioavailability of cis (24.5% ± 6%) and all-trans (23.2% ± 8%) isomers did not differ, endogenous isomerization (0.97 ± 0.25 μmol/d in the fast-turnover tissue lycopene pool) drove tissue and plasma isomeric profiles. Conclusion: 13C-Lycopene combined with physiologic compartmental modeling provides a strategy for following complex in vivo metabolic processes in humans and reveals that postabsorptive trans-to-cis-lycopene isomerization, and not the differential bioavailability of isomers, drives tissue and plasma enrichment of cis-lycopene. This trial was registered at clinicaltrials.gov as {"type":"clinical-trial","attrs":{"text":"NCT01692340","term_id":"NCT01692340"}}NCT01692340.

cope : Diets rich in tomato products are associated with a reduced risk of various chronic disease processes. The carotenoid lycopene is most intensely studied as the bioactive mediating health effects, yet tomatoes contain an array of phytochemicals. We conducted an untargeted metabolomics study on blood plasma to identify novel markers of tomato consumption absorbed from the diet and released into the bloodstream in mice. Methods and results : Male mice were fed a control AIN-93G diet or the same diet supplemented with 0.25% lycopene beadlets, or 10% freeze-dried red tomato, tangerine tomato, or low-carotenoid tomato for 4 weeks. Untargeted UHPLC-QTOF-MS data acquisition and differential analysis of plasma metabolites revealed several structurally related deglycosylated tomato steroidal alkaloids, including tomatidine and hydroxylated/desaturated derivatives, in plasma after the consumption of all 3 tomato varieties. Additionally, plasma metabolite profiles reflected glycoalkaloid forms found in the tomato diets. Conclusion : Dietary tomato glycoalkaloids are cleaved during digestion to aglycones and further metabolized post-absorption. Steroidal alkaloids in plasma may serve as novel and specific biomarkers of tomato consumption and represent a class of phytochemical metabolites that could potentially have in vivo bioactivity impacting health and disease processes. This article is protected by copyright. All rights reserved

Tomato and lycopene (c, c-carotene) consumption is hypothesized to protect against nonalcoholic steatohepatitis and hepatocarcinogenesis, processes that may depend upon diet and gene interactions. To investigate the interaction of tomato or lycopene feeding with b-carotene-9#,10#-monooxygenase (Bco2) on hepatic metabolic and signaling pathways, male wild-type (WT) and Bco2 2/2 mice (3-wk-old; n = 36) were fed semi-purified control, 10% tomato powder‐containing, or 0.25% lycopene beadlet‐containing diets for 3 wk. Serum lycopene concentrations were higher in lycopene- and tomato-fed Bco2 2/2 mice compared with WT (P = 0.03). Tomato- and lycopene-fed mice had detectable hepatic apo-6#-, apo-8#-, and apo-12#-lycopenal concentrations. Hepatic expression of b-carotene-15,15-monooxygenase was increased in Bco2 2/2 mice compared with WT (P = 0.02), but not affected by diet. Evaluation of hepatic gene expression by focused quantitative reverse transcriptase-polymerase chain reaction arrays for nuclear receptors and coregulators (84 genes) and stress and metabolism (82 genes) genes indicates that tomato feeding affected 31 genes ($1.5-fold, P < 0.05) and lycopene feeding affected 19 genes, 16 of which were affected by both diets. Lycopene down-regulation of 7 nuclear receptors and coregulators, estrogen-related receptor-a, histone deacetylase 3, nuclear receptor coactivator 4, RevErbAb, glucocorticoid receptor, peroxisome proliferator-activated receptor (PPAR)-a, and PPAR-g, coactivator 1 b was dependent upon interaction with Bco2 status. Lycopene and tomato feeding induced gene expression patterns consistent with decreased lipid uptake, decreased cell proliferation and mitosis, down-regulated aryl hydrocarbon receptor signaling, and decreased expression of genes involved in retinoid X receptor heterodimer activation. Tomato feeding also caused expression changes consistent with down-regulation of DNA synthesis and terpenoid metabolism. These data suggest tomato components, particularly lycopene, affect hepatic gene expression, potentially affecting hepatic responses to metabolic, infectious, or chemical stress. J. Nutr. doi: 10.3945/jn.113.186676.

Scope Catechin-rich green tea extract (GTE) alleviates nonalcoholic steatohepatitis (NASH) by lowering endotoxin-TLR4 (Toll-like receptor-4)-NFκB (nuclear factor kappa-B) inflammation. This study aimed to define altered MS-metabolomic responses during high-fat (HF)-induced NASH that are restored by GTE utilizing livers from an earlier study in which GTE decreased endotoxin-TLR4-NFκB liver injury. Methods and results Mice are fed a low-fat (LF) or HF diet for 12 weeks and then randomized to LF or HF diets containing 0% or 2% GTE for an additional 8 weeks. Global MS-based metabolomics and targeted metabolite profiling of catechins/catechin metabolites are evaluated. GTE in HF mice restores hepatic metabolites implicated in dyslipidemia insulin resistance, and inflammation. These include 122 metabolites: amino acids, lipids, nucleotides, vitamins, bile acids, flavonoids, xenobiotics, and carbohydrates. Hepatic amino acids, B-vitamins, and bile acids are inversely correlated with biomarkers of insulin resistance, liver injury, steatosis, and inflammation. Further, phosphatidylcholine metabolites are positively correlated with biomarkers of liver injury and NFκB inflammation. Thirteen catechin metabolites are identified in livers of GTE-treated mice, mostly as phase II conjugates of parental catechins or microbial-derived valerolactones. Conclusion The defined anti-inflammatory/metabolic interactions advance an understanding of the mechanism by which GTE catechins protect against NFκB-mediated liver injury in NASH.

OBJECTIVES: Intake of eggs and other lipid-rich foods has been a controversial topic for many years. However, some studies support the notion that regular intake of eggs and other lipid-rich foods does not increase biomarkers of cardiovascular disease and may even promote reductions in disease risk. Despite this consensus, the effect of such lipid-rich foods on plasma concentrations of other lipid metabolites remains unexamined. METHODS: To assess the impact of egg intake on these lipid metabolites, plasma from a previous study of egg intake (n = 35, 19M/18F, age 24.1 ± 2.2 yrs, with no lipid disorders) was obtained for analysis. Original samples were collected following a 0 egg/day washout period and 4-week intake of 3 eggs/day. Targeted lipidomic analysis by direct infused tandem MS using differential mobility spectrometry (Lipidyzer, Sciex) was used to identify and quantitate plasma lipid species. RESULTS: Lipidomic analysis quantified 739 lipid species in 13 different lipid classes. After summing individual species, only 1 of the 13 lipid classes (phosphatidylethanolamines) was significantly different (elevated) with egg consumption (p = 0.048). When applying a multiple testing correction, 62 lipid species were higher in plasma after egg consumption, and 34 were lower (P

Juices from the traditional red tomato and a unique tangerine tomato variety are being investigated as health promoting foods in human clinical trials. However, it is unknown how the tangerine and red tomato juices differ in biologically relevant phytochemicals beyond carotenoids. Here liquid-chromatography high-resolution mass spectrometry metabolomics was used to evaluate broadly the similarities and differences in carotenoids and other phytochemicals between red and tangerine tomato juices intended for clinical interventions. This untargeted approach was successful in the rapid detection and extensive characterization of phytochemicals belonging to various compound classes. The tomato juices were found to differ significantly in a number of phytochemicals, including carotenoids, chlorophylls, neutral lipids, and cinnamic acid derivatives. The largest differences were in carotenoids, including lycopene, phytoene, phytofluene, neurosporene, and ζ-carotene. Smaller, but significant, differences were observed in polar phytochemicals, such as chlorogenic acid, hydroxyferulic acid, phloretin-di-C-glycoside, and isopropylmalic acid.

This chapter discusses methods of carotenoid analysis, including sample preparation, UV/Visible spectroscopy, and high-performance liquid chromatography with a photodiode array detector (HPLC-PDA), and separation of optical isomers. Additionally, this chapter focuses on methodologies of the last 10 years including separation of cis/trans geometrical isomers, liquid chromatography– tandem nuclear magnetic resonance (LC-NMR), liquid chromatography–mass spectrometry (LC-MS), separation and identification of carotenoid metabolites, use of stable isotopes of carotenoids, and Raman resonance spectroscopy. This current and comprehensive review emphasizes techniques used for both foodandbiological samples and focuses on the analysis ofb-carotene,a-carotene, lycopene, b-cryptoxanthin, lutein, zeaxanthin, and astaxanthin.

A new family of sandwich-type polytungstophosphates containing two different types of metals in the central belt, M′2M2(PW9O34)212− (M′ = Na or Li, M = Mn2+, Co2+, Ni2+, and Zn2+), have been synthesized and characterized by infrared spectroscopy, 31P solution NMR spectroscopy, and elemental analysis. Compounds Na2Co2(PW9O34)212− (Na2Co2), Na2Ni2(PW9O34)212− (Na2Ni2), Li2Ni2(PW9O34)212− (Li2Ni2), Na2Mn2(PW9O34)212− (Na2Mn2), and Li2Zn2(PW9O34)212− (Li2Zn2) were characterized by X-ray crystallography. All these compounds have similar structures, in which two transition-metal ions and two alkali metal ions (sodium or lithium) are sandwiched between two [B-α-PW9O34]9− units; the transition and alkali metals reside in the internal and external (solvent exposed) positions of the central belt, respectively. By adding LiCl to aqueous solutions of compounds Na2M2, lithium−sodium exchanges in the external belt positions are observed by 31P solution NMR spectroscopy and X-ray crystallography. Magnetic measurements i...

Lycopene, which is a red carotenoid in tomatoes, has been hypothesized to mediate disease-preventive effects associated with tomato consumption. Lycopene is consumed primarily as the all-trans geometric isomer in foods, whereas human plasma and tissues show greater proportions of cis isomers.With the use of compartmental modeling and stable isotope technology, we determined whether endogenous all-trans-to-cis-lycopene isomerization or isomeric-bioavailability differences underlie the greater proportion of lycopene cis isomers in human tissues than in tomato foods.Healthy men (n = 4) and women (n = 4) consumed (13)C-lycopene (10.2 mg; 82% all-trans and 18% cis), and plasma was collected over 28 d. Unlabeled and (13)C-labeled total lycopene and lycopene-isomer plasma concentrations, which were measured with the use of high-performance liquid chromatography-mass spectrometry, were fit to a 7-compartment model.Subjects absorbed a mean ± SEM of 23% ± 6% of the lycopene. The proportion of plasma cis-(13)C-lycopene isomers increased over time, and all-trans had a shorter half-life than that of cis isomers (5.3 ± 0.3 and 8.8 ± 0.6 d, respectively; P0.001) and an earlier time to reach maximal plasma concentration than that of cis isomers (28 ± 7 and 48 ± 9 h, respectively). A compartmental model that allowed for interindividual differences in cis- and all-trans-lycopene bioavailability and endogenous trans-to-cis-lycopene isomerization was predictive of plasma (13)C and unlabeled cis- and all-trans-lycopene concentrations. Although the bioavailability of cis (24.5% ± 6%) and all-trans (23.2% ± 8%) isomers did not differ, endogenous isomerization (0.97 ± 0.25 μmol/d in the fast-turnover tissue lycopene pool) drove tissue and plasma isomeric profiles.(13)C-Lycopene combined with physiologic compartmental modeling provides a strategy for following complex in vivo metabolic processes in humans and reveals that postabsorptive trans-to-cis-lycopene isomerization, and not the differential bioavailability of isomers, drives tissue and plasma enrichment of cis-lycopene. This trial was registered at clinicaltrials.gov as NCT01692340.

Phytoene (C40H64) is a colorless carotenoid found in tomatoes and other plant foods and is enriched in tomato consumers’ plasma and tissues. Yet, little is known about its absorption, distribution,...

Bright green pistachio kernels are desirable in the food industry and degradation of color is often associated with a loss in quality. Chlorophylls (a and b) and lutein are the major pigments in raw pistachios. The heat treatment of chlorophyll-containing foods results in color alteration, due to the conversion of chlorophylls (bright green color) to pheophytins and pyropheophytins (yellow-brown olive color). In this study, changes in the concentration of chlorophylls, chlorophyll degradation products and lutein in pistachios were monitored during oven roasting. An efficient, high performance liquid chromatography method with photodiode-array detection (HPLC-PDA) was developed to separate and quantitate these pigments in pistachios. Extractable chlorophylls a and b were higher in pistachio kernels roasted for 5 and 10 min than in the raw kernels. The most drastic losses were observed with pheophytins a and b, which both decreased by approximately 85% after 60 min of roasting. Pyropheophytins a and b increased significantly during roasting and were 10–12 fold higher in the pistachios roasted for 60 min than in the raw pistachios. Extractable lutein concentration increased by 37% after 5 min, but did not change significantly with longer roasting times. Initial increases in chlorophylls a and b and lutein were likely due to enhanced extractability with roasting. Color measurements of the pistachios corresponded with changes in concentration of chlorophyll pigments observed at the later roasting times. Interestingly, pyrochlorophylls a and b were detected in pistachios as confirmed by mass spectrometry. There are no prior reports of these compounds being detected in pistachios. We hypothesize that the conditions of pistachio roasting favor the formation of pyrochlorophylls. Color changes observed after oven roasting significantly affect quality and value perceptions of pistachios.

A new family of sandwich-type polytungstophosphates containing two different types of metals in the central belt, M′2M2(PW9O34)212− (M′ = Na or Li, M = Mn2+, Co2+, Ni2+, and Zn2+), have been synthesized and characterized by infrared spectroscopy, 31P solution NMR spectroscopy, and elemental analysis. Compounds Na2Co2(PW9O34)212− (Na2Co2), Na2Ni2(PW9O34)212− (Na2Ni2), Li2Ni2(PW9O34)212− (Li2Ni2), Na2Mn2(PW9O34)212− (Na2Mn2), and Li2Zn2(PW9O34)212− (Li2Zn2) were characterized by X-ray crystallography. All these compounds have similar structures, in which two transition-metal ions and two alkali metal ions (sodium or lithium) are sandwiched between two [B-α-PW9O34]9− units; the transition and alkali metals reside in the internal and external (solvent exposed) positions of the central belt, respectively. By adding LiCl to aqueous solutions of compounds Na2M2, lithium−sodium exchanges in the external belt positions are observed by 31P solution NMR spectroscopy and X-ray crystallography. Magnetic measurements i...

A new family of sandwich-type polytungstophosphates containing two different types of metals in the central belt, M'(2)M(2)(PW(9)O(34))(2)(12-) (M' = Na or Li, M = Mn(2+), Co(2+), Ni(2+), and Zn(2+)), have been synthesized and characterized by infrared spectroscopy, (31)P solution NMR spectroscopy, and elemental analysis. Compounds Na(2)Co(2)(PW(9)O(34))(2)(12-) (Na2Co2), Na(2)Ni(2)(PW(9)O(34))(2)(12-) (Na2Ni2), Li(2)Ni(2)(PW(9)O(34))(2)(12-) (Li2Ni2), Na(2)Mn(2)(PW(9)O(34))(2)(12-) (Na2Mn2), and Li(2)Zn(2)(PW(9)O(34))(2)(12-) (Li2Zn2) were characterized by X-ray crystallography. All these compounds have similar structures, in which two transition-metal ions and two alkali metal ions (sodium or lithium) are sandwiched between two [B-alpha-PW(9)O(34)](9-) units; the transition and alkali metals reside in the internal and external (solvent exposed) positions of the central belt, respectively. By adding LiCl to aqueous solutions of compounds Na2M2, lithium-sodium exchanges in the external belt positions are observed by (31)P solution NMR spectroscopy and X-ray crystallography. Magnetic measurements indicate ferromagnetic exchange interactions between the two Ni(2+) ions in Na2Ni2 at 10-300 K and the two Co(2+) ions in Na2Co2 at 6-30 K. In contrast, Na2Mn2 exhibits an antiferromagnetic interaction between the Mn(2+) ions at 2-50 K.