Miscarriage, Abortion, and Disease

The frequency of death from miscarriage is very high, greater than the number of deaths from induced abortion or major diseases.  Berg (2017, Philosophical Studies 174:1217-26) argues that, given this, those who contend that personhood begins at conception (PAC) are obliged to reorient their resources accordingly-towards stopping miscarriage, in preference to stopping abortion or diseases. This argument depends on there being a basic moral similarity between these deaths. I argue that, for those that hold to PAC, there are good reasons to think that there is no such similarity. There is a morally relevant difference between preventing killing and letting die, giving PAC supporters reasons to prioritize reducing abortion over reducing miscarriage. And the time-relative interest account provides a morally relevant difference in the badness of death of miscarriages and deaths of born adults, justifying attempts to combat major diseases over attempts to combat miscarriage. I consider recent developments in the literature and contend that these new arguments are unsuccessful in establishing moral similarities between deaths from miscarriage and abortion, and deaths from miscarriage and disease.

Side Effects and Complications Associated with Treating Plutonium Intakes: A Retrospective Review of the Medical Records of LANL Employees Treated for Plutonium Intakes, with Supplementary Interviews

ABSTRACT

Anecdotal evidence indicates there may be unpublished physical and psychological events associated with the medical treatment of plutonium intakes. A thorough review was conducted of the medical and bioassay records of current and previous Los Alamos National Laboratory (LANL) employees who had experienced plutonium intakes via wound or inhalation. After finding relatively incomplete information in the medical records, the research team interviewed current LANL employees who had undergone chelation therapy and/or surgical excision. Although the dataset is not large enough to reach statistically significant conclusions, it was observed that adverse events associated with treatment appear to be more frequent and more severe than previously reported.

Jobs and job quality between the eve of the Great Recession and the eve of COVID-19

In 2019, the employment rate among 25- to 64-year-olds in the UK reached 80 per cent - the highest on record, and considerably higher than the 76 per cent rate recorded shortly before the Great Recession. In this paper, we investigate the growth in employment between the eve of the Great Recession and the eve of COVID-19 across several dimensions. We analyse which sectors, demographic groups and regions accounted for the rise. We also investigate how job 'quality' - in both financial and non-financial terms - has changed. We find that almost all demographic groups and regions saw a rise in employment, especially those with low pre-existing employment rates and those near the bottom of the income distribution. Hourly pay growth was very weak over the period, with the median actually slightly falling. Other indicators of job quality show a more mixed picture: employees seem to have greater appreciation of their work and firm, but perceive less security and flexibility in their job.

0687 Comparative Changes Of Patient Reported Outcomes In Positive Airway Pressure And Upper Airway Stimulation For Obstructive Sleep Apnea

Introduction

Upper Airway Stimulation (UAS) is increasingly being used for obstructive sleep apnea (OSA) treatment, however, data comparing changes in patient reported outcomes (PROs) in response to positive airway pressure (PAP) versus UAS are limited. We hypothesize that there will be no difference in PROs between the two groups after treatment.

Methods

UAS and PAP groups were 1:3 matched on age, sex, Body Mass Index (BMI) and Apnea Hypopnea Index (AHI, category 15-30, >30). Linear mixed models assessed the difference of change in Epworth Sleepiness Scale (ESS), Functional Outcomes of Sleep Questionnaire (FOSQ), Patient Health Questionnaire (PHQ9) and Insomnia Severity Index (ISI) measures on matched strata of UAS versus PAP groups with adjustment of baseline and matching factors. All analysis was performed in SAS software (version 9.4, Cary, NC).

Results

The analytic sample comprised 193 PAP patients and 69 UAS patients, with mean age=62.9+/-9.4 years, 27.5% female, mean BMI=29.1+/-3.2kg/m2, and median AHI 42.7, IQR: 31.5, 57.2. ESS in PAP (n=190) reduced by -2.63 (-3.38,-1.88) and in UAS (n=56) reduced by -2.22 (-3.34, -1.10), with a mean difference of 0.41 (-0.70, 1.52, p=.46). FOSQ in PAP (n=188) showed a change of 1.38 (0.99, 1.78) and in UAS (n=49) a change of 1.82 (1.17, 2.46), with a mean difference of 0.43 (-0.23, 1.09, p=.19). PHQ9 in PAP (n=185) showed a significant change of -2.24(-3.00, 1.47) and in UAS (n=45) a change of -3.75(-5.07,-2.42), with a mean difference of -1.51(-2.93,-0.088, p=.038). ISI in PAP (n=193) showed a significant change of -3.20(-4.39,-2.02) and in UAS (n=47) a change of -4.83(-6.77,-2.90), with a mean difference of -1.63(-3.62, 0.37, p=.11).

Conclusion

Similar improvements in PROs were observed in both UAS and PAP patient groups, however UAS appeared to confer greater benefit in depressive symptoms relative to PAP. Randomized clinical trials should be designed to confirm these findings.

Support

N/A

The association between platelet dysfunction and adverse outcomes in cardiac surgical patients

Haemostatic activation during cardiopulmonary bypass is associated with prothrombotic complications. Although it is not possible to detect and quantify haemostatic activation directly, platelet dysfunction, as measured with point-of-care-assays, may be a useful surrogate. In this study, we assessed the association between cardiopulmonary bypass-associated platelet dysfunction and adverse outcomes in 3010 cardiac surgical patients. Platelet dysfunction, as measured near the end of the rewarming phase of cardiopulmonary bypass, was calculated as the proportion of non-functional platelets after activation with collagen. Logistic regression and multivariable analyses were applied to assess the relationship between platelet dysfunction and a composite of in-hospital death; myocardial infarction; stroke; deep vein thrombosis or pulmonary embolism; and acute kidney injury (greater than a two-fold increase in creatinine). The outcome occurred in 251 (8%) of 3010 patients. The median (IQR [range]) percentage platelet dysfunction was less for those without the outcome as compared with those with the outcome; 14% (8-28% [1-99%]) vs. 19% (11-45% [2-98%]), p < 0.001. After risk adjustment, platelet dysfunction was independently associated with the composite outcome (p < 0.001), such that for each 1% increase in platelet dysfunction there was an approximately 1% increase in the composite outcome (OR 1.012; 95%CI 1.006-1.018). This exploratory study suggests that cardiopulmonary bypass-associated platelet dysfunction has prognostic value and may be a useful clinical measure of haemostatic activation in cardiac surgery.

Mitigating the Psychological Harm from Actinide Intakes

Investigations into possible actinide intakes, as well as the intakes themselves, may result in significant psychological harm that should be mitigated by the internal dosimetrist. Many aspects of this psychological impact are unique to actinide intakes and have not been discussed in the literature. This paper discusses some of these unique considerations and describes how the Internal Dosimetry Team at Los Alamos National Laboratory (LANL) has, with input and guidance from LANL psychologists, tried to address them. We feel that much of the psychological harm can be mitigated by educating employees specifically about internal dosimetry and internal doses, and by improving communication with radiation workers.

C-F bond activation of trifluoroethanol and trifluoroacetic acid catalysed by the dimolybdate anion, [Mo2O6(F)]- †

Two gas-phase catalytic cycles involving C-F bond activation of trifluoroethanol and trifluoroacetic acid were detected by multistage mass spectrometry experiments. A binuclear dimolybdate centre [Mo₂O₆(F)]^- acts as the catalyst in each cycle. The first cycle, entered via the reaction of [Mo₂O₆(OH)]^- with trifluoroethanol and elimination of water to form [Mo₂O₆(OCH₂CF₃)]^-, proceeds via four steps: (1) oxidation of the alkoxo ligand and its elimination as aldehyde; (2) reaction of [Mo₂O₅(OH)]^- with trifluoroethanol and elimination of water to form [Mo₂O₅(OCH₂CF₃)]; (3) decomposition of the alkoxo ligand via loss of 1,1 difluoroethene; and (4) reaction of [Mo₂O₆(F)]^- with a second equivalent of trifluoroethanol to regenerate Mo₂O₆(OCH₂CF₃)]^-. Steps (2) and (3) do not occur at room temperature and require collisional activation to proceed. The second cycle is entered via the reaction of [Mo₂O₆(OH)]^- with trifluoroacetic acid and elimination of water to form [Mo₂O₆(O₂CCF₃)]^- and involves two steps only: (1) fluoride transfer to a molybdenum centre to form [Mo₂O₆(F)]^-; (2) reaction of [Mo₂O₆(F)]^- with trifluoroacetic acid and loss of water to regenerate [Mo₂O₆(O₂CCF₃)]^-. Comparisons are made with the chemistry of [Mo₂O₆(OH)]^- reacting with acetic acid.

Considerations for Bioassay Monitoring of Mixtures of Radionuclides

Complying with regulations for bioassay monitoring of radionuclide intakes is significantly more complex for mixtures than it is for pure radionuclides. Different constituents will naturally have different dose coefficients, be detectable at significantly different levels, and may require very different amounts of effort to bioassay. The ability to use certain constituents as surrogates for others will depend on how well characterized the mixture is, as well as whether the employee is also working with other radionuclides. This is further compounded by the fact that the composition of a mixture (or even of a pure radionuclide) is likely to change over time. Internal dosimetrists must decide how best to monitor employees who work with radionuclide mixtures. In particular, they must decide which constituents should be monitored routinely, which constituents only need to be monitored in the case of an intake, and how to estimate doses based on intakes of monitored and unmonitored constituents.

Interpretation of Nasal Swab Measurements Following Suspected Releases of Actinide Aerosols

For radionuclides such as plutonium and americium, detection of removable activity in the nose (i.e., nasal swab measurements) are frequently used to determine whether follow-up bioassay measurements are warranted following a potential intake. For this paper, the authors analyzed 429 nasal swab measurements taken following incidents or suspicious circumstances (such as an air monitor alarming) at Los Alamos National Laboratory (LANL) for which the dose was later evaluated using in vitro bioassay. Nasal swab measurements were found to be very poor predictors of dose and should not be used as such in the field. However, nasal swab measurements can be indicative of whether a reliably detectable committed effective dose (CED) occurred. About 14% of nasal swab measurements between 1.25 and 16.7 Bq corresponded to CEDs greater than 1 mSv, so in general, positive nasal swabs always indicate that follow-up bioassay should be performed (positive nasal swabs less than 1.25 Bq are considered separately). This probability increased significantly for nasal swabs greater than 16.7 Bq. Only about 3% of nasal swabs with no detectable activity (NDA) corresponded to reliably detectable CEDs. A nasal swab with NDA is therefore necessary, but not sufficient, to negate the need for a follow-up bioassay if it was collected following other workplace indicators of a potential intake.

Endocyclic versus exocyclic mechanisms for methyl migration in protonated N,N'-dimethylpropane-1,3-diamine

A recent paper has suggested that an endocyclic methyl transfer pathway occurs in competition with methylamine loss for protonated N,N'-dimethylpropane-1,3-diamine under conditions of low-energy collision induced dissociation [X. Zhang, S. Yao and Y. Guo, Int. J. Mass Spectrom. 214, 277 (2008)]. However, such endocyclic methyl transfers appear to be unprecedented in the gas phase. Therefore, in order to gain additional insights into the competition between methylamine loss and methyl transfer in this system, DFT calculations were performed at the B3LYP/6-311+G(d,p) level of theory for a number of competing mechanisms. Three mechanisms were considered for loss of methylamine: (i) a 1,2-elimination reaction to give N-methylallylamine (TS = 276.7 kJ mol(-1)); (ii) a neighbouring group reaction to give N-methylazitidine (TS = 146.4 kJ mol(-1)); and (iii) a 1,3-hydride shift to give N-methyl-1-propylimine (TS = 248.5 kJ mol(-1)). Accordingly, the neighbouring group pathway is expected to be kinetically favoured and dominate under conditions of low-energy collision-induced dissociation. Similarly, three different mechanisms were considered for intramolecular methyl transfer: (i) the previously proposed endocyclic reaction involving backside attack with inversion of configuration (TS = 252.3 kJ mol(-1)); (ii) the previously proposed endocyclic reaction involving frontside attack with retention of configuration (TS = 272.4 kJ mol(-1)); (iii) a multi-step mechanism which combines the neighbouring group pathway for methylamine loss and combinations of S(N)2 and proton transfer reactions within a series of ion-molecule complexes (highest TS = 201.7 kJ mol(-1)). These results suggest that the alternative pathway proposed here for methyl transfer should be preferred under conditions of low energy collision- induced dissociation.

Uncertainties in internal doses calculated for Mayak workers--a study of 63 cases

This study makes use of 63 cases of Mayak workers exposed to Pu-239 with autopsy data and some late-time urine bioassay data. In addition, air-concentration data--used to construct monthly average values--are available for each case, which provide the time dependence and potential magnitudes of normal inhalation intakes for each case. The purpose of the study is to develop and test Bayesian methods of dose calculation for the Mayak workers. The first part of the study was to quantitatively characterise the uncertainties of the bioassay data. Then, starting with three different published biokinetic models, the data are fit by varying intake and model perturbation parameters, e.g., parameters influencing the lung, thoracic lymph nodes, liver and bone retention. Statistical self-consistency arguments are used to check the measurement uncertainty parameters within the Poisson-lognormal model. The second part of the study is to set up and test Bayesian dose calculations, which use the point determinations of biokinetic parameters from the study cases within a discrete, empirical Bayes approximation. The main conclusion of the study is that these methods are now ready to be applied to the entire Mayak worker population.

Experimental determination of the gas phase proton affinities of the conjugate base anions of 2-iodoxybenzoic acid (IBX) and 2-iodosobenzoic acid (IBA)

The gas phase anion proton affinities of the periodinane anions IBX- and IBA- were examined using mass spectrometry-based experiments, and estimated as 1300 +/- 25 and 1390 +/- 10 kJ mol(-1), respectively. The experimental results were supported by theoretical calculations, which yielded proton affinities of 1336 and 1392 kJ mol(-1) for IBX- and IBA- respectively, at the B3LYP/aug-cc-PVDZ level of theory.

Gas-Phase Reactivity of Metavanadate [VO3]− towards Methanol and Ethanol: Experiment and Theory

The gas-phase reactivity of the metavanadate anion [VO3]- towards methanol and ethanol was examined by a combination of ion-molecule reaction and isotope labelling experiments in a quadrupole ion-trap mass spectrometer. The experimental data were interpreted with the aid of density functional theory calculations. [VO3]- dehydrated methanol to eliminate water and form [VO2(eta2-OCH2)]-, which features an [eta2-C,O-OCH2]2- ligand formed by formal removal of two protons from methanol and which is isoelectronic with peroxide. [VO3]- reacted with ethanol in an analogous manner to form [VO2(eta2-OCHCH3)]-, as well as by loss of ethene to form [VO2(OH)2]-. The calculations predicted that important intermediates in these reactions were the hydroxo alkoxo anions [VO2(OH)(OCH2R)]- (R: H, CH3). These were predicted to undergo intramolecular hydrogen-atom transfer to form [VO(OH)2(eta1-OCHR)]- followed by eta1-O-->eta2-C,O rearrangements to form [VO(OH)2(eta2-OCHR)]-. The latter reacted further to eliminate water and generate the product [VO2(eta2-OCHR)]-. This major product observed for [VO3]- is markedly different from that observed previously for [NbO3]- containing the heavier Group 5 congener niobium. In that case, the major product of the reaction was an ion of stoichiometry [Nb, O3, H2]- arising from the formal dehydrogenation of methanol to formaldehyde. The origin of this difference was examined theoretically and attributed to the intermediate alkoxo anion [NbO2(OH)(OCH3)]- preferring hydride transfer to form [HNbO2(OH)]- with loss of formaldehyde. This contrasts with the hydrogen-atom-transfer pathway observed for [VO2(OH)(OCH3)]-.

Letter: Silver mediated ester bond formation in the gas phase: substrate structure is important

The silver acetate cation CH(3)CO(2)Ag(2)(+) reacted with allyl iodide via C-O bond coupling to produce Ag(2)I(+) and allyl acetate, but only underwent adduct formation with methyl iodide, highlighting the importance of substrate on reactivity. DFT calculations predicted the reaction with allyl iodide to be exothermic by 0.48 eV, and suggested that intermediates in the reaction benefit from multiple interactions between the allyl and iodide moieties of allyl iodide and the two silver atoms in CH(3)CO(2)Ag(2)(+).

Photoelectron Spectroscopy of Free Multiply Charged Keggin Anions α-[PM12O40]3- (M = Mo, W) in the Gas Phase

Two polyoxometalate Keggin-type anions, alpha-PM12O40(3-) (M = Mo, W), were transferred to the gas phase by electrospray; their electronic structure and stability were probed by photoelectron spectroscopy. These triply charged anions were found to be highly stable in the gas phase with large adiabatic electron detachment energies of 1.7 and 2.1 eV for M = Mo and W, respectively. The magnitude of the repulsive Coulomb barrier was measured as approximately 3.4 eV for both anions, providing an experimental estimate for the intramolecular Coulomb repulsion present in these highly charged anions. Density functional theory calculations were carried out and compared with the experimental data, providing insight into the electronic structure and valence molecular orbitals of the two Keggin anions. The calculations indicated that the highest occupied molecular orbital and other frontier orbitals for PM12O40(3-) are localized primarily on the mu2-oxo bridging ligands of the polyoxometalate framework, consistent with the reactivity on the mu2-oxo sites observed in solution. It was shown that the HOMO of PW12O40(3-) is stabilized relative to that of PMo12O40(3-) by approximately 0.35 eV. The experimental adiabatic electron detachment energies of PM12O40(3-) (i.e., the electron affinities of PM12O40(2-)) are combined with recent calculations on the proton affinity of PM12O40(3-) to yield O-H bond dissociation energies in PM12O39(OH)2- as approximately 5.1 eV.

Photoelectron Spectroscopy of the Bis(dithiolene) Anions [M(mnt)2]n- (M = Fe − Zn; n = 1, 2): Changes in Electronic Structure with Variation of Metal Center and with Oxidation

A detailed understanding of the electronic structures of transition metal bis(dithiolene) centers is important in the context of their interesting redox, magnetic, and optical properties. The electronic structures of the series [M(mnt)2]n- (M = Fe - Zn; mnt = 1,2-S2C2(CN)2; n = 1, 2) were examined by a combination of photodetachment photoelectron spectroscopy and density functional theory calculations, providing insights into changes in electronic structure with variation of the metal center and with oxidation. Significant changes were observed for the dianions [M(mnt)2]2- due to stabilization of the metal 3d levels from Fe to Zn and the transition from square-planar to tetrahedral coordination about the metal center (Fe-Ni, D(2h) --> Cu D2 --> Zn, D(2d). Changes with oxidation from [M(mnt)2]2- to [M(mnt)2]1- were largely dependent on the nature of the redox-active orbital in the couple [M(mnt)2](2-/1-). In particular, the first detachment feature for [Fe(mnt)2]2- originated from a metal-based orbital (Fe(II) --> Fe(III)) while that for [Fe(mnt)2]1- originated from a ligand-based orbital, a consequence of stabilization of Fe 3d levels in the latter. In contrast, the first detachment feature for both of [Ni(mnt)2]2- and [Ni(mnt)2]1- originated from the same ligand-based orbital in both cases, a result of occupied Ni 3d levels being stabilized relative those of Fe 3d and occurring below the highest energy occupied ligand-based orbital for both of [Ni(mnt)2]2- and [Ni(mnt)2]1- . The combined data illustrate the subtle interplay between metal- and ligand-based redox chemistry in these species and demonstrate changes in their electronic structures with variation of metal center, oxidation, and coordination geometry.

Probing the Intrinsic Electronic Structure of the Bis(dithiolene) Anions [M(mnt)2]2- and [M(mnt)2]1- (M = Ni, Pd, Pt; mnt = 1,2-S2C2(CN)2) in the Gas Phase by Photoelectron Spectroscopy

A detailed understanding of the electronic structure of transition metal bis(dithiolene) complexes is important because of their interesting redox, magnetic, optical, and conducting properties and their relevance to enzymes containing molybdenum and tungsten bis(dithiolene) centers. The electronic structures of the bis(dithiolene) anions [M(mnt)(2)](n-) (M = Ni, Pd, Pt; mnt = 1,2-S(2)C(2)(CN)(2); n = 0-2) were examined by a combination of photodetachment photoelectron spectroscopy (PES) and density functional theory calculations. The combined experimental and theoretical data provide insight into the molecular orbital energy levels of [M(mnt)(2)](2-) and the ground and excited states of [M(mnt)(2)](1-) and [M(mnt)(2)]. Detachment features from ligand-based orbitals of [M(mnt)(2)](2-) occur at similar energies for each species, independent of the metal center, while those arising from metal-based orbitals occur at higher energies for the heavier congeners. Electronic excitation energies inferred for [M(mnt)(2)](1-) from the PES experiments agree well with those obtained in optical absorption experiments in solution, with the PES experiments providing additional insight into the changes in energy of these transitions as a function of metal. The singly charged anions [M(mnt)(2)](1-) were also prepared and studied independently. Electron detachment from the ground states of these doublet anions accessed the lowest singlet and triplet states of neutral [M(mnt)(2)], thereby providing a direct experimental measure of their singlet-triplet splitting.

Mononuclear metavanadate catalyses gas phase oxidation of methanol to formaldehyde employing dioxygen as the terminal oxidant

Multistage mass spectrometry experiments reveal a sequence of gas phase reactions for the oxidation of methanol to formaldehyde with a mononuclear oxo vanadate anion as the catalyst and dioxygen as the terminal oxidant.

Electronic Structure of the Hydroxo and Methoxo Oxometalate Anions MO3(OH)- and MO3(OCH3)- (M = Cr, Mo, and W)

The electronic structure of the mononuclear hydroxo MO3(OH)- and methoxo MO3(OCH3)- Group 6 oxometalate anions (M = Cr, Mo, and W) were examined by photodetachment photoelectron spectroscopy and electronic structure calculations at the density functional and CCSD(T) levels of theory. All of the anions exhibited high electron binding energies (>4.9 eV), with the lowest-energy detachment features arising from oxygen 2p-based orbitals. The combined experimental and theoretical results allowed the change in molecular orbital energy levels to be investigated as a function of metal (Cr, Mo, or W) and ligand (-OH, -OCH3). A number of fundamental thermodynamic properties of the anions and corresponding neutrals were predicted on the basis of the theoretical calculations. The calculations indicate high O-H bond dissociation energies for MO2(OR)(O-H) (R = H, CH3) and MO3(O-H), consistent with their high Brønsted acidities (just below that of H2SO4 in the gas phase) and the high ionization energies of their conjugate base anions. This suggests that the corresponding radicals should readily abstract H atoms from organic molecules.

Photoelectron Spectroscopy of Doubly and Singly Charged Group VIB Dimetalate Anions: M2O72-, MM‘O72-, and M2O7- (M, M‘ = Cr, Mo, W)

We produced both doubly and singly charged Group VIB dimetalate species-M(2)O(7)(2-), MM'O(7)(2-), and M(2)O(7)(-) (M, M' = Cr, Mo, W)-using two different experimental techniques (electrospray ionization for the doubly charged anions and laser vaporization for the singly charged anions) and investigated their electronic and geometric structures using photoelectron spectroscopy and density functional calculations. Distinct changes in the electronic and geometric structures were observed as a function of the metal and charge state. The electron binding energies of the heteronuclear dianions MM'O(7)(2-) were observed to be roughly the average of those of their homonuclear counterparts (M(2)O(7)(2-) and M'(2)O(7)(2-)). Density functional calculations indicated that W(2)O(7)(2-), W(2)O(7)(-), and W(2)O(7) possess different ground-state structures: the dianion is highly symmetric (D(3d),(1)A(1g)) with a single bridging oxo ligand, the monoanion is a doublet (C(1), (2)A) with two bridging oxo ligands and a radical terminal oxo ligand, whereas the neutral is a singlet (C(1), (1)A) with two bridging oxo ligands and a terminal peroxo ligand. The combined experimental and theoretical study provides insights into the evolution of geometric and electronic structures as a function of charge state. The clusters identified might provide insights into the possible structures of reactive species present in early transition-metal oxide catalysts that are relevant to their reactivity and catalytic function.

Gas-Phase Reactivity of Heterobinuclear Oxometalate Anions [CrMoO6(OR)]-, [CrWO6(OR)]-, and [MoWO6(OR)]- (R = H, nBu)

Heterobinuclear oxometalate anions based upon [CrMoO7]2-, [CrWO7]2-, and [MoWO7]2- were generated and transferred to the gas phase by the electrospray process from acetonitrile solutions containing two of the salts (Bu4N)2[MO4] (M = Cr, Mo, W). Their reactivities were examined and compared with those of the related homobinuclear anions based upon [M2O7]2- (M = Cr, Mo, W). Particular emphasis was placed upon reactions relevant to gas-phase catalytic cycles described previously for oxidation of alcohols by [Mo2O6(OH)]- (Waters, T.; O'Hair, R. A. J.; Wedd, A. G. J. Am. Chem. Soc. 2003, 125, 3384-3396). The protonated anions [MM'O6(OH)]- each reacted with methanol with loss of water to form [MM'O6(OCH3)]- at a rate that was intermediate between those of [M2O6(OH)]- and [M'2O6(OH)]-. The butylated anions [MM'O6(OBu)]- were generated by collisional activation of the ion-pairs {Bu4N+ [MM'O7]2-}-. Collisional activation of [MM'O6(OBu)]- resulted in either the loss of butanal (redox reaction) or the loss of butene (elimination reaction), with the detailed nature of the observations depending on the nature of both M and M'. Selective 18O labeling indicated that the butoxo ligands of [CrMoO6(OBu)]- and [CrWO6(OBu)]- were located on molybdenum and tungsten, respectively. This structural insight allowed a more detailed comparison of reactivity with the homobinuclear species, and highlighted the importance of the neighboring metal center in these reactions.