C≡N and N≡O Bond Cleavages of Acetonitrile and Nitrosyl Ligands at a Dimolybdenum Center to Render Ethylidyne and Acetamidinate Ligands

Extended reduction of [Mo2Cp2(μ-Cl)(μ-PtBu2)(NO)2] (1) with Na(Hg) in acetonitrile (MeCN) at room temperature resulted in an unprecedented full cleavage of the C≡N bond of a coordinated MeCN molecule to yield the vinylidene derivative Na[Mo2Cp2(μ-PtBu2)(μ-CCH2)(NO)2], which upon protonation with (NH4)PF6 gave the ethylidyne complex [Mo2Cp2(μ-PtBu2)(μ-CMe)(NO)2] [Mo1-Mo2 = 2.9218(2) Å] in a selective and reversible way. Controlled reduction of 1 at 273 K yielded instead, after protonation, the 30-electron acetamidinate complex [Mo2Cp2(μ-PtBu2)(μ-κN:κN'-HNCMeNH)(μ-NO)]PF6 [Mo1-Mo2 = 2.603(2) Å], in a process thought to stem from the paramagnetic MeCN-bridged intermediate [Mo2Cp2(μ-PtBu2)(μ-NCMe)(NO)2], followed by a complex sequence of elementary steps including cleavage of the N≡O bond of a nitrosyl ligand.

Postoperative Psychological Predictors for Chronic Postsurgical Pain After a Knee Arthroplasty: A Prospective Observational Study

OBJECTIVE

Chronic postsurgical pain (CPSP) is a significant adverse effect shown in around 20% of people who had undergone a knee arthroplasty (KA). Psychological risk factors have emerged as significant and potentially modifiable risk factors for its development. However, there is still little evidence when assessing these factors during the acute postoperative period. This study aimed to assess the predictive value of postoperative pain catastrophizing, pain-related fear of movement, anxiety, depression, and pain attitudes in developing CPSP after KA.

METHODS

A 6-month follow-up prospective observational study design was used. The study sample comprised 115 people who underwent a KA due to painful primary osteoarthritis. Measures of pain catastrophizing, pain-related fear of movement, anxiety, depression, and pain attitudes were obtained 1 week after surgery. CPSP was set at an intensity of ≥30 using a 100-mm visual analog scale at 3 and 6 months after surgery.

RESULTS

Analysis revealed that baseline pain intensity, pain catastrophizing, pain-related fear of movement, anxiety, depression, and maladaptive pain attitudes were significant predictors of chronic pain at 3 and 6 months after surgery in a univariate analysis. However, at 3 months after surgery, only pain intensity and pain catastrophizing were predictors in the final multivariate model forecasting disturbing pain. Moreover, 6 months after surgery, pain intensity and distrust in medical procedures remained independent predictors. Most of the psychological factors can be grouped into a single dimension defined as pain-related psychological distress.

CONCLUSION

The results suggest that postoperative pain intensity, pain catastrophizing, and pain attitudes are independent predictors for CPSP after KA.

IMPACT

Postoperative cognitive and emotional factors should be considered alongside pain intensity during postoperative rehabilitation after KA because they could influence the development of CPSP.

E-H Bond Cleavage Processes in Reactions of Heterometallic Phosphinidene-Bridged MoRe and MoMn Complexes with Hydrogen and p-Block Element Hydrides

Reactions of complexes [MoMCp(μ-PMes*)(CO)6] with H2 and several p-block element (E) hydrides mostly resulted in the cleavage of E-H bonds under mild conditions [M = Re (1a) and Mn (1b); Mes* = 2,4,6-C6H2tBu3]. The reaction with H2 (ca. 4 atm) proceeded even at 295 K to give the hydrides [MoMCp(μ-H)(μ-PHMes*)(CO)6]. The same result was obtained in the reactions with H3SiPh and, for 1a, upon reduction with Na(Hg) followed by protonation of the resulting anion [MoReCp(μ-PHMes*)(CO)6]-. The latter reacted with [AuCl{P(p-tol)3}] to yield the related heterotrimetallic cluster [MoReAuCp(μ-PHMes*)(CO)6{P(p-tol)3}]. The reaction of 1a with thiophenol gave the thiolate-bridged complex [MoReCp(μ-PHMes*)(μ-SPh)(CO)6], which evolved readily to the pentacarbonyl derivative [MoReCp(μ-PHMes*)(μ-SPh)(CO)5]. In contrast, no P-H bond cleavage was observed in reactions of complexes 1a,b with PHCy2, which just yielded the substituted derivatives [MoMCp(μ-PMes*)(CO)5(PHCy2)]. Reactions with HSnPh3 again resulted in E-H bond cleavage, but now with the stannyl group terminally bound to M, while 1a reacted with BH3·PPh3 to give the hydride-bridged derivatives [MoReCp(μ-H)(μ-PHMes*)(CO)5(PPh3)] and [MoReCp(μ-H){μ-P(CH2CMe2)C6H2tBu2}(CO)5(PPh3)], which follow from hydrogenation, C-H cleavage, and CO/PPh3 substitution steps. Density functional theory calculations on the PPh-bridged analogue of 1a revealed that hydrogenation likely proceeds through the addition of H2 to the Mo=P double bond of the complex, followed by rearrangement of the Mo fragment to drive the resulting terminal hydride into a bridging position.

X-ray-determined structure of the technetium complex [Tc2(μ-CO)2(NC5H5)2(CO)6] revisited: [Tc2(μ-OMe)2(NC5H5)2(CO)6] as the correct formulation

Some of us reported previously the structure of di-μ-carbonyl-bis[tricarbonyl(pyridine)technetium], [Tc2(μ-CO)2(C5H5N)2(CO)6], as the main product of the reaction of [Tc2(CO)10] with pyridine at room temperature, using the reagent itself as solvent [Zuhayra et al. (2008). Inorg. Chem. 47, 10177-10182]. On the basis of an X-ray analysis of the product, a molecular structure was proposed with two bridging carbonyls displaying very unusual geometrical features, not explained at the time. Subsequent chemical considerations, coupled with density functional theory (DFT) calculations, prompted us to revise the original structure determination. Using the original raw diffraction data, we have now performed new refinements to show that the previously proposed `bridging carbonyls' actually correspond to bridging methoxide groups, and that the crystals analyzed at the time therefore would correspond to the complex di-μ-methoxido-bis[tricarbonyl(pyridine)technetium], syn-[Tc2(μ-OMe)2(NC5H5)2(CO)6]. This methoxide-bridged complex likely was a minor side product formed along with the main product in the above reaction, perhaps due to the presence of trace amounts of methanol and air in the reaction mixture.

Cycloaddition and C-S Bond Cleavage Processes in Reactions of Heterometallic Phosphinidene-Bridged MoRe and MoMn Complexes with Alkynes and Phenyl Isothiocyanate

Reactions of [MoReCp(μ-PMes*)(CO)6] with internal alkynes RC≡CR yielded the phosphapropenylidene-bridged complexes [MoReCp(μ-κ2P,C:η3-PMes*CRCR)(CO)5] (Mes* = 2,4,6-C6H2tBu3; R = CO2Me, Ph). Terminal alkynes HC≡CR1 gave mixtures of isomers [MoReCp(μ-κ2P,C:η3-PMes*CHCR1)(CO)5] and [MoReCp(μ-κ2P,C:η3-PMes*CR1CH)(CO)5], with the first isomer being major (R1 = CO2Me) or unique (R1 = tBu), indicating the relevance of steric repulsions during the [2 + 2] cycloaddition step between Mo=P and C≡C bonds in these reactions. Similar reactions were observed for [MoMnCp(μ-PMes*)(CO)6]. Addition of ligands to these complexes promoted rearrangement of the phosphapropenylidene ligand into the allyl-like μ-η3:κ1C mode, as shown by the reaction of [MoReCp(μ-κ2P,C:η3-PMes*CHC(CO2Me)}(CO)5] with CN(p-C6H4OMe) to give [MoReCp{μ-η3:κ1C-PMes*CHC(CO2Me)}(CO)5{CN(p-CH4OMe)}2]. The MoRe phosphinidene complex reacted with S=C=NPh to give as major products the phosphametallacyclic complex [MoReCp{μ-κ2P,S:κ2P,S-PMes*C(NPh)S}(CO)5] and its thiophosphinidene-bridged isomer [MoReCp(μ-η2:κ1S-SPMes*)(CO)5(CNPh)]. The first product follows from a [2 + 2] cycloaddition between Mo=P and C=S bonds, with specific formation of P-C bonds, whereas the second one would arise from the alternative cycloaddition involving the formation of P-S bonds, more favored on steric grounds. The prevalence of the μ-η2:κ1S coordination mode of the SPMes* ligand over the μ-η2:κ1p mode was investigated theoretically to conclude that steric congestion favors the first mode, while the kinetic barrier for interconversion between isomers is low in any case.

Sleep quality and sleep deprivation: relationship with academic performance in university students during examination period

The beginning of the university brings together maturational, psychosocial and academic changes that make university students more prone to suffer from insufficient or poor quality sleep, which can negatively influence their academic performance. The period of taking exams is a key part of the academic year. However, there are few studies that analyze sleep during this period of time. Our aim is to study the association of sleep quality and sleep deprivation with academic performance during the examination period. A descriptive, cross-sectional and correlational study was carried out with the participation of 640 subjects in the first three years of five faculties belonging to the Universidad Autónoma de Madrid. The instrument used consisted of a questionnaire that included sociodemographic and academic data, Pittsburgh Sleep Quality Index, Epworth Sleepiness Scale and information about the academic performance. During the examination period, a positive association was found between sleep quality and academic performance. University students slept less than desired, both on weekdays and weekends, and the sleep debt during the week was associated with a worse students' perception of their academic performance. In total, 61.3% of the students believed that their performance would improve by getting more sleep. In addition, low drowsiness and napping were also found. In conclusion, during periods of greater academic demand, an insufficient sleep and poor quality is commonly observed, affecting negatively to their academic performance. Actually, about 2/3 of our subjects believed that their performance would improve by getting more sleep.

Reactions of Heterometallic Phosphinidene-Bridged MoMn and MoRe Complexes with Sulfur and Selenium: From Chalcogenophosphinidene- to Trithiophosphonate-Bridged Derivatives

Reactions of [MoReCp(μ-PR*)(CO)₆] with S₈ were strongly dependent on experimental conditions (R* = 2,4,6-C₆H₂^tBu₃). When using 1 equiv of sulfur, complex [MoReCp(μ-η²:κ¹_S-SPR*)(CO)₆] was slowly formed at 313 K, with a thiophosphinidene ligand unexpectedly bridging the dimetal center in the novel μ-κ¹_S:η² coordination mode, as opposed to the μ-κ¹_P:η² mode usually found in related complexes. The latter underwent fast decarbonylation at 363 K to give [MoReCp(μ-η²:η²-SPR*)(CO)₅], with a six-electron donor thiophosphinidene ligand rearranged into the rare μ-η²:η² coordination mode. Depending on reaction conditions, reactions with excess sulfur involved the addition of two or three S atoms to the phosphinidene ligand to give new complexes identified as the dithiophosphinidene-bridged complex [MoReCp(μ-η²:κ²_S,S'-S₂PR*)(CO)₅], its dithiophosphonite-bridged isomer [MoReCp(μ-κ²_S,S':κ²_S,S'-S₂PR*)(CO)₅], or the trithiophosphonate-bridged derivative [MoReCp(μ-κ²_S,S':κ²_S,S'-S₃PR*)(CO)₅], all of them displaying novel coordination modes of their PRS₂ and PRS₃ ligands, as determined by X-ray diffraction studies. In contrast, the related MoMn complex yielded [MoMnCp(μ-η²:η²-SPR*)(CO)₅] under most conditions. A similar output was obtained in reactions with gray selenium for either MoRe or MoMn phosphinidene complexes, which under different conditions only gave the pentacarbonyl complexes [MoMCp(μ-η²:η²-SePR*)(CO)₅] (M = Re, Mn), these providing a new coordination mode for selenophosphinidene ligands.

P–C, P–N, and M–N Bond Formation Processes in Reactions of Heterometallic Phosphinidene-Bridged MoMn and MoRe Complexes with Diazoalkanes and Organic Azides to Build Three- to Five-Membered Phosphametallacycles

Reactions of the heterometallic MoRe complex [MoReCp(μ-PR*)(CO)₆] and its MoMn analogue with some small molecules having N–N multiple bonds, such as diazoalkanes and organic azides, were investigated (R* = 2,4,6-C₆H₂^tBu₃). Reactions with excess ethyl diazoacetate proceeded slowly and with concomitant denitrogenation to give complexes [MoMCp(μ-η²_P,C:κ²_P,O-PR*CHCO₂Et)(CO)₅], which display a bridging phosphaalkene ligand in a novel μ-η²:κ² coordination mode, while reactions with other diazoalkanes resulted only in the decomposition of the organic reagent. The MoRe complex reacted with benzyl- or p-tolyl azide at room temperature to give the green complexes [MoReCp(μ-η²_P,N:κ_P,N′²-PR*N₃R)(CO)₆] [R = Bn, p-tol], which display bridging phosphatriazadiene ligands in a novel 6-electron donor coordination mode as a result of a formal [2 + 1] cycloaddition of the terminal N atom of the azide to the Mo–P double bond of the parent complex, followed by coordination of the distal NR nitrogen to the rhenium center. Denitrogenation was only observed for the p-tolyl azide derivative, which upon heating at 333 K yielded [MoReCp{μ-κ_P:κ_N-PR*N(p-tol)}(CO)₆], a molecule displaying a bridging phosphaimine ligand in a rare κ_P:κ_N coordination mode. Analogous reactions of the MoMn phosphinidene complex proceeded similarly at 273 K to give the phosphatriazadiene-bridged derivatives [MoMnCp(μ-η²_P,N:κ²_P,N′-PR*N₃R)(CO)₆], but these were thermally unstable and degraded at room temperature to give the mononuclear triazenylphosphanyl complexes [Mn²(κ_P,N-PR*NHNNR)(CO)₃] as major products, along with small amounts of the phosphaimine-bridged complex [MoMnCp{μ-κ_P:κ_N-PR*N(p-tol)}(CO)₆] in the case of the p-tolyl azide derivative. The structure of the new complexes was analyzed in light of spectroscopic data and single-crystal diffraction studies on selected examples of each type of complex.

Reactions of [MoMCp(μ-PR)(CO)₆] (M = Mn, Re) with N₂CHCO₂Et involved denitrogenation and decarbonylation to give derivatives with a phosphaalkene ligand in a novel μ-κ²:η² coordination mode. However, reactions with organic azides involved [2 + 1] cycloaddition of the terminal nitrogen to the Mo−P double bond of the parent complex and coordination of the distal NR nitrogen without decarbonylation to give phosphatriazadiene derivatives, which evolved differently depending on R and M, to give either phosphaimine or triazenylphosphanyl derivatives.

Chemistry of a Nitrosyl Ligand κ:η-Bridging a Ditungsten Center: Rearrangement and N–O Bond Cleavage Reactions

The novel nitrosyl-bridged complex [W₂Cp₂(μ-P^tBu₂)(μ-κ:η-NO)(CO)(NO)](BAr₄) [Ar = 3,5-C₆H₃(CF₃)₂] was prepared in a multistep procedure starting from the hydride [W₂Cp₂(μ-H)(μ-P^tBu₂)(CO)₄] and involving the new complexes [W₂Cp₂(μ-P^tBu₂)(CO)₄](BF₄), [W₂Cp₂(μ-P^tBu₂)(CO)₂(NO)₂](BAr₄), and [W₂(μ-κ:η⁵-C₅H₄)Cp(μ-P^tBu₂)(CO)(NO)₂] as intermediates, which follow from reactions with HBF₄·OEt₂, NO, and Me₃NO·2H₂O, respectively. The nitrosyl-bridged cation easily added chloride upon reaction with [N(PPh₃)₂]Cl, with concomitant NO rearrangement into the terminal coordination mode, to give [W₂ClCp₂(μ-P^tBu₂)(CO)(NO)₂], and underwent N–O and W–W bond cleavages upon the addition of CN^tBu to give the mononuclear phosphinoimido complex [WCp(NP^tBu₂)(CN^tBu)₂](BAr₄). Another N–O bond cleavage was induced upon photochemical decarbonylation at 243 K, which gave the oxo- and phosphinito-bridged nitrido complex [W₂Cp₂(N)(μ-O)(μ-OP^tBu₂)(NO)](BAr₄), likely resulting from a N–O bond cleavage step following decarbonylation.

The π binding of the NO ligand in the cation [W₂Cp₂(μ-P^tBu₂)(μ-κ:η-NO)(CO)(NO)]⁺ facilitates the addition of ligands with concomitant rearrangement of the bridging nitrosyl into the terminal coordination mode and also facilitates cleavage of the N−O bond of that ligand at low temperature possibly in two different ways: either through the oxidative addition of this ligand to the dimetal center or through deoxygenation by another ligand.

[A comparative study of recreational screen time in neurodevelopmental disorders]

INTRODUCTION

Digital screen time has been largely studied in children populations, but few have focused on children with neurodevelopmental disorders. Our main objective was to study the characteristics of use of recreational screens (television (TV) and video games), in children with neurodevelopmental disorders.

SUBJECTS AND METHODS

We conducted a case-control study in which children with neurodevelopmental disorders under the age of 6 were compared with controls of the same age range. We analysed TV and video game exposure through a designed questionnaire for parents that included daily time exposure, sociodemographic characteristics, home media environment, sociocultural habits, attitudes and beliefs about TV.

RESULTS

Sixty-one individuals with developmental and 153 controls were enrolled. Children with developmental problems spend more time watching TV than controls (124,4 ± 83,4 vs 71,5 ± 47,4 min / day p <0,001), while video game time was similar in both groups (37,6 ± 39, 6 vs 31,7 ± 32,6 min / day p = 0,138). Children with neurodevelopmental disorders began earlier to watch TV than controls. There were no relevant differences between groups in demographics, Sociocultural, environmental and attitudinal and belief variables.

CONCLUSIONS

Children with neurodevelopmental disorders start watching TV at an earlier age and consume more screen time than healthy children. Our findings indicate that Children with neurodevelopmental disorders are more vulnerable to screen abuse, and stress the importance to offer anticipatory guidance to their parents.

[Sleep and academic performance in university students: a systematic review]

INTRODUCTION

University students tend to suffer from problems of sleep regularity, quantity and quality, which can affect their academic performance. These problems are related to changes typical of the phase of the life cycle in which they find themselves due to maturational, psychosocial development (associated with the processes of individuation and socialisation) and academic factors. The study of the relationship between sleep and academic performance in university students is an area of research of growing interest, which has started to be studied over the last two decades.

AIM

To conduct a systematic review of the existing literature on the relationship between sleep and academic performance in university students.

SUBJECTS AND METHODS

The articles included in the PubMed database were selected, following the PRISMA guidelines. Studies evaluating samples of subjects with an average age between 18 and 26 years, published in English or Spanish during the period 2000-2019 were included. Subsequently, the quality of the selected articles was evaluated according to the STROBE standard.

RESULTS

Thirty studies were identified, which were grouped according to different aspects of sleep: drowsiness, duration, experience of total sleep deprivation, sleep quality, chronotype, regularity and sleep disorders.

CONCLUSION

The results of these studies suggest that inadequate sleep has a negative effect on the academic performance of university students.

Electronic Structure and Donor Ability of an Unsaturated Triphosphorus-Bridged Dimolybdenum Complex

The triphosphorus complex [Mo₂Cp₂(μ-η³:η³-P₃)(μ-P^tBu₂)] was prepared in 83% yield by reacting the methyl complex [Mo₂Cp₂(μ-κ¹:η²-CH₃)(μ-P^tBu₂)(μ-CO)] with P₄ at 333 K, a process also giving small amounts of the methyldiphosphenyl complex [Mo₂Cp₂(μ-η²:η²-P₂Me)(μ-P^tBu₂)(CO)₂]. The latter could be better prepared by first reacting the anionic complex Na[Mo₂Cp₂(μ-P^tBu₂)(μ-CO)₂] with P₄ to give the diphosphorus derivative Na[Mo₂Cp₂(μ-η²:η²-P₂)(μ-P^tBu₂)(CO)₂] and further reaction of the latter with MeI. Density functional theory calculations on the title complex revealed that its triphosphorus group can be viewed as an allylic-like P₃^- ligand acting as a six-electron donor via the external P atoms, while coordination of the internal P atom involves donation from the π orbital of the ligand and back-donation to its π* orbital, both interactions having a weakening effect on the Mo-Mo and P-P connections. The reactivity of the title compound is dominated by the electron-donor ability associated with the lone pairs located at the P atoms. Its reaction with CF₃SO₃Me gave [Mo₂Cp₂(μ-η³:η³-P₃Me)(μ-P^tBu₂)](CF₃SO₃) as a result of methylation at an external atom of the P₃ ligand, while its reaction with [Fe₂(CO)₉] enabled the addition of one, two, or three Fe(CO)₄ fragments at these P atoms, but only the diiron derivative [Mo₂Fe₂Cp₂(μ-η³:η³:κ¹:κ¹-P₃)(μ-P^tBu₂)(CO)₈] could be isolated. This complex bears a Fe(CO)₄ fragment at each of the external atoms of the P₃ ligand, and the central P atom of the latter displays the lowest ³¹P chemical shift reported to date (δ_P -721.8 ppm). The related complexes [Mo₂M₂Cp₂(μ-η³:η³:κ¹:κ¹-P₃)(μ-P^tBu₂)(CO)₁₀] (M = Mo, W) were prepared by reacting the title compound with the corresponding [M(CO)₅(THF)] complexes in toluene, while reaction with [Mo(CO)₄(THF)₂] also enabled the formation of the heptanuclear derivative [Mo₇Cp₄(μ-η³:η³:κ¹:κ¹-P₃)₂(μ-P^tBu₂)₂(CO)₁₄]. The interatomic distances in the above compounds indicate that the central Mo₂P₃ skeleton of these molecules is little modified by the attachment of 16-electron M(CO)_n fragments at the external atoms of the P₃ ligand.

Predictive and criterion validity of the Cervantes-SF menopause quality of life questionnaire

OBJECTIVES

To determine the predictive and criterion-based validity of the Cervantes-SF scale that measures the impact of menopause on Health-Related Quality of Life.

METHODS

We recruited a noninstitutionalized sample of peri/postmenopausal women aged 40 to 65 years, who had their last menstrual cycle 12+ months prior to inclusion in the study of the psychometric validity of the Cervantes-SF scale. Predictive validity of the scale was confirmed for various health outcome measures administered concomitantly (years of disability-free life expectancy, work productivity and impact on daily activities, economic impact arising from loss of work productivity, hours of undisturbed sleep each day, and the utilization of healthcare facilities), whilst criterion validity was determined by the likelihood of identifying a moderate-to-severe vasomotor or genital syndrome requiring specific treatment.

RESULTS

A sample of 308 peri/postmenopausal women with a mean age of 55.7 years (SD: 5.3 y) was analyzed in this study. A score >25 points on the dimension of vasomotor problems (or menopausal health) showed values of sensitivity and specificity > 80% for identifying women with moderate-severe vasomotor syndrome requiring pharmacological treatment. Predictive validity was confirmed for menopause-related health outcomes. A change of 6.7 points in the scale score, equivalent to the value of its minimal difference, is indicative of a significant increase in the degree of disability regarding work/day-to-day activities, greater economic loss due to decreased work productivity, fewer years of life expectancy without disability, fewer hours of undisturbed sleep, and more visits to the physician per year due to menopausal symptoms.

CONCLUSIONS

These results confirm the criterion and predictive validity of the Cervantes-SF scale in peri/postmenopausal women.

Postoperative Psychosocial Factors in Health Functioning and Health-Related Quality of Life After Knee Arthroplasty: A 6-Month Follow up Prospective Observational Study

OBJECTIVE

Knee arthroplasty (KA) is an effective and cost-effective treatment for end-stage knee osteoarthritis. Despite high surgical success rates, as many as 25% of patients report compromised postoperative functioning, persistent pain, and reduced quality of life. The purpose of this study was to assess the predictive value of psychological factors in health functioning and quality of life, during a 6-month period after KA.

DESIGN

A prospective observational study.

SETTING

Surgery at two hospitals and follow-up was carried out through the domiciliary rehabilitation service.

SUBJECTS

In total, 89 patients (age 70.27 ± 7.99 years) met the inclusion criteria.

METHOD

A test battery composed of Health functioning associated with osteoarthritis (WOMAC), Health-related quality of life (EQ-5D-5L), Anxiety and Depression (HADS), Pain attitudes (SOPA-B), Pain catastrophizing (PCS), and Fear of Movement (TSK-11) was assessed at 1 week, and 1, 3, and 6 months after surgery. A mixed effects linear model was used to estimate the effect of time and covariates. An exploratory factor analysis was used to identify the number of dimensions underlying the group of psychological measurements.

RESULTS

In WOMAC model, anxiety level (F = 120.8), PCS (F = 103.9), depression level (F = 93.6) and pain score (F = 72.8) were the most influential variables. Regarding EQ-5D-5L model, anxiety level (F = 98.5), PCS (F = 79.8), depression level (F = 78.3) and pain score (F = 45) were the most influential variables. Pain score and the psychosocial variables of PCS, TSK, HADS-A, HADS-D, SOPA-B Emotion, SOPA-B Harm and SOPA-B Disability loaded in one single dimension.

CONCLUSIONS

Postoperative acute pain and psychosocial factors of pain catastrophizing, anxiety, depression, and pain attitudes might influence health functioning and quality of life during KA rehabilitation. Such factors could be gathered into one single dimension defined as pain-related psychologic distress.

Efficient Synthesis and Multisite Reactivity of a Phosphinidene-Bridged Mo-Re Complex. A Platform Combining Nucleophilic and Electrophilic Features

The heterometallic complex [MoReCp(μ-PR*)(CO)₆] (3) was prepared in 60% overall yield from syn-[MoCp(PHR*)(CO)₂] via a three-step procedure involving complexes syn-[MoCp(PClR*)(CO)₂] and [MoReCp(μ-PR*)(CO)₇] as intermediate species (R* = 2,4,6-C₆H₂^tBu₃). The PR* ligand in 3 displays a novel asymmetric interaction with the dimetal center, involving a double bond with one atom (Mo) and a dative single bond with the other one (Re). Compound 3 underwent thermal isomerization involving a C-H bond cleavage to yield the hydride [MoReCp(μ-H){μ-P(CH₂CMe₂)C₆H₂^tBu₂}(CO)₆] and reacted with I₂ to give [MoReCpI₂(μ-PR*)(CO)₆], which displays a symmetrical phosphinidene bridge. Its reaction with methyl propiolate at 293 K proceeded with [2 + 2] cycloaddition of the alkyne and decarbonylation to yield the phosphapropenylidene-bridged complex [MoReCp{μ-κ²_P,C:η³-PR*CHC(CO₂Me)}(CO)₅] as the major product, whereas its reaction with excess CN(4-C₆H₄OMe) at 273 K proceeded with formal [2 + 1] cycloaddition of the isocyanide and further isocyanide addition at the Re site to yield the complex [MoReCp{μ-η²_P,C:κ¹_P-PR*CN(4-C₆H₄OMe)}(CO)₆{CN(4-C₆H₄OMe)}], which displays an azaphosphaallene ligand in a novel bridging coordination mode.

Coordination and Dehydrogenation of Diphosphine-Borane Ph2PCH2PPh2·BH3 at a Heterometallic MoRe Center to Give an Agostic Boryl-Bridged Derivative

The coordination chemistry of the title diphosphine-borane adduct at heterometallic MoRe centers was examined through its reactions with the hydride complex [MoReCp(μ-H)(μ-PCy₂)(CO)₅(NCMe)] (Cp = η⁵-C₅H₅). The latter reacted rapidly with stoichiometric amounts of dppm·BH₃ (dppm = Ph₂PCH₂PPh₂) in refluxing toluene solution, with displacement of the nitrile ligand, to give [MoReCp(μ-H)(μ-PCy₂)(CO)₅(κ¹_P-dppm·BH₃)], with a P-bound diphosphine-borane ligand arranged trans to the PCy₂ group. Decarbonylation of the latter complex was accomplished rapidly upon irradiation with visible-UV light in toluene solution at 263 K, to give the agostic derivative [MoReCp(μ-H)(μ-PCy₂)(CO)₄(κ¹_P,η²-dppm·BH₃)] as major product (Mo-Re = 3.2075(5) Å), along with small amounts of the diphosphine-bridged complex [MoReCp(μ-H)(μ-PCy₂)(CO)₄(μ-dppm)]. Extended photolysis of the agostic complex at 288 K promoted an unprecedented dehydrogenation process involving the borane group and the hydride ligand, to give the diphosphine-boryl complex [MoReCp(μ-η²:κ²_P,B-H₂B·dppm)(μ-PCy₂)(CO)₄] (Mo-Re = 3.075(1) Å). The latter displayed a boryl ligand in a novel bridging coordination mode, it being σ-bound to one of the metal atoms (B-Re = 2.38(2) Å) while interacting with the second metal atom via a strong side-on tricentric B-H-M interaction (B-Mo = 2.31(1); H-Mo = 1.9(1) Å). The overall dehydrogenation process was endergonic by 43 kJ/mol, according to density functional theory calculations.

One-step synthesis and P-H bond cleavage reactions of the phosphanyl complex syn-[MoCp{PH(2,4,6-C6H2tBu3)}(CO)2] to give heterometallic phosphinidene-bridged derivatives

Photolysis of [Mo2Cp2(CO)6] and PH2R* (R* = 2,4,6-C6H2tBu3) yielded the title complex, which turned out to be a versatile precursor of novel heterometallic phosphinidene-bridged complexes via three different P-H bond activation processes: photolysis, deprotonation and reduction. In this way the new complexes [MoReCp(μ-PR*)(CO)n] (n = 6,7), [MoFeCp2(μ-PR*)(CO)m], (m = 3, 4) and [MoAuCp(μ-PR*)(CO)2{P(p-tol)3}] were prepared.

N-O Bond Activation and Cleavage Reactions of the Nitrosyl-Bridged Complexes [M2Cp2(μ-PCy2)(μ-NO)(NO)2] (M = Mo, W)

The title complexes (1a,b) were prepared in two steps by first reacting the hydrides [M₂Cp₂(μ-H)(μ-PCy₂)(CO)₄] with [NO](BF₄) in the presence of Na₂CO₃ to give dinitrosyls [M₂Cp₂(μ-PCy₂)(CO)₂(NO)₂](BF₄), which were then fully decarbonylated upon reaction with NaNO₂ at 323 K. An isomer of the Mo₂ complex having a cisoid arrangement of the terminal ligands ( cis-1a) was prepared upon irradiation of toluene solutions of 1a with visible-UV light at 288 K. The structure of these trinitrosyl complexes was investigated using X-ray diffraction and density functional theory (DFT) calculations, these revealing a genuine pyramidalization of the bridging NO that might be associated in part to an increase of charge at the N atom and anticipated a weakening of the N-O bond upon reaction with bases or reducing reagents. Complexes 1a,b reacted with [FeCp₂](BF₄) to give first the radicals [M₂Cp₂(μ-PCy₂)(μ-NO)(NO)₂](BF₄) according to CV experiments, which then underwent H-abstraction to yield the nitroxyl-bridged complexes [M₂Cp₂(μ-PCy₂)(μ-κ¹:η²-HNO)(NO)₂](BF₄), alternatively prepared upon protonation with HBF₄·OEt₂. The novel coordination mode of the nitroxyl ligand in these products was thermodynamically favored over its tautomeric hydroximido form, according to DFT calculations, and similar nitrosomethane-bridged cations [M₂Cp₂(μ-PCy₂)( μ-κ¹:η²-MeNO)(NO)₂]⁺ were prepared by reacting 1a,b with CF₃SO₃Me or [Me₃O]BF₄. Complexes 1 reacted with M(Hg) (M = Zn, Na) in tetrahydrofuran to give the amido-bridged derivatives [M₂Cp₂(μ-PCy₂)(μ-NH₂)(NO)₂] with retention of stereochemistry, a transformation also induced by using mild O atom scavengers such as CO and phosphites in the presence of water. In the absence of water, phosphites accomplished a deoxygenation of the bridging NO of the Mo₂ complexes to yield the phosphoraniminato-bridged derivatives [Mo₂Cp₂(μ-PCy₂){μ-NP(OR)₃}(NO)₂] (R = Et, Ph), also with retention of stereochemistry.

Mapping of the Gastrointestinal Short Form Questionnaire (GSF-Q) into EQ-5D-3L and SF-6D in patients with gastroesophageal reflux disease

BACKGROUND

The short, self-administered Gastroesophageal Reflux Disease (GERD) Symptom Frequency Questionnaire (GSFQ) is a specific Quality of Life (QoL) instrument which measures the impact of GERD symptoms on QoL. This study aims to map the specific scores in GSFQ into two generic instruments: SF-6D and EQ-5D-3 L, in order to obtain utility estimates derived from the GERD condition.

METHOD

A national representative sample of GERD patients was selected, stratified by gender, age (< 45, ≥45 years) and GERD severity (0-I, II-IV Savary-Miller score) for validation purposes. Age, gender, BMI, GERD diagnose, GERD severity, associated comorbidities and risk factors were recorded. GSFQ, SF-6D, EQ-5D-3 L, and the HRQoL Visual Analogue Scale (VAS) were answered by patients. Several mapping methods were estimated, regression using dummy variables, and linear, quadratic and cubic regression using optimal factor scores. The use of a GERD aggregated summary severity derived from the GSFQ was dimed the best predictor. Overall Mean Absolute Error (MAE), overall Mean Absolute Percentage Error (MAPE) were used as goodness-of-fit (GOF) indexes to compare models.

RESULTS

A total of 3405 patients were recruited by 490 clinicians. Mean age was 49 (±14.4) years and 49.8% were women. Reported comorbidities were clustered in 6 antecedents and 15 concomitant pathologies. Aggregation of levels for the frequency of symptoms items was found more suitable for estimation. Regression weights were found to follow a monotonous progressive pattern. Overall MAE ranged from 0.092 to 0.094 for SF-6D utility prediction and from 0.008 to 0.08 for EQ-5D-3 L, while MAPE values ranged from 27.9 to 29% for SF-6D and from 36.8 to 38.4% for EQ-5D-3 L. Cubic regression GOF demonstrated a better fit.

CONCLUSIONS

It is possible to translate specific GSFQ scores assessing GERD condition into generic SF-6D and EQ-5D-3 L utility values. Although regression using dummy variables is a suitable mapping procedure, other alternative mapping methods convey better fit, in particular cubic regression.

Phosphinidene-Bridged MoMn Derivatives of the Thiophosphinidene Complex [Mo2Cp2(μ-κ2:κ1,η6-SPMes*)(CO)2] (Mes* = 2,4,6-C6H2tBu3)

The title complex (1) reacted with [Mn₂(CO)₁₀] under visible-UV irradiation (toluene solution and quartz glassware) to give a mixture of the phosphinidene complex [MnMoCp(μ-κ¹:κ¹,η⁶-PMes*)(CO)₄], the cluster [Mn₂Mo₂Cp₂(μ-κ¹:κ¹,η⁶-PMes*)(μ₃-S)(CO)₈], and the thiophosphinidene complex [MnMoCp(μ-κ²:κ¹,η⁴-SPMes*)(CO)₅], in yields of ca. 60, 20, and 10% respectively (Mes* = 2,4,6-C₆H₂^tBu₃). The major product follows from formal replacement of the SMoCp(CO)₂ fragment in 1 with a Mn(CO)₄ fragment, and displayed multiple bonding to phosphorus (Mn-P = 2.1414(8) Å); the tetranuclear cluster results from formal insertion of a Mn₂(CO)₆ fragment in 1, with cleavage of P-S and P-Mo bonds, to render a μ₃-S bridged Mn₂Mo core bearing an exocyclic phosphinidene ligand involved in multiple bonding to one of the Mn atoms (Mn-P = 2.140(2) Å); the thiophosphinidene complex (Mn-P = 2.294(1) Å) formally results from addition of sulfur and carbon monoxide to the major MnMo product, a transformation which actually could be performed stepwise, via the MnMo thiophosphinidene complex [MnMoCp(μ-κ²:κ¹,η⁶-SPMes*)(CO)₄]. When the photolysis of 1 and [Mn₂(CO)₁₀] was performed in tetrahydrofuran solution and using conventional glassware, then the V-shaped cluster [Mn₂MoCp{μ-κ¹:κ¹:κ¹,η⁵-P(C₆H₃^tBu₃)}(CO)₈] was obtained selectively (Mo-Mn = 3.2910(5) Å, Mn-Mn = 2.9223(5) Å), which unexpectedly displays a cyclohexadienylidene-phosphinidene ligand resulting from H atom abstraction at the aryl ring of the precursor. Density functional theory calculations on the complexes [L_nM(μ-κ¹:κ¹,η⁶-PMes*)MoCp] (ML_n = MoCp(CO)₂, Mn(CO)₄, Co(CO)₃) revealed that the degree of delocalization of the metal-phosphorus π-bonding interaction over the Mo-P-M chain is significantly conditioned by the heterometal fragment ML_n, it being increased in the order Mn ≤ Mo < Co.

E-H Bond Activation and Insertion Processes in the Reactions of the Unsaturated Hydride [W2Cp2(μ-H)(μ-PPh2)(NO)2]

The reactions of the title complex (1) with different p-block element (E) molecules was examined. Compound 1 reacted with BH₃·THF at room temperature to give the trihydride [W₂Cp₂(μ-H)H₂(μ-PPh₂)(NO)₂], which formally results from hydrogenation of 1, a reaction that actually does not take place when neat dihydrogen is used. Clean E-H bond oxidative addition, however, took place when 1 was reacted with HSnPh₃, to give the related dihydride stannyl derivative [W₂Cp₂(μ-H)H(μ-PPh₂)(NO)₂(SnPh₃)]. In contrast, the reaction of 1 with HSPh involved H₂ elimination to give the thiolate-bridged complex [W₂Cp₂(μ-SPh)(μ-PPh₂)(NO)₂], while that with (p-tol)C(O)H resulted in insertion of the aldehyde to yield the related alkoxide complex [W₂Cp₂{μ-OCH₂(p-tol)}(μ-PPh₂)(NO)₂]. Insertion also prevailed in the reactions of 1 with CN^tBu, which, however, involved the competitive formation of new C-H or N-H bonds, to give a mixture of formimidoyl and aminocarbyne derivatives, [W₂Cp₂(μ-κ¹:η²-HCN^tBu)(μ-PPh₂)(NO)₂] (W-W = 3.0177(2) Å) and [W₂Cp₂{μ-C(NH^tBu)}(μ-PPh₂)(NO)₂] (W-W = 2.9010(4) Å), respectively, even though the latter was thermodynamically preferred, according to density functional theory calculations. The former represents the first structurally characterized complex displaying a formimidoyl or iminoacyl ligand in the alkenyl-like μ-κ¹:η² coordination mode. The reaction of 1 with diazomethane proceeded with N₂ elimination and C-H coupling to yield the agostic methyl-bridged complex [W₂Cp₂(μ-κ¹:η²-CH₃)(μ-PPh₂)(NO)₂] (calculated W-W = 2.923 Å), whereas the reaction with N₂CH(SiMe₃) proceeded with insertion of the diazoalkane to give the corresponding hydrazonide complex [W₂Cp₂{μ-NH(NCHSiMe₃)}(μ-PPh₂)(NO)₂] (W-W = 2.8608(4) Å). The latter was converted under alkaline conditions to the methyldiazenide derivative [W₂Cp₂{μ-N(NMe)}(μ-PPh₂)(NO)₂] (W-W = 2.8730(2) Å), in a process involving hydrolysis of the C-Si bond coupled with a 1,3-H shift from N to C.

Acetonitrile Adduct [MoReCp(μ-H)(μ-PCy2)(CO)5(NCMe)]: A Surrogate of an Unsaturated Heterometallic Hydride Complex

The title compound was prepared upon irradiation of acetonitrile solutions of the readily available hexacarbonyl [MoReCp(μ-H)(μ-PCy₂)(CO)₆]. The acetonitrile ligand in this compound could be replaced easily by donor molecules or displaced upon two-electron reduction. In most cases, the substitution step was followed by additional processes such as insertion into the M-H bonds, E-H bond cleavage, H₂ elimination, and other transformations.

Reply to the ‘Comment on “Hydride, gold(i) and related derivatives of the unsaturated ditungsten anion [W2Cp2(μ-PCy2)(μ-CO)2]−”’ by M. Green, Dalton Transactions, 2018, , DOI: 10.1039/C8DT00044A

The half-electron and CBC representations of the unsaturated complexes [M₂Cp₂(μ-H)(μ-PR₂)(CO)₂] (M = Mo, W) are equivalent descriptions of the tricentric M₂H bonding in these hydride-bridged molecules.

Structure and dynamics of heterometallic clusters derived from addition of metal carbonyl fragments to the unsaturated hydride [W2Cp2(μ-H)(μ-PPh2)(NO)2]

The title complex reacted with [Fe₂(CO)₉] to give the trinuclear derivative [FeW₂Cp₂(μ-H)(μ-PPh₂)(CO)₄(NO)₂] (W-W = 3.044(1) Å) as a result of full insertion of the 16-electron Fe(CO)₄ fragment into the tricentric W-H-W bond of the parent substrate. In contrast, the reactions with the THF adducts [M(CO)₅(THF)] (M = W, Mo) and [MnCp'(CO)₂(THF)] (Cp' = C₅H₄Me) yielded the μ₃-hydride derivatives [MW₂Cp₂(μ₃-H)(μ-PPh₂)(CO)₅(NO)₂] (W-W = 3.006(1) to 3.164(1) Å for the W₃ compound) and [MnW₂Cp₂Cp'(μ₃-H)(μ-PPh₂)(CO)₂(NO)₂] respectively, all of them resulting from addition (rather than insertion) of the corresponding 16-electron fragment to the W₂H moiety of the parent compound. Density Functional Theory calculations revealed that edge- and face-bridged hydride clusters were of similar energy in the W₂Fe system, while the face-bridged structure was significantly more stable (by more than ca. 40 kJ mol^-1) for the W₃ system. Both clusters displayed fast rearrangement in solution involving a flapping movement of the puckered PW₂M core of these molecules. This was combined, in the W₂Fe cluster, with fast exchange between the almost isoenergetic edge- and face-bridged hydride isomers. The reactions of the title compound with several carbonyl dimers were also examined as an additional synthetic approach to the rational synthesis of heterometallic clusters, but were unsuccessful except in the case of [Co₂(CO)₈], which reacted at 253 K in the dark to give a mixture of the binuclear complex [CoWCp(μ-PPh₂)(CO)₄(NO)] (Co-W = 2.8623(6) Å) and the trinuclear cluster [CoW₂Cp₂(μ-PPh₂)(CO)₄(NO)₂] (W-W = 3.1654(4) Å; W-Co = 2.638(1), 2.829(1) Å), the latter resulting from formal replacement of the hydride ligand with the 17-electron fragment Co(CO)₄, which displayed an asymmetric binding to the W₂ centre.

C-C and C-N Couplings Following Hydride Addition on Isocyanide Cyclopolyenyl Dimolybdenum Complexes to Give Tethered Aldimine and Aminocarbene Derivatives

Reaction of [Mo₂ Cp₂ (μ-κ¹ :κ¹ ,η⁶ -PMes*)(CO)₂ ] with S or Se followed by protonation with [H(OEt₂ )₂ ](BAr'₄ ) gave the cationic derivatives [Mo₂ Cp₂ {μ-κ²_P,E :κ¹_P ,η⁵ -EP(C₆ H₃ tBu₃ )}(CNR)(CO)₂ ](BAr'₄ ) (E=S; R=tBu, iPr, Ph, 4-C₆ H₄ OMe, Xyl; or E=Se; R=tBu; Ar'=3,5-C₆ H₃ (CF₃ )₂ ). Reaction of the latter with K[BHsBu₃ ] yielded the aldimine complexes [Mo₂ Cp₂ {μ-κ²_P,E :κ²_P,N ,η⁴ -SP(C₆ H₃ tBu₃ (CHNR))}(CO)₂ ] and their aminocarbene isomers [Mo₂ Cp₂ {μ-κ²_P,E :κ²_P,C ,η⁴ -SP(C₆ H₃ tBu₃ (NRCH))}(CO)₂ ] (R ≠ Xyl), following C-C and C-N couplings, respectively. Monitoring of these reactions revealed that the initial H^- attack takes place at a Cp ligand to give cyclopentadiene intermediates [Mo₂ Cp{μ-κ²_P,S :κ¹_P ,η⁵ -SP(C₆ H₃ tBu₃ )}(η⁴ -C₅ H₆ )(CNR)(CO)₂ ], which then undergo C-H oxidative addition to give the hydride isomers [Mo₂ Cp₂ {μ-κ²_P,S :κ¹_P ,η³ -SP(C₆ H₃ tBu₃ )}(H)(CNR)(CO)₂ ]. In turn, the latter rearrange to give the aldimine and aminocarbene complexes. DFT calculations revealed that the hydride intermediates first undergo migratory insertion of the isocyanide ligand into the Mo-H bond to give unobservable formimidoyl intermediates, which then evolve either by nucleophilic attack of the N atom on the C₆ ring (C-N coupling) or by migratory insertion of the formimidoyl ligand into the C₆ ring (C-C coupling). Our data suggest that increasing the size of the substituent R at the isocyanide ligand destabilizes the aldimine isomer to a greater extent, thus favoring formation of the aminocarbene complex.

Role of the different eyes in the visual odometry in the wolf spider Lycosa tarantula (Araneae, Lycosidae)

The wolf spider Lycosa tarantula returns home by means of path integration. Previous studies demonstrated: (i) that the angular component of the outbound run is measured using a polarized-light compass associated with the anterior median eyes; (ii) changes in direction of the substratum are detected by the anterior lateral eyes (ALEs); and (iii) in relation to the linear component of the outbound run, an increase of optic flow, in either the lateral or ventral fields of view, caused spiders to search for the burrow at a point nearer to the goal. However, the role of the secondary eyes [ALEs, posterior lateral eyes (PLEs) and posterior median eyes (PMEs)] in the perception of this optic flow and the importance of them for gauging the distance walked is still unknown. In this study, lateral or ventral gratings of wavelength λ=1 cm were used, with two groups of spiders in each setup: (1) PLEs+PMEs covered and (2) ALEs covered. The largest reduction in the distance walked to return to the burrow was observed with the ventral grating/ALEs covered. These results show the importance of the previously neglected ALEs for the visual behavior of these spiders. The possibility of gathering information for locomotion from the three pairs of secondary eyes in the mushroom bodies is discussed.

Terminal vs. bridging coordination of CO and NO ligands after decarbonylation of [W2Cp2(μ-PR2)(CO)3(NO)] complexes (R = Ph, Cy). An experimental and computational study

Compounds [M₂Cp₂(μ-PPh₂)(CO)₃(NO)] (M = Mo, W) were prepared by reacting the corresponding radicals [M₂Cp₂(μ-PPh₂)(CO)₄] with NO, and displayed a terminal, linear NO ligand arranged cis to the P-donor ligand (Mo-Mo = 3.1400(7) Å). The related PCy₂-bridged complex [W₂Cp₂(μ-PCy₂)(CO)₃(NO)] was prepared in a one-pot, three step procedure first involving deprotonation of the hydride complex [W₂Cp₂(μ-H)(μ-PCy₂)(CO)₄] with K[BH(sec-Bu)₃], then oxidation of the resulting salt K[W₂Cp₂(μ-PCy₂)(CO)₄] with [FeCp₂]BF₄ at 243 K, and eventually by reacting the so-formed radical [W₂Cp₂(μ-PCy₂)(CO)₄] with NO. Photochemical decarbonylation of the Mo₂ complex gave intractable mixtures of products. In contrast, photolysis of the ditungsten complexes yielded the corresponding dicarbonyls [W₂Cp₂(μ-PR₂)(μ-κ¹:η²-CO)(CO)(NO)] (R = Ph, Cy) as major products, which were characterized spectroscopically. The latter reacted readily with P(OMe)₃ to give the corresponding derivatives [W₂Cp₂(μ-PR₂)(CO)₂(NO){P(OMe)₃}], displaying a cisoid conformation of the P-donor ligands (P-W-P = 83.7(1)° when R = Cy). Density functional theory calculations on [W₂Cp₂(μ-PCy₂)(μ-κ¹:η²-CO)(CO)(NO)] and several potential isomers revealed that this electron-precise molecule (W-W = 3.121 Å) is almost isoenergetic with an unsaturated isomer having a μ-κ¹:κ¹-NO ligand (W-W = 2.677 Å) but their interconversion has a large kinetic barrier. It was concluded that formation of the κ¹:η²-CO-bridged isomers in the photolytic experiment is favoured by the cisoid disposition of NO and PR₂ ligands at the parent tricarbonyls, which precludes the NO ligand from easily rearranging into a bridging position after decarbonylation. The above calculations also revealed that the CO ligand is much better suited than NO for the μ-κ¹:η² coordination mode, since it can establish stronger end-on and side-on interactions with the dimetal centre.

Chemistry of CS2- and SCNPh-adducts of the pyramidal phosphinidene-bridged complex [Mo2Cp(μ–κ1:κ1,η5-PC5H4)(CO)2(η6-HMes*)(PMe3)]

Heterocumulene insertion into the metallocene Mo–P bond of the title complex enables further addition of different electrophiles at the P, S or N sites.

Sn–H bond additions to asymmetric trigonal phosphinidene-bridged dimolybdenum complexes

Organotin hydrides add across the Mo–P double bond of binuclear phosphinidene complexes, sometimes undergoing dehydrogenation involving a cyclopentadienyl ring.

Mapping of the OAB-SF Questionnaire onto EQ-5D in Spanish Patients with Overactive Bladder

BACKGROUND AND OBJECTIVE

Mapping disease-specific measures onto generic preference-based indexes allows estimating utility values in specific conditions to determine gain of quality-adjusted-life-years when the status of condition varies. The aim of this study was to map a disease specific scale, the Overactive Bladder Questionnaire 5-dimensional health classification system (OAB-5D) derived from the Overactive Bladder questionnaire-Short Form (OABq-SF), onto a preference-based scale, the EuroQol-5D (EQ-5D), in a sample of patients with overactive bladder (OAB) in a Spanish population.

METHOD

A survey addressed to value the health states was conducted among 246 patients at 18 clinics of urology from Spain. A total of 43 out of 243 possible health states have been valued, using VAS (Visual Analog Scale) and TTO (time trade-off) techniques. In addition, ordinary least squares (OLS), generalized linear models (GLM) and Tobit models were estimated. Resulting models were compared and the best one was selected in terms of goodness of fit measures, attribute sign, coefficient magnitude, and statistical significance of regression coefficients. Finally, the internal validity of the best model was calculated by bootstrap resampling.

RESULTS

The best model to map the OAB-5D onto EQ-5D could be estimated and the stability of parameter estimations was proved. The mentioned model estimated through OLS regression attained R (2) value of 0.892, with the aggregated data; with GLM (efficient maximum likelihood regression), Pearson χ (2) of 15.3 has been obtained; AIC (Akaike information criterion) = -550.9 and BIC (Bayesian information criterion) = -475.4. OLS model included the following OABq-SF items (and range of weights): A1 (0.102, 0.216); A3 (0.070, 0.171); B3 (0.071, 0.078); B1 (0.076, 0.136); B2 (-0.132, -0.028).

CONCLUSION

It is possible to map the OAB-5D scores onto EQ-5D in the Spanish population, allowing estimating EQ-5D utility scores from OAB specific health conditions.

The doubly-bonded ditungsten anion [W2Cp2(μ-PPh2)(NO)2](-): an entry to the chemistry of unsaturated nitrosyl complexes

Complex [W2Cp2(μ-I)(μ-PPh2)(NO)2] was prepared by reacting [W2Cp2(μ-I)(μ-PPh2)(CO)2] with NO at 233 K followed by decarbonylation in refluxing toluene. It was reduced by Na(Hg) in acetonitrile to give Na[W2Cp2(μ-PPh2)(NO)2], the first anionic nitrosyl complex featuring a metal-metal double bond (computed W-W = 2.580 Å). Reactions of the latter anion with (NH4)PF6 and [AuCl{P(p-tol)3}] gave the hydride [W2Cp2(μ-H)(μ-PPh2)(NO)2] and the cluster [AuW2Cp2(μ-PPh2)(NO)2{P(p-tol)3}] respectively, also featuring multiple W-W bonding (experimental W-W ca. 2.75 Å), and its reaction with S8 yielded the electron-precise derivative Na[W2Cp2(μ-PPh2)(μ-S)(NO)2], which was methylated by Me2SO4 to give the thiolate complex [W2Cp2(μ-PPh2)(μ-SMe)(NO)2].

Sonographer-Fetus Bonding

A survey of 50 obstetrical sonographers was conducted in the Phoenix metropolitan area to assess certain aspects of fetal ultrasound. The primary concern was the evaluation of sonographer opinions on abortion prior to their experience in ultrasound as compared to their current views, and if "seeing" the fetus sonographically had altered their beliefs. Attention was also placed on the sonographer's perspective on maternalfetal bonding as a result of ultrasound, as well as on sonographer practices of communicative feedback to patients during obstetrical ultrasound examinations. The results of the survey indicate that: 1) seeing the fetus has indeed altered sonographers' opinions on abortion; 2) sonographers strongly believe that maternal-fetal bonding is strengthened by the sonographic demonstration of the fetus; and 3) there is widespread practice of high-feedback sonography.

Synthesis and DFT Study of a Diphenylsilanone-Bridged Dimolybdenum Complex

Reaction of the 30-electron benzylidyne complex [Mo2 Cp2 (μ-CPh)(μ-PCy2 )(μ-CO)] with excess Ph2 SiH2 under visible-UV irradiation yields the silylene-bridged complex [Mo2 Cp2 (μ-CPh)(μ-PCy2 )(μ-SiPh2 )]. This compound undergoes selective oxidation with O2 to give the unsaturated complex [Mo2 Cp2 (μ-CPh)(μ-PCy2 )(μ-κ(1) :κ(1) -OSiPh2 )], which contains an unprecedented bridging diphenylsilanone ligand, as confirmed by X-ray diffraction analysis and DFT calculations. The bonding within the central Mo2 SiO ring of this complex approaches the extreme description of a dimetallacyclosiloxane according to the relevant solid-state bond lengths and theoretical calculations.

Insertion and C-C coupling processes in reactions of the unsaturated hydride [W2Cp2(H)(μ-PCy2)(CO)2] with alkynes

The title compound reacted with p-tolylacetylene at room temperature to give the 32-electron σ:π-bound alkenyl complexes trans-[W2Cp2{μ-κ:η(2)-C(p-tol)CH2}(μ-PCy2)(CO)2] and trans-[W2Cp2{μ-κ:η(2)-CHCH(p-tol)}(μ-PCy2)(CO)2], with the former complex fully rearranging into the latter one after 1 h at 363 K. Both compounds exist in solution as an isomeric equilibrium mixture (rapid on the NMR timescale) involving the alternate π-coordination of the alkenyl ligand to each of the tungsten atoms. In the presence of CO or certain solvents (THF or CH2Cl2) the α-substituted alkenyl complex was transformed instead into the cis-dicarbonyl isomer cis-[W2Cp2{μ-κ:η(2)-C(p-tol)CH2}(μ-PCy2)(CO)2] (W-W = 2.7273(8) Å). In contrast, the β-substituted alkenyl complex reacted with CO to give the saturated tricarbonyl [W2Cp2{μ-κ:η(2)-CHCH(p-tol)}(μ-PCy2)(CO)3], and with excess alkyne (under moderate heating) to yield the alkyne/alkenyl complex [W2Cp2{μ-κ:η(2)-CHCH(p-tol)}(μ-PCy2){η(2)-CHC(p-tol)}(CO)], with both products also displaying a cisoid disposition of the Cp ligands. In contrast, reactions of the title hydride with tert-butylacetylene were significantly slower and led to very air-sensitive compounds, the only isolable product from these reactions being the oxo alkenyl complex trans-[W2Cp2{μ-κ:η(2)-CHCH((t)Bu)}(O)(μ-PCy2)(CO)]. The title hydride reacted with methyl propiolate at room temperature to give selectively the α-substituted alkenyl complex cis-[W2Cp2{μ-κ:η(2)-C(CO2Me)CH2}(μ-PCy2)(CO)2], but yielded instead the dienyl complex [W2Cp2{μ-κ(2):η(3)-CH(CO2Me)CHC(CO2Me)CH}(μ-PCy2)(CO)2] (W-W = 2.944(1) Å) when the reaction was carried out at high temperature (393 K), with the latter generated from an alkenyl/alkyne C-C coupling process. The title hydride also reacted with dimethyl acetylenedicarboxylate, to give three products mainly depending on the reaction temperature; at moderate temperature (343 K) this reaction led exclusively to the saturated alkenyl complex trans-[W2Cp2{μ-κC,κO:η(2)-C(CO2Me)CH(CO2Me)}(μ-PCy2)(CO)2] (W-W = 2.9329(8) Å), in which the σ:π-bound alkenyl ligand is additionally coordinated through the oxygen atom of the carboxylate group so as to render a O,C:C,C' five-electron coordination mode. At 273 K this reaction led instead to a mixture of the unsaturated alkenyl cis-[W2Cp2{μ-κ:η(2)-C(CO2Me)[double bond, length as m-dash]CH(CO2Me)}(μ-PCy2)(CO)2] and the dienyl complex [W2Cp2{μ-κC,κO:η(2)-C(CO2Me)[double bond, length as m-dash]C(CO2Me)C(CO2Me)[double bond, length as m-dash]CH(CO2Me)}(μ-PCy2)(CO)2] (W-W = 3.0273(6) Å).

P-S bond cleavage in reactions of thiophosphinidene-bridged dimolybdenum complexes with [Co2(CO)8] to give phosphinidene-bridged heterometallic derivatives

The thiophosphinidene complex [Mo2Cp2(μ-κ(2):κ(1),η(6)-SPMes*)(CO)2] (Mes* = 2,4,6-C6H2(t)Bu3) reacted with [Co2(CO)8] at room temperature or below to give several of the following phosphinidene-bridged products, depending on reaction conditions: the MoCo complexes [CoMoCp(μ-κ(1):κ(1),η(6)-PMes*)(CO)3] and [CoMoCp(μ-PMes*)(CO)5] (Co-Mo = 2.972(1) Å), the MoCo3 cluster [Co3MoCp(μ3-PMes*)(CO)9] (Co-Mo = 2.664(1), 2.810(1) Å), and the sulphido-bridged tetranuclear complexes [Co2Mo2Cp2(μ-κ(1):κ(1):κ(1),η(4)-PMes*)(μ3-S)(CO)7] and [Co3MoCp(μ-κ(1):κ(1):κ(1),η(4)-PMes*)(μ3-S)(CO)8]. In contrast, the thiophosphinidene complex [Mo2Cp2(μ-κ(2):κ(1),η(4)-SPMes*)(CO)3] reacted with the same cobalt reagent selectively to give the above Mo2Co2 complex in very high yield. The latter could be decarbonylated photochemically to give [Co2Mo2Cp2(μ-κ(1):κ(1):κ(1),η(6)-PMes*)(μ3-S)(CO)6] (Co-Co = 2.435(3), Co-Mo = 2.769(2), 2.798(2) Å), after an η(4)- to η(6)-haptotropic rearrangement of the aryl ring of the phosphinidene ligand that could be reversed upon reaction with CO. The related complex [Mo2Cp2(μ-κ(2):κ(1),η(4)-SPMes*)(CO)2(CN(t)Bu)], however, displayed poor selectivity towards the cobalt dimer and yielded a mixture of CoMo complexes [CoMoCp(μ-PMes*)(CO)5] and [CoMoCp(μ-PMes*)(CO)3(CN(t)Bu)2], and the tetranuclear sulphido-bridged ones [Co2Mo2Cp2(μ-κ(1):κ(1):κ(1),η(4)-PMes*)(μ3-S)(CO)6(CN(t)Bu)] (Co-Co = 2.533(1), Co-Mo = 2.7485(9), 2.770(1) Å) and [Co3MoCp(μ-κ(1):κ(1):κ(1),η(4)-PMes*)(μ3-S)(CO)7(CN(t)Bu)] (Co-Co = 2.4120(7) to 2.5817(7) Å). This reduction in selectivity might have an electronic origin rather than a steric origin, since the related but cationic substrate [Mo2Cp2{μ-κ(2):κ(1),η(5)-SP(C6H3(t)Bu3)}(CO)2(CN(t)Bu)]BAr [Ar' = 3,5-C6H3(CF3)2] reacted with [Co2(CO)8] more selectively to give the sulphido-bridged Co2Mo2 complex [Co2Mo2Cp2{μ-κ(1):κ(1):κ(1),η(5)-P(C6H3(t)Bu3)}(μ3-S)(CO)6(CN(t)Bu)]BAr, along with small amounts of the Co3Mo complex [Co3MoCp{μ-κ(1):κ(1):κ(1),η(5)-P(C6H3(t)Bu3)}(μ3-S)(CO)7(CN(t)Bu)]BAr (Co-Co = 2.414(2) to 2.560(2) Å). The structure of the new complexes was analyzed on the basis of the corresponding X-ray diffraction and spectroscopic data, and likely reaction pathways were discussed on the basis of the above results and some additional experiments.