A General Rhodium Catalyst for the Deuteration of Boranes and Hydrides of the Group 14 Elements

Pinacolborane, catecholborane, triethylsilane, triphenylsilane, dimethylphenylsilane, 1, 1, 1, 3, 5, 5, 5-heptamethyltrisiloxane, triethylgermane, triphenylgermane, and triphenylstannane deuterated at the heteroatom position have been catalytically prepared in 50-70% isolated yield, through H/D exchange between the D2 molecule and the respective boranes and hydrides of the group 14 elements, in the presence of the rhodium(I)-monohydride catalyst precursor RhH{¿3-P, O, P-[xant(PiPr2)2]} (xant(PiPr2)2 = 9, 9-dimethyl-4, 5-bis(diisopropylphosphino)xanthene)

Kinetic Analysis and Sequencing of Si-H and C-H Bond Activation Reactions: Direct Silylation of Arenes Catalyzed by an Iridium-Polyhydride

The saturated trihydride IrH3{¿3-P, O, P-[xant(PiPr2)2]} (1; xant(PiPr2)2 = 9, 9-dimethyl-4, 5-bis(diisopropylphosphino)xanthene) coordinates the Si-H bond of triethylsilane, 1, 1, 1, 3, 5, 5, 5-heptamethyltrisiloxane, and triphenylsilane to give the s-complexes IrH3(¿2-H-SiR3){¿2-cis-P, P-[xant(PiPr2)2]}, which evolve to the dihydride-silyl derivatives IrH2(SiR3){¿3-P, O, P-[xant(PiPr2)2]} (SiR3 = SiEt3 (2), SiMe(OSiMe3)2 (3), SiPh3 (4)) by means of the oxidative addition of the coordinated bond and the subsequent reductive elimination of H2. Complexes 2-4 activate a C-H bond of symmetrically and asymmetrically substituted arenes to form silylated arenes and to regenerate 1. This sequence of reactions defines a cycle for the catalytic direct C-H silylation of arenes. Stoichiometric isotopic experiments and the kinetic analysis of the transformations demonstrate that the C-H bond rupture is the rate-determining step of the catalysis. As a consequence, the selectivity of the silylation of substituted arenes is generally governed by ligand-substrate steric interactions

Tuning the Nature and Formation of Bis(dihydrogen)-Osmium Species

The influence of chelate ligands in the formation and nature of bis(dihydrogen) units of OsH4 complexes has been studied. The classical trihydride OsH3{¿2-C, N-(C6H4-py)}(PiPr3)2 (1) reacts with HBF4·OEt2 to give the Kubas-type dihydrogen-elongated dihydrogen derivative [Os{¿2-C, N-(C6H4-py)}(¿2-H2)2(PiPr3)2]BF4 (2), as a result of the protonation of one of the hydride ligands. Triflate (OTf) displaces the Kubas-type dihydrogen and elongates the elongated dihydrogen ligand, which is converted into a compressed dihydride. Thus, the addition of 1 equiv of HOTf to 1 leads to Os(H···H){¿2-C, N-(C6H4-py)}(OTf)(PiPr3)2 (3). Similar to [OTf]-, acetone reacts with 2 to afford the related compressed dihydride [Os(H···H){¿2-C, N-(C6H4-py)}(¿1-OCMe2)(PiPr3)2]BF4 (4), whereas acetonitrile leads to a 1:8 mixture of the monohydride [OsH(CH3CN)3(PiPr3)2]BF4 (5) and the trihydride [OsH3(CH3CN)2(PiPr3)2]BF4 (6). Reactions of 2 with toluene and p-xylene yield the half-sandwich derivatives [Os{¿2-C, N-(C6H4-py)}(¿6-toluene)(PiPr3)]BF4 (7) and [Os{¿2-C, N-(C6H4-py)}(¿6-p-xylene)(PiPr3)]BF4 (8), respectively. The acyl oxygen atom of the C, C-chelate ligand of the trihydride OsH3{¿2-C, C-[C(O)CH2ImMe]}(PiPr3)2 (10; Im = imidazolylidene) provides reliable and effective protection of the hydride ligands against the protonation. Thus, the addition of HBF4·OEt2 or HOTf to 10 leads to the trihydride-hydroxycarbene cation [OsH3{¿2-C, C-[C(OH)CH2ImMe]}(PiPr3)2]+ (11). The hydroxycarbene-NHC ligand of the latter is unstable, undergoing an intramolecular 1, 3-hydrogen shift, which produces the rupture of the chelate ligand and the formation of the cis-hydride dihydrogen (12a) and trans-hydride-dihydrogen (12b) derivatives [OsH(¿2-H2)(CO)(Me2Im)(PiPr3)2]+ (12). The protonation of 11 with a second equivalent of HOTf affords the transient bis(Kubas-type dihydrogen) [Os(¿2-H2)2{¿2-C, C-[C(OH)CH2ImMe]}(PiPr3)2](OTf)2, which undergoes the displacement of a coordinated hydrogen molecule by a [OTf]- anion to give the Kubas-type dihydrogen [Os(OTf)(¿2-H2){¿2-C, C-[C(OH)CH2ImMe]}(PiPr3)2]OTf (13). The addition of MeOTf to 10 leads to [OsH3{¿2-C, C-[C(OMe)CH2ImMe]}(PiPr3)2]OTf (14) which, in contrast to 11, is stable. Similar to the latter, the protonation of 14 with HOTf yields the Kubas-type dihydrogen complex [Os(OTf)(¿2-H2){¿2-C, C-[C(OMe)CH2ImMe]}(PiPr3)2]OTf (15)

Iridium-Promoted B-B Bond Activation: Preparation and X-ray Diffraction Analysis of a mer-Tris(boryl) Complex

The tris(boryl) complex Ir(Bcat)3{¿3-P,O,P-[xant(PiPr2)2]} has been prepared. Its X-ray diffraction analysis structure reveals that the boryl groups are disposed in a mer rearrangement despite of the very strong trans influence of the boryl ligands. An energy decomposition analysis method coupled to natural orbitals for chemical valence suggests that the p-backdonation from the metal to the pz atomic orbital of the boron atom decreases about 43% in the Ir-B bonds disposed mutually trans with regard to the other one

Osmium- And Iridium-Promoted C-H Bond Activation of 2, 2'-Bipyridines and Related Heterocycles: Kinetic and Thermodynamic Preferences

The d2-hexahydride complex OsH6(PiPr3)2 (1) promotes the activation of C-H bonds of 2, 2'-bipyridines and related heterocycles. The study of the same reactions with the deuteride counterpart OsD6(PiPr3)2 (1-d) reveals that the activation of the C-H bonds situated in the sterically less hindered positions is kinetically preferred. However, the isolated products are the result of the thermodynamic control of the reactions. Thus, reactions of 1 with 2, 2'-bipyridine, 6-phenyl-2, 2'-bipyridine, and 6-methyl-2, 2'-bipyridine give the "rollover cyclometalation" products OsH3{¿2-C, N-[C5(R)H2N-py]}(PiPr3)2 (R = H (2), Ph (3), Me (4)), whereas 3, 5-dimethyl-6-phenyl-2, 2'-bipyridine affords OsH2{¿3-C, N, C-[C5H3N-(Me)2py-C5H4]}(PiPr3)2 (5), containing a dianionic C, N, C-pincer ligand. The behavior of substrates pyridyl-benzimidazolium and -imidazolium is similar. Reaction of 1 with 3-methyl-1-(6-phenylpyridin-2-yl)-1H-benzimidazolium tetrafluoroborate leads to OsH3{¿2-C, C-[MeBzim-C5(Ph)H2N]}(PiPr3)2 (6), bearing an anionic Cpy, CNHC-chelate. On the other hand, 3-methyl-1-(6-phenylpyridin-2-yl)-1H-imidazolium tetrafluoroborate yields [OsH2{¿3-C, N, C-(MeIm-py-C6H4)}(PiPr3)2]BF4 (7), containing a monoanionic C, N, C-pincer with a NHC-unit coordinated in an abnormal fashion. The reactivity pattern of these substrates is also observed with the d4-iridium-pentahydride IrH5(PiPr3)2 (8), which has generated IrH2{¿2-C, N-[C5(R)H2N-py]}(PiPr3)2 (R = H, (9), Ph (10)) and IrH{¿3-C, N, C-[C5H3N-(Me2)py-C5H4]}(PiPr3)2 (11). The osmium(IV)-carbon bonds display a higher degree of covalency than the iridium(III)-carbon bonds. In contrast to 2, the metalated carbon atom of 9 undergoes the addition of a proton of methanol to give [IrH2{¿2-N, N-(bipy)}(PiPr3)2]BF4 (12)

Variables associated with a higher awareness of gender-based violence by students of the health sciences and social work

Objective To determine the attitudes towards equality and prevention of gender-based violence, and analyze variables associated with a higher awareness of gender-based violence by students of the health sciences and social work degrees. Method A cross-sectional descriptive study was carried out. The sample consisted of 437 students of the health sciences and social work degrees at the University of Zaragoza (Spain) during 2018 and 2019. The variables of the study were: Socio-demographic variables, academic variables, feminism attitudes towards women''s movement using Feminism and the women''s movement scale (FWMS), attitudes on gender-based violence using the Gender Equality and Prevention of Gender-based Violence Scale (GEPGVS). A correlational study and multiple linear regression were performed, in order to analyze the associated variables. Results Differences in attitudes towards gender-based violence were observed according to sex, age and attitudes in line with the feminist movement. Regarding the linear regression model, the results showed that the FWMS is a predictor of GEPGVS, as well as sex. Conclusions Holding attitudes in line with the feminist movement is a factor that may be promoted in order to increase the awareness of gender-based violence. Objetivo Determinar las actitudes hacia la igualdad y la sensibilización en cuanto a la violencia de género, y analizar las variables asociadas a una mayor sensibilización sobre la violencia de género de los estudiantes de ciencias de la salud y trabajo social. Método Se realizó un estudio descriptivo transversal. La muestra consistió en 437 estudiantes de los grados de ciencias de la salud y trabajo social de la Universidad de Zaragoza (España) durante 2018 y 2019. Las variables del estudio fueron variables sociodemográficas, variables académicas, actitudes hacia el movimiento feminista usando la Feminism and the women''s movement scale (FWMS) y actitudes hacia la violencia de género mediante la Escala sobre Igualdad y Prevención de la Violencia de Género (EIPVG). Se realizaron un estudio correlacional y una regresión lineal múltiple para conocer las variables asociadas a una mayor sensibilización. Resultados Se observaron diferencias en las actitudes hacia la violencia de género en función del sexo, la edad y las actitudes favorables al movimiento feminista. Con respecto al modelo de regresión lineal, los resultados mostraron que la FWMS es un predictor de la EIPVG, así como el sexo. Conclusiones Las actitudes favorables al movimiento feminista son un factor que puede promoverse para incrementar la sensibilización sobre la violencia de género

Perception of the primary health care response capacity by patients with and without mental health problems, and health professionals: qualitative study

BACKGROUND: The objective of this study is to deepen our understanding of perceptions towards Primary Health Care Response Capacity by specifically using patients with and without mental disorders, as well as family doctors and a manager, in order to compare and endorse perspectives. For it, a qualitative study was performed. In-depth interviews were conducted with 28 patients with and without mental health disorders and focus groups were held with 21 professionals and a manager. An inductive thematic content analysis was performed in order to explore, develop and define the emergent categories of analysis. RESULTS: The fundamental domains for patients are dignity, communication, and rapid service. People with mental health problems also highlight the domain of confidentiality as relevant, while patients who do not have a mental health problem prioritize the domain of autonomy. Patients with mental health disorders report a greater number of negative experiences in relation to the domain of dignity. Patients do not consider their negative experiences to be a structural problem of the system. These findings are also endorsed by health care professionals. CONCLUSIONS: It is necessary to take these results into account as responsive systems can improve service uptake, ensure adherence to treatment, and ultimately enhance patient welfare