Cleavage of Carbon Dioxide C=O Bond Promoted by Nickel-Boron Cooperativity in a PBP-Ni Complex.

The synthesis and characterization of (tBu PBP)Ni(OAc) (5) by insertion of carbon dioxide into the Ni-C bond of (tBu PBP)NiMe (1) is presented. An unexpected CO2 cleavage process involving the formation of new B-O and Ni-CO bonds leads to the generation of a butterfly-structured tetra-nickel cluster (tBu PBOP)2 Ni4 (µ-CO)2 (6). Mechanistic investigation of this reaction indicates a reductive scission of CO2 by O-atom transfer to the boron atom via a cooperative nickel-boron mechanism. The CO2 activation reaction produces a three-coordinate (tBu P2 BO)Ni-acyl intermediate (A) that leads to a (tBu P2 BO)-NiI complex (B) via a likely radical pathway. The NiI species is trapped by treatment with the radical trap (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO) to give (tBu P2 BO)NiII (η2 -TEMPO) (7). Additionally, 13 C and 1 H NMR spectroscopy analysis using 13 C-enriched CO2 provides information about the species involved in the CO2 activation process.

Reversible Carbene Insertion into a Ge-N Bond and Insights into CO and Carbene Substitution Reactions Involving Amidinatogermylenes and Fischer Carbene Complexes.

The formation of the five-membered-ring germylene complexes [M(CO)5 {Ge(tBu2 bzamC(OEt)Me)tBu}] (3M ; M=Cr, W), which occurs readily at room temperature from the germylene Ge(tBu2 bzam)tBu (1tBu ) and Fischer carbenes [M(CO)5 {C(OEt)Me}] (2M ; M=Cr, W), has been found to be reversible. Upon heating at 60 °C, complexes 3M undergo epimerization to an equilibrium mixture of 3M and 3'M . At that temperature, the chromium epimers (but not the tungsten ones) release CO to end in the mixed germylene-Fischer carbene complexes [Cr(CO)4 {C(OEt)Me}{Ge(tBu2 bzam)tBu}] (cis-4Cr and trans-4Cr ). The latter decompose at 120 °C to [Cr(CO)5 {Ge(tBu2 bzam)tBu}] (6Cr ). Because the formation of cis-4Cr and trans-4Cr from 3Cr or 3'Cr requires the presence of free 1tBu and 2Cr in the reaction solutions, the reactions of 1tBu with 2M to give 3M (and 3'M at 60 °C) should be reversible. This proposal has been proven by germylene-exchange crossover reactions in which free 1tBu and [M(CO)5 {Ge(tBu2 bzamC(OEt)Me)CH2 SiMe3 }] (5'M ; M=Cr, W) were formed when complexes 3M were treated at room temperature with the germylene Ge(tBu2 bzam)CH2 SiMe3 (1tmsm ). A clear differential behavior between N-heterocyclic carbenes (NHCs) and amidinatogermylenes (1tBu and 1tmsm ) in their reactivity against group 6 metal Fischer carbene complexes is demonstrated. The higher electron-donor capacity of amidinatogermylenes with respect to NHCs and the bias of the former to get involved in ring expansion processes are responsible for this differential behavior.

From a Diphosphanegermylene to Nickel, Palladium, and Platinum Complexes Containing Germyl PGeP Pincer Ligands.

The PGeP pincer-type germylene Ge(NCH2 PtBu2 )C6 H4 (1) has been used to prepare a family of group 10 metal complexes, namely, [MCl{κ3 P,Ge,P-GeCl(NCH2 PtBu2 )2 C6 H4 }] (M=Ni (2Ni ), Pd (2Pd ), Pt (2Pt )), featuring a chloridogermyl PGeP pincer ligand and a Cl-Ge-M-Cl bond sequence. Their reactivity is not initially centered on the metal atom but on their Ge atom. Complexes 2Ni and 2Pd easily led to the hydrolyzed products [Ni2 Cl2 {µ-(κ3 P,Ge,P-Ge(NCH2 PtBu2 )2 C6 H4 )2 O}], which features a Cl-Ni-Ge-O-Ge-Ni-Cl bond sequence, and [PdCl{κ3 P,Ge,P-Ge(OH)(NCH2 PtBu2 )2 C6 H4 }], which contains a hydroxidogermyl PGeP pincer ligand (2Pt is reluctant to undergo hydrolysis). Simple chloride exchange reactions led to the methoxidogermyl, methylgermyl, and phenylgermyl derivatives [MCl{κ3 P,Ge,P-GeR(NCH2 PtBu2 )2 C6 H4 }] (M=Pd, Pt; R=OMe, Me, Ph). Whereas the palladium complexes [PdCl{κ3 P,Ge,P-GeR(NCH2 PtBu2 )2 C6 H4 }] (R=Me, Ph) reacted with more MeLi or PhLi to give palladium black and GeR2 (NCH2 PtBu2 )2 C6 H4 (R=Me, Ph), similar reactions with the analogous platinum complexes afforded the transmetalation derivatives [PtR{κ3 P,Ge,P-GeR(NCH2 PtBu2 )2 C6 H4 }] (R=Me, Ph). The short length of the CH2 PtBu2 arms of the PGeP pincer ligands forces the metal atoms of all these complexes to be in a very distorted square-planar ligand environment. The reactivity results have been rationalized with theoretical calculations.

First Insertions of Carbene Ligands into Ge-N and Si-N Bonds.

The insertion of carbene ligands into Ge-N (three examples) and Si-N (one example) bonds has been achieved for the first time by treating Fischer carbene complexes (M=W, Cr) with bulky amidinatotetrylenes (E=Ge, Si). These reactions, which start with a nucleophilic attack of the amidinatotetrylene heavier group 14 atom to the carbene C atom, proceed through a stereoselective insertion of the carbene fragment into an E-N bond of the amidinatotetrylene ENCN four-membered ring, leading to [M(CO)5 L] derivatives in which L belongs to a novel family of tetrylene ligands comprising an ECNCN five-membered ring.

[Fundamental aspects in the choice of renal replacement therapy].

Chronic kidney disease (CKD) is a disease with a high prevalence in our environment, and those suffering the disease should be as clear as possible that renal replacement therapy (RRT) may better suit your lifestyle. It is important that the patient has enough information about the techniques that can be accessed in a clear manner, so as to evaluate the different possibilities, advantages and disadvantages. The timing on this election is crucial and stressful for the patient's life, not only by the effects of the disease itself, but also by the assimilation of a new lifestyle that should keep the rest of it. This work was done thinking about the need for patients and health professionals in acquiring a holistic and comprehensive understanding of all the features that can have both peritoneal dialysis (PD) and hemodialysis (HD); form own patient factors (diet, family environment, etc.) related to nurses (care, information provided, etc.) without forgetting the conditions outside the patient and the nurse as they can be structural and economic aspects.

Amidinatogermylene derivatives of ruthenium carbonyl: new insights into the reactivity of [Ru3(CO)12] with two-electron-donor reagents of high basicity.

The reactivity of ruthenium carbonyl with amidinatogermylenes of the type Ge(R2bzam)(t)Bu (R2bzam = N,N'-disubstituted benzamidinate) was studied for R = (t)Bu (1tBu) and (i)Pr (1iPr). The mono-, bi-, and/or trinuclear derivatives [Ru(1R)(CO)4], [Ru(1R)2(CO)3], [Ru2(1iPr)(CO)7], [Ru3(1tBu)(CO)11], [Ru3(1tBu)2(CO)10], and [Ru3(1R)3(CO)9] (R = (t)Bu, (i)Pr) were isolated in yields that depend upon the reactant ratio and the reaction temperature. The experimental data are consistent with the proposal that, at room temperature, the trinuclear complexes [Ru3(CO)12], [Ru3(1R)(CO)11], and [Ru3(1R)2(CO)10] form an adduct with the germylene 1R that may evolve through two different reaction pathways, (a) releasing a CO ligand (thus leading to the corresponding trinuclear CO-substituted product) and/or (b) cleaving the cluster framework (thus leading to mononuclear germylene-containing products). At 90 °C, additional processes are also possible, such as the reactions of 1R with [Ru(1R)(CO)4] or [Ru3(1R)3(CO)9], which both give [Ru(1R)2(CO)3], or the reactions of [Ru(1tBu)(CO)4] and [Ru(1iPr)(CO)4] with [Ru3(CO)12], which give [Ru3(1tBu)(CO)11] and [Ru2(1iPr)(CO)7], respectively. This wide reaction panorama helps rationalize previously reported outcomes of reactions of [Ru3(CO)12] with other reagents of high basicity, such as trialkylphosphines or N-heterocyclic carbenes, including results for which no satisfactory explanation has been hitherto provided.

Synthesis and initial transition metal chemistry of the first PGeP pincer-type germylene.

A PGeP pincer-type germylene, Ge(NCH2PtBu2)2C6H4, which contains two phosphane groups hanging from the N atoms of an N-heterocyclic germylene fragment, has been isolated for the first time. This compound has already furnished a rich transition metal derivative chemistry (Co, Rh, and Pd) that includes complexes containing bridging P,Ge,P-, chelating P,Ge- and pincer P,Ge,P-ligands.

Aspectos fundamentales en la elección de la terapia renal sustitutiva / Fundamental aspects in the choice of renal replacement therapy

La insuficiencia renal crónica (IRC) es una enfermedad con una gran prevalencia en nuestro medio, y las personas que sufren dicha enfermedad deben tener claro que la terapia renal sustitutiva (TRS) puede adaptarse mejor a su forma de vida. Es importante que el paciente tenga la suficiente información sobre las técnicas a las que puede acceder de una manera clara, para así valorar las diferentes posibilidades, ventajas y desventajas. El momento de esta elección es crucial y estresante en la vida del paciente, no solo por los efectos de la propia enfermedad, sino también por la asimilación de un nuevo estilo de vida con el que debe mantenerse el resto de la misma. Este trabajo ha sido realizado pensando en la necesidad de los pacientes y de los profesionales sanitarios a la hora de adquirir un conocimiento holístico e integral sobre todas las características que puede tener tanto la diálisis peritoneal (DP) como la hemodiálisis (HD); desde los factores propios del paciente (dieta, entorno familiar, etc.), hasta los relacionados con los profesionales de enfermería (cuidados, información facilitada, etc.), sin olvidarnos de los condicionantes ajenos tanto al paciente como al profesional de enfermería, como pueden ser los aspectos estructurales y económicos (AU)

Chronic kidney disease (CKD) is a disease with a high prevalence in our environment, and those suffering the disease should be as clear as possible that renal replacement therapy (RRT) may better suit your lifestyle. It is important that the patient has enough information about the techniques that can be accessed in a clear manner, so as to evaluate the different possibilities, advantages and disadvantages. The timing of this election is crucial and stressful for the patient’s life, not only by the effects of the disease itself, but also by the assimilation of a new lifestyle that should keep the rest of it. This work was done thinking about the need for patients and health professionals in acquiring a holistic and comprehensive understanding of all the features that can have both peritoneal dialysis (PD) and hemodialysis (HD); from own patient factors (diet, family environment, etc.) related to nurses (care, information provided, etc.) without forgetting the conditions outside the patient and the nurse as they can be structural and economic aspects (AU)