RESUMEN
The high demand for organs in kidney transplantation and the expansion of the donor pool have led to the widespread implementation of machine perfusion technologies. In this study, we aim to provide an up-to-date systematic review of the developments in this expanding field over the past 10 years, with the aim of answering the question: "which perfusion technique is the most promising technique in kidney transplantation?" A systematic review of the literature related to machine perfusion in kidney transplantation was performed. The primary outcome measure was delayed graft function (DGF), and secondary outcomes included rates of rejection, graft survival, and patient survival rates after 1 year. Based on the available data, a meta-analysis was performed. The results were compared with data from static cold storage, which is still the standard of care in many centers worldwide. A total of 56 studies conducted in humans were included, and 43 studies reported outcomes of hypothermic machine perfusion (HMP), with a DGF rate of 26.4%. A meta-analysis of 16 studies showed significantly lower DGF rates in the HMP group compared to those of static cold storage (SCS). Five studies reported outcomes of hypothermic machine perfusion + O2, with an overall DGF rate of 29.7%. Two studies explored normothermic machine perfusion (NMP). These were pilot studies, designed to assess the feasibility of this perfusion approach in the clinical setting. Six studies reported outcomes of normothermic regional perfusion (NRP). The overall incidence of DGF was 71.5%, as it was primarily used in uncontrolled DCD (Maastricht category I-II). Three studies comparing NRP to in situ cold perfusion showed a significantly lower rate of DGF with NRP. The systematic review and meta-analysis provide evidence that dynamic preservation strategies can improve outcomes following kidney transplantation. More recent approaches such as normothermic machine perfusion and hypothermic machine perfusion + O2 do show promising results but need further results from the clinical setting. This study shows that the implementation of perfusion strategies could play an important role in safely expanding the donor pool.
RESUMEN
BACKGROUND: Decision-making in the management of patients with retroperitoneal sarcoma is complex and requires input from a number of different specialists. The aim of this study was to evaluate the levels of agreement in terms of resectability, treatment allocation, and organs proposed to be resected across different retroperitoneal sarcoma multidisciplinary team meetings. METHODS: The CT scans and clinical information of 21 anonymized retroperitoneal sarcoma patients were sent to all of the retroperitoneal sarcoma multidisciplinary team meetings in Great Britain, which were asked to give an opinion about resectability, treatment allocation, and organs proposed to be resected. The main outcome was inter-centre reliability, which was quantified using overall agreement, as well as the chance-corrected Krippendorff's alpha statistic. Based on the latter, the level of agreement was classified as: 'slight' (0.00-0.20), 'fair' (0.21-0.40), 'moderate' (0.41-0.60), 'substantial' (0.61-0.80), or 'near-perfect' (>0.80). RESULTS: Twenty-one patients were reviewed at 12 retroperitoneal sarcoma multidisciplinary team meetings, giving a total of 252 assessments for analysis. Consistency between centres was only 'slight' to 'fair', with rates of overall agreement and Krippendorff's alpha statistics of 85.4 per cent (211 of 247) and 0.37 (95 per cent c.i. 0.11 to 0.57) for resectability; 80.4 per cent (201 of 250) and 0.39 (95 per cent c.i. 0.33 to 0.45) for treatment allocation; and 53.0 per cent (131 of 247) and 0.20 (95 per cent c.i. 0.17 to 0.23) for the organs proposed to be resected. Depending on the centre that they had attended, 12 of 21 patients could either have been deemed resectable or unresectable, and 10 of 21 could have received either potentially curative or palliative treatment. CONCLUSIONS: Inter-centre agreement between retroperitoneal sarcoma multidisciplinary team meetings was low. Multidisciplinary team meetings may not provide the same standard of care for patients with retroperitoneal sarcoma across Great Britain.
Asunto(s)
Neoplasias Retroperitoneales , Sarcoma , Humanos , Reproducibilidad de los Resultados , Neoplasias Retroperitoneales/diagnóstico por imagen , Neoplasias Retroperitoneales/cirugía , Sarcoma/diagnóstico por imagen , Sarcoma/cirugía , Grupo de Atención al Paciente , Reino UnidoRESUMEN
Introduction: The gap between available donor grafts and patients on the waiting lists is constantly growing. This leads to an increased utilization of high-risk and therefore more vulnerable kidney grafts. The use of high-risk organs requires further optimization of machine preservation and assessment strategies before transplantation. Hypothermic machine perfusion (HMP) is the standard of care for kidneys originating from donation after circulatory death (DCD), whereas the evidence of HMP with additional oxygen (HOPE) is still very limited. Furthermore, an objective quality assessment of HMP-perfused kidneys is lacking. Recently, the release of mitochondria derived fragments, i.e., flavin mononucleotide (FMN) of complex I during machine liver perfusion was shown to be predictive for liver graft function before implantation. Therefore, the aim of this study was to evaluate, if FMN is useful also for assessment of kidney injury before use. Methods: A porcine perfusion model was used to investigate the feasibility of assessment of kidney grafts during hypothermic oxygenated perfusion (HOPE) with either 0, 30 or 60 minutes of warm ischemia. The model with warm ischemia times (WIT) of 30â min and 60â min, was used to mimic a clinically relevant scenario. A group with no warm ischemia time (0' WIT) served as control group. The groups underwent minimal static cold storage (SCS) of 2â h followed by 2â h of end-ischemic HOPE with repeated real-time FMN measurements. In a further step, these values were related to the release of damage-associated molecular patterns (DAMPs) and to the functionality of the respiratory chain, represented by the capacity of ATP production. Results: We demonstrate, first, feasibility of perfusate FMN measurements in perfused kidneys, and secondly its correlation with donor warm ischemia time. Accordingly, FMN measurement showed significantly higher release in the 60-minute WIT group (n = 4) compared to the 30-minute WIT (n = 4) and the control group (n = 4). FMN release correlated also with DAMP signaling, such as the release of 8-OHdG and HMGB1. Finally, ATP replenishment proved to be best in control kidneys, followed by kidneys with 30â min and then by kidneys with 60â min of WIT. Discussion: This study demonstrates the feasibility of FMN measurement in kidneys during HOPE. In addition, we show a correlation between FMN quantification and pre-existing kidney graft injury. Based on this, real-time FMN measurement during HOPE may be an objective assessment tool to accept high-risk kidneys for transplantation while minimizing post-transplant dysfunction, moving away from former "gut feeling" towards objective criteria in accepting marginal kidney grafts for transplantation. Graft evaluation based on these results may close the gap between available grafts and patients on the waiting lists by increasing utilization rates without significant impact for the recipients.
RESUMEN
o-Carboranes C-functionalized by (4-substituted-phen-1-yl)ethynyl-1,4-phenyl groups or (2-substituted-fluoren-7-yl)ethynyl-2,7-fluorenyl groups, in which the pendant functionalization is electron-withdrawing nitro or electron-donating diphenylamino groups, have been synthesized and in many cases structurally characterized. Diphenylamino-containing examples coupled via the two π-delocalizable bridges to the electron-accepting o-carborane unit exhibit the greater quadratic optical nonlinearities at 1064 nm (hyper-Rayleigh scattering, ns pulses), the nonlinearities also increasing on proceeding from 1,4-phenylene- to 2,7-fluorenylene-containing bridge. The most NLO-efficient example 2-(n-butyl)-1-(2-((9,9-di(n-butyl)-2-(N,N-diphenylamino)-9H-fluoren-7-yl)ethynyl)-9,9-di(n-butyl)-9H-fluoren-7-yl)-1,2-ortho-carborane, consisting of diphenylamino donor, fluorenyl-containing bridge, o-carborane acceptor, and solubilizing n-butyl units, exhibits large ãßãHRS (230 × 10-30 esu) and frequency-independent (two-level model) ãß0ã (96 × 10-30 esu) values. Coupling two (2-((9,9-di(n-butyl)-2-(N,N-diphenylamino)-9H-fluoren-7-yl)ethynyl)-9,9-di(n-butyl)-9H-fluoren-7-yl) units to the 1,2-ortho-carborane core affords a di-C-functionalized compound with enhanced nonlinearities (309 × 10-30 esu and 129 × 10-30 esu, respectively).
RESUMEN
BACKGROUND: No data exist to evaluate how hepatectomy time (HT), in the context of donation after cardiac death (DCD) procurement, impacts short- and long-term outcomes after liver transplantation (LT). In this study, we analyze the impact of the time from aortic perfusion to end of hepatectomy on outcomes after DCD LT in the United Kingdom. METHODS: An analysis of 1112 DCD donor LT across all UK transplant centers between 2001 and 2015 was performed, using data from the UK Transplant Registry. Donors were all Maastricht Category III. Graft survival after transplantation was estimated using Kaplan-Meier method and logistic regression to identify risk factors for primary nonfunction (PNF) and short- and long-term graft survivals after LT. RESULTS: Incidence of PNF was 4% (40) and in multivariate analysis only cold ischemia time (CIT) longer than 8 hours (hazard ratio [HR], 2.186; 95% confidence interval [CI], 1.113-4.294; P = 0.023) and HT > 60 minutes (HR, 3.669; 95% CI, 1.363-9.873; P = 0.01) were correlated with PNF. Overall 90-day, 1-, 3-, and 5-year graft survivals in DCD LT were 91.2%, 86.5%, 80.9%, and 77.7% (compared with a donation after brain death cohort in the same period [n = 7221] 94%, 91%, 86.6%, and 82.6%, respectively [P < 0.001]). In multivariate analysis, the factors associated with graft survival were HT longer than 60 minutes, donor older than 45 years, CIT longer than 8 hours, and recipient previous abdominal surgery. CONCLUSIONS: There is a negative impact of prolonged HT on outcomes on DCD LT and although HT is 60 minutes or longer is not a contraindication for utilization, it should be part of a multifactorial assessment with established prognostic donor factors, such as age (>45 y) and CIT (>8 h) for an appropriately selected recipient.
Asunto(s)
Hepatectomía , Trasplante de Hígado , Donantes de Tejidos , Obtención de Tejidos y Órganos , Adulto , Isquemia Fría , Femenino , Supervivencia de Injerto , Humanos , Trasplante de Hígado/efectos adversos , Trasplante de Hígado/mortalidad , Masculino , Persona de Mediana Edad , Factores de TiempoRESUMEN
Aim of the study: Intestinal transplantation (IT) is a life-saving procedure for carefully selected patients with intestinal failure. We evaluated patients who had undergone simultaneous intestinal and kidney transplantation (SIKT) to determine whether UK guidelines for inclusion of a renal allograft (dialysis dependent or estimated glomerular filtration rate ((eGFR)) < 45 ml/min/1.73 m2) are justified. Methods: A single centre analysis was undertaken of adults undergoing IT at the Cambridge Transplant Centre between December 2007 and January 2016. A prospectively maintained database was used to identify SIKT recipients and determine outcomes. Results: Over this period, 63 intestinal transplants were performed. Seven (11.1%) recipients received a SIKT. Five were pre-dialysis (median eGFR 29 ml/min/1.73 m2, range 16-36 ml/min/1.73 m2). One recipient was on dialysis, and one needed bilateral nephrectomy at transplant. There were no primary kidney allograft failures and at three months, the median eGFR (55 ml/min/1.73 m2 range 39-124) was similar to recipients of IT alone (median eGFR 56 ml/min/1.73 m2 range 17-143 ml/min/1.73 m2). Two recipients required dialysis due to sepsis related kidney injury and died from multi-organ failure (20 and 63 months). Two died with a functioning renal transplant (10 and 15 months). The remaining three patients are alive at follow up (12-96 months) with an eGFR of 20-45 ml/min/1.73 m2. Conclusion: Patients with significant renal impairment (eGFR <45 ml/min/1.73 m2), and receiving dialysis may benefit from SIKT. Patient survival and renal function are broadly comparable to those undergoing IT alone. Further studies are required to justify allocation of a kidney to this complex high risk group.
Asunto(s)
Enfermedades Intestinales/cirugía , Intestinos/trasplante , Fallo Renal Crónico/terapia , Trasplante de Riñón/métodos , Adolescente , Adulto , Femenino , Estudios de Seguimiento , Tasa de Filtración Glomerular , Rechazo de Injerto/epidemiología , Humanos , Enfermedades Intestinales/complicaciones , Enfermedades Intestinales/mortalidad , Fallo Renal Crónico/etiología , Fallo Renal Crónico/mortalidad , Trasplante de Riñón/normas , Masculino , Persona de Mediana Edad , Guías de Práctica Clínica como Asunto , Estudios Prospectivos , Diálisis Renal/estadística & datos numéricos , Análisis de Supervivencia , Resultado del Tratamiento , Reino Unido/epidemiología , Adulto JovenRESUMEN
A new Zn(ii) porphyrin-based dendrimer (52) containing twelve Ru(ii) alkynyl fragments, has been prepared following a convergent approach in two steps from 5,10,15,20-tetra(4-ethynylphenyl)porphyrinatozinc(ii) (6). The cubic nonlinear optical (NLO) properties of 52 and other derivatives of 6 have been measured by third-harmonic generation (THG) at 1907 nm and by Z-scan over the spectral range 500-1700 nm, revealing the remarkable NLO response of 52 in the near-IR range. These results highlight the beneficial role of the extended "cross fourchée"-like polymetallic structure of 52 on its third-order NLO properties.
RESUMEN
PURPOSE OF REVIEW: The choice of optimum transplant in a patient with type 1 diabetes mellitus (T1DM) and chronic kidney disease stage V (CKD V) is not clear. The purpose of this review was to investigate this in more detail-in particular the choice between a simultaneous pancreas-kidney transplantation (SPKT) and living donor kidney transplantation (LDKT), including recent evidence, to aid clinicians and their patients in making an informed choice in their care. RECENT FINDINGS: Analyses of large databases have recently shown SPKT to have better survival rates than a LDKT in the long-term, despite an early increase in morbidity and mortality in SPKT recipients. This survival advantage has only been shown in those SPKT recipients with a functioning pancreas and not those who had early pancreas graft loss. The choice of SPKT or LDKT should not be based on patient and graft survival outcomes alone. Individual patient circumstances, preferences, and comorbidities, among other factors should form an important part of the decision-making process. In general, an SPKT should be considered in those patients not on dialysis and LDKT in those nearing or already on dialysis.
Asunto(s)
Trasplante de Riñón , Donadores Vivos , Trasplante de Páncreas , Comorbilidad , Supervivencia de Injerto , Humanos , Resultado del TratamientoRESUMEN
1-Nitronaphthalenyl-4-alkynyl and 9-nitroanthracenyl-10-alkynyl complexes [M](C[triple bond, length as m-dash]C-4-C10H6-1-NO2) ([M] = trans-[RuCl(dppe)2] (6b), trans-[RuCl(dppm)2] (7b), Ru(PPh3)2(η5-C5H5) (8b), Ni(PPh3)(η5-C5H5) (9b), Au(PPh3) (10b)) and [M](C[triple bond, length as m-dash]C-10-C14H8-9-NO2) ([M] = trans-[RuCl(dppe)2] (6c), trans-[RuCl(dppm)2] (7c), Ru(PPh3)2(η5-C5H5) (8c), Ni(PPh3)(η5-C5H5) (9c), Au(PPh3) (10c)) were synthesized and their identities were confirmed by single-crystal X-ray diffraction studies. Electrochemical studies and a comparison to the 1-nitrophenyl-4-alkynyl analogues [M](C[triple bond, length as m-dash]C-4-C6H4-1-NO2) ([M] = trans-[RuCl(dppe)2] (6a), trans-[RuCl(dppm)2] (7a), Ru(PPh3)2(η5-C5H5) (8a), Ni(PPh3)(η5-C5H5) (9a), Au(PPh3) (10a)) reveal a decrease in oxidation potential for ruthenium and nickel complexes on proceeding from the phenyl- to naphthalenyl- and then anthracenyl-containing bridge. HOMO â LUMO transitions characteristic of MC[triple bond, length as m-dash]C-1-C6H4 to 4-C6H4-1-NO2 charge transfer red-shift and gain in intensity on proceeding to the ruthenium complexes; the low-energy transitions have increasing ILCT character on proceeding from the phenyl- to naphthalenyl- and then anthracenyl-containing bridge. Spectroelectrochemical studies of the Ru-containing complexes reveal the appearance of low-energy bands corresponding to chloro-to-RuIII charge transfer that red-shift on proceeding from the phenyl- to naphthalenyl- and then anthracenyl-containing bridge. Second-order nonlinear optical (NLO) studies at 1064 nm employing ns pulses and the hyper-Rayleigh scattering technique reveal an increase in quadratic optical nonlinearity upon introduction of metal to the precursor alkyne to afford alkynyl complexes and on proceeding from ligated-gold to -nickel and then to -ruthenium for a fixed alkynyl ligand. Quadratic NLO data of the gold complexes optically transparent at the second-harmonic wavelength reveal an increase in ßHRS on proceeding from the phenyl- to the naphthalenyl-containing complex. Broad spectral range third-order nonlinear optical studies employing fs pulses and the Z-scan technique reveal an increase in two-photon absorption cross-section on replacing ligated-gold by -nickel and then -ruthenium for a fixed alkynyl ligand. Computational studies undertaken using time-dependent density functional theory have been employed to assign the nature of the key optical transitions and suggest that the significant optical nonlinearities observed for the ruthenium-containing complexes correlate with the low-energy formally Ru â NO2 band which possesses strong MLCT character, while the more moderate nonlinearities of the gold complexes correlate with a band higher in energy that is primarily ILCT in character.
RESUMEN
Very large molecular two- and three-photon absorption cross-sections are achieved by appending ligated bis(diphosphine)ruthenium units to oligo(p-phenyleneethynylene) (OPE)-based "stars" with arms up to 7â phenyleneethynylene (PE) units in length. Extremely large three- and four-photon absorption cross-sections, through the telecommunications wavelengths range and beyond, are obtained for these complexes upon optimizing OPE length and the ruthenium-coordinated peripheral ligand. Multi-photon absorption (MPA) cross-sections are optimized with stars possessing arms 2â PE units in length. Peripheral ligand variation modifies MPA merit and, in particular, 4-nitrophenylethynyl ligand incorporation enhances maximal MPA values and "switches on" four-photon absorption (4PA) in these low molecular-weight complexes. The 4-nitrophenylethynyl-ligated 2PE-armed star possesses a maximal four-photon absorption cross-section of 1.8×10-108 â cm8 s3 at 1750â nm, and significant MPA activity extending beyond 2000â nm.
RESUMEN
Transplant options for patients with type 1 diabetes and end-stage renal disease (ESRD) include deceased donor kidney, live donor kidney (LDK) and simultaneous pancreas-kidney (SPK) transplantation. The aim of this study was to compare outcomes between LDK and SPK for patients with type 1 diabetes and ESRD in the UK. Data on all SPK (n = 1739) and LDK (n = 385) transplants performed between January 2001 and December 2014 were obtained from the UK Transplant Registry. Unadjusted patient and kidney graft survival were calculated using the Kaplan-Meier method. Multivariate analysis of kidney graft and patient survival was performed using Cox proportional hazards regression. There was no significant difference in patient (P = 0.435) or kidney graft survival (P = 0.204) on univariate analysis. On multivariate analysis there was no association between LDK/SPK and patient survival [HR 0.71 (0.47-1.06), P = 0.095]. However, LDK was associated with an overall lower risk for kidney graft failure [HR 0.60 (0.38-0.94), P = 0.025]. SPK recipients with a functioning pancreas graft had significantly better kidney graft and patient survival than LDK recipients or those with a failed pancreas graft. SPK transplantation does not confer an overall survival advantage compared to LDK. However, those SPK recipients with a functioning pancreas have significantly better outcomes.
Asunto(s)
Diabetes Mellitus Tipo 1/cirugía , Fallo Renal Crónico/cirugía , Trasplante de Riñón/métodos , Donadores Vivos , Trasplante de Páncreas/métodos , Adulto , Diabetes Mellitus Tipo 1/complicaciones , Diabetes Mellitus Tipo 1/mortalidad , Femenino , Estudios de Seguimiento , Supervivencia de Injerto , Humanos , Fallo Renal Crónico/complicaciones , Fallo Renal Crónico/mortalidad , Masculino , Persona de Mediana Edad , Análisis Multivariante , Estudios Retrospectivos , Análisis de Supervivencia , Resultado del TratamientoRESUMEN
Oligo(p-phenylenevinylene)s (OPVs) containing up to 8 PV units and end-functionalized by ruthenium alkynyl groups have been prepared and their nonlinear absorption properties assessed using the Z-scan technique and employing low repetition rate femtosecond pulses. Exceptionally large two-photon absorption (ca. 12 500 GM at 725 nm) and three-photon absorption cross sections (ca. 1.6 × 10(-76) cm(6) s(2) at 1100 nm) are found for the 8PV-containing example, highlighting the potential of an "organometalation" approach to NLO-efficient organic materials.
RESUMEN
Permutational isomers of trigonal bipyramidal [W2RhIr2(CO)9(η(5)-C5H5)2(η(5)-C5HMe4)] result from competitive capping of either a W2Ir or a WIr2 face of the tetrahedral cluster [W2Ir2(CO)10(η(5)-C5 H5)2] from its reaction with [Rh(CO)2(η(5)-C5HMe4)]. The permutational isomers slowly interconvert in solution by a cluster metal vertex exchange that is proposed to proceed by Rh-Ir and Rh-W bond cleavage and reformation, and via the intermediacy of an edge-bridged tetrahedral transition state. The permutational isomers display differing chemical and physical properties: replacement of CO by PPh3 occurs at one permutational isomer only, while the isomers display distinct optical power limiting behavior.
RESUMEN
Large increases in molecular two-photon absorption, the onset of measurable molecular three-photon absorption, and record molecular four-photon absorption in organic π-delocalizable frameworks are achieved by incorporation of bis(diphosphine)ruthenium units with alkynyl linkages. The resultant ruthenium alkynyl-containing dendrimers exhibit strong multiphoton absorption activity through the biological and telecommunications windows in the near-infrared region. The ligated ruthenium units significantly enhance solubility and introduce fully reversible redox switchability to the optical properties. Increasing the ruthenium content leads to substantial increases in multiphoton absorption properties without any loss of optical transparency. This significant improvement in multiphoton absorption performance by incorporation of the organometallic units into the organic π-framework is maintained when the relevant parameters are scaled by molecular weights or number of delocalizable π-electrons. The four-photon absorption cross-section of the most metal-rich dendrimer is an order of magnitude greater than the previous record value.
Asunto(s)
Derivación Arteriovenosa Quirúrgica/efectos adversos , Arteria Axilar/cirugía , Implantación de Prótesis Vascular/efectos adversos , Gasto Cardíaco Elevado/etiología , Insuficiencia Cardíaca/etiología , Vena Ilíaca/cirugía , Fallo Renal Crónico/terapia , Diálisis Renal , Anciano de 80 o más Años , Arteria Axilar/diagnóstico por imagen , Arteria Axilar/fisiopatología , Gasto Cardíaco Elevado/diagnóstico , Gasto Cardíaco Elevado/fisiopatología , Insuficiencia Cardíaca/diagnóstico , Insuficiencia Cardíaca/fisiopatología , Hemodinámica , Humanos , Vena Ilíaca/diagnóstico por imagen , Vena Ilíaca/fisiopatología , Fallo Renal Crónico/diagnóstico , Ligadura , Masculino , Flebografía , Reoperación , Resultado del TratamientoRESUMEN
Ischemic conditioning involves the delivery of short cycles of reversible ischemic injury in order to induce protection against subsequent more prolonged ischemia. This randomized controlled trial was designed to determine the safety and efficacy of remote ischemic conditioning (RC) in live donor kidney transplantation.This prospective randomized clinical trial, 80 patients undergoing live donor kidney transplantation were randomly assigned in a 1:1 ratio to either RC or to a control group. RC consisted of cycles of lower limb ischemia induced by an arterial tourniquet cuff placed around the patient's thigh. In the RC treatment group, the cuff was inflated to 200 mm Hg or systolic pressure +25 mm Hg for 4 cycles of 5 min ischemia followed by 5 min reperfusion. In the control group, the blood pressure cuff was inflated to 25 mm Hg. Patients and medical staff were blinded to treatment allocation. The primary end-point was renal function measured by estimated glomerular filtration rate (eGFR) at 1 and 3 months posttransplant.Donor and recipient demographics were similar in both groups (Pâ<â0.05). There were no significant differences in eGFR at 1 month (control 52â±â14 vs RC 54â±â17âmL/min; Pâ=â0.686) or 3 months (control 50â±â14 vs RC 49â±â18âmL/min; Pâ=â0.678) between the control and RC treatment groups. The RC technique did not cause any serious adverse effects.RC, using the protocol described here, did not improve renal function after live donor kidney transplantation.
Asunto(s)
Precondicionamiento Isquémico , Fallo Renal Crónico/cirugía , Trasplante de Riñón , Acondicionamiento Pretrasplante , Adulto , Método Doble Ciego , Femenino , Tasa de Filtración Glomerular , Humanos , Donadores Vivos , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Resultado del TratamientoRESUMEN
The synthesis of fac-[Ir{N,C1'-(2,2'-NC5H4C6H3-5'-C≡C-1-C6H2-3,5-Et2-4-C≡CC6H4-4-C≡CH)}3] (10), which bears pendant ethynyl groups, and its reaction with [RuCl(dppe)2]PF6 to afford the heterobimetallic complex fac-[Ir{N,C1'-(2,2'-NC5H4C6H3-5'-C≡C-1-C6H2-3,5-Et2-4-C≡CC6H4-4-C≡C-trans-[RuCl(dppe)2])}3] (11) is described. Complex 10 is available from the two-step formation of iodo-functionalized fac-tris[2-(4-iodophenyl)pyridine]iridium(III) (6), followed by ligand-centered palladium-catalyzed coupling and desilylation reactions. Structural studies of tetrakis[2-(4-iodophenyl)pyridine-N,C1'](µ-dichloro)diiridium 5, 6, fac-[Ir{N,C1'-(2,2'-NC5H4C6H3-5'-C≡C-1-C6H2-3,5-Et2-4-C≡CH)}3] (8), and 10 confirm ligand-centered derivatization of the tris(2-phenylpyridine)iridium unit. Electrochemical studies reveal two (5) or one (610) Ir-centered oxidations for which the potential is sensitive to functionalization at the phenylpyridine groups but relatively insensitive to more remote derivatization. Compound 11 undergoes sequential Ru-centered and Ir-centered oxidation, with the potential of the latter significantly more positive than that of Ir(N,C'-NC5H4-2-C6H4-2)3. Ligand-centered ππ* transitions characteristic of the Ir(N,C'-NC5H4-2-C6H4-2)3 unit red-shift and gain in intensity following the iodo and alkynyl incorporation. Spectroelectrochemical studies of 6, 7, 9, and 11 reveal the appearance in each case of new low-energy LMCT bands following formal IrIII/IV oxidation preceded, in the case of 11, by the appearance of a low-energy LMCT band associated with the formal RuII/III oxidation process. Emission maxima of 610 reveal a red-shift upon alkynyl group introduction and arylalkynyl π-system lengthening; this process is quenched upon incorporation of the ligated ruthenium moiety on proceeding to 11. Third-order nonlinear optical studies of 11 were undertaken at the benchmark wavelengths of 800â nm (fs pulses) and 532â nm (ns pulses), the results from the former suggesting a dominant contribution from two-photon absorption, and results from the latter being consistent with primarily excited-state absorption.
RESUMEN
Substitution of the halide ligands in (Bu4N)2[Mo3S7X6] (X = Cl, Br) by diimine ligands, such as 4,4'-dimethyl-2,2'-bipyridine (dmbpy), 2,2'-bipyridine (bpy) and 1,10-phenanthroline (phen), affords the neutral heteroleptic clusters Mo3S7Cl4(dmbpy) (), Mo3S7Br4(dmbpy) (), Mo3S7Br4(bpy) (), and Mo3S7Br4(phen) (). Further substitution of the halide ligands in Mo3S7Br4(diimine) clusters by dmit (1,3-dithiole-2-thione-4,5-dithiolate) allows the preparation of the mixed diimine-dithiolene neutral cluster complexes Mo3S7(dnbpy)(dmit)2 (, dnbpy = 4,4'-dinonyl-2,2'-bipyridine), Mo3S7(dcmbpy)(dmit)2 (, dcmbpy = 4,4'-dimethoxycarbonyl-2,2'-bipyridine), and Mo3S7(dcbpy)(dmit)2 (, dcbpy = 2,2'-bipyridine-4,4'-dicarboxylic acid). The optical limiting properties of complexes have been assessed by the open-aperture Z-scan technique at 570 nm, employing a nanosecond optical parametric oscillator. In order to investigate the effect of increasing the π-system, complexes , with the general formula Mo3S7X4(diimine), (X = Cl, Br), were compared to clusters , containing the dmit ligand. The influence of the metal content on the optical power limiting properties was also investigated by comparing the trinuclear series of complexes prepared herein with the bis(dithiolene) dinuclear cluster (Et4N)2[Mo2O2S2(BPyDTS2)2], which has been recently prepared by our group. All trinuclear clusters are efficient optical limiters (σeff > σ0) with the threshold limiting fluence F15% decreasing on proceeding from dinuclear to trinuclear clusters and, generally, on extending the π-system.
RESUMEN
The title compound, C29H37BrSi, was synthesized by the Sonogashira coupling of [(3,5-diethyl-4-ethynylphen-yl)ethyn-yl]triiso-propyl-silane with 4-bromo-1-iodo-benzene. In the structure, the two phenyl rings are nearly parallel to each other with a dihedral angle of 4.27â (4)°. In the crystal, π-π inter-actions between the terminal and central phenyl rings of adjacent mol-ecules link them in the a-axis direction [perpendicular distance = 3.5135â (14); centroid-centroid distance = 3.7393â (11)â Å]. In addition, there are weak C-Hâ¯π inter-actions between the isopropyl H atoms and the phenyl rings of adjacent mol-ecules.
RESUMEN
A new Zn(ii) porphyrin-cored ruthenium alkynyl dendrimer (2) containing twelve Ru(κ(2)-dppe)2 bis-alkynyl fragments has been prepared in two steps from 5,10,15,20-tetra(4-ethynylphenyl)porphyrinatozinc(ii) and shown to be highly active for third-harmonic generation (THG) at 1907 nm.