Samarium- and Ytterbium-Grafted Periodic Mesoporous Silica for Carbon Dioxide Capture and Conversion

Immobilized coordination compounds of Lewis acidic metals are powerful catalytic components of systems for the cycloaddition of CO2 to epoxides that do not require sophisticated coordination frameworks to harness the metal center and modulate its activity. Surface organometallic chemistry (SOMC) is a valuable methodology to prepare well-defined and site-isolated surface complexes and coordination compounds on metal oxides, with ligand environments easily adjustable to a targeted catalytic reaction. In this work, the SOMC methodology is applied to prepare SmII, YbII, and SmIII alkoxide surface complexes on periodic mesoporous (organo)silica of distinct pore symmetry/size for application in the CO2 cycloaddition reaction. The surface complexes are readily accessible by the grafting of the bis(trimethylsilyl)amide precursors LnII[N(SiMe3)2]2(THF)2 (Ln = Sm, Yb) and SmIII[N(SiMe3)2]3, followed by ligand exchange with alcohols (ethanol and neopentanol). The use of periodic mesoporous supports led to hybrid materials with relatively high surface areas and pore sizes, affording good performance in CO2 capture and in the cycloaddition of CO2 to epoxides under mild conditions (60-80 °C, 1-10 bar). In terms of catalytic performance, recyclability, and low amount of added nucleophile TBAX (X = Br, I), the most active materials prepared in this work compare well to a variety of previously reported SOMC-derived surface complexes and to other heterogeneous Lewis acids displaying more elaborate ligand environments.

Potential precursors for terminal ytterbium(II) imide complexes bearing the hydrotris(3-tert-butyl-5-methylpyrazolyl)borato ligand

Monomeric, divalent ytterbium primary amides Tp^tBu,MeYb(NHR)(thf)_x (R = C₆H₃iPr₂-2,6 = Ar^iPr = Dipp, C₆H₃(CF₃)₂-3,5 = Ar^CF3, SiPh₃) supported by the bulky hydrotris(3-tBu-5-Me-pyrazolyl)borato scorpionate ligand are synthesized acccording to salt metathesis and protonolysis protocols, respectively. Yb(II) precursors comprise YbI₂(thf)₂, Yb[N(SiMe₃)₂]₂(thf)₂ and Tp^tBu,MeYb[N(SiMe₃)₂]. Complexes Tp^tBu,MeYb(NHR)(thf)_x readily engage in donor (thf) exchange with nitrogen donors like DMAP (4-dimethylaminopyridine) and pyridine. Treatment of Tp^tBu,MeYb(NHAr^CF3)(thf)₂ with the Lewis acids AlMe₃ and GaMe₃ results in the heterobimetallic complexes Tp^tBu,MeYb(NHAr^CF3)(MMe₃) (M = Al, Ga). Reactions of Tp^tBu,MeYb(NHR)(thf)_x (R = Ar^iPr, Ar^CF3) with the halogenating agents C₂Cl₆ and TeBr₄ give access to trivalent complexes [Tp^tBu,MeYb(NHR)(X)] (X = Cl, Br). The ytterbium(II) complexes under study display ¹⁷¹Yb NMR chemical shifts in the range 582 ppm for Tp^tBu,MeYb(NHAr^CF3)(GaMe₃) to 954 ppm for Tp^tBu,MeYb(NHSiPh₃)(dmap). The salt-metathesis route is also applicable for the synthesis of complexes Tp^tBu,MeLn(NHAr^iPr)(thf) (Ln = Sm, Eu) and Tp^tBu,MeYb(NHAr^Me) (Ar^Me = C₆H₃Me₂-2,6).

[(CH3 )Al(CH2 )]12 : Methylaluminomethylene (MAM-12)

The molecular structure of enigmatic “poly(aluminium‐methyl‐methylene)” (first reported in 1968) has been unraveled in a transmetalation reaction with gallium methylene [Ga₈(CH₂)₁₂] and AlMe₃. The existence of cage‐like methylaluminomethylene moieties was initially suggested by the reaction of rare‐earth‐metallocene complex [Cp*₂Lu{(μ‐Me)₂AlMe₂}] with excess AlMe₃ affording the deca‐aluminium cluster [Cp*₄Lu₂(μ₃‐CH₂)₁₂Al₁₀(CH₃)₈] in low yield (Cp*=C₅Me₅). Treatment of [Ga₈(CH₂)₁₂] with excess AlMe₃ reproducibly gave the crystalline dodeca‐aluminium complex [(CH₃)₁₂Al₁₂(μ₃‐CH₂)₁₂] (MAM‐12). Revisiting a previous approach to “poly(aluminium‐methyl‐methylene” by using a (C₅H₅)₂TiCl₂/AlMe₃ (1 : 100) mixture led to amorphous solids displaying solubility behavior and spectroscopic features similar to those of crystalline MAM‐12. The gallium methylene‐derived MAM‐12 was used as an efficient methylene transfer reagent for ketones.

Rare-earth-metal trimethylsilylmethyl ate complexes

En route to putative rare-earth-metal alkylidene complex Li[Lu(CH2SiMe3)2(CHSiMe3)], according to Schumann’s original protocol, the reaction of YCl3 with LiCH2SiMe3 in a mixture of diethyl ether and n-pentane afforded a neosilyl...

Describing people with cognitive impairment and their complex treatment needs during routine care in the hospital - cross-sectional results of the intersec-CM study

BACKGROUND

Cognitive impairment is an important determinant in health care. In the acute hospital setting cognition has a strong impact on treatment and care. Cognitive impairment can negatively affect diagnostics and treatment success. However, little is known about the individual situation and specific risks of people with cognitive impairments during hospital stays. The aim of the present research is to describe and analyze the treatment needs of people with cognitive impairments in acute hospital care.

METHODS

The analyses use baseline data of the ongoing multisite, longitudinal, randomized controlled intervention trial intersec-CM (Supporting elderly people with cognitive impairment during and after hospital stays with Intersectoral Care Management), which recruited 402 participants at baseline. We assessed sociodemographic aspects, cognitive status, functional status, frailty, comorbidities, level of impairment, formal diagnosis of dementia, geriatric diagnoses, delirium, depression, pharmacological treatment, utilization of health care services and health care related needs.

RESULTS

The sample under examination had been on average mildly cognitively impaired (MMSE M = 22.3) and had a mild to moderate functional impairment (Barthel Index M = 50.4; HABAM M = 19.1). The Edmonton Frail Scale showed a mean of 7.4 and half of the patients (52.3%) had been assigned a care level. About 46.9% had a geriatric diagnosis, 3.0% had a diagnosis of dementia. According to DSM-V 19.2% of the patients had at least one main symptom of depression. The mean number of regularly taken drugs per patient was 8.2. Utilization of health care services prior to the hospital stay was rather low. On average, the sample showed 4.38 care related needs in general, of which 0.60 needs were unaddressed at the time of assessment.

CONCLUSIONS

Descriptive analyses highlight an in-depth insight into impairments and different care needs of people with cognitive impairments. The results emphasize the need for gender-specific analyses as well as an increased attention to the heterogeneity of needs of people with cognitive impairments related to specific wards, settings and regions where they are admitted. Our results indicate also that people with cognitive impairments represent a high proportion of older patients in acute hospital care.

TRIAL REGISTRATION

The intersec-CM trial is registered at ClinicalTrials.gov ( NCT03359408 ).

Prevalence of renal cysts and association with risk factors in a general population: an MRI-based study

PURPOSE

To assess the prevalence and size of renal cysts and to analyze associated risk factors in a general population using magnetic resonance imaging (MRI).

METHODS

Data of 2063 participants (1052 women) of the Study of Health in Pomerania who underwent whole-body MRI were included. Renal cyst prevalence was calculated separately for men and women and for 10-year age groups. The association between risk factors and occurrence of renal cysts was estimated.

RESULTS

The prevalence of renal cysts was 27% and higher in men (34%) than in women (21%; p < 0.001). Renal cyst prevalence increased from 14% in the youngest age group (20-29 years) to 55% in the oldest age group (≥ 70 years) for men and from 7% to 43% for women (both p < 0.001). In the subset of participants with renal cysts, the total mean number was higher in men (1.9) compared to women (1.6, p = 0.012) and was significantly associated with age. Mean renal cyst size was higher in men (1.50 cm) compared to women (1.18 cm, p < 0.001). Male sex (OR 1.83, 95% CI 1.47; 2.26), older age (OR 1.05, 95% CI 1.04; 1.06, per 1-year increment), and hypertension (OR 1.27, 95% CI 1.00; 1.61) were associated with higher renal cyst prevalence. In additional analyses, current smoking and ex-smoking showed a significantly higher risk for renal cysts (OR 1.47, 95% CI 1.05; 2.05 and OR 1.38, 95% CI 1.04; 1.82, respectively).

CONCLUSIONS

The prevalence, number, and mean size of renal cysts are higher in men compared to women and are associated with age. In addition, renal cyst prevalence is higher in hypertensive and smoking subjects.