13 research outputs found
Redox-responsive phosphonite gold complexes in hydroamination catalysis
Very high activities were observed in the redox-induced hydroamination of alkynes by employing a redox-active gold(I) complexfeaturingan electron-deficient, terphenyl-substituted phosphonite-based ligand. The hydroamination proceeds roughly two-fold faster with the in situ oxidized catalysts than with their reduced form
Star-shaped triarylamines - One-step metal-free synthesis and optoelectronic properties
Triarylamine derivatives are often implemented in organic optoelectronic devices due to their excellent hole-transport properties and their versatile structural tuneability. Common synthetic routes to obtain functionalized triarylamines follow multi-step procedures utilizing transition metal catalysts. Here, we investigate the synthesis of a series of star-shaped tris(biphenylamines) by a one-step base-promoted homolytic aromatic substitution (BHAS), simultaneously attaching three peripheral arenes to the triarylamine core. We demonstrate the versatility of this synthetic route by coupling four different functionalized arenes to the core and study their influence on the optoelectronic properties. BHAS as a metal-free synthetic route produces pure organic semiconductors without transition metal residues.Peer reviewe
Canagliflozin and renal outcomes in type 2 diabetes and nephropathy
BACKGROUND Type 2 diabetes mellitus is the leading cause of kidney failure worldwide, but few effective long-term treatments are available. In cardiovascular trials of inhibitors of sodiumâglucose cotransporter 2 (SGLT2), exploratory results have suggested that such drugs may improve renal outcomes in patients with type 2 diabetes. METHODS In this double-blind, randomized trial, we assigned patients with type 2 diabetes and albuminuric chronic kidney disease to receive canagliflozin, an oral SGLT2 inhibitor, at a dose of 100 mg daily or placebo. All the patients had an estimated glomerular filtration rate (GFR) of 30 to <90 ml per minute per 1.73 m2 of body-surface area and albuminuria (ratio of albumin [mg] to creatinine [g], >300 to 5000) and were treated with reninâangiotensin system blockade. The primary outcome was a composite of end-stage kidney disease (dialysis, transplantation, or a sustained estimated GFR of <15 ml per minute per 1.73 m2), a doubling of the serum creatinine level, or death from renal or cardiovascular causes. Prespecified secondary outcomes were tested hierarchically. RESULTS The trial was stopped early after a planned interim analysis on the recommendation of the data and safety monitoring committee. At that time, 4401 patients had undergone randomization, with a median follow-up of 2.62 years. The relative risk of the primary outcome was 30% lower in the canagliflozin group than in the placebo group, with event rates of 43.2 and 61.2 per 1000 patient-years, respectively (hazard ratio, 0.70; 95% confidence interval [CI], 0.59 to 0.82; P=0.00001). The relative risk of the renal-specific composite of end-stage kidney disease, a doubling of the creatinine level, or death from renal causes was lower by 34% (hazard ratio, 0.66; 95% CI, 0.53 to 0.81; P<0.001), and the relative risk of end-stage kidney disease was lower by 32% (hazard ratio, 0.68; 95% CI, 0.54 to 0.86; P=0.002). The canagliflozin group also had a lower risk of cardiovascular death, myocardial infarction, or stroke (hazard ratio, 0.80; 95% CI, 0.67 to 0.95; P=0.01) and hospitalization for heart failure (hazard ratio, 0.61; 95% CI, 0.47 to 0.80; P<0.001). There were no significant differences in rates of amputation or fracture. CONCLUSIONS In patients with type 2 diabetes and kidney disease, the risk of kidney failure and cardiovascular events was lower in the canagliflozin group than in the placebo group at a median follow-up of 2.62 years
Molecular Spin Crossover in Slow Motion: Light-Induced Spin-State Transitions in Trigonal Prismatic Iron(II) Complexes
A straightforward access is provided
to ironÂ(II) complexes showing exceedingly slow spin-state interconversion
by utilizing trigonal-prismatic directing ligands (<b>L</b><sup><i><b>n</b></i></sup>) of the extended-tripod type.
A detailed analysis of the interrelations between complex structure
(X-ray diffraction, density functional theory) and electronic character
(SQUID magnetometry, MoÌssbauer spectroscopy, UV/vis spectroscopy)
of the ironÂ(II) center in mononuclear complexes [<b>FeL</b><sup><i><b>n</b></i></sup>] reveals spin crossover to
occur along a coupled breathing/torsion reaction coordinate, shuttling
the complex between the octahedral low-spin state and the trigonal-prismatic
high-spin state along Bailarâs trigonal twist pathway. We associate
both the long spin-state lifetimes in the millisecond domain close
to room temperature and the substantial barriers against thermal scrambling
(<i>E</i><sub>a</sub> â 33 kJ mol<sup>â1</sup>, from Arrhenius analysis) with stereochemical constraints. In particular,
the topology of the Îș<sup>6</sup>N ligands controls the temporary
and structural dynamics during spin crossover
Molecular Spin Crossover in Slow Motion: Light-Induced Spin-State Transitions in Trigonal Prismatic Iron(II) Complexes
A straightforward access is provided
to ironÂ(II) complexes showing exceedingly slow spin-state interconversion
by utilizing trigonal-prismatic directing ligands (<b>L</b><sup><i><b>n</b></i></sup>) of the extended-tripod type.
A detailed analysis of the interrelations between complex structure
(X-ray diffraction, density functional theory) and electronic character
(SQUID magnetometry, MoÌssbauer spectroscopy, UV/vis spectroscopy)
of the ironÂ(II) center in mononuclear complexes [<b>FeL</b><sup><i><b>n</b></i></sup>] reveals spin crossover to
occur along a coupled breathing/torsion reaction coordinate, shuttling
the complex between the octahedral low-spin state and the trigonal-prismatic
high-spin state along Bailarâs trigonal twist pathway. We associate
both the long spin-state lifetimes in the millisecond domain close
to room temperature and the substantial barriers against thermal scrambling
(<i>E</i><sub>a</sub> â 33 kJ mol<sup>â1</sup>, from Arrhenius analysis) with stereochemical constraints. In particular,
the topology of the Îș<sup>6</sup>N ligands controls the temporary
and structural dynamics during spin crossover