Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 3 de 3
Filter
Add more filters










Database
Language
Publication year range
1.
Acta Crystallogr E Crystallogr Commun ; 80(Pt 6): 555-560, 2024 May 01.
Article in English | MEDLINE | ID: mdl-38845710

ABSTRACT

The calixarenes, 5,17-di-bromo-26,28-dihy-droxy-25,27-dipropynyloxycalix[4]arene (C34H26Br2O4, 1), 5,17-di-bromo-26,28-dipropoxy-25,27-dipropynyloxycalix[4]arene (C40H38Br2O4, 2) and 25,27-bis-(2-azido-eth-oxy)-5,17-di-bromo-26,28-di-hydroxy-calix[4]arene (C32H28Br2N6O4, 3) possess a pinched cone mol-ecular shape for 1 and 3, and a 1,3-alternate shape for compound 2. In calixarenes 1 and 3, the cone conformations are additionally stabilized by intra-molecular O-H⋯O hydrogen bonds, while in calixarene 2 intra-molecular Br⋯Br inter-actions consolidate the 1,3-alternate mol-ecular conformation. The dense crystal packing of the cone dialkyne 1 is a consequence of π-π, C-H⋯π and C-H⋯O inter-actions. In the crystal of the diazide 3, there are large channels extending parallel to the c axis, which are filled by highly disordered CH2Cl2 solvent mol-ecules. Their contribution to the intensity data was removed by the SQUEEZE procedure that showed an accessible void volume of 585 Å3 where there is room for 4.5 CH2Cl2 solvent mol-ecules per unit cell. Rigid mol-ecules of the 1,3-alternate calixarene 2 form a columnar head-to-tail packing parallel to [010] via van der Waals inter-actions, and the resulting columns are held together by weak C-H⋯π contacts.

2.
Europace ; 25(4): 1458-1466, 2023 04 15.
Article in English | MEDLINE | ID: mdl-36857597

ABSTRACT

AIMS: Pacing remote from the latest electrically activated site (LEAS) in the left ventricle (LV) may diminish response to cardiac resynchronization therapy (CRT). We tested whether proximity of LV pacing site (LVPS) to LEAS, determined by non-invasive three-dimensional electrical activation mapping [electrocardiographic Imaging (ECGI)], increased likelihood of CRT response. METHODS AND RESULTS: Consecutive CRT patients underwent ECGI and chest/heart computed tomography 6-24 months of post-implant. Latest electrically activated site and the distance to LVPS (dp) were assessed. Left ventricular end-systolic volume (LVESV) reduction of ≥15% at clinical follow-up defined response. Logistic regression probabilistically modelled non-response; variables included demographics, heart failure classification, left bundle branch block (LBBB), ischaemic heart disease (IHD), atrial fibrillation, QRS duration, baseline ejection fraction (EF) and LVESV, comorbidities, use of CRT optimization algorithm, angiotensin-converting enzyme inhibitor(ACE)/angiotensin-receptor blocker (ARB), beta-blocker, diuretics, and dp. Of 111 studied patients [64 ± 11 years, EF 28 ± 6%, implant duration 12 ± 5 months (mean ± SD), 98% had LBBB, 38% IHD], 67% responded at 10 ± 3 months post CRT-implant. Latest electrically activated sites were outside the mid-to-basal lateral segments in 35% of the patients. dp was 42 ± 23 mm [31 ± 14 mm for responders vs. 63 ± 24 mm non-responders (P < 0.001)]. Longer dp and the lack of use of CRT optimization algorithm were the only independent predictors of non-response [area under the curve (AUC) 0.906]. dp of 47 mm delineated responders and non-responders (AUC 0.931). CONCLUSION: The distance between LV pacing site and latest electrical activation is a strong independent predictor for CRT response. Non-invasive electrical evaluation to characterize intrinsic activation and guide LV lead deployment may improve CRT efficacy.


Subject(s)
Cardiac Resynchronization Therapy , Heart Failure , Humans , Cardiac Resynchronization Therapy/adverse effects , Cardiac Resynchronization Therapy/methods , Heart Ventricles/diagnostic imaging , Angiotensin Receptor Antagonists , Angiotensin-Converting Enzyme Inhibitors , Electrocardiography/methods , Bundle-Branch Block/diagnosis , Bundle-Branch Block/therapy , Arrhythmias, Cardiac/therapy , Heart Failure/diagnosis , Heart Failure/therapy , Treatment Outcome , Ventricular Function, Left
3.
Org Biomol Chem ; 20(41): 8092-8103, 2022 10 26.
Article in English | MEDLINE | ID: mdl-36205261

ABSTRACT

Triazolated calix[4]semitubes comprising several binding sites were studied for complexation of Ag+ to get insight into the ability of the multitopic semi-tubular environment to host cation(s) in a structure-specific/switchable manner. For this purpose, a series of triazolated calix[4]semitubes having two or three 1,3-alternate calix[4]arene cores and crown-5-ether loops in the structures were prepared using the recently developed stepwise synthesis approach. Crown-5-ether loops were used as model receptor units which could be filled with K+ to charge positively either a specific 'end' or both 'ends' of the semi-tubular assemblies and to affect the complexation abilities of the internal binding sites of triazolated calix[4]semitubes. Comparative analysis of complexation-induced broadening in the 1H NMR spectra of three isomeric tris(calixarenes) having different mutual arrangements of the internal binding sites upon addition of Ag+ suggested intramolecular rather than intermolecular migrations of the bound cation between two bistriazole units. The study on Ag+/K+ complexation by the crowned biscalixarene semitubes revealed strong dependence of the ditopic complexation mode on the mutual arrangement of the triazole and crownether sites within the molecule, which managed either the heterodinuclear Ag+/K+ binding, or switching between two single-nuclear complexes. In crowned triscalixarene semitubular systems, the same structure/complexation mode correlation was observed, but in this case, binding of K+ by an appropriately arranged crownether loop did not destroy the initial silver complex, but stopped the above migrations of Ag+ between the internal sites of heteromultitopic ligands, thus indicating the applicability of the triscalixarene semitubular core for the design of multipositioned molecular switches.


Subject(s)
Calixarenes , Calixarenes/chemistry , Silver/chemistry , Cations/chemistry , Triazoles , Ethers
SELECTION OF CITATIONS
SEARCH DETAIL
...