Adducts of rhodium(II) tetraacylates with methionine and its derivatives: 1H and 13C nuclear magnetic resonance spectroscopy and chiral recognition

Complexation of rhodium(II) dimeric tetraacylates: tetraacetate Rh₂AcO₄, tetratrifluoroacetate Rh₂TFA₄ , and (S)-Mosher’s acid salt Rh₂MTPA₄ with both enantiomerically pure and racemic methionine and its derivatives: hydrochloric salt of methionine, hydrochloric salt of methionine methyl ester, N-formyl methionine, N-phthaloyl methionine, N-phthaloyl methyl ester of methionine, and methyl ester of N,N-dimethylmethionine has been investigated by means of ¹H and ¹³C nuclear magnetic resonance (¹H and ¹³C NMR) and absorption electronic spectroscopy in the visible range. Complexation processes were investigated in D₂O or CDCl₃ solutions, depending on the ligands’ and rhodium salts’ solubilities. Some supporting measurements were performed in the solid phase, using ¹³C and ¹⁵N CPMAS NMR techniques.All ligands investigated form 1:1 and 1:2 adducts in the solution, depending on the rhodium salt to ligand molar ratios. The complexation site in the ligands (S atom) was deduced on the basis of the NMR parameter adduct formation shift (Δδ = δ_adduct ? δ_ligand) and calculated chemical shifts (DFT, NMR GIAO). In the cases of the Rh₂TFA₄ and Rh₂MTPA₄ adducts, decreasing the temperature within the range 220–254 K slowed down the ligand exchange and allowed us to observe the signals of all diastereoisomers in the ¹H and ¹³C NMR spectra.     

Influence of metal ions on the 44Sc-labeling of DOTATATE

Journal of Radioanalytical and Nuclear Chemistry - The aim of the study was to evaluate the labeling yield of 44Sc-DOTATATE radiobioconjugate when the labeling is performed in the presence of...     

On Hindman spaces and the Bolzano–Weierstrass property

We examine relationships between two classes of topological spaces defined with the aid of the Hindman ideal. We also do the same for another ideal—instead of sums, as in the Hindman ideal, we consider differences.     

C(1)-Phenethyl Derivatives of [closo-1-CB11H12]− and [closo-1-CB9H10]− Anions: Difunctional Building Blocks for Molecular Materials

C(1)-vinylation of [closo-1-CB₉H₁₀]⁻ ( A ) and [closo-1-CB₁₁H₁₂]⁻ ( B ) with 4-benzyloxystyryl iodide followed by hydrogenation of the double bond and reductive deprotection of the phenol functionality led to C(1)-(4-hydroxyphenethyl) derivatives. The phenol functionality was protected as the acetate. The esters were then treated with PhI(OAc)₂ and the resulting isomers were separated kinetically (for derivatives of anion A ) or by chromatography (for derivatives of anion B ) giving the difunctionalized building blocks in overall yields of 9 % and 50 %, respectively. A similar series of reactions was performed starting with anions A and B and 4-methoxystyryl bromide and iodide. Significant differences in the reactivity of derivatives of the two carborane anions were rationalized with DFT computational results. Application of the difunctionalized carboranes as building blocks was demonstrated through preparation of two ionic liquid crystals. The extensive synthetic work is accompanied by single crystal XRD analysis of six derivatives.     

Clinical Trials and Basic Research in Photodynamic Diagnostics and Therapies from the Center for Laser Diagnostics and Therapy in Poland

The purpose of this review is to present an overview of the development of photodiagnostic and photodynamic therapy (PDD and PDT) techniques in Poland. The paper discusses the principles of PDD, including fluorescent techniques in determining precancerous conditions and cancers of the skin, digestive tract, bladder and respiratory tract. Methods of PDT of cancer will be discussed and the current state of knowledge as well as future trends in the development of photodynamic techniques will be presented, including the possibility of using photodynamic antimicrobial therapy. Research pioneers in photodynamic medicine such as Thomas Dougherty are an inspiration for the development of methods of PDD and PDT in our Clinic. The Center for Laser Diagnostics and Therapy in Bytom, Poland, promotes the propagation of PDD and PDT through the training of clinicians and raising awareness among students in training and the general public. Physicians at the Center are engaged in photomedical research aimed at clinical implementation and exploration of new avenues in photomedicine while optimizing existing modalities. The Center promotes dissemination of clinical results from a wide range of topics in PDD and PDT and serving as representative authorities of photodynamic medicine in Poland and Europe.     

Influence of Fluorine Substitution on Nonbonding Interactions in Selected Para-Halogeno Anilines

A series of 4-halogeno aniline derivatives was studied employing combined theoretical and experimental methods (i. e. crystal structure analysis and vibrational spectroscopies). This simplified model system was selected to shed light on the impact of fluorine substitution on the formation of noncovalent interactions such as halogen bonds (XBs) and hydrogen bonds (HBs), which are key interactions in fluorinated/halogenated drug-protein complex formation. Comparative analysis of three previously reported and five newly determined crystal structures indicated that, in most cases, 2-fluoro and 2,6-difluoro substitution of 4-X anilines increases the ability of adjacent amine to form strong N−H⋅⋅⋅N HBs. Additionally, fluorine substituents in the difluorinated derivatives are competitive and attractive HB and XB acceptors and increase the probability of halogen-halogen contacts. A peculiar observation was made for 4-iodoaniline and 2,6-difluoro-4-iodoaniline, which form distinct interaction patterns compared to the corresponding 4-Cl and 4-Br analogs. The observed intramolecular N−H⋅⋅⋅F interactions lead to additional NH bands in the FT-IR spectra.     

Convergence acceleration of alternating series

Numerical Algorithms - We propose a new simple convergence acceleration method for a wide range class of convergent alternating series. It has some common features with Smith’s and...     

Adducts of nitrogenous ligands with rhodium(II) tetracarboxylates and tetraformamidinate: NMR spectroscopy and density functional theory calculations

Complexation of tetrakis(μ₂‐N,N'‐diphenylformamidinato‐N,N')‐di‐rhodium(II) with ligands containing nitrile, isonitrile, amine, hydroxyl, sulfhydryl, isocyanate, and isothiocyanate functional groups has been studied in liquid and solid phases using ¹H, ¹³C and ¹⁵N NMR, ¹³C and ¹⁵N cross polarisation–magic angle spinning NMR, and absorption spectroscopy in the visible range. The complexation was monitored using various NMR physicochemical parameters, such as chemical shifts, longitudinal relaxation times T₁, and NOE enhancements. Rhodium(II) tetraformamidinate selectively bonded only unbranched amine (propan‐1‐amine), pentanenitrile, and (1‐isocyanoethyl)benzene. No complexation occurred in the case of ligands having hydroxyl, sulfhydryl, isocyanate, and isothiocyanate functional groups, and more expanded amine molecules such as butan‐2‐amine and 1‐azabicyclo[2.2.2]octane. Such features were opposite to those observed in rhodium(II) tetracarboxylates, forming adducts with all kind of ligands. Special attention was focused on the analysis of Δδ parameters, defined as a chemical shift difference between signal in adduct and corresponding signal in free ligand. In the case of ¹H NMR, Δδ values were either negative in adducts of rhodium(II) tetraformamidinate or positive in adducts of rhodium(II) tetracarboxylates. Experimental findings were supported by density functional theory molecular modelling and gauge independent atomic orbitals chemical shift calculations. The calculation of chemical shifts combined with scaling procedure allowed to reproduce qualitatively Δδ parameters. Copyright © 2013 John Wiley & Sons, Ltd.