Replacing the Z-phenyl Ring in Tamoxifen® with a para-Connected NCN Pincer-Pt-Cl Grouping by Post-Modification

Post-modification of a series of NCN-pincer platinum(II) complexes [PtX(NCN-R-4)] (NCN = [C6H2(CH2NMe2)2-2,6]–, R = C(O)H, C(O)Me and C(O)Et), X = Cl– or Br–) at the para-position using the McMurry reaction was studied. The synthetic route towards two new [PtCl(NCN-R-4)] (R = C(O)Me and C(O)Et) complexes used above is likewise described. The utility and limitations of the McMurry reaction involving these pincer complexes was systematically evaluated. The predicted “homo-coupling” reaction of [PtBr(NCN-C(O)H-4)] led to the unexpected formation of 3,3′,5,5′-tetra[(dimethylamino)methyl]-4,4′-bis(platinum halide)-benzophenone (halide = Br or Cl), referred to hereafter as the bispincer-benzophenone complex 13. This material was further characterized using X-ray crystal structure determination. The applicability of the pincer complexes in the McMurry reaction is shown to open a route towards the synthesis of tamoxifen-type derivatives of which one phenyl ring of Tamoxifen® itself is replaced by an NCN arylplatinum pincer fragment. The newly synthesized derivatives can be used as potential candidates in anti-cancer drug screening protocols. Two NCN-arylpincer platinum tamoxifen type derivatives, 5 and 6, were successfully synthesized and of 5 the separation of the diastereomeric E-/Z-forms was achieved. Compound 6, which is the pivaloyl protected NCN pincer platinum hydroxy-Tamoxifen® derivative, was obtained as a mixture of E-/Z-isomers. The new derivatives were further analyzed and characterized with 1H-, 13C{1H}- and 195Pt{1H}-NMR, IR, exact mass MS and elemental analysis.This research was partly funded by the Council for Chemical Sciences of the Netherlands Organization for Scientific Research (NWO/CW) G.D.B., M.L

Imidazolylidene Cu(II) complexes: synthesis using imidazolium carboxylate precursors and structure rearrangement pathways

Copper(II) complexes of type (NHC)CuX2 (X = OAc, Cl, Br, BF4, NO3) bearing monodentate N-heterocyclic carbenes (NHCs) were prepared by in situ decarboxylation of imidazolium carboxylates as a new synthetic methodology for Cu(II)-NHC complexes. In contrast to the classical deprotonation method, the decarboxylation protocol does not require anaerobic conditions and provides access to complexes with NHCs that are unstable as free carbenes such as N,N’-diisopropyl-imidazolylidene and N,N’-dimethyl-imidazolylidene. Spectroscopic evidence of the formation of the Cu‒CNHC bond is provided by UV-vis and EPR, in particular by the 44 MHz carbene hyperfine coupling constant using a 13C-labelled imidazolylidene ligand. A variation of the nature of the carbene N-substituents and the anions bound to the Cu(II) center is possible with this methodology. These variations strongly influence the stability of the complexes. Structural rearrangement and ligand reorganization was observed during recrystallisation, which are comprised of heterolytic Cu‒CNHC bond dissociation for unstable NHC ligands as well as homolytic Cu‒X bond cleavage and disproportionation reactions depending on the nature of the anion X in the copper complex

Indole-3-thio­uronium nitrate

In the title compound, C9H10N3S+·NO3 −, the indole ring system and the thiouronium group are nearly perpendicular, with a dihedral angle of 88.62 (6)°. Hydrogen bonding generates two-dimensional networks which are linked to each other via π stacking inter­actions of the indole groups [average inter-planar ring–ring distance of 3.449 (2) Å]

Художній світ Василя Стуса

В статье рассматривается жизненный и творческий путь Василия Стуса, который за непокорность, за своё личное мнение, за гордость провёл долгие годы в ссылке. Исследования проводятся на архивных материалах, воспоминаниях современников поэта. Рассматривается следующая проблема: определить роль и место творческого наследия Василия Стуса в развитии украинской культуры. Цель: раскрыть идейно-художественные тенденции поэзии В.Стуса, подчеркнуть его обширный словарь.Дана стаття присвячена життєвій та творчій стежині Василя Стуса, який за нескореність, за непокірність, за свою власну думку, за гордість, за неприниження зазнав довгих років заслання. Дослідження проводиться на архівних матеріалах, спогадах сучасників поета. Розв’язується така проблема: визначити роль і місце творчого доробку В.Стуса у розвитку української культури. Мета: розкрити ідейно-художні особливості поезій В.Стуса, підкреслити його надзвичайно широкий словник.The article deals with Vasyl Stys’ life and creative way why speut many years in exile for his disobeying and own way of thinking. The investigation helds upon archive materials, recollections of the poet’s contemporaries. Defining the position and the place of creative heredity of Vasyl Stys is under the problem stated. Setting out the ideal and exressive tendencies of V.Stys’ poetry, underlying of his vast verbal stock is a main goa

Indole-3-thio­uronium iodide

In the title compound, C9H10N3S+·I−, the indole ring system and the thiouronium group are essentially perpendicular, with a dihedral angle of 89.87 (8)°. By inter­molecular hydrogen bonding, a three-dimensional network is formed, which is additionally supported by inter­molecular C—H⋯π inter­actions

Highlights of 45 years of research: A personal account

This part of my biosketch, which I prepared on invitation by the Editors, made me realize again how entangled my interest for doing research and teaching and management have been over the years. Working together with my students and colleagues has always been a strong motivation and pleasure for me and I hope that this sketch of our research reflects our common enthusiasm for what we achieved. In hindsight, trying to overlook almost 45 years of research, various main themes can be discerned that marked my fundamental research in the subsequent periods at TNO Utrecht (1968–1977), University of Amsterdam (1977–1986) and University of Utrecht (1986–2007). Overarching has been my preference and fascination for working with nitrogen based ligands (culminating in the design and use of the NCN-pincer ligand platform, vide infra), the study of synthetic routes for organometallics (most importantly trans- and cyclo-metallation routes), the use of NMR for the study of the stereochemistry of organometallics (cf. the early use of 107,109Ag NMR for detecting and following the formation of coordination compounds with helical structures), chemistry involving organometallic radicals (cf. organozinc and aluminum α-diimine chemistry, development of β-lactam synthesis routes), self-assembly of organometallics to discrete aggregated species (cf. organo-Cu, -Li and cuprate chemistry), the development of palladium complexes and homogeneous metal catalysts with simple amine ligands, the synthesis of, and catalysis with, dendrimers decorated with organometallic catalysts, mimicking the active center of metallo-enzymes as well as the synthesis of organometal-lipase hybrids for catalysis. Being educated in an "eco"-system of contract research, in concert with fundamental research, the results of the above outlined items were not only published in journals with peer review (>850) but also in the patent literature (>40). Most important were the results reported in over 85 PhD theses that I had the privilege to supervise as PI. The references refer to key-papers describing this body of work. The respective reference numbers are given at the heading of each paragraph. The full list of publications in peer reviewed Journals can be found in http://www.gerardvankoten.nl and www.uu.nl/staff/GvanKoten