Rhodium(I) pentasubstituted cationic complexes on the basis of 1,2-O-Alkylidene-3,5,6-O-phosphinetriyl-α-D-glucofuranose

Abstract

Reaction of 1,2-O-alkylidene-a-D-glucofuranose 3,5,6-phosphites with dicarbonylrhodium(I) acetylacetonate was studied. The structure of the reaction products is determined by the reagent ratio. At a 5 : 1 molar ratio, the step ligand-exchange process yields chiral complexes of the [RhL 5 ] + acac ! type. Dynamics of and anion exchange in these complexes are considered.Homoligand cationic complexes of rhodium(I) [RhL 5 ] + X ! have been scarcely explored. They have largely been synthesized on the basis of symmetrical acyclic trialkyl phosphites, as well as carcass phosphorinane3phosphorinane ligands, such as etriol phosphite, metriol phosphite, and adamantyl phosphite [1,2]. Described homoligand cationic rhodium(I) complexes are interesting from the chemical viewpoint. In the solid state they are stable and convenient to operate, and in solutions they undergo fluctuations due to the interconversion of the trigonal bipyramid and distorted tetragonal bipyramid forms [3,4]. It is very important that such complexes can be formed in situ during catalyst formation [5].Here we report on the first synthesis of optically active complexes [RhL 5 ] + X ! on the basis of acac .Rh(CO) 2 as complex-forming agent and unsymmetrical phospholane3phosphorinane systems, such as 1,2-O-isopropylidene-3,5,6-phosphabicyclo-a-Dglucofuranose (I), 1,2-O-cyclohexylidene-3,5,6-phos-ÄÄÄÄÄÄÄÄÄÄÄÄ phabicyclo-a-D-glucofuranose (II), and model 2,7,8-trioxa-1-phosphabicyclo[3,2,1]octane (III), as ligands. These compounds are available, stable, and exhibit a tendency for coordination with transition metals [6,7].Initiating these studies we expected that the ligandexchange reactions of acacRh(CO) 2 with compounds I and II would have certain specific features associated with the large size of the five carbohydratecontaining bicyclophosphite molecules coordinating to one rhodium atom. At the same time, the steric hindrance created by these ligands should not be too strong in view of the fact that the ligated part of the bicyclophosphites is a cone with small O3P3O bond angles. The sums of these angles in ligands I and II are as little as 293o and 295o, respectively [8].

In Vitro Anticancer Activity and Biologically Relevant Metabolization of Organometallic Ruthenium Complexes with Carbohydrate‐Based Ligands

“…[21,26,27] Herein we report on the synthesis and (bio)analytical characterization of RAPTA-C analogues in which the pta has been replaced by 3,5,6-bicyclophosphite-a-d-glucofuranoside ligands. [28][29][30] By modification of the carbohydrate moiety, the lipophilicity of the complexes can be modulated to yield coordination compounds with high aqueous solubility ideally suited for intravenous administration, or hydrophobic species that facilitate cellular uptake. [31] The compounds were characterized by different analytical methods, and the molecular structures of three complexes were determined by X-ray diffraction analysis.…”