bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hexacyanometalate Molecular Chemistry: Di‐, Tri‐, Tetra‐, Hexa‐ and Heptanuclear Heterobimetallic Complexes; Control of Nuclearity and Structural Anisotropy
Authors: Marvaud Valérie , Decroix Caroline , Scuiller Ariane , Tuyèras Fabien , Guyard‐Duhayon Carine , Vaissermann Jacqueline , Marrot Jérome , Gonnet Florence , Verdaguer Michel 
Published: April 2003

AbstractFollowing a bottom‐up approach to nanomaterials, we present a rational synthetic route to high‐spin and anisotropic molecules based on hexacyanometalate [M(CN)6]3− cores. Part 1 of this series was devoted to isotropic heptanuclear clusters; herein, we discuss the nuclearity and the structural anisotropy of nickel(II) derivatives. By changing either the stoichiometry, the nature of the terminal ligand, or the counterion, it is possible to tune the nuclearity of the polynuclear compounds and therefore to control the structural anisotropy. We present the synthesis and the characterisation by mass spectrometry, X‐ray crystallography and magnetic susceptibility of bi‐, tri‐, tetra‐, hexa‐ and heptanuclear species [M(CN)n(CNM′L)6−n]m+ (with n=0–5; M=CrIII, CoIII, M′=NiII; L=pentadentate ligand). Thus, with M=CrIII, d3, S=3/2, a dinuclear complex [CrIII(CN)5(CNNiLn)]9+, (Ln=polydentate ligand) was built and characterised, showing a spin ground state, SG=5/2, with a ferromagnetic interaction JCr,Cu=+18.5 cm−1. With M=CoIII (d6, S=0) were built di‐, tri‐, tetra‐, hexa and hepanuclear CoNi species: CoNi, CoNi2, CoNi3, CoNi5 and CoNi6. By a first approximation, they behave as one, two, three, five and six isolated nickel(II) complexes, respectively, but more accurate studies allow us to evaluate the weak antiferromagnetic coupling constant between two next‐nearest neighbours M′‐Co‐M′.
Organic Chemistry on Cold Molecular Films: Kinetic Stabilization of SN1 and SN2 Intermediates in the Reactions of Ethanol and 2‐Methylpropan‐2‐ol with Hydrogen Bromide
Authors: Park Seong‐Chan , Maeng Kye‐Won , Kang Heon 
Published: April 2003

AbstractWe prepared thin molecular films of ethanol and 2‐methylpropan‐2‐ol on Ru(001) substrates at temperature of 100–150 K and examined their reactivity toward HBr. The reaction intermediates and products formed at the surfaces were unambiguously identified by the techniques of Cs+ reactive ion scattering (RIS) and low‐energy sputtering. The reaction on the ethanol surface produced protonated ethanol, which is stabilized on the surface and does not proceed to further reactions. On the 2‐methylpropan‐2‐ol surface, protonated alcohol [(CH3)3COH2+] and carbocation [(CH3)3C+] were formed with the respective yield of 20 and 78 %. Alkyl bromides, which are the final products of the corresponding reactions in liquid solvents, have extremely small yields on these surfaces (< 0.3 % for ethyl bromide and 2 % for tert‐butyl bromide). The results indicate that the reactions on frozen films are characterized by kinetic control, stabilization of ionic intermediates (protonated alcohols and tert‐butyl cation), and effective blocking of the charge recombination steps in SN1 and SN2 paths. The implication of these findings for the molecular evolution process in interstellar medium is also discussed.
Binding Site Optimisation for Artificial Enzymes by Diffusion NMR of Small Molecules
Authors: Atkinson Catherine E. , Aliev Abil E. , Motherwell William B. 
Published: April 2003

AbstractA binding site optimisation protocol for the design of artificial enzymes based on “small molecule–small molecule” binding studies by diffusion NMR is presented. Since the reaction chosen was the hydrolysis of ester 1 ([4‐(4‐carboxy‐1‐oxobutyl)‐aminobenzyl]‐phenethyl ester), an analogous phosphonate ester 2 ([4‐(4‐carboxy‐1‐oxobutyl)‐aminobenzyl]‐phosphonic phenethyl ester) was selected as a suitable transition state analogue (TSA). The key objective of the NMR studies was to find a unit with functional groups capable of binding to the acidic sites of the TSA. Nine dipeptides, mainly with basic and hydroxyl groups, were used and their affinity to the TSA was studied by measuring the change in the diffusion coefficient, Dpep, upon binding by pulse field gradient NMR. The value of Dpep at 298 K in D2O at pD 5, 7 and 10 was measured both in free solution, and mixtures containing one dipeptide and the TSA. As both components are low molecular weight species with M < 500, a TSA‐to‐dipeptide ratio of 10:1 was used to detect significant changes in Dpep. The results revealed that dipeptides with basic residues show higher affinity to the TSA than those with hydroxyl or aliphatic side chains in aqueous solutions. The dipeptide showing the most significant relative change in Dpep was H‐Arg‐Arg‐OH, and the binding constant was estimated to be 86 L M−1 by measuring Dpep at varying concentrations of the TSA. In addition, binding of the TSA to a new water‐soluble polymer with a polyallylamine backbone and randomly distributed Arg‐Arg binding sites was examined, and the binding constant was estimated to be ≥1500 L M−1. As confirmed by further catalytic activity tests, polymers containing Arg‐Arg as a binding site are capable of significant rate accelerations in the hydrolysis of ester 1.
Cover Picture: The First Self‐Assembled Trimetallic Lanthanide Helicates Driven by Positive Cooperativity (Chem. Eur. J. 8/2003)
Authors: Floquet Sébastien , Ouali Nadjet , Bocquet Bernard , Bernardinelli Gérald , Imbert Daniel , Bünzli Jean‐Claude G. , Hopfgartner Gérard , Piguet Claude 
Published: April 2003

AbstractThe cover picture shows the emergence of the first self‐assembled trimetallic lanthanide helicate in which positive cooperativity overcomes strong intermetallic electrostatic repulsions occurring between the metals. The D3 symmetry of the final edifice provides two different metallic sites that are insensitive to the relative orientation of the ligand strands. This unique feature offers novel perspectives for the rational programming of magnetic and optical properties in polymetallic lanthanide complexes. An investigation on the influence of the fine tuning of crystal‐field parameters on multicentre paramagnetic NMR spectra and luminescence is reported by C. Piguet et al. on p. 1860 ff.
Natural Abundance Deuterium NMR Spectroscopy in Polypeptide Liquid Crystals as a New and Incisive Means for the Enantiodifferentiation of Chiral Hydrocarbons
Authors: Lesot Philippe , Sarfati Muriel , Courtieu Jacques 
Published: April 2003

AbstractPolymeric chiral liquid‐crystalline solvents based on homopolypeptides are of interest with the view to discriminate between enantiomeric pairs of chiral hydrocarbons using proton‐decoupled deuterium one‐ and two‐dimensional NMR spectroscopy at natural abundance level. This method offers the major advantage that neither chemical modification nor isotopic labelling of the solutes to be studied is required. Chiral differentiation between optical isomers is observed through a difference in residual deuterium quadrupolar splittings. The spectroscopic separations and the S/N ratio from the spectra are usually large enough to measure the enantiomeric excess with an accuracy varying between 5 to 10 %. This analytical approach is successfully applied to a large collection of chiral, rigid or flexible unsaturated as well as saturated hydrocarbons, including cases of axial chirality, atropoisomerism, and moieties existing as a mixture of enantiomers interconverting by ring inversion. Using the results reported in literature, a systematic comparison with other analytical strategies (NMR, GC, HPLC, VCD) is made and discussed. Also, a tentative proposal to rationalise the various results in terms of chiral differentiation and enantioselective shape recognition is presented. We show that this original tool provides an attractive and incisive alternative to the existing analytical techniques for studying nonfunctionalised chiral materials.
Unique Coordination of Two CC Double Bonds to an Electron‐Deficient Lead Center
Authors: Müller Thomas , Bauch Christian , Bolte Michael , Auner Norbert 
Published: April 2003

AbstractReaction of bis(cyclopentenemethyl)diethylplumbane (2) with trityl cation leads to the formation of the plumbyl cation bis(cyclopentenemethyl)plumbylium (1), in which the positively charged lead atom interacts with the two CC double bonds of the cyclopentene ligands. The plumbyl cation1is characterized by NMR spectroscopy (δ(207Pb)=807 ppm,δ(13C(CC))= 136.1 ppm,1J(Pb,CC)=14.4 Hz) and Xray crystallography. The structure of1reveals a distorted trigonal‐bipyramidal coordination sphere for the lead atom with a unique coordination of two CC double bonds in apical positions. According to quantum‐mechanical calculations (MP2/6‐311G(d,p) (C, H), SDD (Pb)//MP2/6‐31G(d), SDD (Pb)) this interaction stabilizes1by 28.3 kcal mol−1relative to the tricoordinated plumbylium ion10. An “atoms in molecules” (AIM) analysis indicates a π‐type interaction between the lead atom and the CC double bonds, reminiscent of that in the 2norbornyl cation.
Ethene/Norbornene Copolymerization with Palladium(II) α‐Diimine Catalysts: From Ligand Screening to Discrete Catalyst Species
Authors: Kiesewetter Jens , Kaminsky Walter 
Published: April 2003

AbstractSixteen palladium(II) α‐diimine catalysts were investigated in a screening‐like procedure for the copolymerization of ethene with norbornene. The resulting copolymers were characterized by 13C NMR spectroscopy, differential scanning calorimetry, gel permeation chromatography, and viscosimetry. The degree of incorporation of norbornene in the polymer chain is very high for most of the catalysts. To validate the results achieved in the screening, two catalysts, [{ArNCHCHNAr}Pd(Me)(CH3CN)]BArf4 (1 b′; Ar=2,6‐Me2C6H3, BArf4=B[3,5‐C6H3(CF3)2]4) and [{ArNC(CH3)C(CH3)NAr}Pd(Me)(CH3CN)]BArf4 (2 c′; Ar=2,6‐iPr2C6H3), were synthesized as discrete catalytically active species, and their copolymerization behavior was investigated in detail. In agreement with the screening results, 1 b′ incorporates norbornene much better in the polymer chain than ethene, a property that has no analogue in metallocene catalysts.
Double Bonds in Motion: Bis(oxazolinylmethyl)pyrroles and Their Metal‐Induced Planarization to a New Class of Rigid Chiral C2‐symmetric Complexes
Authors: Mazet Clément , Gade Lutz H. 
Published: April 2003

AbstractThe synthesis of a new class of chiral C2‐symmetric tridentate Ndonor ligands, a series of 2,5‐bis(2‐oxazolinylmethyl)pyrroles, was achieved in four steps starting from the known 2,5‐bis(trimethylammoniomethyl)pyrrole diiodide (1). Reaction of 1 with NaCN in dimethyl sulfoxide gave 2,5‐bis(cyanomethyl)pyrrole (2) cleanly, which was then cyclized with amino alcohols to give the 2,5‐bis(2‐oxazolinylmethyl)pyrroles 3 a–c (3 a: bis[2‐(4,4′‐dimethyl‐5‐hydrooxazolyl)methyl]pyrrole; 3 b: (S,S)‐bis[2‐(4‐isopropyl‐4,5‐dihydrooxazolyl)methyl]pyrrole; 3 c: (S,S)‐bis[2‐(4‐tertiobutyl‐4,5‐dihydrooxazolyl)methyl]pyrrole). Metallation of 3 a–c with one molar equivalent of tBuLi and their subsequent reaction with a stoichiometric amount of [PdCl2(cod)] (cod=cyclooctadiene) gave the palladium(II) complexes 4 a–c. Whereas the arrangement of the Ndonor atoms in the crystallographically characterized complex 4 a is almost ideally square planar, all three heterocycles in the ligand are twisted out of the coordination plane, leading to a chiral conformation of the complex. Attempts to freeze out these two conformers in solution at 200 K (NMR) failed, and this suggests that the activation barrier for conformational racemization is significantly below 10 kcal mol−1. The palladium‐induced shift of two double bonds as well as the porphyrinogen/porphyrin‐type oxidation of the complexes 4 a–c led to the planarization of the 2,5‐bis(oxazolinylmethyl)pyrrolide ligands in the palladium(II) complexes 5 a–c, 6 b, and 6 c, and to the formation of rigid chiral C2‐symmetric systems as shown by Xray diffraction studies. The formation of the conjugated system of double bonds in this transformation is accompanied by the emergence of an intra‐ligand chromophore. This is evident in the absorption spectrum of 6 c which displays an intense band with a maximum at 485 nm attributable to an intra‐ligand π*←π transition and a characteristic vibrational progression of ν≈1350 cm−1. Complexes 4 b and 4 c were tested in the catalytic asymmetric Michael addition of ethyl 2cyanopropionate to methyl vinylketone (catalyst loading: 1 mol %) and were found to give maximum ee values of 43 % (4 b) and 21 % (4 c) at low conversions.
Modulation of a Supramolecular Bowl and Pot by Changing Solvent Systems and/or Metal/Ligand Ratios
Authors: Park Seong Jin , Lee Jae Woo , Sakamoto Shigeru , Yamaguchi Kentaro , Hong Jong‐In 
Published: April 2003

AbstractA resorcin[4]arene‐based ligand 2 a with four pyrimidine substituents at the upper rim was synthesized, and the generation of different metal‐mediated superstructures from the same ligand and metal ions utilizing the unfavorable incorporation of the third and fourth PdII ions to ligand 2 a was investigated. The supramolecular bowl 3 a, which comes from a 1:2 combination of ligand 2 a and [Pd(en)(NO3)2], was obtained in water even though excess of PdII complexes were employed. By adding methanol, the supramolecular pot 4 gradually formed, which was the major product when the ratio of mixed solvent reached methanol/water=5:1 (v/v). Host–guest complexation phenomena of 3 a toward several aromatic carboxylates were demonstrated by isothermal titration calorimetry (ITC) and by 1H NMR spectroscopy; both the enthalpy gain from electrostatic and hydrophobic interactions, and the entropy gain from desolvation cooperatively contribute to the binding of anionically charged guests. The crystal structure of supramolecular pot 4 shows direct evidence for the hydrogen bonding between water and the aromatic π electrons in the solid state. The modulation between supramolecular bowl 3 a and pot 4 was also made possible by changing the metal/ligand ratios in aqueous methanol solution as well as by varying the water content of the mixed solvent.
Helical Polymer‐Anchored Porphyrin Nanorods
Authors: de Witte Pieter A. J. , Castriciano Mariangela , Cornelissen Jeroen J. L. M. , Monsù Scolaro Luigi , Nolte Roeland J. M. , Rowan Alan E. 
Published: April 2003

AbstractWell‐defined arrays of porphyrins attached to a rigid polyisocyanide backbone have been synthesized and their physical and optical properties studied. The helical polymers are rigidified by an inter‐side chain hydrogen‐bonded network and have an average mass of 1.1×106 Daltons and a polydispersity index of 1.3. Each of the polymer strands contains four columns of around 200 stacked porphyrins and has an overall length of 87 nm. The chromophores are arranged in a left‐handed helical fashion along the polymer backbone. Photophysical studies show that at least 25 porphyrins within one column are excitationally coupled.
Homochiral Oligopeptides by Chiral Amplification within Two‐Dimensional Crystalline Self‐Assemblies at the Air–Water Interface; Relevance to Biomolecular Handedness
Authors: Weissbuch Isabelle , Zepik Helmut , Bolbach Gérard , Shavit Edna , Tang Mao , Jensen Torben R. , Kjaer Kristian , Leiserowitz Leslie , Lahav Meir 
Published: April 2003

AbstractA possible role that might have been played by ordered clusters at interfaces for the generation of homochiral oligopeptides under prebiotic conditions has been probed by a catalyzed polymerization of amphiphilic activated α‐amino acids, in racemic and chiral non‐racemic forms, which had self‐assembled into two‐dimensional (2D) ordered crystallites at the air–aqueous solution interface. As model systems we studied Nε‐stearoyl‐lysine thioethyl ester (C18‐TE‐Lys), γ‐stearyl‐glutamic thioethyl ester (C18‐TE‐Glu), Nα‐carboxyanhydride of γ‐stearyl‐glutamic acid (C18‐Glu NCA) and γ‐stearyl‐glutamic thioacid (C18‐thio‐Glu). According to in‐situ grazing incidence Xray diffraction measurements on the water surface, (R,S)‐C18‐TE‐Lys, (R,S)‐C18‐TE‐Glu, and (R,S)‐C18‐Glu‐NCA amphiphiles self‐assembled into ordered racemic 2D crystallites. Oligopeptides 2–12 units long were obtained at the air–aqueous solution interface after injection of appropriate catalysts into the water subphase. The experimental relative abundance of oligopeptides with homochiral sequence generated from (R,S)‐C18‐TE‐Lys and (R,S)‐C18‐TE‐Glu, as determined by mass spectrometry on enantioselectively deuterium‐labeled samples, was found to be significantly larger than that obtained from (R,S) C18‐thio‐Glu which polymerizes randomly. An efficient chiral amplification was obtained in the polymerization of non‐racemic mixtures of C18‐Glu‐NCA since the monomer molecules in the racemic 2D crystallites are oriented such that the reaction occurs between heterochiral molecules related by glide symmetry to yield heterochiral oligopeptides whereas the enantiomer in excess, in the enantiomorphous crystallites, yield oligopeptides of a single handedness.
Spontaneously Organizing Metal Connectors as Supramolecular Structure Directors of Two‐ and Three‐Dimensional Organometallic Assemblies
Authors: Eckhardt Rolf , Hanika‐Heidl Hilka , Fischer R. Dieter 
Published: April 2003

AbstractThe supramolecular interplay of Me3Sn+ and [M(CN)2n]n− ions (n=3 and 4) with either 4,4′‐bipyridine (bpy), trans‐bis(4‐pyridyl)ethene (bpe) or 4cyanopyridine (cpy) in the presence of H2O has been investigated for the first time. Crystal structures of the six novel assemblies: [(Me3Sn)4MoIV(CN)8⋅2 H2O⋅bpy] (8) and [(Me3Sn)4MoIV(CN)8⋅2 H2O⋅bpe] (8 a; isostructural), [(Me3Sn)3FeIII(CN)6⋅4 H2O⋅bpy] (9), [(Me3Sn)3CoIII(CN)6⋅3 H2O⋅3/2 bpy] (10), [(Me3Sn)4FeII(CN)6⋅H2O⋅3/2 bpy] (11), and [(Me3Sn)4RuII(CN)6⋅2 H2O⋅3/2 cpy] (12) are presented. H2O molecules are usually coordinated to tin atoms and involved in two significant OH⋅⋅⋅N hydrogen bonds, wherein the nitrogen atoms belong either to bpy (bpe, cpy) molecules or to Mcoordinated cyanide ligands. Extended supramolecular assemblies such as ‐CN→Sn(Me3)←O(H⋅⋅⋅)H⋅⋅N(L)N⋅⋅HO(H⋅⋅⋅)→Sn(Me3)←NC‐ (L=bpy, bpe or cpy) function as efficient metal connectors (or spacers) in the structures of all six compounds. Only in the three‐dimensional framework of 11, one third of all bpy molecules is involved in coordinative N→Sn bonds. The supramolecular architecture of 9 involves virtually non‐anchored (to cyanide N atoms), Me3Sn+ units with a strictly planar SnC3 skeleton, and two zeolitic H2O molecules. Pyrazine (pyz) is surprisingly reluctant to afford assemblies similar to 8–12, however, the genuine host–guest systems [(Me3Sn)4Mo(CN)8⋅0.5pyz] and [(Me3Sn)4Mo(CN)8⋅pym] (pym=pyrimidine) could be isolated and also structurally characterized.
Formation, Preservation, and Cleavage of the Disulfide Bond by Vanadium
Authors: Wang Dongren , Behrens Axel , Farahbakhsh Mahin , Gätjens Jessica , Rehder Dieter 
Published: April 2003

AbstractReaction of the disulfide {HpicanS}2 (HpicanS is the carboxamide based on picolinate (pic) and o‐mercaptoaniline (anS); the {} brackets are used to denote disulfides) with [VOCl2(thf)2] leads to reductive scission of the disulfide bond and formation of the mixed‐valence (VIV/VV) complex anion [(OVpicanS)2μ‐O]− (1), with the dianionic ligand coordinating through the pyridine‐N atom, the deprotonated amide‐N atom, and thiophenolate‐S atom. Reductive cleavage of the SS bond is also observed as [VCl2(tmeda)2] (tmeda=tetramethylethylenediamine) is treated with the disulfides {HsalanS}2 or {HvananS}2 (HsalanS and HvananS are the Schiff bases formed between o‐mercaptoaniline and salicylaldehyde (Hsal) or vanillin (Hvan), respectively), yielding the VIII complexes [VCl(tmeda)(salanS)] (2 a), or [VCl(tmeda)(vananS)] (2 b). The disulfide bond remains intact in the aerial reaction between {HsalanS}2 and [VCl3(thf)3] to yield the VV complex [VOCl{salanS}2] (3), where (salanS)2− coordinates through the two phenolate and one of the imine functions. The SS bond is also preserved as [VO(van)2] or [VO(nap)2] (Hnap=2‐hydroxynaphthalene‐1‐carbaldehyde) is treated with bis(2‐aminophenyl)disulfide, {anS}2, a reaction which is accompanied by condensation of the aldehyde and the diamine, and complexation of the resulting bis(Schiff bases) {HvananS}2 or {HnapanS}2 to form the complexes [VO{vananS}2] (4 a) or [VO{napanS}2] (4 b). In 4 a and 4 b, the phenolate and imine functions, and presumably also one of the disulfide‐S atoms, coordinate to VIV. 2Mercaptophenyl‐2′‐pyridinecarboxamide (H2picanS) retains its identity in the presence of VIII; reaction between [VCl3(thf)3] and H2picanS yields [V{picanS}2]− (5). The dithiophenolate 2,6‐bis(mercaptophenylthio)dimethylpyridine (6 a) is oxidized, mediated by VO2+, to the bis(disulfide) octathiadiaza‐cyclo‐hexaeicosane 6 b. The relevance of these reactions for the speciation of vanadium under physiological conditions is addressed. [HNEt3]‐1⋅0.5 NEt3, 3⋅3 CH2Cl2, {HsalanS}2, [HNEt3]‐5, and 6 b⋅4 THF have been characterized by Xray diffraction analysis.
Transannular Reactions of Two Parallel 1,3‐Butadiynes: Syntheses, Structures, and Reactions of 1Azacyclotetradeca‐3,5,10,12‐tetrayne Derivatives
Authors: Schmidt Erik M. , Gleiter Rolf , Rominger Frank 
Published: April 2003

AbstractThe synthesis of 1alkyl and 1aryl‐1‐azacyclotetradeca‐3,5,10,12‐tetraynes was achieved in a stepwise approach. The key intermediate was 1,13‐dibromotrideca‐2,4,9,11‐tetrayne (18). Reaction with methyl‐ (19 a), ethyl‐ (19 b), isopropyl‐ (19 c), n‐butyl‐ (19 d), and tert‐butylamine (19 e) as well as aniline (19 f) and p‐methoxyaniline (19 g) gave the corresponding 14‐membered tetraynes 20 a–20 g. The ring inversion process of 20 b was studied by variable temperature 1H NMR spectroscopy. From these measurements a value of 10.6 kcal mol−1 was calculated for ΔG≠. Xray investigations on single crystals of 20 b, 20 c, and 20 f revealed the axial position for the substituent at each nitrogen atom. For 20 b we encountered the chair conformation, for 20 c both chair and boat conformations, and for 20 f the boat conformation in the solid state. The reaction of 20 c with concentrated HCl in ethanol yielded 2,10‐dichloro‐6‐isopropyl‐6‐azatricyclo[9.3.0.04,8]tetradeca‐1(11),2,4(8),9‐tetraene (25 c). Compound 25 c was oxidized by 2,3‐dichloro‐5,6‐dicyano‐1,4‐benzoquinone (DDQ) to 27 c. The structure of the latter was confirmed by Xray investigations. The reaction of 20 c in aqueous HCl lead to the formation of 10‐chloro‐2‐isopropyl‐1,3,4,6,7,8‐hexahydro‐2H‐benzo[g]isoquinolin‐9‐one (37 c). The structure of 37 c was verified by Xray studies on single crystals.
A Versatile Approach Towards Regioselective Platinated DNA Sequences
Authors: Heetebrij Robert J. , de Kort Martin , Meeuwenoord Nico J. , den Dulk Hans , van der Marel Gijs A. , van Boom Jacques H. , Reedijk Jan 
Published: April 2003

AbstractUndesired N7 platination of 2′‐deoxyguanosine residues at predetermined sites in an oligodeoxynucleotide (ODN) sequence is prevented by applying the sterically demanding diphenylcarbamoyl (DPC) as an O6‐protecting group. The presence of a base‐labile oxalyl linker between the immobilized 3′‐nucleotide and controlled pore glass (CPG) allows cleavage of the protected ODN from the support and leaves DPC protection unaffected. This method provides an ODN with specifically blocked guanine‐N7 sites for platination. In the hexanucleotides prepared in this study, 5′‐GGBGGT‐3′(for B=T, C and A), a platinum GG adduct is introduced at G4,G5. These site‐specific platinated hexamers were isolated in a yield of 65 %, and were fully characterized by using reversed‐phase HPLC (high performance liquid chromotography), LCMS (liquid chromatography‐mass spectrometry), MALDI‐TOF MS (matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry), PAGE (polyacrylamide gel electrophoresis) and Maxam–Gilbert sequencing analysis.