The preparation of carrier-free102Rh and102m Rh

Long-lived rhodium radionuclides were produced by the following reactions:¹⁰³Rh(n, 2n)^102(m)Rh;¹⁰³Rh(γ,xn)¹⁰⁰Rh,¹⁰¹Rh,^102(m)Rh;¹⁰⁴Pd(d, α)^102(m)Rh; Ru(d, n)⁹⁹Rh,^101(m)Rh,^102(m)Rh; and . The average cross-section of the¹⁰³Rh(n, 2n)¹⁰²Rh reaction in a fission neutron spectrum is about 0.75 mb. Irradiation of rhodium in the bremsstrahlung spectrum of 50 MeV electrons yielded a¹⁰²Rh activity of 0.11 μCi/g after 3 days at a power of 2 kW. The thick target yield of the reaction¹⁰⁴Pd(d, α)¹⁰²Rh was 0.002 μCi/μAh for 12 MeV deuterons. The thick target yield of the reaction Ru(d,xn)¹⁰²Rh was 0.05 μCi/μAh for 12 MeV deuterons and 4.8 μCi/μAh for 18 MeV deuterons. The best yield was obtained by deuteron bombardment of ruthenium. The chemical separation of carrier-free Rh radionuclides from deuteron-irradiated ruthenium is described, with a chemical yield better than 90%. The same procedure has also been applied for the isolation of¹⁰⁵Rh from neutron-irradiated ruthenium. γ-Ray spectra of⁹⁹Rh,^101(m)Rh and^102(m)Rh from deuteron-irradiated ruthenium and of¹⁰⁵Rh from neutron-irradiated ruthenium, taken with a Ge(Li) detector, are shown; a number of γ-rays, not reported in the literature, were observed. The γ-ray energies were determined with a precision of ca. 0.3–0.4 keV.     

Cross sections of isomeric ratios of /α, αn/ and /α, 2p3n/ reactions on103Rh

Excitation functions and isomeric ratios for¹⁰²Rh, from the -induced reactions on¹⁰³Rh, have been measured between 15 and 89 MeV. The results show characteristic features of the pre-equilibrium process. The excitation functions were determined by the stacked foil method.     

Measurement of103mRh produced by the103Rh/γ, γ′ /103mRh reaction with liquid scintillation counting

A liquid scintillation counting technique was applied to measure the isotope^103mRh /half life = 56.12 min/ which is difficult to detect because its -ray is of low energy and low emission probability. Tris-/2,4-pentanedionato/ rhodium /III/ /Rh/ acac/₃/ was irradiated with bremsstrahlung of accelerated 3.2 MeV electrons by LINAC. The method has given a reliable calibration curve for the determination of^103mRh radioactivity below Rh/acac/₃ concentrations of 2 mM. The integrated cross section of¹⁰³Rh/,/^103mRh determined by this method was found to be 6.8±3.4 b MeV at 3.2 MeV.     

103Rh-NMR-spektroskopischer Nachweis der gemischten Nonahalogenodirhodate(III), [Rh2ClnBr9–n]3−, n = 0–9

¹⁰³Rh NMR Spectroscopic Evidence of Mixed Nonahalogenodirhodates(III), [Rh₂Cl_nBr_9–n]^3?, n = 0–9 On heating a mixture of the tetrabutylammonium salts (TBA)₃[Rh₂Cl₉] and (TBA)₃[Rh₂Br₉] at 60°C in propylenecarbonate the complete system of the mixed nonahalogenodirhodates(III) [Rh₂Cl_nBr_9–n]^3?, n = 0–9 is formed. In the ¹⁰³Rh nmr spectra 40 different species have been detected, 16 with two equivalent ¹⁰³Rh atoms each resulting in one singlet and 24 with inequivalent ¹⁰³Rh atoms each pair giving two resonances. The signals of the geometric isomeres are not resolved. All 64 expected resonances are really observed. By additional measuring of the ¹⁰³Rh nmr spectra of the fractions n = 0–4 separable by ion exchange chromatography on DEAE cellulose, and utilizing characteristic increments of chemical shifts the complete and unambiguous assignment of all signals is achieved.     

14N, 17O, 103Rh NMR Studies of Rh(III) State in Diluted Nitric Acid Solutions

The state of rhodium(III) in nitric acid solutions diluted with 3M HNO₃ or water was studied by ¹⁴N, ¹⁷O, and ¹⁰³Rh NMR methods. The ¹⁰³Rh NMR chemical shifts significantly depend on the ionic background of the solution. Concentrated nitric acid solutions (c _Rh = 0.5–1 mol/l) diluted 100 to 200 times retain the polynuclear Rh(III) forms with double (-NO₃, -OH) bridges. The predominant form in the diluted solutions is a dimer.     

<Superscript>103</Superscript>Ru/<Superscript>103m</Superscript>Rh generator

^103mRh is a very promising radionuclide for Auger electron therapy due to its very low photon/electron ratio. The goal of the present work was the elaboration a method for production of large quantities of ^103mRh for generator system. It was found that the combination of solvent extraction with evaporation of ¹⁰³RuO₄ followed by decomposition of H₅IO₆ makes it possible to produce ^103mRh of high radionuclidic and chemical purity.     

Hyperfine structure measurements of103Rh

Hyperfine structure has been measured in 28 states of¹⁰³Rh below 34,000 cm^?1. The magnetic dipole interactionA constants in the metastable states 4d ⁸ 5s ⁴ P _5/2,3/2,² P _3/2,1/2,² D _5/2,3/2,² G _9/2,7/2 and 4d ⁷ 5s ^{2 4} F _{9/2,7/2,5/2,3/2} have been determined using the laser radio-frequency double-resonance method and in the states 4d ⁸ 5p ⁴ D _{7/2,5/2,3/2,1/2},⁴ G _7/2,5/2,⁴ F _{9/2,7/2,5/2,3/2},² G _9/2,7/2,² F _7/2,5/2 and² D _5/2,3/2 by high-resolution laser spectroscopy.     

Probing the stereo‐electronic properties of cationic rhodium complexes bearing chiral diphosphine ligands by 103Rh NMR

¹⁰³Rh NMR represents a powerful tool to assess the global electronic and steric contribution of diphosphine ligands on [Rh(COD)(diphosphine)]⁺ complexes. In the case of DIOP, BINAP and MeDUPHOS, this approach proved to be more informative than classical CO‐stretching frequency measurements. After validation, this method has been extended to a set of seven diphosphines. ¹⁰³Rh NMR measurements on [Rh(COD)(diphosphine)]PF₆ lead to the following order of donor properties: dppe > MeBPE > MeDUPHOS > dppb > DIOP > BINAP > Tol‐BINAP. This trend has been validated by DFT in the case of DIOP, BINAP and MeDUPHOS. In conjunction, ³¹P NMR chemical shift has been shown to reflect the ring constraints of the Rh‐diphosphine scaffold. This contribution is a step towards a mechanistic investigation of the catalytic hydrogenation of unsaturated substrates by ¹⁰³Rh NMR and DFT. Copyright © 2010 John Wiley & Sons, Ltd.     

Isobaric yields and radiochemistry of near-target residues in the interaction of 12C and 16O with 103Rh at an incident energy of 400 MeV

Production cross sections of residues with mass near to that of the target were measured in ¹²C and ¹⁶O induced reactions on Rh at an incident energy of 400 MeV. An ion-exchange method has been developed for the separation of Rh, Pd and Ag nuclides from all other produced activities. Rh and Ag nuclides were separated from elements such as Pd, Ru, and Tc, amongst others, on an AG1-X8 anion exchange resin in 6M HCl. The Ag nuclides were then removed from the effluent using a precipitation technique so that only Rh remained in the final solution. The Pd was afterwards separated from Ru and Tc by eluting it from the resin with 5% ammonia solution. This procedure made it possible to accurately measure production cross sections for ^103mRh and ¹⁰³Pd. Cross sections for the production of various other observed residues are also presented. The results are consistent with an enhanced isobaric yield in the near-target mass region. The radiochemical separation technique is also suitable for the routine production of Pd and Rh nuclides, e.g., ¹⁰³Pd and ^101mRh, in proton-induced reactions on Rh targets     

Parameterization of the hyperfine structure of metastable states in103Rh

The experimental data on the hyperfine structure of metastable even parity states in¹⁰³Rh have been analysed by means of an effective-operator formalism. The effective radial parameters of the magnetic dipole interaction are determined, using wave functions in intermediate coupling. The comparison with relativistic calculations gives an estimate of the effects due to configuration interaction.     

Observation of solid-state 103Rh NMR by cross-polarization

Using 103Rh[1H] cross-polarization (CP) methods, we have obtained solid-state 103Rh NMR spectra for diamagnetic Rh(III) compounds. The isotropic chemical shift and chemical shift anisotropy (CSA) are reported for a crystalline form of the dihydroxy-bridged Rh(III) dimer and for a salt of the oxo-centered acetate-bridged Rh(III) trimer, from analysis of conventional CP/MAS spectra. Comparison of the CP kinetics of the dimer with new crystal structure data suggests a strategy for predicting 103Rh CP/MAS properties in solids.     

The production of 103Pd and 109Cd from a proton irradiated tandem natAg/natAg targets

This paper describes a new method for the production of ¹⁰³Pd and ¹⁰⁹Cd using the 66 MeV proton beam of iThemba LABS on a tandem natural silver target (Ag/Ag). The radiochemical separation of the Pd radionuclides (¹⁰³Pd, ¹⁰⁰Pd) from the bulk ^natAg was done using a Chelex-100 chelating resin column. The recovery of ¹⁰³Pd from the irradiated ^natAg target was found to be >98 % without any Ag or Rh impurities detected. The radiochemical separation of ¹⁰⁹Cd from the bulk ^natAg target was done by the precipitation of Ag ions by Cu followed by the separation of ¹⁰⁹Cd, traces of Ag, Cu²⁺ and Rh using a AG1-X10 anion exchange resin column. The recovery yield of ¹⁰⁹Cd was >99 % without any Ag or Rh impurities detected.     

Development of [103Pd]-2-acetylpyridine 4 N-methyl thiosemicarbazone complex for targeted therapy

Summary Due to interesting biological properties of palladium-thiosemicarbazono complexes, production of a ¹⁰³Pd-labeled anti-cancer complex, i.e., [¹⁰³Pd]-2-acetylpyridine ⁴N-methylthiosemicarbazone ([¹⁰³Pd]-APMTS) was developed. Palladium-103 (T_1/2 = 16.96 d) produced via the ¹⁰³Rh(p,n)¹⁰³Pd nuclear reaction using natural rhodium target, was separated from the irradiated target material. Proton energy was 18 MeV with 200 mA irradiation for 15 hours (final activity 700 mCi of ¹⁰³Pd²⁺, RCY>95%, radionuclidic purity>99%). The final activity was eluted in form of Pd(NH₃)₂Cl₂ in order to react with 2-acetylpyridine-⁴N-methylthiosemicarbazone to yield [¹⁰³Pd]-APMTS. Chemical purity of the final product was confirmed to be within the accepted limits by polarography. [¹⁰³Pd]-APMTS was prepared with a radiochemical yield of more than 80% at room temperature after 3 hours. The labeling reaction was optimized for time, temperature and radioactivity and ligand ratio. A mixture of APMTS and Pd activity in ethanol was heated at 90 °C for 3 hours followed by reverse phase SPE purification using C₁₈ plus Sep-Pak. Radiochemical purity of more than 99% using RTLC and specific activity of about 12500 Ci/mol was obtained. The stability of the tracer was checked in the final product and the presence of human serum at 37 °C up to 3 hours. The partition coefficient of the final complex was determined by octanol : saline buffer distribution.     

Cl/Cl isotope effects in Rh NMR of [RhCln(H2O)6−n] complex anions in hydrochloric acid solution as a unique ‘NMR finger-print’ for unambiguous speciation

A detailed analysis of the ³⁵Cl/³⁷Cl isotope effects observed in the 19.11 MHz ¹⁰³Rh NMR resonances of [RhCl_n(H₂O)_6−n]³⁻ⁿ complexes (n = 3–6) in acidic solution at 292.1 K, shows that the ‘fine structure’ of each ¹⁰³Rh resonance can be understood in terms of the unique isotopologue and in certain instances the isotopomer distribution in each complex. These ³⁵Cl/³⁷Cl isotope effects in the ¹⁰³Rh NMR resonance of the [Rh^35/37Cl₆]³⁻ species manifest only as a result of the statistically expected ³⁵Cl/³⁷Cl isotopologues, whereas for the aquated species such as for example [Rh^35/37Cl₅(H₂O)]²⁻, cis-[Rh^35/37Cl₄(H₂O)₂]⁻ as well as the mer-[Rh^35/37Cl₃(H₂O)₃] complexes, additional fine-structure due to the various possible isotopomers within each class of isotopologues, is visible. Of interest is the possibility of the direct identification of stereoisomers cis-[RhCl₄(H₂O)₂]⁻, trans-[RhCl₄(H₂O)₂]⁻, fac-[RhCl₃(H₂O)₃] and mer-[RhCl₃(H₂O)₃] based on the ¹⁰³Rh NMR line shape, other than on the basis of their very similar δ(¹⁰³Rh) chemical shift. The ¹⁰³Rh NMR resonance structure thus serves as a novel and unique ‘NMR-fingerprint’ leading to the unambiguous assignment of [RhCl_n(H₂O)_6−n]³⁻ⁿ complexes (n = 3–6), without reliance on accurate δ(¹⁰³Rh) chemical shifts.     

Separation of 103Pd from Rh and Ag by the macroporous AG MP-1 anion exchange resin in Ag targets

A radiochemical process is reported for the production of ¹⁰³Pd from Ag targets for use in brachytherapy. The procedure, which is based on anion exchange chromatography, separates Pd from a large amount of target material (16 g Ag), as well as Rh radioisotopes (mainly ¹⁰¹Rh and ¹⁰⁰Rh), which are produced from decays of their Pd parents. The AG MP-1 anion exchange resin was used for the process. For elution of Rh and Ag, 3M nitric acid solution was used and 5% ammonia solution was used to elute the Pd. The average recovery of Pd was 97.4%. An elution curve for Pd was set up and a panel for the radiochemistry designed and installed in a hot cell.     

103Rh and 33s hyperfine interactions in tetraphenylarsonium-bis ( maleonitriledithiolato ) rhodate (II), (Ph4As)2[Rh(mnt)2]: a single-crystal EPR-ENDOR study

The complete ¹⁰³Rh and ³³S hyperfine coupling tensors of the 4d⁷ low-spin chelate tetraphenylarsoniumbis (maleonitriledithiolato)rhodate(II) doped into the corresponding nickel complex salt have been measured by EPR-ENDOR spectroscopy. Both interactions are small and confirm that the unpaired electron is in an “out-of-plane” π-type molecular orbital. The Rh-S bonds are less covalent than bonds in the isoelectronic Pd(III) complex.     

The first (<Superscript>31</Superscript>P, <Superscript>17</Superscript>O,and <Superscript>103</Superscript>Rh) NMR observation complex formation of rhodium(III) with phosphoric acid

³¹P, ¹⁷O, and ¹⁰³Rh NMR spectroscopy shows that rhodium(III) reacts with phosphoric acid to generate polynuclear aquaphosphate complexes in which phosphate ions mostly have a bridging function. Assignment of ¹⁰³Rh NMR signals in dominant rhodium complexes is suggested.     

Darstellung und Schwingungsspektren von Chloro-Bromo-Dirhodaten(III), [Rh2ClnBr9−n]3−, n = 0–9

Preparation and Vibrational Spectra of Nonahalogenodirhodates(III), [Rh₂Cl_nBr_9-n]^3?, n = 0–9 The pure nonahalogenodirhodates(III), A₃[Rh₂Cl_nBr_9-n], A = K, Cs, (TBA); n = 0–4, 9, have been prepared. They are formed from the monomer chlorobromorhodates(III), [RhCl_nBr_6-n]^3?, n = 0–6, which are bridged to confacial bioctahedral complexes by ligand abstraction in less polar organic solvents. From the mixtures the complexions are separated by ion exchange chromatography on DEAE-cellulose. The solid, air-stable, air-stable, K-, Cs- and (TBA)-salts of [Rh₂Cl_nBr_9-n]^3?, n = 0–4, are green, of [Rh₂Cl₉]^3? are brown. The IR and Raman spectra of [Rh₂Br₉]^3? and [Rh₂Cl₉]^3? are assigned according to the point group D_3h. The chlorobromodirhodates exist as mixtures of geometrical and structural isomers, which belong to different point groups. The vibrational spectra exhibit bands in characteristic regions; at high wavenumbers stretching vibrations with terminal ligands v(Rh—Cl_t): 360–320, v(Rh—Br_t): 280–250; in a middle region with bridging ligands v(Rh—Cl_b): 300–270, v(Rh—Br_b): 210–170 cm^?1; the deformation bands are observed at distinct lower frequencies. The terminal ligands are fixed very strong, and the distance between v(Rh—X_t) and v(Rh—X_b) increases with decreasing size of the cations.     

<Superscript>103</Superscript>Rh, <Superscript>17</Superscript>O,and <Superscript>31</Superscript>P NMR study of Rh(III) complex formation in acidic sulfate-phosphate media

Rhodium(III) complex formation with phosphoric acid in strong acidic solutions has been studied by ¹⁰³Rh, ¹⁷O, and ³¹P NMR. Phosphoric acid is mainly coordinated to rhodium as a monodentate terminal HPO₄²⁻ ion, while the coordinated phosphate ion accounts for no more than 7%.     

Electronic structure of (μ2-CO)[(η5-C5H5)Rh(CO)]2 by UV photoelectron spectroscopy and CNDO calculations

The electronic structure of (μ₂-CO)[(η⁵-C₅H₅)Rh(CO)]₂ is discussed on the basis of the gas-phase UV photoelectron spectrum and CNDO quantum-mechanical calculations. The two lower ionization energy bands are assigned to ionizations from two MOs representing

and RhRh bonding interactions, respectively. The results are compared with those previously reported for the

triangular entity in analogous molecules. Evidence for a higher π-acceptor capability of μ₂-CH₂ compared with μ₂-CO is reported.