Substitution reactions of metallic complexes of .beta.,.beta.',.beta.''-triaminotriethylamine. 14. Base hydrolysis, chloride anation, and synthesis of some rhodium(III) complexes of .beta.,.beta.',.beta.''-triaminotriethylamine: evidence for chemically nonequivalent coordination sites in the [Rh(tren)XY]n+ cation

Abstract

The base hydrolysis of [Rh(tren)Cl,]+ generates fi-[Rh(tren)ClOH]+ identical with the photochemical product, while earlier work shows that aquation of [Rh(tren)CI,]+ in acidic solution gives the a isomer. The kinetics of the hydrolysis of [Rh(tren)Cl,]+ and a-and fi-[Rh(tren)ClOH]+ in alkaline solution have been investigated, as have the kinetics of the acid hydrolysis of fi-[Rh(tren)Cl(H20)]2+. The hydrolyses of the dichloro and achlorohydroxo ions (k, and k2) are accelerated by hydroxide, whereas the rate of hydrolysis of the fi isomer (k,) is only marginally affected by the presence of hydroxide. In acidic solution in the presence of excess CI-, [Rh(tren)(OH2)2]3+ undergoes two distinct chloride anation steps (k, and k5). Kinetic data were collected on the following reactions: [Rh(tren)Cl,]' P-[Rh(tren)ClOH]-0 Hk OH--1 k, CT [ Rh(tren)Cl(OH)] + -0' ;;t [ Rh (tr en)(OH) ,I + [Rh(tren)(OH,),] 3+-?-B-[Rh(t~en)C10H,1 4 [Rh(tren)Cl,]' k k c1-c1-Reaction products were characterized in solution by electronic spectra and chemical analyses. The stereospecific substitutions and differences in substitution rates, for both the hydrolyses and anations, are explained in terms of different environments of the two nonamine coordination sites in [Rh(tren)XY]"+ complexes. The base hydrolysis and chloride anation data have been used in the synthesis of some new Rh(II1)-tren complexes. These have been isolated as solids and characterized by elemental analysis and visible and ultraviolet spectra. IntroductionIn recent studies,2J the thermal and photochemical reactions of [Rh(tren)C12]+ (tren = P,fl,P"-triaminotriethylamine) were

Characteristic Spin−Orbit Induced 1H(CH2) Chemical Shifts upon Deprotonation of Group 9 Polyamine Aqua and Alcohol Complexes

“…The rhodium-tren-diaqua complex 1[Rh(H 2 O) 2 ] 3+ was prepared from the corresponding chloro complex [Rh(tren)Cl 2 ]Cl . Since reanation was observed for 1[Rh(H 2 O) 2 ] 3+ in chloride containing media, a quantitative removal of Cl − from the reaction mixture was necessary. The aquation reaction was, therefore, performed at elevated temperature using Ag(CF 3 SO 3 ) for a quantitative precipitation of chloride and [Rh(tren)(OH 2 ) 2 ] 3+ ( 1[Rh(H 2 O) 2 ] 3+ ) was then obtained as a very hygroscopic triflate salt.…”

“…That is, we provide detailed 1 H NMR titration experiments for [Rh III (tren)(OH 2 ) 2 ] 3+ ( 1[Rh(H 2 O) 2 ] 3+ , tren = tris(2-aminoethyl)-amine) in comparison with its Co analogue [Co(tren)(OH 2 ) 2 ] 3+ ( 1[Co(H 2 O) 2 ] 3+ ) , which forms one single stereoisomer with a rather rigid structure, making it suitable for our purposes. Surprisingly enough, we find the nonintuitive deshielding deprotonation shifts of 1[Rh(H 2 O) 2 ] 3+ to be substantially smaller than those for 1[Co(H 2 O) 2 ] 3+ or even absent.…”

Discrete RhIII/FeIIand RhIII/FeII/CoIIICyanide-Bridged Mixed Valence Compounds

“…The values of these constants at different temperatures ( k iso = 3.5 × 10 −6 , 1.1 × 10 −5 , and 3.2 × 10 −5 s −1 at 60, 70, and 80 °C respectively) produced values of Δ H ⧧ = 110 ± 1 kJ/mol and Δ S ⧧ = −36 ± 3 J K/mol according to Eyring plots. These indicate a much less dissociative activation character than those determined for other base-hydrolysis reactions on Rh III -amine complexes, , as well as for the analogous isomerization of the {Co III L 15 } systems. The suitable fit of the Rh III ion within the cis-VI -L 15 cavity is probably responsible for this decrease in the dissociative activation nature of the process.…”