Ligand Fluorination to Optimize Preferential Oxidation (PROX) of Carbon Monoxide by Water-Soluble Rhodium Porphyrins

Catalytic, low temperature preferential oxidation (PROX) of carbon monoxide by aqueous [5,10,15,20-tetrakis(4-sulfonatophenyl)-2,3,7,8,12,13,17,18-octafluoroporphyrinato]rhodium(III) tetrasodium salt, (1[Rh(III)]) and [5,10,15,20-tetrakis(3-sulfonato-2,6-difluorophenyl)-2,3,7,8,12,13,17,18-octafluoroporphyrinato]rhodium(III) tetrasodium salt, (2[Rh(III)]) is reported. The PROX reaction occurs at ambient temperature in buffered (4 ≤ pH ≤ 13) aqueous solutions. Fluorination on the porphyrin periphery is shown to increase the CO PROX reaction rate, shift the metal centered redox potentials, and acidify ligated water molecules. Most importantly, β-fluorination increases the acidity of the rhodium hydride complex (pK(a) = 2.2 ± 0.2 for 2[Rh-D]); the dramatically increased acidity of the Rh(III) hydride complex precludes proton reduction and hydrogen activation near neutral pH, thereby permitting oxidation of CO to be unaffected by the presence of H(2). This new fluorinated water-soluble rhodium porphyrin-based homogenous catalyst system permits preferential oxidation of carbon monoxide in hydrogen gas streams at 308 °K using dioxygen or a sacrificial electron acceptor (indigo carmine) as the terminal oxidant.     

Reversible electrochemical conversion between Rh(II) and Rh(III) states in Rh porphyrin adsorbed on carbon black

We have clearly demonstrated reversible cyclic voltammograms for the redox reaction between the Rh(II) and Rh(III) states in rhodium octaethylporphyrin [Rh(OEP)] adsorbed on carbon black in an acidic aqueous solution. The emergence of the reversible wave can be ascribed to the suppression of the undesirable reactions between two molecules of [Rh(II)(OEP)] because of its strong interaction with the carbon black. The generated [Rh(II)(OEP)] exhibits a potent catalytic O(2) reduction activity.     

Unprecedented formation of a rhodium cluster triggered by rhodium-fastened N-confused gable porphyrin

Thermal reaction of N-confused porphyrin (NCP) with [RhCl(CO)2]2 caused unprecedented formation of tetranuclear rhodium complex Rh4(NCP)2(CO)4 having a gable-porphyrin-type structure, where two porphyrin pi systems were electronically connected by the rhodium cluster.     

Reactivity and equilibrium thermodynamic studies of rhodium tetrakis(3,5-disulfonatomesityl)porphyrin species with H2, CO, and olefins in water

Aqueous (D2O) solutions of tetrakis(3,5-disulfonatomesityl)porphyrin rhodium(III) aquo/hydroxo complexes ([(TMPS)Rh(III)(D2O)2]-7 (1), [(TMPS)Rh(III)(OD)(D2O)]-8 (2), and [(TMPS)Rh(III)(OD)2]-9 (3)) react with hydrogen (D2) to form an equilibrium distribution with a rhodium hydride ([(TMPS)Rh-D(D2O)]-8 (4)) and a rhodium(I) complex ([(TMPS)Rh(I)(D2O)]-9 (5)). Equilibrium constants (298 K) are measured that define the distribution for all five of these (TMPS)Rh species in this system as a function of the dihydrogen (D2) and hydrogen ion (D+) concentrations. The hydride complex [(TMPS)Rh-D(D2O)]-8 is a weak acid in D2O (Ka(298 K) = 4.3 x 10(-8)). Steric demands of the TMPS porphyrin ligand prohibit formation of a Rh(II)-Rh(II)-bonded complex, related rhodium(I)-rhodium(III) adducts, and intermolecular association of alkyl complexes which are prominent features of the rhodium tetra(p-sulfonatophenyl)porphyrin ((TSPP)Rh) system. The rhodium(II) complex ([(TMPS)Rh(II)(D2O)]-8) reacts with water to form hydride and hydroxide complexes and is not observed in D2O. The (TMPS)Rh-OD and (TMPS)Rh-D bond dissociation free energies (BDFE) are virtually equal and have a value of approximately 60 kcal mol(-1). Reactions of [(TMPS)Rh-D(D2O)]-8 in water with CO and olefins produce rhodium formyl and alkyl complexes which have equilibrium thermodynamic values comparable to the values for the corresponding substrate reactions of [(TSPP)Rh-D(D2O)]-4.     

Catalytic reactions on neutral Rh oxide clusters more efficient than on neutral Rh clusters

Gas phase catalytic reactions involving the reduction of N(2)O and oxidation of CO were observed at the molecular level on isolated neutral rhodium clusters, Rh(n) (n = 10-28), using mass spectrometry. Sequential oxygen transfer reactions, Rh(n)O(m-1) + N(2)O → Rh(n)O(m) + N(2) (m = 1, 2, 3,…), were monitored and the rate constant for each reaction step was determined as a function of the cluster size. Oxygen extraction reactions by a CO molecule, Rh(n)O(m) + CO → Rh(n)O(m-1) + CO(2) (m = 1, 2, 3,…), were also observed when a small amount of CO was mixed with the reactant N(2)O gas. The rate constants of the oxygen extraction reactions by CO for m ≥ 4 were found to be two or three orders of magnitude higher than the rate constants for m ≤ 3, which indicates that the catalytic reaction proceeds more efficiently when the reaction cycles turn over around Rh(n)O(m) (m ≥ 4) than around bare Rh(n). Rhodium clusters operate as more efficient catalysts when they are oxidized than non- or less-oxidized rhodium clusters, which is consistent with theoretical and experimental studies on the catalytic CO oxidation reaction on a rhodium surface.     

New catalysts for borohydride electro-oxidation using Rh porphyrins

New borohydride electro-oxidation catalysts for direct borohydride fuel cells were developed. These catalysts use rhodium porphyrins on carbon black. The overpotential for borohydride electro-oxidation is much lower than that for a gold electrode. Hydrogen generation by the hydrolysis of borohydride is suppressed much more with rhodium porphyrin catalysts than with a platinum catalyst. Rh porphyrins oxidized borohydride below 0 V vs. a reversible hydrogen electrode. The measurement of hydrogen generation after electrolysis indicates that the apparent number of electrons transferred in rhodium octaethylporphyrin exceeds 7.     

Selection and amplification of mixed-metal porphyrin cages from dynamic combinatorial libraries

Mixed metallo-porphyrin cages were selected and amplified from dynamic combinatorial libraries (DCLs) by using appropriate templates. The cages are composed of two bisphosphine substituted zinc(II) porphyrins as ligand donors and two rhodium(III) or ruthenium(II) porphyrins as ligand acceptors, and are connected through metal-phosphorus coordination. Ru and Rh porphyrins that display a large structural diversity were employed. The templating was achieved by using 4,4'-bpy, 3,3'-dimethyl-4,4'-bipyridine and benzo[lmn]-3,8-phenanthroline, and acts through zinc-nitrogen coordination. The absolute amount of amplification from the DCLs is strongly dependent on the combination of the Ru/Rh porphyrin and the template; cages with sterically demanding porphyrins can only form with smaller templates. In the case of tert-butyl-substituted TPP (TPP=tetraphenylporphyrin), cages are not formed at all. The formation of the cages is usually complete within 24 h at an ambient temperature; in the case of the cage containing Rh(III)OEP (OEP=octaethylporphyrin) and bpy, the pseudo-first-order rate constant of cage formation was determined to be 2.1+/-0.1x10(-4) s(-1) (CDCl(3), 25 degrees C). Alternatively, heating the mixtures to 65 degrees C and cooling to room temperature yields the cages within minutes. The (1)H NMR chemical shifts of several characteristic protons show large differences upon changing the identity of the Ru/Rh porphyrin and the central metal; this is most likely to arise from variations in the geometry of the cages. The X-ray crystal structure of a cage, which contains Rh(III)OEP as a porphyrin acceptor and bpy as template, demonstrates that the cages can adopt severely distorted conformations to accommodate the relatively short templates. An extension to mixed DCLs showed that only limited selectivity is displayed by the various templates. Formation of mixed cages that contain two different rhodium porphyrins prevents effective selection, although the kinetic lability of the systems allows for some amplification. This lability, however, also prevents isolation of the individual cages. Removal of the template leads to re-equilibration, thus the templates act as scaffolds to keep the structures intact.     

Visible light promoted hydroxylation of a Si-C(sp3) bond catalyzed by rhodium porphyrins in water

Catalytic activation of an unstrained, unactivated Si-C(sp(3)) bond in water to form methane and silanol by electrophilic rhodium(III) porphyrin [(por)Rh(III)] in acidic aqueous solutions under visible light (λ ≥ 420 nm) has been developed. Activation of the Si-C(sp(3)) bond occurs through direct Si-C bond cleavage, with methyl group transfer to rhodium to give a porphyrin rhodium methyl complex. Photolysis of (por)Rh-CH(3) in water yields methyl radical and (por)Rh(II). Subsequently, (por)Rh(II) reacts with water rapidly to produce (por)Rh-H and (por)Rh-OH. (por)Rh-OH is then protonated to regenerate (por)Rh(III)-OH(2), and (por)Rh-H undergoes hydrogen atom abstraction by methyl radical to form the observed methane.     

An infrared study of the oxidation of carbon monoxide over supported rhodium catalysts

The reaction of carbon monoxide and oxygen over supported rhodium films has been studied using infrared spectroscopy. The focus of the work was the reactivity of the various CO/Rh/X (X = Al₂O₃, SiO₂, TiO₂) surface states for supported catalysts having high and low Rh loading. Under the reaction conditions the “linear CO” species was the most stable toward oxidation, but this could have been a result of an oxidized Rh surface. A new CO/Rh surface species has been proposed which exhibits an infrared band at 2000 cm⁻¹ for a 0.5% Rh/TiO₂ film. This species is believed to be a bridged carbonyl between Rh¹⁺ and the TiO₂ support.     

Electrocatalytic Oxidation of Glucose by Rhodium Porphyrin-Functionalized MWCNT Electrodes: Application to a Fully Molecular Catalyst-Based Glucose/O(2) Fuel Cell

This paper details the electrochemical investigation of a deuteroporphyrin dimethylester (DPDE) rhodium(III) ((DPDE)Rh(III)) complex, immobilized within a MWCNT/Nafion electrode, and its integration into a molecular catalysis-based glucose fuel cell. The domains of present (DPDE)Rh(I), (DPDE)Rh-H, (DPDE)Rh(II), and (DPDE)Rh(III) were characterized by surface electrochemistry performed at a broad pH range. The Pourbaix diagrams (plots of E(1/2) vs pH) support the stability of (DPDE)Rh(II) at intermediate pH and the predominance of the two-electron redox system (DPDE)Rh(I)/(DPDE)Rh(III) at both low and high pH. This two-electron system is especially involved in the electrocatalytic oxidation of alcohols and was applied to the glucose oxidation. The catalytic oxidation mechanism exhibits an oxidative deactivation coupled with a reductive reactivation mechanism, which has previously been observed for redox enzymes but not yet for a metal-based molecular catalyst. The MWCNT/(DPDE)Rh(III) electrode was finally integrated in a novel design of an alkaline glucose/O(2) fuel cell with a MWCNT/phthalocyanin cobalt(II) (CoPc) electrode for the oxygen reduction reaction. This nonenzymatic molecular catalysis-based glucose fuel cell exhibits a power density of P(max) = 0.182 mW cm(-2) at 0.22 V and an open circuit voltage (OCV) of 0.64 V.     

The RhX n (X = S,Se, Te) Coordination Polyhedra in Crystal Structures

The Voronoi–Dirichlet polyhedra (VDP) and the method of intersecting spheres were applied to crystal-chemical analysis of all known compounds whose structures contain rhodium atoms surrounded by chalcogen atoms. The influence of the rhodium valence state and the nature of the chalcogen on the main features of Rh stereochemistry are discussed. Rhodium atoms exhibit coordination numbers of 6, 5, or 4 with respect to S, Se, or Te atoms; in addition to the bonds with chalcogens, rhodium can form 1 to 4 bonds with metal atoms. The VDP volume for Rh(III), Rh(2.67), and Rh(II) atoms in selenides and tellurides very weakly depends on the valence state, whereas in the case of sulfides, the volume increases rather regularly with a decrease in the metal oxidation number from Rh(III) to Rh(I).     

Coordination chemistry of Rh(III) porphyrins: complexes with hydrazine, disulfide, and diselenide bridging ligands

Rh(III) porphyrin complexes with bridging hydrazine and substituted hydrazine ligands were characterized in solution by (1)H NMR spectroscopy and in the solid state by X-ray diffraction. Addition of further ligand to these species afforded 1:1 complexes in which methylhydrazine and N,N-dimethylhydrazine preferentially bound to the Rh center through the substituted nitrogen atom, as evidenced by (1)H NMR chemical shifts. An alkylated Rh(III) porphyrin was isolated as a decomposition product of the reaction of N,N-dimethylhydrazine with Rh(III) porphyrin in the presence of light and oxygen. Me(2)Se(2) and Me(2)S(2) formed bridging and nonbridging complexes with Rh(III) porphyrin, analogous to that observed with N,N'-dimethylhydrazine.     

Rh(III) porphyrins as building blocks for porphyrin coordination arrays: from dimers to heterometallic undecamers

The coordination chemistry of a Rh(III) porphyrin building block was investigated with a view to the construction of heterometallic arrays of porphyrins. The Rh(III) porphyrin was found to coordinate methanol in the solid state and weakly in CDCl(3) solution. Crystallization afforded five coordinate pi stacked Rh(III) porphyrins. The distribution of products from reaction of Rh(III) porphyrin with DABCO, 4,4'-bipyridine, and 4,4'-bipyrimidine could be displaced toward dimeric species by silica gel column chromatography or recrystallization which served to remove excess ligand. Weak coordination to nitriles was observed, although it was sufficiently strong to organize a dimeric complex of 5,5'-dicyano-2,2'-bipyridine in the solid state. Complexes with 4,4'-bipyrimidine and 5,5'-dicyano-2,2'-bipyridine possess uncoordinated chelating nitrogen atoms. Larger heterometallic porphyrin arrays were assembled using a combination of Sn(IV) and Rh(III) porphyrin coordination chemistry. A Sn(IV) porphyrin acted as a core around which were coordinated two isonicotinate groups, carboxylic acid functionalized porphyrins, or porphyrin trimer dendrons. Rh(III) porphyrins were coordinated to pyridyl groups at the periphery of these entities. In this way an eleven porphyrin array, with four different porphyrin metalation states, was assembled. The diamagnetic nature of both the Rh(III) and Sn(IV) porphyrins, the slow ligand exchange kinetics on the NMR time scale, and tight ligand binding permitted the porphyrin arrays to be analyzed by two-dimensional (1)H NMR techniques.     

State of supported rhodium nanoparticles for methane catalytic partial oxidation (CPO): FT-IR studies

The effect of pretreatments as well as of rhodium precursor and of the support over the morphology of Rh nanoparticles were investigated by Fourier transform infrared (FT-IR) spectroscopy of adsorbed CO. Over a Rh/alumina catalyst, both metallic Rh particles, characterized by IR bands in the range 2070-2060 cm-1 and 1820-1850 cm-1, and highly dispersed rhodium species, characterized by symmetric and asymmetric stretching bands of RhI(CO)2 gem-dicarbonyl species, are present. Their relative amount changes following pretreatments with gaseous mixtures, representative of the catalytic partial oxidation (CPO) reaction process. The Rh metal particle fraction decreases with respect to the Rh highly dispersed fraction in the order CO approximately CO/H2 > CH4/H2O, CH4/O2 > CH4 > H2. The metal particle dimensions decrease in the order CH4/O2 > H2 > CH4/H2O > CO > CO/H2. Grafting from a carbonyl rhodium complex also increases the amount and the dimensions of Rh0 particles at the catalyst surface. Increasing the ratio (extended rhodium metal particles/highly dispersed Rh species) allows a shorter conditioning process. The surface reconstruction phenomena going on during catalytic activity are related to this effect.     

Thermodynamics of rhodium hydride reactions with CO, aldehydes, and olefins in water: organo-rhodium porphyrin bond dissociation free energies

Tetra(p-sulfonato-phenyl) porphyrin rhodium hydride ([(TSPP)Rh-D(D2O)](-4)) (1) reacts in water (D2O) with carbon monoxide, aldehydes, and olefins to produce metallo formyl, alpha-hydroxyalkyl, and alkyl complexes, respectively. The hydride complex (1) functions as a weak acid in D2O and partially dissociates into a rhodium(I) complex ([(TSPP)Rh(I)(D2O)](-5)) and a proton (D+). Fast substrate reactions of 1 in D2O compared to reactions of rhodium porphyrin hydride ((por)Rh-H) in benzene are ascribed to aqueous media promoting formation of ions and supporting ionic reaction pathways. The regioselectivity for addition of 1 to olefins is predominantly anti-Markovnikov in acidic D2O and exclusively anti-Markovnikov in basic D2O. The range of accessible equilibrium thermodynamic measurements for rhodium hydride substrate reactions is substantially increased in water compared to that in organic media through exploiting the hydrogen ion dependence for the equilibrium distribution of species in aqueous media. Thermodynamic measurements are reported for reactions of a rhodium porphyrin hydride in water with each of the substrates, including CO, H2CO, CH3CHO, CH2=CH2, and sets of aldehydes and olefins. Reactions of rhodium porphyrin hydrides with CO and aldehydes have nearly equal free-energy changes in water and benzene, but alkene reactions that form hydrophobic alkyl groups are substantially less favorable in water than in benzene. Bond dissociation free energies in water are derived from thermodynamic results for (TSPP)Rh-organo complexes in aqueous solution for Rh-CDO, Rh-CH(R)OD, and Rh-CH2CH(D)R units and are compared with related values determined in benzene.     

Self-assembly of polyoxotungstate with tetrarhodium-oxo core: synthesis, structure and 183W NMR studies

A sandwich-type rhodium polyoxotungstate with unprecedented tetrarhodium-oxo core Na(12)[(Rh(4)(μ(3)-O)(2)(H(2)O)(2))(H(2)W(9)O(33))(2)]·38H(2)O (1) was obtained by hydrothermal reaction of rhodium(II) acetate and sodium tungstate; crystal structure was determined by X-ray diffractometry and was confirmed by (183)W NMR data; 1 is active in electrocatalytic water oxidation.     

Synthesis and properties of rhodium(III) porphyrin cyclic tetramer and cofacial dimer

Rhodium(III) porphyrin complexes, [Rh(4-PyT(3)P)Cl](4) (1) and [Rh(2-PytB(3)P)Cl](2) (2) (4-PyT(3)P = 5-(4-pyridyl)-10,15,20-tritolylporphyrinato dianion, 2-PytB(3)P = 5-(2-pyridyl)-10,15,20-tri(4-tert-butyl)phenylporphyrinato dianion), were self-assembled and characterized by (1)H nuclear magnetic resonance spectroscopy, infrared spectroscopy, and electron spray ionization-mass spectroscopy methods. The spectroscopic results certified that the rhodium porphyrin complexes 1 and 2 have a cyclic tetrameric structure and a cofacial dimeric structure, respectively. The X-ray structure analysis of 1 confirmed the cyclic structure of the complex. The Soret bands of both oligomers were significantly broadened by excitonic interactions between the porphyrin units, compared to those observed for a corresponding analogue of Rh(TTP)(Py)Cl (TTP = 5,10,15,20-tetratolylporphyrinato dianion, Py = pyridine). Stepwise oxidation of the porphyrin rings in the oligomers was observed by cyclic voltammetry. The oligomers 1 and 2 are very stable in solution, and they slowly undergo reactions with pyridine to give corresponding monomer complexes only at high temperatures (approximately 80 degrees C).     

Cationic carbonyl complexes of rhodium(I) and rhodium(III): syntheses,vibrational spectra,NMR studies,and molecular structures of tetrakis(carbonyl)rhodium(I) heptachlorodialuminate and -gallate, [Rh(CO)4][Al2Cl7] and [Rh(CO)4][Ga2Cl7

Dimeric rhodium(I) bis(carbonyl) chloride, [Rh(CO)(2)(mu-Cl)](2), is found to be a useful and convenient starting material for the syntheses of new cationic carbonyl complexes of both rhodium(I) and rhodium(III). Its reaction with the Lewis acids AlCl(3) or GaCl(3) produces in a CO atmosphere at room temperature the salts [Rh(CO)(4)][M(2)Cl(7)] (M = Al, Ga), which are characterized by Raman spectroscopy and single-crystal X-ray diffraction. Crystal data for [Rh(CO)(4)][Al(2)Cl(7)]: triclinic, space group Ponemacr; (No. 2); a = 9.705(3), b = 9.800(2), c = 10.268(2) A; alpha = 76.52(2), beta = 76.05(2), gamma = 66.15(2) degrees; V = 856.7(5) A(3); Z = 2; T = 293 K; R(1) [I > 2sigma(I)] = 0.0524, wR(2) = 0.1586. Crystal data for [Rh(CO)(4)][Ga(2)Cl(7)]: triclinic, space group Ponemacr; (No. 2); a = 9.649(1), b = 9.624(1), c = 10.133(1) A; alpha = 77.38(1), beta = 76.13(1), gamma = 65.61(1) degrees; V = 824.4(2) A(3); Z = 2; T = 143 K; R(1) [I > 2sigma(I)] = 0.0358, wR(2) = 0.0792. Structural parameters for the square planar cation [Rh(CO)(4)](+) are compared to those of isoelectronic [Pd(CO)(4)](2+) and of [Pt(CO)(4)](2+). Dissolution of [Rh(CO)(2)Cl](2) in HSO(3)F in a CO atmosphere allows formation of [Rh(CO)(4)](+)((solv)). Oxidation of [Rh(CO)(2)Cl](2) by S(2)O(6)F(2) in HSO(3)F results in the formation of ClOSO(2)F and two seemingly oligomeric Rh(III) carbonyl fluorosulfato intermediates, which are easily reduced by CO addition to [Rh(CO)(4)](+)((solv)). Controlled oxidation of this solution with S(2)O(6)F(2) produces fac-Rh(CO)(3)(SO(3)F)(3) in about 95% yield. This Rh(III) complex can be reduced by CO at 25 degrees C in anhydrous HF to give [Rh(CO)(4)](+)((solv)); addition of SbF(5) at -40 degrees C to the resulting solution allows isolation of [Rh(CO)(4)][Sb(2)F(11)], which is found to have a highly symmetrical (D(4)(h)()) [Sb(2)F(11)](-) anion. Oxidation of [Rh(CO)(2)Cl](2) in anhydrous HF by F(2), followed in a second step by carbonylation in the presence of SbF(5), is found to be a simple, straightforward route to pure [Rh(CO)(5)Cl][Sb(2)F(11)](2), which has previously been structurally characterized by us. All new complexes are characterized by vibrational and NMR spectroscopy. Assignment of the vibrational spectra and interpretation of the structural data are supported by DFT calculations.     

Synthesis and structural characterization of two novel heterometallic clusters: [Rh4Pt2(CO)11(dppm)2] and [Ru2Rh2Pt2(CO)12(dppm)2

Two novel heterometallic octahedral clusters [Rh(4)Pt(2)(CO)(11)(dppm)(2)](1) and [Ru(2)Rh(2)Pt(2)(CO)(12)(dppm)(2)](2) were synthesized by the reaction of [Rh(2)Pt(2)(CO)(6)(dppm)(2)] with [Rh(6)(CO)(14)(NCMe)(2)] and Ru(3)(CO)(12), respectively. Solid state structures of 1 and 2 have been established by a single crystal X-ray diffraction study. Two dppm ligands in 1 are bonded to one platinum and three rhodium atoms, which form an equatorial plane of the Rh(4)Pt(2) octahedron. Two rhodium and two platinum atoms bound to the diphosphine ligands in 2 are nonplanar to give an octahedral C2 symmetric Ru(2)Rh(2)Pt(2)(dppm)2 framework. The (31)P NMR investigation of and (1D, (31)P COSY, (31)P-[(103)Rh] HMQC) and simulation of 1D spectral patterns showed that in both clusters the structures of the M(6)(PP)(2) fragments found in the solid state are maintained in solution.     

Reactivity of novel N,N'-diphosphino-silanediamine-based rhodium(I) derivatives

The coordination abilities of the novel N,N'-diphosphino-silanediamine ligand of formula SiMe(2)(NtolPPh(2))(2) (SiNP, 1) have been investigated toward rhodium, and the derivatives [RhCl(SiNP)](2) (2), [Rh(SiNP)(COD)][BF(4)] (3), and Rh(acac)(SiNP) (4) have been synthesized. The stability of the dinuclear frame of [RhCl(SiNP)](2) (2) toward incoming nucleophiles has been shown to be dependent on their π-acceptor ability. Indeed, the mononuclear complexes RhCl(SiNP)(L) (L = CO, 5; CN(t)Bu, 6) have been isolated purely and quantitatively upon reaction of 2 with CO and CN(t)Bu, respectively. Otherwise, PPh(3) and RhCl(SiNP) equilibrate with Rh(Cl)(SiNP)(PPh(3)) (7). Carbon electrophiles such as MeI and 3-chloro-1-proprene afforded the oxidation of rhodium(I) to rhodium(III) and the formation of RhCl(2)(η(3)-C(3)H(5))(SiNP) (8) and Rh(Me)(I)(SiNP)(acac) (10), respectively. The methyl derivative 10 is thermally stable and does not react either with CO or with CN(t)Bu even in excess. Otherwise, RhCl(2)(η(3)-C(3)H(5))(SiNP) (8) is thermally stable but reacts with CO, affording 3-chloro-1-proprene and RhCl(SiNP)(CO) (5). Finally, upon reaction of Rh(acac)(SiNP) (4) and 3-chloro-1-proprene, RhCl(acac)(η(1)-C(3)H(5))(SiNP) (9a) and [Rh(acac)(η(3)-C(3)H(5))(SiNP)]Cl (9b) could be detected at 233 K. At higher temperatures, 9a and 9b smoothly decompose, affording the dinuclear derivative [RhCl(SiNP)](2) (2) and the CC coupling product 3-allylpentane-2,4-dione.