Alkyl- und aryl-komplexe des iridiums und rhodiums: X. Chelatphosphin-stabilisierte rhodiumorganyle Rh(R)[PhP(CH2CH2CH2PPh2)2]: synthese,NMR-spektroskopischer cis,trans-einfluss und molekülstruktur von Rh(2-MeC6H4)[PhP(CH2CH2CH2PPh2)2]

The organorhodium(I) complexes Rh(R)[PhP(CH₂CH₂CH₂PPh₂)₂] (R  CH₂CMe₃, CH₂SiMe₃; 2-MeC₆H₄, 4-MeC₆H₄, 2,4-Me₂C₆H₃, 2,4,6-Me₃C₆H₂; C₂Ph) have been prepared and characterized by ³¹P and ¹H NMR spectroscopy and an X-ray structure determination of the tolyl derivative Rh(2-MeC₆H₄)-[PhP(CH₂CH₂CH₂PPh₂)₂].For these compounds, the relative ³¹P coordination shifts Δ(PPh₂) > Δ(PPh) distinctly reflect the electron-releasing properties of the organoligands σ-bonded trans to PPh. As expected, coupling between the ¹⁰³Rh nucleus and phenylphosphino P atoms is weak and varies only little as the strong trans influence groups R are changed. In contrast to this insensitivity of ¹J(Rh-PPh) to R, Rh-P coupling within the Ph₂P-Rh-PPh₂ moieties shows considerable dependence upon the nature of the C-donor producing the cis influence series sp³-C <sp²-C < sp-C.The ortho-tolyl complex crystallizes from toluene as 1/1 solvate Rh(2-MeC₆H₄)[PhP(CH₂CH₂CH₂PPh₂)₂] · C₇H₈. Crystals are orthorhombic, space group Pbc2₁, with a 1017.9(7), b 1974.3(14), c 2177.6(11) pm, and Z = 4. The structure has been refined to R = 0.079 for 2249 unique data with F₀ > 3σ(F₀). Metal-phosphorus distances are 225.7(5) and 229.6(6) pm for Rh-PPh₂ and 227.3(6) pm for Rh-PPh.     

On the Hydrolytic Stability of Organic Ligands in Al-, Ti- and Zr-Alkoxide Complexes

The complexation degrees of Al-, Ti- and Zr-butoxide (M) with unsaturated and saturated -diketones (3-allylpentane-2.4-dione-APD, acetylacetone-ACAC) and -ketoesters (methacryloxyethyl-acetoacetate-MEAA, allylacetoacetate-AAA, ethylacetoacetate-EAA) as organic ligands (L) were examined by IR and ¹³ C NMR spectroscopy and were found to be L:M 1.5. The hydrolytic stability of the ligands of the metal alkoxide complexes (L:M = 1) during hydrolysis/condensation reactions at the molar ratio h (H₂O : OR) = 0.5–2.0 decreases with increasing H$$₂O:complex ratio. Furthermore, the ligand stability depends on the type of metal in the complexes and decreases in the order Al- > Zr- > Ti-butoxide complexes at h=1. The ACAC ligand likewise shows in the Al-, Ti- and Zr-butoxide complexes a high hydrolytic stability (95–100%) at h=1 within 7 days. The Ti- and Zr-butoxide complexes with -ketoesters as ligand show at h=1> a release to a different extent e.g., up to 60% in the case of the MEAA-ligand in the Ti-butoxide complex after 2 days. In general, the hydrolytic stability of the ligands in the Ti-butoxide complexes (L:M = 1, h=1) decreases in the order ACAC > APD > AAA > EAA MEAA. The hydrolysis/condensation reaction of complexes having a weak ligand stability leads to larger particle sizes in the sols than those with stable ACAC ligands. The results contribute to a more controlled synthesis of sols and of new inorganic-organic hybrid polymers via the sol-gel process.     

Alkyl- und Arylkomplexe des Iridiums und Rhodiums. XIX. Reaktion von Carbonsäuren mit ausgewählten Organoverbindungen von Ir(I) und Rh(I): Bildung von Arylhydrido-, Carboxylatohydrido- und Carboxylato-Derivaten

Alkyl and Aryl Complexes of Iridium and Rhodium. XIX. Reaction of Carboxylic Acids with Selected Organo Compounds of Ir(I) and Rh(I): Formation of Arylhydrido, Carboxylatohydrido, and Carboxylato Derivatives cis-Arylhydridoiridium(III) complexes IrH(Ar)(O₂CR)(CO)(PPh₃)₂ (R = Me: Ar = C₆H₅, 4-MeC₆H₄; R = Et: Ar = 4-MeC₆H₄, 2,4-Me₂C₆H₃) could be prepared by oxidative addition of carboxylic acids to aryliridium(I) compounds Ir(Ar)(CO)(PPh₃)₂. Reaction of aliphatic carboxylic acids with alkyliridium(I) derivatives Ir(Alk)(CO)(PPh₃)₂ and Ir(Alk)[PhP(CH₂CH₂CH₂PPh₂)₂] (Alk = CH₂CMe₃, CH₂SiMe₃) lead to dicarboxylatoiridium(III) hydrides IrH(O₂CR)₂(CO)(PPh₃)₂ (R = Me, Et, i-Pr) and IrH(O₂CR)₂[PhP(CH₂CH₂CH₂PPh₂)₂] (R = Me, Et). Ir(4-MeC₆H₄CO₂)(CO)(PPh₃)₂ was obtained from Ir(CH₂SiMe₃)(CO)(PPh₃)₂ and 4-MeC₆H₄CO₂H. Interaction of organorhodium complexes Rh(R′)(CO)(PPh₃)₂ (R′ = CH₂SiMe₃, 4-MeC₆H₄) and Rh(R′)[PhP(CH₂CH₂CH₂PPh₂)₂] (R′ = CH₂CMe₃, 4-MeC₆H₄) with aliphatic and aromatic carboxylic acids yielded carboxylatorhodium(I) compounds Rh(O₂CR)(CO)(PPh₃)₂ (R = Me, t-Bu, 4-MeC₆H₄) and Rh(O₂CR)[PhP(CH₂CH₂CH₂PPh₂)₂] (R = Me, 4-MeC₆H₄).     

Alkyl- und arylkomplexe des iridiums und rhodiums: XXI. Chelatphosphan-stabilisiertepentakoordinierte organoiridium(I)-komplexe Ir(R)(CO)( chel-P33)

Novel five-coordinate organoiridium(I) complexes of the type Ir(R)(CO)(chel-P₃) (chel-P₃=PhP(CH₂CH₂CH₂PPh₂)₂: R = CH₂CMe₃, CH₂SiMe₃; chel-P₃ = MeP-(CH₂CH₂CH₂PPh₂)₂: R = CH₂SiMe₃; chel-P₃PhP(CH₂CH₂PPh₂)₂; R = CH₂SiMe₃, 4-MeC₆H₄) have been prepared from Ir(R)(CO)(PPh₃)₂ and the respective triphosphine. According to ³¹P NMR, these compounds are stereochemically rigid at normal temperatures. The reaction of Rh(R)(CO)(PPh₃)₂, where R = CH₂CMe₃ or 2-MeC₆H₄, with PhP(CH₂CH₂CH₂PPh₂)₂ yielded the four-coordinate derivatives Rh(CH₂CMe₃)[PhP(CH₂CH₂CH₂PPh₂)₂] and Rh(2-MeC₆H₄)[PhP(CH₂CH₂CH₂PPh₂)₂]), which arealready known from the literature.