82871-03-2Relevant academic research and scientific papers
Structural and electronic properties of (2,2-trans)-dirhodium(II) tetrakis(N-phenylacetamidate)
Eagle, Cassandra T.,Farrar, David G.,Holder, Grant N.,Pennington, William T.,Bailey, Rosa D.
, p. 90 - 94 (2007/10/03)
We have synthesized and characterized the first known 2,2-trans isomer of the N-substituted dirhodium(II) tetrakisacetamidate, Rh2(RNAc)4, class of compounds. The bis benzonitrile adduct exhibits a unique orthogonal arrangement of the axial aromatic rings in the solid state. Structural and electronic features suggest the presence of π-backbonding.
Reaction of Rh2(O2CCH3)4 with N-phenylacetamide: Substitution products and geometric isomers
Lifsey,Lin,Chavan,Ahsan,Kadish,Bear
, p. 830 - 836 (2008/10/08)
The products from the reaction of Rh2(O2CCH3)4 with N-phenylacetamide, PhNHOCCH3, were isolated by high-performance liquid chromatography and characterized by mass spectrometry, 13C NMR spectroscopy, and electronic absorption spectroscopy. These results indicate that 7 out of 12 possible products with the general formula Rh2(O2CCH3)n(PhNOCCH 3)4-n were formed. Formation constants for mono- and bis(dimethyl sulfoxide) adducts of each complex were determined in methylene chloride by using spectrophotometric methods. Half-wave potentials for the oxidation of each complex were also determined in methylene chloride (CH2Cl2) and dimethyl sulfoxide (Me2SO). Two Rh2(PhNOCCH3)4 isomers were investigated in detail and showed significant isomer effects in both the formation constants for Me2SO addition and the electronic absorption spectra. Isomer 8 formed a bis(dimethyl sulfoxide) adduct while isomer 7 was capable of forming only a monoadduct. The two geometric isomers of Rh2(O2CCH3)(PhNOCCH3)3 exhibited a smaller isomer effect in the formation constants and spectra. Crystal and molecular structures of the two tetrakis(N-phenylacetamidate) isomers Rh2(PHNOCCH3)4(Me2SO)2 (8(Me2SO)2) and Rh2(PhNOCCH3)4(Me2SO) (7(Me2SO)) were determined by single-crystal X-ray diffraction techniques. The bis(dimethyl sulfoxide) adduct of 8 crystallizes as blood red tabular crystals in the orthorhombic space group Pna21 with four formula weights in the unit cell of dimensions a = 15.780 (4) ?, b = 11.170 (5) ?, and c = 21.212 (4) ? with a final convergence to R = 0.027 and Rw = 0.031. The four equatorial positions of each rhodium are occupied by two N and two O atoms cis to their own kind. The two axial positions are occupied by Me2SO bound through the sulfur atoms. The two Rh-S bond lengths are 2.606 (2) and 2.566 (2) ?, and the Rh-Rh distance is 2.448 (1) ?. The mono(dimethyl sulfoxide) adduct of 7 crystallizes as a deep aquamarine block in the triclinic P1 space group with two formula weights in the unit cell of dimensions a = 8.333 (8) ?, b = 13.069 (4), and c = 17.641 (7) ? with a final convergence to R = 0.038 and Rw = 0.440. One rhodium is bound to three N's and one O in the basal plane whereas the second rhodium is bound equatorially to three O's and one N. One Me2SO is bound axially via its S atom to the rhodium with three equatorial oxygens, and the axial site of the second rhodium is not occupied. The Rh-Rh and Rh-S bond distances for 7(Me2SO) are 2.397 (1) and 2.395 (1) ?, respectively, and are considerably shorter than those found for the bis(dimethyl sulfoxide) adduct of compound 8.
