Synthesis of asymmetric Rh/sub 2//sup 4+/ complexes. X-ray crystal structure of Rh/sub 2/(form)/sub 3/(NO/sub 3/)(PPh/sub 3/)/center dot/0. 5CH/sub 2/Cl/sub 2/ and Rh/sub 2/(form)/sub 3/(NO/sub 3/)(C/sub 5/H/sub 5/N) (form = N,N'-di-p-tolylformamidinate)
The reaction of the paramagnetic Rh/sub 2//sup 5+/ complex Rh/sub 2/(form)/sub 3/(NO/sub 3/)/sub 2/ (form = N,N'-di-p-tolylformamidinate) with an excess of the neutral ligands PPh/sub 3/, pyridine, and dimethylamine leads, via reductive elimination of one nitrate group, to the formation of the asymmetric Rh/sub 2//sup 4+/ complexes Rh/sub 2/(form)/sub 3/(NO/sub 3/)L L = PPh/sub 3/ (1), pyridine (2), N(CH/sub 3/)/sub 2/H (3). The two rhodium atoms in complexes 1-3 display different coordinations and reduced average formal oxidation states. The complexes have been characterized by IR, /sup 31/P NMR, and /sup 103/Rh NMR spectroscopic methods, which point out the nonequivalence of the two rhodium atoms. Complexes 1 and 2 have also been characterized by single-crystal X-ray analysis. Complex 1 belongs to the monoclinic space group system P2/sub 1//n, with a = 21.529 (3) /angstrom/; b = 23.990 (3) /angstrom/, c = 11.944 (1) /angstrom/, /beta/ = 102.13 (4)/degree/, Z = 4, and R = 0.057 for 2046 reflections with I > 3/sigma/(I). The crystal structure reveals that one of the three formamidinate groups spanning the dimetal center (Rh-Rh = 2.498 (2) /angstrom/) is bonded in an unusual way, namely, /sigma/,/sigma/-N,N' with a localized double bond. Complex 2 forms monoclinic crystals in space group P2/sub 1//c with a = 10.238 (1) /angstrom/, b = 16.567 (2) /angstrom/, /beta/ = 955.6 (3)/degree/, Z = 4, and R = 0.041 for 3392 reflections with I > 3/sigma/(I). In complexes 2 and 3 of all the bridging ligands are bonded in the usual fashion, namely, /sigma/,/sigma/-N,N' with delocalized double bonds. 18 refs., 3 figs., 6 tabs..
- Research Organization:
- Universite di Messina (Italy)
- OSTI ID:
- 5761824
- Journal Information:
- Inorg. Chem.; (United States), Vol. 28:1
- Country of Publication:
- United States
- Language:
- English
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Synthesis, X-ray, crystal structure, and electrochemical properties of the Rh/sub 2//sup 4 +/ complex Rh/sub 2/(form)/sub 4/ (form = N,N'-Di-p-tolylformamidinate anion)
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
AROMATICS
CRYSTAL STRUCTURE
NITRATES
ORGANIC NITROGEN COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
RHODIUM COMPLEXES
EXPERIMENTAL DATA
NMR SPECTRA
PHOSPHORUS 31
RHODIUM 103
COMPLEXES
DATA
INFORMATION
INTERMEDIATE MASS NUCLEI
INTERNAL CONVERSION RADIOISOTOPES
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
LIGHT NUCLEI
MINUTES LIVING RADIOISOTOPES
NITROGEN COMPOUNDS
NUCLEI
NUMERICAL DATA
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
PHOSPHORUS ISOTOPES
RADIOISOTOPES
RHODIUM ISOTOPES
SPECTRA
STABLE ISOTOPES
TRANSITION ELEMENT COMPLEXES
400201* - Chemical & Physicochemical Properties
400202 - Isotope Effects
Isotope Exchange
& Isotope Separation