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Title: 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)

Journal Article · · Inorg. Chem.; (United States)
DOI:https://doi.org/10.1021/ic00261a009· OSTI ID:5522704

The reaction of the dirhodium(II) mixed-ligand complex Rh/sub 2/(form)/sub 2/(O/sub 2/CCF/sub 3/)/sub 2/(H/sub 2/O) (form = N,N'-di-p-tolylformamidinate anion) with free N,N'-di-p-tolylformamidine (mole ratio 1:4) leads to the formation of the complex Rh/sub 2/ (form)/sub 4/ (1) in excellent yield. The complex was characterized by a single-crystal X-ray diffraction analysis, crystallizing in the space group Pnanti3n, with a = 20.990 (2) A, V = 9248 A/sup 3/, Z = 6, R = 0.036, and R/sub w/ = 0.0378. The Rh-Rh (2.4336 (4) A) and the Rn-N (2.050 (5) A) bond distances are well in the range observed for this class of compounds. The molecule is in a staggered conformation, with N-Rh-Rh-N torsion angles of 16.7 (2)/sup 0/. Complex 1 reacts with carbon monoxide, giving the monocarbonyl adduct Rh/sub 2/-(form)/sub 4/(CO) (2), characterized by elemental analysis and IR, /sup 13/C NMR, and electrochemical measurements. Unlike other dirhodium(II) carbonyl derivatives, 2 is remarkably stable. In the /sup 13/C NMR spectrum a dramatic upfield shift is seen for the carbonyl resonance (delta 144.06); the IR spectrum shows v(CO) at 2040 cm/sup -1/. These data coupled to electrochemical measurements suggest that the ..pi.. back-bonding is reasonably strong in 2. The electrode behavior of 1 has been investigated in different nonaqueous solvents.

Research Organization:
Universita di Messina, Italy
OSTI ID:
5522704
Journal Information:
Inorg. Chem.; (United States), Vol. 26:14
Country of Publication:
United States
Language:
English