N,N′-Di-p-tolylcarbodiimide (tolN=C=Ntol) (tol = p-tolyl) reacts with platinum group metal hydrides to afford products containing the symmetrical N,N′-bonded ligand N,N′-di-p-tolylformamidinato (tolN[Formula Omitted]CH[Formula Omitted]Ntol = dtfa). Thus, the hydrides [MHX(CO)(PPh3)3] (M = Ru or Os; X = Cl, Br, or OCOCF3), [MH2(CO)(PPh3)3], [RuH2(PPh3)4] or [OsH4(PPh3)3], [IrHCl2(PPh3)3] (trans chlorides), and mer-[IrH3(PPh3)3] yield the complexes [MX(dtfa)(CO)(PPh3)2] (two isomers), [MH(dtfa)(CO)(PPh3)2], [M(dtfa)2(PPh3)2], [IrCl2(dtfa)(PPh3)2], and [IrH2(dtfa)(PPh3)2], respectively. The structure and stereochemistry of the new complexes have been deduced from 1H and 31P NMR data. In addition, the structure of the complex tras-RuH(dtfa)(CO)(PPh3)2 has been unambiguously established by x-ray diffraction methods. The compound crystallizes in the monoclinic space group C2h6-C2/c with eight molecules in the unit cell of dimensions a = 24.465 (4) Å,b = 11.845 (2) Å,c = 30.260 (5) Å, β = 98.38 (1)°, and V= 8674.9 Å3; ρcalcd = 1.344 and ρobsd = 1.34 g cm-3. A full-matrix least-squares refinement of the structure by standard procedures resulted in an R index of 0.063 for the 5805 independent data for which F02 > 3σ(F02). The coordination about the ruthenium atom is approximately octahedral. The formamidinato ligand is coordinated to the metal atom in a bidentate mode with an N(1)-Ru-N(2) angle of 59.8 (2)° and an N(1)-C(2)-N(2) angle of 114.7 (5)°. The Ru-N(2) bond length is 2.248 (5) Å compared with the Ru-N(1) distance of 2.183 (5) Å. The N-C bond lengths within the formamidinato moiety are equal with N(1)-C(2) and C(2)-N(2) distances of 1.308 (7) and 1.315 (7) Å, respectively. The two tolyl rings are twisted approximately 70° with respect to one another. The position of the hydride ligand was refined in the structural analysis; the Ru-H distance is 1.58 (7) Å.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Inorganic Chemistry