Aryldiazo complexes. Syntheses and reactions of new complexes of osmium and ruthenium

Abstract

Aryldiazo complexes, [M(CO)2(NNPh)(PPh3)2] [PF6] (M = Os, Ru; Ph = C6H5), have been prepared by allowing diazonium salts to react with M(CO)3(PPh3)2. Infrared spectra of the Ru complex suggest the presence of two isomers both in solution and in the solid state. These complexes react with a variety of coordinating anions (X-), to form MX(CO)2(NNPh)(PPh3)2. The osmium derivatives have v(NN) near 1455 cm-1, which is the lowest value yet reported for a nonbridging aryldiazo ligand. The first aryldiazo-hydrido complexes, MH(C0)2(NNPh)(PPh3)2 and MH(CO)(NNPh)(PPh3)2, were prepared by deprotonation of the respective phenyldiazene complexes, MH(CO)2(HNNPh)(PPh3)2+ and MH(CO)(HNNPh)(PPh3)3+. The compound OsCh(NNPh)(PPh3)2 has also been prepared. A large number of the foregoing complexes have been synthesized with selective 2H and 15N labels. Infrared and NMR spectra show MX(C0)2(NNPh)(PPh3)2 and the analogous hydrido complex to be pseudooctahedral with trans phosphine ligands, cis carbonyl ligands, and a doubly bent phenyldiazenido (NNPh-) ligand. Similarly, MH(CO)(NNPh)(PPh3)2 possesses a trigonal-bipyramidal geometry with trans phosphine ligands and an equatorial, singly bent phenyldiazoniumato (NNPh+) ligand. Isotopic substitution of the diazo ligand shows that v(NN) is often vibrationally coupled with phenyl vibrational modes and that two or three bands sometimes shift upon l5N substitution. Vibrational coupling is also observed in the higher energy region (1850-1900 cm-I) in the compound R U C I , ( N N C~D~) ( P P~~)~. The wide range in the values of u(NN), RuCh(NNPh)(PPh3)2 (I882 cm-I), vs. RuCI-(C0)2(NNPh)(PPh3)2 (I462 cm-I), indicates that the N-N stretching frequencies are sensitive to the electronic and steric environment of the diazo ligand. The aryldiazo complexes are compared with analogous, isoelectronic nitrosyl complexes of Os and Ru.been reported for all members of the Cr, Mn, Fe, Co, and Ni triads with the exception of Ni, Pd, and Tc.4>5 Part of the interest in aryldiazo and other diazo ligands has been generated by the close relationship of these ligands to dinitrogen and nitrosyl ligands. Recent work has shown that diazo ligands can be prepared from coordinated dinitrogen in Re, Mo, and W complexes.6 Furthermore, aryldiazo ligands resemble

Aryldiazenido complexes: structure, fluxionality, and properties of the iridium ethylene aryldiazenido complex [(η5-C5Me5)Ir(C2H4)(p-N2C6H4OMe)][BF4] and a comparison with the analogous nitrosyl complex [(η5-C5Me5)Ir(C2H4)(NO)][BF4]

“…No observable ' 5~ coupling to either the hidride or the phosphorus was evident for 4. The absence of 1 5~, -~ coupling was also noted by Haymore and Ibers for their complexes (43). However, ,'P-' 5~ coupling was observed in the ' 5~ NMR spectrum of the singly bent aryldiazenido cation 3-15~,, so it appears that this coupling is very sensitive to the geometry of the ArN, ligand and perhaps the relative disposition of it and the PPh, and hydrido ligands.…”

“…This simple transformation of the singly bent aryldiazenido ligand to a doubly bent one to incorporate an additional ligand at the metal has, to our knowledge, rarely been observed before (43). However, there are several established examples in which such a transformation effectively occurs, but is accompanied by protonation of the doubly bent aryldiazenido ligand thus formed so that an aryldiazene complex is the actual product.…”

“…This type of complex, in which a hydrido ligand coexists with a doubly bent aryldiazenido ligand, is not common. The only other examples of which we are aware are those reported by Haymore and Ibers (43). These are the complexes MH(CO),(PPh,),(N,Ph) (M = Os, Ru), and they were prepared by a very different method, the deprotonation of the corresponding aryldiazene complexes [MH(CO),(PPh,),(NHNPh)]+.…”

Cyclopentadienyl ruthenium complexes. Part III. Reactivity of some η5-cyclopentadienylbis(triphenylphosphine)ruthenium(II) complexes with nitrosyl tribromide and dinitrogen trioxide

“…The ir spectra of the remaining complexes (other than trichlorostannate ones) showed an intense absorption band in the region 1840-1880 cm-' besides the bands due to other coligands (29)(30)(31)(32). Since the position of ir frequency due to v,, corrected by lbers rule (28) in the complexes has been found to be greater than 1620 cm-I, these can be regarded as complexes between Ru(l1) and N O k .…”

Revisit of Unusual Ruthenium(III) Dichloro Complex

“…8,9 Table 2, the difference in crystallographic system is Cl − complex crystallizes in the triclinic space group of P1, whereas monoclinic C2/c for the complex containing PF 6 − . Effects of ligand electronic asymmetry observed in the crystal structure are, once again, evident in the Ru(III)-N(bpy) distances for both complexes.…”