CP*I~(C~H~)(N~A~)][BF~] (1; Ar = p-CfiOMe) reacts with PMe3 to give [Cp*Ir(PMe3)2(N2Ar)][BF4] (4), which has been shown by an X-ray structure determination and by I5N NMR spectroscopy to possess the aryldiazenido ligand bound with doubly-bent geometry. As is the case in 1, the complexes [Cp*Ir(PPh3)(N2Ar)][BF4] (2) and [Cp*Ji{P(p-t01)3)(N2Ar)l[BF4] (3) have the N2Ar ligand bound with singly-bent geometry. This has been demonstrated by an X-ray structure determination for 3. Complexes 2 and 3 react with PMe3 to give [CP*I~(PP~~)(PM~~)(N~A~)][BF~] (5) and [Cp*Ir{P(p-t01)3)(PMe3)(N2Ar)][BF41 (a), and 2 reacts with CO or CNto give [Cp*Ir(CO)(PPh3)(N2Ar)][BF4] (7) or Cp*Ir(CN)(PPh3)(N2Ar) (8). All these reactions are shown by I5N NMR to involve the transformation of the N2Ar ligand from singly-bent to doubly-bent as a consequence of coordination by the incoming ligand. Diphos (Ph2P(CH2)2PPh2) reacts with 1 to give [Cp*Ir(diphos)(N2Ar)]-[BF4] (9), but no complex of stoichiometry [Cp*Ir(PPh3)z(NzAr)][BF4] could be obtained from 1 or 2 with excess PPh3; this complex is presumably sterically disfavored. Crystal structures: 3, T = 295 K, orthorhombic, space group P212121, Z = 4; a = 12.974(2) A; b = 13.449(2) A, c = 16.213(4) A, V = 2829.0 A3, RF = 0.032 for 2974 data (Io I 2.50 (Io)) and 241 variables; 4, T = 295 K, monoclinic, space group P2l/n, Z = 4; a = 9.906(2) A, b = 12.084(3) A, c = 30.545(6) A, , 8 = 93.296(13)", V = 3650.2 A3, RF = 0.029 for 3606 data (Io 2 2% (Io)) and 422 variables.@ (1) (JD (111)NMR spectroscopy to contain a doubly-bent N2Ar group.6 This appeared to be a new example of eq 1 and prompted us to examine additions of other potential ligands to 2 or its precursor, the ethylene complex 1.
Experimental SectionAll solvents were dried and purified by standard methods and were freshly distilled under nitrogen immediately before use. All reactions and manipulations were carried out in standard Schlenk ware, connected to a switchable double manifold providing vacuum and nitrogen. Reactions were performed at room temperature, unless otherwise mentioned. Infrared spectra were measured for solutions in CaF2 cells by using a Bomem Michelson 120 FTIR instrument. Routine IH NMR spectra were recorded at 100 MHz by using a Bruker SY-100 Fourier transform spectrometer. Chemical shifts (6) are reported in ppm, downfield positive, relative to tetramethylsilane (TMS). I5N NMR and 3'P NMR spectra were obtained by Mrs. M. M. Tracey of the NMR service of Simon Fraser University on a Bruker AMX-400 Fourier transform instrument at operating frequencies of 40.5 and 162 MHz for I5N and 3'P, respectively. Chemical shifts (ppm) are reported (5) (a) Linear (3e-) to bent (le-) transformations of nitrosyl ligands by coordination of an additional 2ec-donor ligand are somewhat better established. See: Weiner, W. P.; Bergman, R. G. J. Am. Chem. SOC. 1983,105,3922. Enemark, J. H.; Feltham, R. D.; Huie, B. T.; Johnson, P. L.; Swedo, K. B. J. Am. Chem. SOC. 1977, 99, 3285. Enemark, J. H.; Feltham, R. D.; Riker-Nappier, J.; Bizot, K. ...