Structural Versatility of 5-Methyltetrazolato Complexes of (η⁵-Pentamethylcyclopentadienyl)iridium(III) Incorporating 2,2′-Bipyridine,N,N-Dimethyldithiocarbamate, or 2-Pyridinethiolate Ligands

Abstract

Several new mono- and dinuclear eta (5)-pentamethylcyclopentadienyl (Cp*) iridium(III) complexes bearing 5-methyltetrazolate (MeCN 4 (-)) have been synthesized and their molecular and crystal structures have been determined. For complexes incorporating 2,2'-bipyridine (bpy) or 1,10-phenanthroline (phen), both mononuclear kappa N (2)-coordinated and dinuclear mu-kappa N (1):kappa N (3)-bridging MeCN 4 complexes were obtained: [Cp*Ir(bpy or phen)(MeCN 4-kappa N (2))]PF 6 ( 1 or 3) and [{Cp*Ir(bpy or phen)} 2(mu-MeCN 4-kappa N (1):kappa N (3))](PF 6) 3 ( 2 or 4), respectively. It was confirmed by X-ray analysis that the dinuclear complex in 2 has a characteristic structure with a pyramidal pocket constructed from a mu-kappa N (1):kappa N (3)-bridging MeCN 4 (-) and two bpy ligands. In the case of analogous complexes with N, N-dimethyldithiocarbamate (Me 2dtc (-)), yellow platelet crystals of mononuclear kappa N (1)-coordinated complex, [Cp*Ir(Me 2dtc)(MeCN 4-kappa N (1))].HN 4CMe ( 5.HN 4CMe), and yellow prismatic crystals of dinuclear mu-kappa N (1):kappa N (4)-bridging one, [{Cp*Ir(Me 2dtc)} 2(mu-MeCN 4-kappa N (1):kappa N (4))]PF 6 ( 6), were deposited. The kappa N (1)- and kappa N (1):kappa N (4)-bonding modes of MeCN 4 (-) in these complexes presumably arise from the compactness of the Me 2dtc (-) coligand. 6 is the first example in which tetrazolates act as a mu-kappa N (1):kappa N (4)-bridging ligand. Furthermore, the molecular and crystal structures of dinuclear complexes having mu-kappa (2) S, N:kappa S-bridging 2-pyridinethiolate (2-Spy (-)) or 8-quinolinethiolate (8-Sqn (-)) ligands have been determined: [(Cp*Ir) 2(mu-2-Spy or 8-Sqn-kappa (2) S, N:kappa S) 2] ( 7 or 8). These thiolato-bridging complexes were stable toward the addition of 5-methyltetrazole (HN 4CMe), owing to the characteristic intramolecular stacking interaction between the pyridine or the quinoline rings. The 2-Spy complex of 7, however, reacted with an excess amount of Na(N 4CMe), resulting in cleavage of the IrN(py) bond and coordination of MeCN 4 (-) in the mu-kappa N (2):kappa N (3)-bridging mode: [(Cp*Ir) 2(mu-2-Spy-kappa S:kappa S) 2(mu-MeCN 4-kappa N (2):kappa N (3))]PF 6 ( 9). This bridging mode of MeCN 4 (-) was also observed in the triply bridging MeCN 4 complex: [(Cp*Ir) 2(mu-MeCN 4-kappa N (2):kappa N (3)) 3]PF 6 ( 10). In these various MeCN 4 complexes, the structural parameters of the MeCN 4 moiety were not perturbed by the difference in the bonding modes.

Binuclear rhodium(III) and iridium(III) monoselenocarboxylates: Synthesis, spectroscopy and structure of an ortho-metallated iridium complex featuring an IrCCC(μ-Se) chelate ring

“…Summarizing, the ortho-metallation observed here follows a general tendency of iridium(III) to engage in cyclometallation and of [Cp*Ir] 2+ in particular to stabilize highly basic and p donating chelate configurations [28][29][30][31][32] such as 1,2-enediamido. To our knowledge, however, it is the first time that an [IrCCCSe] fivemembered chelate ring has been obtained, distinguished by three sp 2 carbon centres (including one aromatic carbanion C and one uncoordinated carbonyl function), and by one bridging selenolato-Se.…”

Azide Chemistry – An Inorganic Perspective, Part II[‡][3+2]‐Cycloaddition Reactions of Metal Azides and Related Systems

“…+ (L,L = bpy or phen) [180] offer at least as stable residual ligand spheres as the tridentate chelate complexes mentioned above, [181] and …”

“…Potential η 1 -co-ordination modes of 5-substituted tetrazolates. [180] Still, the μ 2 -κN 1 :κN 2 -bridging mode is a common motif, occurring, e.g., in the 1D coordination polymer Na(N 4 CMe)(H 2 O) 2 as well as within more complex tetrazolato-bridged structures. [108,158,201,203,204] Figure 1 and section 1.6.).…”

Synthesis, characterization of novel half-sandwich iridium and rhodium complexes containing pyridine-based organochalcogen ligands

“…Assuming that the Cp* rings serve as three-coordinated ligand, the metal centers of 1aÁCl 2 , 1bÁCl 2 , 2bÁCl 2 and 3bÁCl 2 exist in the three-legged pianostool conformation with two six-membered chelate rings and one ten-membered chelate ring formed by coordination of the pyridine-based organochalcogen ligands to the metal center, which are common in Cp*M III (M = Ir, Rh) complexes [24][25][26][27][28][29][30][31][32][33].…”