Doubly- and triply-bridging ligands derived from 2-pyridone and 2-aminopyridine. Crystal and molecular structure of the 2-pyridylamido complex [Os₃H(CO)₉{µ₃-NC₅H₄(NH)}]* formed from 2-aminopyridine and dodecacarbonyltriosmium

New triosmium–iridium clusters: Synthesis and molecular structure of [Os3Ir2(Cp∗)2(μ-OH)(μ-CO)2(CO)8Cl] (1), [Os3IrCp∗(μ-OH)(CO)10Cl] (2), [Os3IrCp∗(μ-H)(μ-Cl)(η3,μ3-C5H2N(NH2)Br)(CO)9] (3) and [Os3IrCp∗(μ-Cl)2(η2,μ3-C5H3N(NH)Br)(CO)7] (4)

“…A different coordination mode for the pyridyl ligand is observed in 4, i.e., it acts as a bidentate ligand, bridging over three osmium atoms. A similar coordination mode of the aminopyridyl ligand has been observed for a triosmium cluster, [Os 3 (CO) 10 (g 2 ,l 3 -C 5 H 4 N 2 Ph)] [27]. The two chloride ligands bridge the Ir center and Os center asymmetrically, with shorter Ir-Cl bond lengths observed (average Ir-Cl = 2.428 Å , Os-Cl = 2.539 Å ).…”

“…The average Os-Os bond length observed is 2.7923 Å , with the longer Os(1)-Os(2) bond due to the steric hindrance from the bridging pyridyl group (Os(1)-Os(2) 2.8998(7) Å ). The average Os-N bond observed is 2.163 Å , which is comparable to that of [Os 3 (CO) 10 (g 2 ,l 3 -C 5 H 4 N 2 Ph)] [27]. The ORTEP drawing of the molecular structure of 4 and selected bond parameters are shown in Fig.…”

Formation of Cyclopentadienyl and Ruthenacyclopentadienyl Derivatives through Ynenyl-Diyne and Ynenyl-Alkyne Couplings onto a Triruthenium Cluster Core

“…In trinuclear rhenium clusters, [25] these ligands have hitherto behaved as m 3 -h 2 five-electron donor ligands. In the case of triruthenium [9±20] and triosmium clusters, [26] the m 3 -h 2 fiveelectron-donor coordination mode predominates (there are hundreds of examples) over the m-h 2 three-electron-donor coordination mode, for which only two examples, one for ruthenium [9] and one for osmium, [26] have been reported.…”

Complexation and C–H bond activation of 2,2′:6′,2″-terpyridyl molecules on triosmium carbonyl clusters: Synthesis and characterization of the double-cluster {Cp3Fe4(CO)4(C5H4-terpyridyl)Os3(μ-H)(CO) } (n= 9, 10)

“…The ESI mass spectra of 1, 3 and 5 present the (M þ H) þ peaks at m/z 1684, 1184 and 1090 ( 192 Os), corresponding to combination of Os 3 (CO) 10 with one respective ligand. Their IR spectra in the terminal carbonyl region (2200e1900 cm À1 ) have a similar absorption pattern and are closely resemblant to the pyridyl clusters (m-H)Os 3 (m,h 2 - [23,24]. The absorption for m 3 -CO groups of 1 is recorded at 1653 cm À1 .…”

“…Shielding of H 3 , H 4 and H 5 is apparently due to electron back-donation from the Os 3 cluster and anionic character of the metalated ligand, while shielding of H 3 0 may be attributed to ring-current from the coordinated pyridyl species.The ESI mass spectra of 2 and 4 present the (M þ H) þ peaks at m/z 1656 and 1156 ( 192 Os), corresponding to loss of one carbonyl from 1 and 3. Their IR spectra in the carbonyl region are comparable and resemblant to the 2,2 0 -bipyridyl clusters (m-H)Os 3 (m,h 3 -N 2 C 10 H 6 R)(CO) 9 (R ¼ H, Et)[23,25]. Compounds 2 and 4 contain 1 H resonances in the range 8.9e7.2 ppm for the aromatic protons, and an upfield resonance at À21.6 ppm for the bridging-hydride.…”