Synthesis of Unsaturated Os3W2 and Metastable Os4W Oxo-Ethylidyne Clusters by Solid-State Pyrolysis. Direct C-O Bond Cleavage of a Coordinated Ketenyl Ligand

Abstract

Heterometallic ketenyl complex Os&O)1O(p-H) [C(O)CH2(W(CO)&p)l (la) possessing a pendant CpW(CO)3 substituent was prepared by condensation of O S ~( C O ) ~O ( N C M ~) ~ with the metal-aldehyde complex CpW(CO)&H2CHO. Pyrolysis of la in the solid state a t 185 OC afforded two heteropentametallic cluster compounds, C~~W~OS~(CO)~~(~-O)(II~-CM~) (2) and CpWOs4-(CO)12(p-O)(p3-CMe) (3), demonstrating a unique example of C-0 bond scission of a ligated ketene fragment and a cluster aggregation process. Complex 2 crystallizes in orthorhombic space group Pnma with a = 18.913(4) A, b = 16.229(3) A, c = 9.129(2) A, 2 = 4, R = 0.054, and R, = 0.055 for 2551 observed reflections. The W20s3 cluster t h a t contains 72 cluster valence electrons has a distorted square-pyramidal array of metal atoms with one Os-H-0s hydride ligand, one bridging oxo ligand associated with a W-W double bond, and a n ethylidyne ligand bridging a unique W20s triangle. Crystals of 3 are monoclinic of space group P21/n with a = 15.941(2) A, b = 19.395(4) A, c = 16.369(4) A, ,t? = 94.72(2)', 2 = 8, R = 0.050, and R, = 0.041 for 6568 observed reflections. This molecule possesses a WOS4 trigonal-bipyramidal skeleton with an oxo ligand bridging a W-Os edge and a n ethylidyne ligand capping a WOs2 face.

Strategic Design and Synthesis of Osmium(II) Complexes Bearing a Single Pyridyl Azolate π-Chromophore: Achieving High-Efficiency Blue Phosphorescence by Localized Excitation

“…The blue-emitting complex [Os(CO) 3 (tfa)(fppz)] ( 1) was prepared by treatment of Os(II) reagent [Os(CO) 3 (tfa) 2 ] (tfa ) trifluoroacetate) 18 and 3-(trifluoromethyl)-5-(2-pyridyl)pyrazole (fppz)H in refluxing toluene or using the so-called solid-state pyrolysis technique. 19 Both methods were initially utilized for the preparation of emissive Os(II) complexes. 20 After isolation and purification of 1, its IR ν(CO) data showed three CO stretching bands at 2132, 2063, and 2040 cm -1 in CH 2 Cl 2 , which are characteristic for a facial-[Os(CO) 3 ] unit.…”

“…Spectral data for 1: MS (EI, 192 Os) m/z 601 (M + ); IR (CH 2 -Cl 2 ) ν(CO), 2132 (vs), 2063 (vs), 2040 (vs) cm -1 ; 1 H NMR (500 MHz, acetone-d 6 , 298 K) δ 9.13 (d, 1H, J HH ) 5.5 Hz, CH), 8.34 (dt, 1H, J HH ) 7.9, 1.5 Hz, CH), 8.22 (d, 1H, J HH ) 7.5 Hz, CH), 7.34 (ddd, 1H, J HH ) 6.0, 5.5, 1.5 Hz, CH), 7.28 (s, 1H, CH); 13 C NMR (126 MHz, acetone-d 6 , 298 K) δ 173.1 (CO), 169.6 (CO), 167.5 (CO), 162.7 (q, 2 J CF ) 37 Hz, CCF 3 ), 155.4 (CH), 155.0, 152.4, 146.0 (q, 2 J CF ) 37 Hz, CCF 3 ), 143.3 (CH), 125.4 (CH), 122.9 (q, 1 J CF ) 266 Hz, CF 3 ), 122.2 (CH), 115.1 (q, 1 J CF ) 287 Hz, CF 3 ), 104.0 (CH); 19 F NMR (470 MHz, acetone-d 6 , 298 K) δ -61.35 (s, 3F), -74.77 (s, 3F). Anal.…”

“…Spectral data for 5: MS (EI, 192 Os) m/z 658 (M + ); IR (CH 2 -Cl 2 ) ν(CO), 2134 (vs), 2066 (vs), 2046 (vs) cm -1 ; 1 H NMR (500 MHz, acetone-d 6 , 298 K) δ 9.12 (d, 1H, J HH ) 6.0 Hz), 8.26 (d, 1H, J HH ) 2.5 Hz), 7.84 (dd, 1H, J HH ) 6.0, 2.5 Hz), 1.48 (s, 9H); 13 C NMR (125.7 MHz, acetone-d 6 , 298 K) δ 172.1 (CO), 169.0 (CO), 168.9 (CO), 166.4 (CO), 165.8, 162.7 (q, 2 J CF ) 38 Hz, CCF 3 ), 157.2 (q, 2 J CF ) 37 Hz, CCF 3 ), 155.7 (CH), 149.9, 125.1 (CH), 121.0 (q, 1 J CF ) 270 Hz, CF 3 ), 120.4 (CH), 115.0 (q, 1 J CF ) 289 Hz, CF 3 ), 36.7 (CMe 3 ), 30.2 (3C); 19 -8). An acetonitrile solution (5 mL) of freshly sublimed Me 3 NO (27 mg, 0.365 mmol) was added dropwise into a stirred solution of 1 (200 mg, 0.332 mmol) in toluene (25 mL) over a period of 5 min.…”

“…Spectral data for 8: MS (FAB, 192 Os) m/z 945 (M + ), 832 (M + tfa); IR (CH 2 Cl 2 ) ν(CO), 1948 (vs) cm -1 ; 1 H NMR (500 MHz, acetone-d 6 , 298 K) δ 8.05 (d, 1H, J HH ) 6.5 Hz), 7.95-7.91 (m, 3H), 7.82 (dt, 1H, J HH ) 7.5, 1.5 Hz), 7.62-7.55 (m, 3H), 7.48 (dt, 2H, J HH ) 7.3, 2.5 Hz), 7.39-7.34 (m, 3H), 7.28 (s, 1H), 7.24 (dt, 1H, J HH ) 7.5, 1.5 Hz), 7.18-7.14 (m, 5H), 7.06 (dt, 2H, J HH ) 7.5, 2.5 Hz), 6.82-6.77 (m, 3H), 2.39 (d, 3H, J HP ) 10.5 Hz), 1.49 (d, 3H, J HP ) 9.5 Hz); 19 F NMR (470.3 MHz, acetone-d 6 , 298 K) δ -60.90 (s, 3F), -75.00 (s, 3F); 31 P NMR (202.3 MHz, acetone-d 6 , 298 K) δ -15.15 (d, J PP ) 11.1 Hz), -15.97 (d, J PP ) 11.1 Hz).…”

Synthesis and characterization of luminescent osmium(ii) carbonyl complexes based on chelating dibenzoylmethanate and halide ligandsElectronic supplementary information (ESI) available: experimental details and the spectral data of all isolated Os complexes. See http://www.rsc.org/suppdata/cc/b3/b308340c/

“…This solid-state pyrolysis allowed us to conduct the experiments at higher temperatures and to avoid the usage of solvents that may interfere with the reactions. 4 [Os 2 (CO) 6 (m-X) 2 ] + (dbm)H ? [Os(CO) 3 X(dbm)] X = tfa (1) and I (4)…”