With osmium hydride complexes

Also, Os3(H)2(CO)9(PMe2Ph) reacts with p-tolyl isocyanate to give a bridged carbamate complex . When Os3(H)2(CO)io is used, formamide complexes and other products resulting from fragmentation reactions are obtained. For example, p-tolyl isocyanate reacts with the osmium hydride complex and ruthenium complexes to form formamido, ureylene... 

Since electronegative groups at C-20 or C-21 deactivate a A hdouble bond towards attack by osmium tetroxide, Swiss workers have devised procedures wherein these groups are first reduced with lithium aluminum hydride, and the resulting aluminum complexes are then treated with osmium tetroxide... 

A ruthenium porphyrin hydride complex was lirst prepared by protonation of the dianion, [Ru(TTP) in THF using benzoic acid or water as the proton source. The diamagnetic complex, formulated as the anionic Ru(If) hydride Ru(TTP)(H )(THF)l , showed by H NMR spectroscopy that the two faces of the porphyrin were not equivalent, and the hydride resonance appeared dramatically shifted upheld to —57.04 ppm. The hydride ligand in the osmium analogue resonates at —66.06 ppm. Reaction of [Ru(TTP)(H)(THF)j with excess benzoic-acid led to loss of the hydride ligand and formation of Ru(TTP)(THF)2. 

Treatment of OsT rf-T BT XCOXP Pr with ethanol under reflux does not lead to the formation of OsH2(CO)2(P Pr3)2 but instead gives the hydride-methyl osmium(II) compound OsHMe(CO)2(P Pr3)2 in good yield. 2-Methoxyethanol behaves in a manner similar to ethanol, and the reaction with the tetrahydridoborate complex yields OsH(CH2OMe)(CO)2(P Pr3)2 (Scheme 38).79... 

Similar reactions of the other group 14 hydrides with ruthenium(O) and osmium(O) complexes have also been described. 

Numerous phosphine and arsine complexes have been synthesized and characterized predominately with osmium in the +2, + 3 or +4 oxidation states. Examples include [OsCl2(dppm)2] [108341-10-2], [OsC13(P(CH3)2(C6H5)3] [20500-70-3], [0s2Cl6(dppm)2(0)] [87883-12-3], and [Os(AsC2Hb(C6Hb)2)4H2] [27498-19-7]. An example of an unusually low oxidation state is the Os(—2) complex K2[Os(PF3)4] [26876-74-4]. High coordination numbers and formal oxidation states are found in the phosphine hydrides, eg, [Os(P(CH3)(C(5HB)2)H6] [25895-55-0] and... 

Heterometal alkoxide precursors, for ceramics, 12, 60-61 Heterometal chalcogenides, synthesis, 12, 62 Heterometal cubanes, as metal-organic precursor, 12, 39 Heterometallic alkenes, with platinum, 8, 639 Heterometallic alkynes, with platinum, models, 8, 650 Heterometallic clusters as heterogeneous catalyst precursors, 12, 767 in homogeneous catalysis, 12, 761 with Ni—M and Ni-C cr-bonded complexes, 8, 115 Heterometallic complexes with arene chromium carbonyls, 5, 259 bridged chromium isonitriles, 5, 274 with cyclopentadienyl hydride niobium moieties, 5, 72 with ruthenium—osmium, overview, 6, 1045—1116 with tungsten carbonyls, 5, 702 Heterometallic dimers, palladium complexes, 8, 210 Heterometallic iron-containing compounds cluster compounds, 6, 331 dinuclear compounds, 6, 319 overview, 6, 319-352... 

Allyl hydride complexes of osmium are isolated from treatment of phosphine-substituted osmacyclobutane complex 114 with a thallium salt (Scheme 21). The reaction initially provides a mixture of an unstable -benzyl hydride complex 115 and the rf -allyl hydride complex 116 the -benzyl intermediate ultimately isomerizes to the latter complex, a very rare instance of isolable allylic hydride products generated from a starting metallacyclobutane <2004OM4858>. 

Protonation of 322 with tetrafluoroboric acid in diethyl ether gives the cyclohexadienyl derivative 325 in 70% yield. Treatment of 325 with lithium aluminum hydride yields the biscyclohexadienyl osmium(II) complex 326. Treatment of 322 with PMe3 at 60°C gives the hydridophenyl osmium-(II) complex 181, rather than the expected arene bistrimethylphosphine osmium(O) compound, via intramolecular C—H bond activation of the benzene ligand (192,193) (Scheme 38). Compound 181 as well as the analogous ruthenium complex (92) have also been obtained directly by cocondensation of osmium or ruthenium atoms with benzene and tri-methylphosphine (62) [Eq. (44)]. 

As ligands for osmium, ammonia and ethylenediamine (en 1,2-diaminoethane) would be expected to have broadly similar properties, and this is on the whole true — there are stable osmium(III) complexes such as [Os(en)3]3+, trans-[Os(en)2 X2]+ (X — Cl, Br) and [Os(en)Cl4], and more recently the tetravalent Os(en)X4 (X = Cl, Br, I) has been made. There is, however, an interesting chemistry of the l,2-ethanediaminato-(l —) and -(2 —) ligands with osmium in the higher IV, V and VI states, and another unusual feature is the existence of the hydride [OsH2(en)2f. ... 

Some analogous rathenium- and osmium-bismuth clusters have been found. Examples include Bi2M3(CO)9 and H3BiM3(CO)9 (M = Ru, Os). The stmctures of the hydride compounds have both been determined and they are isostractural with the iron complexes as is Bi2Ru3(CO)9 withBi2Fe3(CO)9. The structure 0fBi2Os3(CO)9, on the other hand, has not been determined and its IR spectrum indicates that it probably has a different structure. A spirocyclic cluster [Ru2(CO)8(/X4-Bi)Ru3(CO)io(/x-Ft)] (39) has been reported. 

---