The monohydride complexes CpFeH(P-P) (P-P = dppe and dppp) were synthesized by reactions of CpFeCl(P-P) with NaBH
4. Protonation of CpFeH(P-P) with HBF
4Et
2O produced the molecular dihydrogen complexes [CpFe(η
2-H
2(P-P)]BF
4. The dihydrogen complexes were thermally unstable in solution. Treatment of CpOsBr(P-P) (P-P = dppm, dppe and dppp) with NaOMe in methanol gave the corresponding monohydride complexes CpOsH(P-P). Protonation of CpOsH(P-P) with HBF
4Et
2O at -78 ℃ gave a mixture of dihydride complexes cis-[CpOsH
2(P-P)] BF
4 and trans-[CpOsH
2(P-P)] BF
4. At room temperature in dichloromethane solutions, [CpOsH
2(dppm)]BF
4 exists as a mixture of cis and tram isomers in a ratio of 10: 1, [CpOsH
2 (dppe)]BF
4 exists as a mixture of cis and tram isomers in a ratio of 1:70, and [CpOsH
2(dppp)]BF
4 adop...[
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The monohydride complexes CpFeH(P-P) (P-P = dppe and dppp) were synthesized by reactions of CpFeCl(P-P) with NaBH
4. Protonation of CpFeH(P-P) with HBF
4Et
2O produced the molecular dihydrogen complexes [CpFe(η
2-H
2(P-P)]BF
4. The dihydrogen complexes were thermally unstable in solution. Treatment of CpOsBr(P-P) (P-P = dppm, dppe and dppp) with NaOMe in methanol gave the corresponding monohydride complexes CpOsH(P-P). Protonation of CpOsH(P-P) with HBF
4Et
2O at -78 ℃ gave a mixture of dihydride complexes cis-[CpOsH
2(P-P)] BF
4 and trans-[CpOsH
2(P-P)] BF
4. At room temperature in dichloromethane solutions, [CpOsH
2(dppm)]BF
4 exists as a mixture of cis and tram isomers in a ratio of 10: 1, [CpOsH
2 (dppe)]BF
4 exists as a mixture of cis and tram isomers in a ratio of 1:70, and [CpOsH
2(dppp)]BF
4 adopts only the trans geometry.
The pseudo-aqueous pK
a values of the [CpOsH
2(PR
3)
2)]BF
4((PR[subscrip 3])
2 = (PPh
3)
2, dppm, dppe, and dppp) series have been determined in dichloromethane. The pseudo-aqueous pK
a values indicate that the acidities of trans-[CpOsH
2(P-P)] BF
4(P-P = dppm, dppe, dppp) decrease as the size of the chelating ring increases. cis-[CpOsH
2(dppm)] BF
4 has been found to be less acidic than cis-[CpOsH
2(dppe)] BF
4 For the relative acidities of cis and transisomers in equilibrium, it has been shown that the major tautomer is always the weaker acid. The pseudo- aqueous pK
a values of the osmium complexes are consistently larger than those of the corresponding ruthenium analogs.
Protonation of Cp*RuH(COD) with HBF
4Et
2O at -78 ℃ produced [Cp*Ru(η
2-H
2)(COD)]BF
4. The dihydrogen complex was thermally unstable and decomposed to [Cp*Ru(η[to the power of 6]-COT)]BF
4, on warming up to room temperature. The previously unknown hydride Cp*RuH(NBD) was synthesized from the reaction of [Cp*Ru(H
2O)(NBD)]BF
4 with sodium formate in THF. Reaction of Cp*RuH(NBD) with HBF
4Et
2O produced a mixture of nortricyclene and the novel bimetallic complex [(Cp*Ru)
2(μ-H)(μ-C
5H
5CH=CHH
agostic)] BF
4. The bimetallic complex was unstable and decomposed in solution. Among the decomposed products, two were identified as [(Cp*Ru)
2(μ-CpCH
2CH
3)] BF
4 and [(Cp*Ru)
2(μ-Cp*RuC
5H
4CHH
agostic CH
3)](BF
4)
2. Protonation of the structural related complex RuHCl(NBD)(PPh
3)
2, with HBF
4.H
2O gave norbornene and a mixture of polyaqua complexes.
Treatment of Cp*RuCl(dppm) with NaBPh
4 in methanol in air produced the dioxygen complex [CpRu(η
2-O
2)(dppm)]BPh
4 which was characterized by X-ray crystallography. Exposure of acetone solutions of [Cp*RuH
2(dppm)]BF
4 to air led to the formation of [Cp*Ru(η
2-O
2)(dppm)]BF
4 and and [Cp*Ru(η
2-O
2) ((K-P,O)Ph
2CH
2P(=O)Ph
2)]BF
4 in approximately 1:4 ratio. A series of dihydrido-silyl complexes with the formula trans-{Cp*RuH
2[(K-P,Si)Ph
2 PCH
2P(OSiRR')Ph
2)]}BPh
4 (RR' = HPh, Ph
2, Et
2) were synthesized by reactions of [Cp*Ru(η
2-O
2)(dppm)]BPh
4 with 1° and 2° silanes. Reaction of HC≡CCH(OH)C≡CH with coordinated unsaturated d
6 complexes [Cp*Ru(dppe)]
+ gave the C
5H
2-bridged bimetallic complex [Cp*(dppe)Ru=C=C=CH-CH=C=Ru(dppe)Cp*](BF
4)
2. Deprotonation of the C
5 H
2-bridged bimetallic complex by neutral alumina led to the formation of the C
5H- bridged complex [Cp*(dppe)Ru=C=C=CH-C≡C-Ru(dppe)Cp*]BF
4, The analogous C
5H-bridged complexes [Cp(PPh
3)
2,Os=C=C=CH-C[≡C- Os(PPh
3)
2Cp]BF
4 and [Cp(dppe)Fe=C=C=CH-C≡C-Fe(dppe)Cp] BF
4 were synthesized similarly. The structure of [Cp(PPh
3)
2)Os=C=C= CH-C≡C-Os(PPh
3)
2)Cp]BF
4 was confirmed by X-ray crystallography and showed the bridging C
5H ligand to be a delocalized π-system. Reaction of [Cp*(dppe)Ru=C=C=CH-C≡C-Ru(dppe)Cp*]BF
4 with acetone in the presence of KOBu
t produced the neutral complex Cp*(dppe)RuC≡C-CH( CH
2COMe)C[≡C-Ru(dppe)Cp*.
The [2+2+2] cycloaddition reactions have been studied by using [Cp*Ru(H
2O)(NBD)]BF
4 and phenyl-functionalized acetylenes. Treatment of [Cp*Ru(H
2O)(NBD)]BF
4 with 1 equiv. of diphenylacetylene gave the π-arene complex [Cp*Ru(η[to the power of 6]-Ph
2C
2(C
7H
8)] BF
4. Analogous complex [Cp*Ru(η[to the power of 6]-PhCH
3 (C
7H
8)]BF
4 was obtained by using methylphenylacetylene. The above two complexes contain deltacyclene ligands which was formed by [2+2+2] cycloaddition of the acetylene with the coordinated NBD.
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