Alkenyl and alkynyl complexes of osmium(II) derived from [OsH(Cl)(Co)(BTD)(PPh<sub>3</sub>)<sub>2</sub>] (BTD = 2,1,3-benzothiadiazole)

Abstract

Treatment of [OsH(CA)(NCMe)(2)(PPh3)(2)](+) (A = O or S) with [NEt4]Cl and 2,1,3-benzothiadiazole (BTD) provided [osH(Cl)(CA)(BTD)(PPh3)(2)] (A = O Or S). Under mild conditions, the complex [OsH(Cl)(CO)(BTD)(PPh3)(2)] hydroosmiates ethynyltoluene, ethyne and di(4-tolyl)butadiyne to provide vinyl complexes [Os(CH=CHR)Cl(CO)(BTD)(PPh3)(2)]. (R = C6H4Me-4), [Os(CH=CH2)Cl(CO)(BTD)(PPh3)(2)] and [Os {C(C=CR)=CHR}Cl(CO)(BTD)(PPh3)(2)]. Complex [OsH(CO)(NCMe)(2)(PPh3)(2)](+) reacted with HC=CR to provide [Os(CH=CHR)(CO)(NCMe)(2)(PPh3)(2)](+) which is converted by [NEt4]Cl into [Os(CH=CHR)Cl(CO)(NCMe)(PPh3)(2)]. Treatment of [Os(CH=CHR)CI(CO)(BTD)(PPh3)(2)] with CNCMe3 or CO provided [Os(CH=CHR)Cl(CO)(L)(PPh3)(2)] (L = CNCMe3 or CO). The dithiocarbamate complex [Os(CH=CHR)(S2CNMe2)(CO)(PPh3)(2)] and the osmatetraborane [Os(CH=CHR)(B3H8)(CO)(PPh3)(2)] resulted from the reactions of [Os(CH=CHR)Cl(CO)(BTD)(PPh3)(2)] with Na[S2CNMe2] and [NBu4n][B3H8], respectively, whereas with K[HB(pz)(3)] (pz = pyrazolyl) initially [Os(CH=CHR)(CO)(PPh3)(2)- {eta(2)-HB(pz)(3)}] was formed which is converted into [Os(CH=CHR)(CO)(PPh3){HB(pz)(3)}] on heating. No intermediates ape however observed in the corresponding reaction with 1,4,7-trithiacyclononane ([9]aneS(3)) to provide [Os(CH=CHR)(CO)(PPh3)([9]aneS(3))](+). The alkynyl complex [Os(C+CR)CI(CO)(BTD)(PPh3)(2)] was obtained from either (i) the reaction of [OsH(Cl)(CO)(BTD)(PPh3)(2)] with [Hg(C=CR)(2)] or (ii) [Os(CH=CHR)Cl(CO)(BTD)(PPh3)(2)] with an excess of HC=CR. Treatment of [Os(C+CR)Cl(CO)(BTD)(PPh3)(2)] with Na[S2CNMe2] or alternatively [Os(CH=CHR)(S2CNMe2)(CO)(PPh3)(2)] with an excess of HC=CR provided [Os(C=CR)(S2CNMe2)(CO)(PPh3)(2)], which can also be obtained from [OsH(S2CNMe2)(CO)(PPh3)(2)] and [Hg(C=CR)(2)]. The BTD in [Os(C=CR)Cl(CO)(BTD)(PPh3)(2)] is substituted by CNCMe3 to provide [Os(C=CR)Cl(CO)(CNCMe3)(PPh3)(2)]. The reaction of [OsH(Cl)(CS)(BTD)(PPh3)(2)] with HC=CR provided [Os(CH=CHR)Cl(CS)(BTD)(PPh3)(2)] which in contrast to [Os(CH=CHR)Cl(CO)(BTD)(PPh3)(2)] reacts with carbon monoxide to provide the thiocinnamoyl complex [Os(eta(2)-SCCH=CHR)Cl(CO)(PPh3)(2)].