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The versatile rhenium complex [ReCl(CO)3(bpyC[triple bond, length as m-dash]CH)] (HC[triple bond, length as m-dash]Cbpy = 5-ethynyl-2,2'-bipyridine) is used to generate a series of bimetallic complexes through the hydrometallation of [MHCl(CO)(BTD)(PPh3)2] (M = Ru, Os; BTD = 2,1,3-benzothiadiazole). The ruthenium complex [Ru{CH[double bond, length as m-dash]CH-bpyReCl(CO)3}Cl(BTD)(CO)(PPh3)2] was characterised structurally. Ligand exchange reactions with bifunctional linkers bearing oxygen and sulfur donors provide access to tetra- and pentametallic complexes such as [{M{CH[double bond, length as m-dash]CH-bpyReCl(CO)3}(CO)(PPh3)2}2(S2CNC4H8NCS2)] and Fe[C5H4CO2M{CH[double bond, length as m-dash]CH-bpyReCl(CO)3}(CO)(PPh3)2]2. The effect of the group 8 metal on the photophysical properties of the rhenium centre was investigated using the complexes [Ru{CH[double bond, length as m-dash]CH-bpyReCl(CO)3}Cl(BTD)(CO)(PPh3)2] and [M{CH[double bond, length as m-dash]CH-bpyReCl(CO)3}{S2P(OEt)2}(CO)(PPh3)2] (M = Ru, Os). This revealed the quenching of the rhenium-based emission in favour of weak radiative processes based on the Ru and Os centres. The potential for exploiting this effect is illustrated by the reaction of [Ru{CH[double bond, length as m-dash]CH-bpyReCl(CO)3}Cl(CO)(BTD)(PPh3)2] with carbon monoxide, which results in a 5-fold fluorescence enhancement in the dicarbonyl product, [Ru{CH[double bond, length as m-dash]CH-bpyReCl(CO)3}Cl(CO)2(PPh3)2], as the quenching effect is disrupted.

The aza-crown ether compounds 1-aza-15-crown-5 and 1,10-diaza-18-crown-6 react with sodium hydroxide and carbon disulfide to provide the dithiocarbamates [15]aneO4-NCS2Na and NaS2CN-[18]aneO4-NCS2Na in good yield. The complexes [MRCl(CO)(L)(PPh3)2] (M = Ru, R = H, CH═CHC6H4Me-4, CH═CHBut, CH═CH-pyrenyl-1, C(C≡CPh)═CHPh; M = Os, R = H, CH═CH-pyrenyl-1; L = 2,1,3-benzothiadiazole or no ligand) undergo reaction with [15]aneO4-NCS2Na and NaS2CN-[18]aneO4-NCS2Na to yield [MR(S2CN-[15]aneO4)(CO)(PPh3)2] and [{MR(CO)(PPh3)2}2(S2CN-[18]aneO4-NCS2)], respectively. In a similar manner, cis-[RuCl2(dppm)2] provides [Ru(S2CN-[15]aneO4)(dppm)2]+ and [{Ru(dppm)2}2(S2CN-[18]aneO4-NCS2)]2+, respectively. Reaction of [Ru(CH═CHC6H4Me-4)(S2CN-[15]aneO4)(CO)(PPh3)2] with excess HC≡CBut leads to the formation of the alkynyl complex [Ru(C≡CBut)(S2CN-[15]aneO4)(CO)(PPh3)2]. Treatment of [OsHCl(CO)(BTD)(PPh3)2] with [HC≡C-bpyReCl(CO)3] results in the bimetallic compound [Os{CH═CH-bpyReCl(CO)3}Cl(CO)(BTD)(PPh3)2]. This reacts with...