Reactions of Ru(HCCHR)Cl(CO)(PPh3)2 with functionalized carboxylates. Crystal structure of Ru(HCCHPh)(O2CCHCHCHCHCH3)(CO)(PPh3)2

The stepwise generation of multimetallic complexes based on a vinylbipyridine linkage and their photophysical properties

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.

Redox-Active Tetraruthenium Macrocycles Built from 1,4-Divinylphenylene-Bridged Diruthenium Complexes

Metallamacrocylic tetraruthenium complexes were generated by treatment of 1,4-divinylphenylene-bridged diruthenium complexes with functionalized 1,3-benzene dicarboxylic acids and characterized by HR ESI-MS and multinuclear NMR spectroscopy. Every divinylphenylene diruthenium subunit is oxidized in two consecutive one-electron steps with half-wave potential splittings in the range of 250 to 330 mV. Additional, smaller redox-splittings between the +/2+ and 0/+ and the 3+/4+ and 2+/3+ redox processes, corresponding to the first and the second oxidations of every divinylphenylene diruthenium entity, are due to electrostatic effects. The lack of electronic coupling through bond or through space is explained by the nodal properties of the relevant molecular orbitals and the lateral side-by-side arrangement of the divinylphenylene linkers. The polyelectrochromic behavior of the divinylphenylene diruthenium precursors is retained and even amplified in these metallamacrocyclic structures. EPR studies down to T=4 K indicate that the dications 1-H(2+) and 1-OBu(2+) are paramagnetic. The dications and the tetracation of macrocycle 3-H display intense (dications) or weak (3-H(4+) ) EPR signals. Quantum chemical calculations indicate that the four most stable conformers of the macrocycles are largely devoid of strain. Bond parameters, energies as well as charge and spin density distributions of model macrocycle 5-H(Me) were calculated for the different charge and spin states.

The functionalisation of ruthenium(II) and osmium(II) alkenyl complexes with amine- and alkoxy-terminated dithiocarbamates

The complex cis-[RuCl(2)(dppm)(2)] reacts with the amine-terminated dithiocarbamates KS(2)CN(CH(2)CH(2)NEt(2))(2) and KS(2)CN(CH(2)CH(2)CH(2)NMe(2))(2) to form the compounds [Ru{S(2)CN(CH(2)CH(2)NEt(2))(2)}(dppm)(2)](+) and [Ru{S(2)CN(CH(2)CH(2)CH(2)NMe(2))(2)}(dppm)(2)](+), respectively. The methoxy-terminated dithiocarbamate compound [Ru{S(2)CN(CH(2)CH(2)OMe)(2)}(dppm)(2)](+) was also prepared from the same precursor using KS(2)CN(CH(2)CH(2)OMe)(2). The alkenyl complexes [RuRCl(CO)(BTD)(PPh(3))(2)] (R = CH=CHBu(t), CH=CHC(6)H(4)Me-4, CH=CHCPh(2)OH), [Ru(C(C[triple bond]CBu(t))=CHBu(t))Cl(CO)(PPh(3))(2)] and [Os(CH=CHC(6)H(4)Me-4)Cl(CO)(BTD)(PPh(3))(2)] also react cleanly with KS(2)CN(CH(2)CH(2)CH(2)NMe(2))(2) and KS(2)CN(CH(2)CH(2)NEt(2))(2) to yield [MR{S(2)CN(CH(2)CH(2)CH(2)NMe(2))(2)}(CO)(PPh(3))(2)] and [MR{S(2)CN(CH(2)CH(2)NEt(2))(2)}(CO)(PPh(3))(2)], respectively. In a similar fashion, the compounds [RuR{S(2)CN(CH(2)CH(2)OMe(2))(2)}(CO)(PPh(3))(2)] (R = CH=CHBu(t), CH=CHC(6)H(4)Me-4, C(C[triple bond]CBu(t))=CHBu(t)) were also prepared. Treatment of [Ru(CH=CHBu(t)){S(2)CN(CH(2)CH(2)CH(2)NMe(2))(2)}(CO)(PPh(3))(2)] and [Ru{S(2)CN(CH(2)CH(2)NEt(2))(2)}(dppm)(2)](+) with trifluoroacetic acid affords the ammonium complexes [Ru(CH=CHBu(t)){S(2)CN(CH(2)CH(2)CH(2)NHMe(2))(2)}(CO)(PPh(3))(2)](2+) and [Ru{S(2)CN(CH(2)CH(2)NHEt(2))(2)}(dppm)(2)](2+), while the same reagent generates the tricationic vinylcarbene complex [Ru(=CHCH=CPh(2)){S(2)CN(CH(2)CH(2)CH(2)NHMe(2))(2)}(CO)(PPh(3))(2)](3+) through loss of water from [Ru(CH=CHCPh(2)OH){S(2)CN(CH(2)CH(2)CH(2)NMe(2))(2)}(CO)(PPh(3))(2)]. The structures of [Ru{S(2)CN(CH(2)CH(2)OMe)(2)}(dppm)(2)]PF(6) and [Ru(CH=CHC(6)H(4)Me-4){S(2)CN(CH(2)CH(2)OMe)(2)}(CO)(PPh(3))(2)] were determined crystallographically.