Acetylene Dithiolate Linking up the [Tp′W(CO)(CN)] Moiety with Ru^II or Pd^II

Abstract

A series of heterodinuclear complexes with acetylene dithiolate (acdt(2-) ) as the bridging moiety were synthesised by a facile one-pot procedure that avoided use of the highly elusive acetylene dithiol. Generation of the W-Ru complex [Tp'W(CN)(CO)(C2 S2 )Ru(η(5) -C5 H5 )(PPh3 )] (Tp'=hydrotris(3,5-dimethylpyrazolyl)borate) and the W-Pd complexes [Tp'W(CN)(CO)(C2 S2 )Pd(dppe)] and [Tp'W(CO)2 (C2 S2 )Pd(dppe)][PF6 ] (dppe=1,2-bis(diphenylphoshino)ethane), which exhibit a [W(η(2) -κ(2) -C2 S2 )M] core (M=Ru, Pd), was accomplished by using a transition-metal-assisted solvolytical removal of the Me3 Si-ethyl thiol protecting groups. All intermediate species of the reaction have been fully characterised. The highly coloured W-Ru complex [Tp'W(CN)(CO)(C2 S2 )Ru(η(5) -C5 H5 )(PPh3 )] shows reversible redox chemistry, as does the prototype complex [Tp'W(CO)2 (C2 S2 )Ru(η(5) -C5 H5 )(PPh3 )][PF6 ]. Single crystal X-ray diffraction and IR, EPR and UV/Vis spectroscopic studies in conjunction with DFT calculations prove the high electronic delocalisation of states over the acdt(2-) linker. Comparative studies revealed a higher donor strength and more pronounced dithiolate character of acdt(2-) in [Tp'W(CN)(CO)(C2 S2 )Ru(η(5) -C5 H5 )(PPh3 )] relative to [Tp'W(CO)2 (C2 S2 )Ru(η(5) -C5 H5 )(PPh3 )](+) . In addition, the influence of the overall complex charge on the metric parameters was investigated by single-crystal X-ray diffraction studies with the W-Pd complexes [Tp'WL2 (C2 S2 )Pd(dppe)] (L=(CN(-) )(CO) or (CO)2 ). The central [W(C2 S2 )Pd] units exhibit high structural similarity, which indicates the extensive delocalisation of charge over both metals.

CS2 Reductive Coupling to Acetylenedithiolate by a Dinuclear Ytterbium(II) Complex

“…The structure of 2 (Figure ) shows the presence of a dimer in which the C 2 S 2 2− ligand bridges the two Yb III ions in an unprecedented linear μ‐η 2 ‐C,S: η 2 ‐C′,S′ fashion. The observed binding mode is consistent with the formulation of the ligand acetylenedithiolate and differs significantly from the side‐on bridging mode (μ‐η 2 ‐C,C′) found in homo‐ and heterobimetallic complexes of d‐block metals –…”

Spontaneous Formation of an η2‐C, S‐Thioketene Complex in Pursuit of Tungsten(IV)‐Sulfanylalkyne Complexes

“…The W–C1 bonds are slightly shorter in 2 and 3 as compared with the tolane complex 1 , which can be attributed to the better π ⟂ donation ability of S‐substituted alkynes. Interestingly, the W–alkyne–C bonds in 2 and 3 are about 0.05 Å longer as compared with those in related W II complexes [Tp′W(CO)(L) {η 2 ‐C 2 (SR) 2 }] +/0 (L = CO, CN – , R = Bn, C 2 H 4 TMS) 1b,1d. In this context the competition between π ⟂ donation of the alkyne and π p donation of the terminal oxygen is crucial for 2 and 3 , while the same interaction is rather synergistic with π acceptor co‐ligands.…”

Pathways to Polynuclear Complexes with α-S,N-Substituted Alkynes as Bridging Ligands

“…In addition, the high conjugation of metals over the π-system in corresponding polynuclear complexes causes remarkable electronic cooperativity. Alkynes bearing third period element based α-substituents like phosphines or thiolates allow the formation of dinuclear complexes of types B and C depicted in Chart . − The generation of B -type dinuclear complexes with N donor atoms was serendipitously observed by isocyanide dimerization. , In contrast, bridging mode A featuring a linear alkyne is well-known for bis­(diphenylphosphino)­acetylene (dppa) − and was successfully applied in the assembly of supramolecular complex architectures. − Only recently, mode A was reported for oxygen donor atoms. − Our long-standing interest is focused on coordination mode B , showing a side-on coordination of the alkyne in the first place. The resulting bend back of the α-substituted donors enables coordination of a second metal in a chelating manner via the donor atoms.…”

“…In the recent past, strong intermetallic cooperativity was established for polynuclear complexes of type B featuring the ambident ligand (S–CC–S) 2– (acdt 2– ). − , However, rational synthetic concepts for the preparation of polynuclear complexes with the lighter congeners N or O as donor atoms are much less developed. Complexes of C 2 O 2 2– were obtained by reductive coupling of coordinated CO leading either to mononuclear η 2 - C , C ′-complexes of acetylenediol (Figure , complex D + ), as presented by Lippard et al, , or dinuclear κ 2 - O , O ′-complexes of type E without any coordination at the triple bond as published by the groups of Cloke and Arnold. , The synthesis of free alkynes with tertiary amine substituents is cumbersome but well established, so far. , Accordingly, Filippou and Rosenauer utilized Me 2 N–C 2 –NMe 2 to form an Fe complex, whereas Tamm and co-workers used bis­(piperidine)­acetylene for the coordination at Ru­(II) in F + (Figure ).…”

“…1,3,28 In the recent past, strong intermetallic cooperativity was established for polynuclear complexes of type B featuring the ambident ligand (S−CC−S) 2− (acdt 2− ). [1][2][3]5 However, rational synthetic concepts for the preparation of polynuclear complexes with the lighter congeners N or O as donor atoms are much less developed. Complexes of C 2 O 2 2− were obtained by reductive coupling of coordinated CO leading either to mononuclear η 2 -C,C′-complexes of acetylenediol (Figure 1, complex D + ), as presented by Lippard et al, 29,30 or dinuclear κ 2 -O,O′-complexes of type E without any coordination at the triple bond as published by the groups of Cloke 25 and Arnold.…”