Ruthenium and Rhodium Complexes of Thioether-Alkynylborates

Abstract

The species ((C 6 F 5 ) 2 BCH 2 SPh) 2 reacts with P h C C L i t o gi v e t h e t h i o e t h e r -a l k y n y l b o r a t e (C 6 F 5 ) 2 BCH 2 SPh(CCPh)Li(THF) 2 (1). Subsequent reaction with (Ph 3 P) 3 RuHCl, (Ph 3 P) 3 RhCl, and [(COD)Rh(μ-Cl)] 2 gives (C 6 F 5 ) 2 BCH 2 SPh(CCPh)RuH(PPh 3 ) 2 (2), ( C 6 F 5 ) 2 B C H 2 S P h ( C  C P h ) R h ( P P h 3 ) 2 ( 4 ) , a n d (C 6 F 5 ) 2 BCH 2 SPh(CCPh)Rh(COD) (5), respectively, demonstrating a bidentate binding mode via the alkynyl and thioether donors of the borate. Subsequent reactions of 2 and 4 with H 2 gave (C 6 F 5 ) 2 BCH 2 SPh(CH 2 CH 2 Ph)RuH(PPh 3 ) 2 (3) and ((C 6 F 5 ) 2 BCH 2 SPh(CHCHPh))Rh(PPh 3 ) 2 (6). In the former case, the borate remains bound to the metal via a π-interaction with the thioether-arene ring, while in the latter case, S and alkene binding is observed. ■ INTRODUCTIONPolydentate B-based ligands have garnered much attention over the past four decades. The quintessential example of such ligands are tris(pyrazolyl)borates. Such ligands have been popular for use in coordination chemistry, as a large range of modifications altering the steric and electronic properties of these ligands is conveniently achieved. Such chemistry has been widely explored and extensively reviewed. 1−21 Other boratebased anionic ligands have garnered attention as well. For example, Peters and co-workers have exploited monodentate, bidentate, and tridentate borate-based ligands of the general forms [R 3 BC 6 H 4 PR′ 2 ] − , [RB(CH 2 PR′ 2 ) 3 ] − , and [R 2 B-(CH 2 PR′ 2 ) 2 ] − (Scheme 1) in a variety of creative developments. 22−45 For example, these authors have developed unique approaches to Fe hydrazine, CO 2 , and nitride chemistry, 42,45,46 Cu aminyl radicals 44 as well as novel routes to stabilize unusual main-group species. 23,32 Peters has also employed the heteroleptic bis(phosphino)pyrazolylborate ligand [PhB-(CH 2 PtBu 2 ) 2 (pz)] to prepare terminal Fe(IV) imides. 46 Related borate ligands with sulfur donors have been studied and reviewed by Riodan and co-workers. 47 In these cases, the coordination chemistry and subsequent reactivity of complexes derived from the related class of ligands polythioether borates, [RB(CH 2 SR′) 3 ] − , [RB(CH 2 SR′) 2 (pz)] − , and [R 2 B(CH 2 SR′) 2 ] − (Scheme 1), have been explored. On the other hand, borate ligands with alkyl, vinyl, or aryl borate ligands have been derived from reactions of donor-borane species with suitable metal precursors, resulting in abstraction of metal-bound fragments and the formation of chelating donor-borate systems. 48−52 In our own work, we have recently prepared the thioetherborane species ((C 6 F 5 ) 2 BCH 2 SPh) 2 and shown that it is capable of reacting with alkyne to generate B/S-based heterocycles via frustrated Lewis pair (FLP) addition reactions. 53 In this paper, we explore the utility of this species as a precursor to a thioether alkynyl-borate ligand. Herein, we demonstrate that this ligand forms dissymmetric chelating thioether alkynyl-borate complexes of Ru and Rh. ...

Pseudotetrahedral Rhodium(I) Complexes

“…From the few examples that have been crystallographically characterized, electronically saturated TBPY complexes are derived from 16 electron metal fragments such as RhCl(PMe 3 ) 3 ,18 RhCpP i Pr 3 ,19 or RhTp(L),20 (Tp=tris(pyrazolylborate)) while T‐shaped 14 electron fragments such as Rh(X)(P i Pr 3 ) 2 (X=Cl, I)21 and Rh(acac)(olefin)22 (acac=acetylacetonate) bind alkynes to yield 16 electron SP compounds. Functionalized alkynes like thioether alkynylborates,23 and P(CC)P pincer‐type ligands24 also bind rhodium centers as two‐electron donors. Consequently, complex 2 represents the first authenticate rhodium complex with the alkyne donating more than two electrons, thus resulting in the unusual coordination environment for rhodium.…”

Pseudo‐tetrahedral Rhodium and Iridium Complexes: Catalytic Synthesis of E‐Enynes

“…Of the few examples crystallographically characterized, electronically saturated TBPY complexes are derived from metal fragments such as “RhCl(PMe 3 ) 3 ”, “RhCp′P i Pr 3 ”, or “RhTp(L)”, whereas the metallic fragments “Rh(X)(P i Pr 3 ) 2 ” (X=Cl, I) and “Rh(acac)(olefin)” are suitable for binding alkynes to electronically unsaturated 16‐electron SP compounds. More recently, SP complexes with functionalized alkynes, such as thioether‐alkynylborates, and P(C≡C)P pincer‐type ligands, have been described.…”

“…Structure (ORTEPdiagram, ellipsoids at the 50 %p robability level) of [Rh(PhBP 3 )(CCCO 2 Me)(H)(PMe 3 )](19). Hydrogen atomsh ave been omitted and only the C ipso atoms of the phenyl groups of PhBP 3 are shownfor clarity.Selectedb ond lengths []a nd angles [8]: RhÀP1 2.367(1), RhÀP2 2.460(1), RhÀP3 2.355(1), RhÀP4 2.345(1), RhÀC49 2.017(4),C49ÀC50 1.212(5),C 50ÀC51a 1.438(5), C50ÀC51b1 .440(7), P1-Rh-P4 167.4(4), P2-Rh-H 174(2),P3-Rh-C49 166.0(1).…”

9,10-Dihydroanthracenyl structures: original ligands for the synthesis of polymetallic complexes through selective π-coordination

“…We chose the organometallic precursor [RuCp-(CH 3 CN) 3 ]PF 6 as a source of the electrophilic moiety RuCp + known for its affinity towards η 6 -coordination. 17,18 We selected two aniline derivatives being differentiated by the nature of the heterocycle, N-phenylsuccinimide (A and B) and N-phenylpyrrolidine (C and D) groups (Fig. 1), also giving the possibility to study the steric influence on the coordination by the substitution at the 9 and 10 positions (non-substituted ligands A and C vs. di-ethoxy B and D derivatives).…”