No abstract

New mono-and dinuclear aryltrialkylsilanes and-stannanes [Me 3 M{C 6 H 3 (CH 2 NMe 2) 2-2,6}] (M) Si (5), Sn (6)) and [(Me 3 M) 2-1,4-{C 6 (CH 2 NMe 2) 4-2,3,5,6}] (M) Si (9), Sn (10)) have been prepared from transmetalation reactions of dimeric [Li{C 6 H 3 (CH 2 NMe 2) 2-2,6}] 2 and new polymeric [Li 2-1,4-{C 6 (CH 2 NMe 2) 4-2,3,5,6}] ∞ with (trimethylsilyl)trifluoromethanesulfonate or trimethyltin chloride. The X-ray crystal structures of dinuclear 9 and 10 have been determined and in the molecular geometries found the central 1,4-phenylene dimetalated aryl ligand system provides bidentate C,N-coordination to silicon in 9 and terdentate pseudofacial N,C,N′-coordination to tin in 10. Reactions of the newly prepared silanes 5 and 9 and stannanes 6 and 10 with diverse palladium(II) and platinum(II) substrates afford organometallic products arising from both aryl and methyl group transfer. For example, the reaction of dinuclear stannane 10 (or dinuclear silane 9) with palladium(II) species gives the bimetallic complex [(PdCl) 2-1,4-{C 6 (CH 2 NMe 2) 4-2,3,5,6}] (15), whereas its reaction with [PtCl 2 (COD)] (COD) cycloocta-1,5-diene) or Me 3 SnCl gives the ionic tin(IV) species [(Me 2-Sn) 2-1,4-{C 6 (CH 2 NMe 2) 4-2,3,5,6}] 2+ (X-) 2 with X being Cl (18a) or Me 3 SnCl 2 (18b). The X-ray crystal structure of 18b has been determined and the molecular geometry found shows that the central dimetalated aryl ligand system provides terdentate meridional N,C,N′-coordination to both tin centers.

Copper(II)-mediated oxidative coupling of the blue, 18-electron mononuclear complex [Ru II -{C 6 H 3 (CH 2 NMe 2 ) 2 -2,6}(terpy)]Cl, 3 (terpy ) 2,2′;6′,2′′-terpyridine), affords the unique diamagnetic, binuclear 34-electron complex [(Ru III ) 2 (4,4′-{C 6 H 2 (CH 2 NMe 2 ) 2 -2,6} 2 )(terpy) 2 ]-(CuCl 2 ) 4 , 5a. This intensely green complex has been the subject of an X-ray crystal structure determination, and the molecular geometry of the tetracation shows the C4-C4′-coupled bridging biphenylene dianion to be planar. Two-electron reduction of this tetracation as its PF

The new anionic functionalized

The synthesis and characterization of new, five-coordinate, diamagnetic, 16-electron arylruthenium(II) complexes [RuIIX{C6H2(CH2PPh2)2-2,6-R-4}(PPh3)] (1, X = Cl, R = H; 2, X = Cl, R = Ph; 3, X = OSO2CF3, R = H; 4, X = I, R = H) are described. These coordinatively unsaturated complexes contain a stable Caryl−Ru σ-bond resulting from pseudomeridional terdentate P,C,P‘-bonding of the monoanionic {C6H2(CH2PPh2)2-2,6-R-4}- ligand (general abbreviation PCP-R-4; for R = H and R = Ph, abbreviated as PCP and PCP-Ph, respectively) that also provides two P → Ru bonds. This bonding mode of the PCP-R-4 ligands adopted in complexes 1−4 means that these species are structurally closely related to the complexes [RuCl{C6H2(CH2NMe2)2-2,6-R-4}(PPh3)] (R = H, Ph) in which there is terdentate N,C,N‘-coordination. Complexes 1 and 2 were synthesized via cyclometalation reactions of the respective neutral diphosphine compounds C6H3(CH2PPh2)2-2,6-R-4 (general abbreviation PC(H)P-R-4; for R = H and R = Ph, abbreviated as PC(H)P and PC(H)P-Ph, respectively) with [RuIICl2(PPh3)4]. The complex [RuII(OTf)(PCP)(PPh3)], 3, prepared by reaction of 1 with AgOTf (OTf = OSO2CF3 = triflate), has the triflate anion bound to ruthenium in noncoordinating solvents. On the NMR time scale complex 3 in solution exhibits temperature-dependent fluxionality that is associated with reversible changes of the complex stereochemistry. The triflate PCP complex 3 reacts cleanly with the neutral N-donor ligand 2,2‘:6‘,2‘‘-terpyridine (terpy) to afford [RuII(PCP)(terpy)][OTf], 5. However, whereas the reaction of terpy with the PCP-Ph complex 2 affords [RuII(PCP-Ph)(terpy)]Cl, 6, its reaction with PCP chloro complex 1 generates a mixture of products. These reactivities of PCP and PCP-Ph complexes (1−3) toward terpy are compared and contrasted with those of related ruthenium complexes containing the monoanionic aryldiamine ligand {C6H2(CH2NMe2)2-2,6-R-4}- (abbreviated as NCN-R-4).