“Redox‐Switch” Catalysis of CC Bond Formation with H₂: One‐Electron Reduction of the Trityl Cation

Abstract

COMMUNICATIONS results for each T1 atom. For TI4 the shortest TILT1 distance in the cluster is part of this approximately linear arrangement (T12-T14-C4 169.1 "), The triangle T11, T12, TI3 can be compared with a recently calculated triplumbane (H,Pb), , for which a paddle wheel arrangement of the substituents with Pb-Pb distances longer than a Pb-Pb single bond was obtained as the energy minimum. [' 71 The bonding in this triangle is best described similarly to that in tetrakis[bis(trimethylsilyl)methyl]distannene from Lappert et aI.['*] by a Lewis acid-base interaction between three plumbanediyl (H,Pb) or thalliumdiyl (RT1) fragments through their lone pair of electrons and their empty p orbital, which in contrast to the dimeric Sn compound with a nonclassical Sn -Sn double bond results in a cyclic trimer. The atom TI4 is located above the T1, triangle with, however, significantly longer TI-T1 distances, which might indicate only very weak TI-TI bonding interactions. Thus, in addition to the cryoscopically determined molar mass of 1 in solution, the crystal structure analysis clearly confirms weaker element-element bonding than in the analogs with the lighter elements Ga and In. The TI-C bond lengths of 238 pm (to TII, T12 and T13) and 233 pm (T14-C4) are longer than the values in compounds with trivalent T1 atoms (av 215 pm).[t91 Experimenial SrctionA solution of LiC(SiMe,), 2 T H F (2.13 g, 5.58 mmol) [131 in toluene (25 mL) was added dropwise to a cooled ( -40 C) suspension of sublimed cyclopentadienylthallium(r) (1 -58 g, 5.87 mmol) in toluene (25 mL) under argon. The solution was slowly allowed to warm to 0 -C and the solvent rapidly evaporated at room temperature. The residue WAS treated with pentane (10 mL) and filtered. The red-violet filtrate was evaporated to dryness, diisopropyl ether was added, and the solution quickly cooled to -50 C Compound 1 crystallized as pyrophoric, extremely sensitive, almost black crystals. which appeared deep red-violet in thin layers. Yield: 1.58 g ( 6 5 % ) . Decomposition at 65 'C (under argon). Molar mass (determined cryoscopically in benzene) [gmol-'1: found 413; calcd 435.96 (for the monomer) 'H NMR (C,D,): d = 0.13; '"C NMR (C,D,): 6 = 6.6 (SiMe,), 30.5 (TIC). IR (Nujoi; Cs-Br):i.[cm ' ] = 1 2 5 0 m B C H , ; 1 1 6 9~, 1 1 1 3 v w , 1 0 9 3 v w , 1 0 4 4~, 1 0 0 9 m ; 8 8 3 v s , 850 vs, 766 s. 745 ni. 723 s pCH,(Si); 673 s. 665 s vJiC; 640 m, 61 1 m v$iC; 525 vs. 465 m vTI,C,. 363 w. 312 w 6SiC. UV/Vis (pentane): i . , , ,[nm] (Ige) = 215 (3.7). 245 (3.8). 320 (sh. 3 0). 380 (sh, 2.7). 515 (2.7).

Synthesis and properties of carboxy-substituted half-sandwich ruthenium complexes with chelating bisphosphine ligands (η5-C5H4CO2H)Ru(η2-L)X (X=I, H)

“…2) [17]. We therefore conclude that 12 is a trans dihydride complex; [Cp * Ru(dppf)H 2 ] + is believed to be trans on the basis of a similar argument [18].…”

Experimental and Computational Studies on Quadruply Bonded Dimolybdenum Complexes with Terminal and Bridging Hydride Ligands

“…Its cationic moiety solvated by Et 2 O or thf was additionally generated in NMR‐tube‐scale reactions of complex 1⋅thf with [H(OEt 2 ) 2 ][BAr F ] (BAr F =tetrakis[3,5‐bis(trifluoromethyl)phenyl]borate) [46] and [CPh 3 ][B(C 6 F 5 ) 4 ]. The protonation reaction originates H 2 as a side‐product, whereas use of the trityl reagent produces HCPh 3 and Gomberg's dimer [47] (see Scheme S1 in the Supporting Information). Complex 1⋅py also reacted readily with AgNTf 2 , affording a somewhat similar product of composition [Mo 2 (H)(μ‐Ad Dipp2 ) 2 (py) 2 ][NTf 2 ].…”

Using a Two-Step Hydride Transfer To Achieve 1,4-Reduction in the Catalytic Hydrogenation of an Acyl Pyridinium Cation

“…The title dihydride complex27 may be prepared by treating 5 with HBF 4 ·OMe 2 at room temperature, or by warming a solution of 10a to room temperature. 1 H NMR (300 MHz, 279.5 K, CD 2 Cl 2 ): δ −7.80 (t, Ru (H) 2 , J P–H = 25.8 Hz, 2H), 1.24 (s, Cp*, 15H), 4.19 (s, dppf Cp, 4H), 4.21 (s, dppf Cp, 4H), 7.58–7.66 (m, Ar, 12H), 7.85–7.96 (m, Ar, 8H).…”