Syntheses, Structures, and Spectro-electrochemistry of {Cp*(PP)Ru}C⋮CC⋮C{Ru(PP)Cp*} (PP = dppm, dppe) and Their Mono- and Dications

Abstract

The complexes {Cp*(PP)Ru}2(μ-C⋮CC⋮C) (PP = dppm 5a, dppe 5b) have been synthesized from RuCl(PP)Cp* (1a/b) via the corresponding vinylidenes [Ru(CCH2)(PP)Cp*]+ (2a/b), deprotonation (KOBut) to the ethynyls Ru(C⋮CH)(PP)Cp* (3a/b), oxidative coupling ([FeCp2][PF6]) to the bis(vinylidenes) [{Ru(PP)Cp*}2{μ-(CCHCHC)}]2+ (4a/b), and deprotonation [dbu (4a), KOBut (4b)]. Electrochemistry of 5a/b revealed the expected sequence of four 1e redox steps, which occurred at significantly lower E° values than found for the Ru(PPh3)2Cp analogue. Single-crystal X-ray structure determinations are reported for 1a/b, 2a/b, 3a/b, 4a/b, and 5a/b, together with the oxidized products [5b][PF6] n (n = 1, 2). In the monocation [5b][PF6] the Ru−C(1) [1.931(2) Å] and C−C distances [1.248−1.338(3) Å] are intermediate between those found in 5b and the dication [5b]2+. The short Ru−C [1.857(5) Å] and experimentally equal C−C distances [1.269−1.280(6) Å] in [5b][PF6]2 confirm the anticipated dicarbene-cumulene structure for the RuCCCCRu bridge.

Cationic Ruthenium‐Cyclopentadienyl‐Diphosphine Complexes as Catalysts for the Allylation of Phenols with Allyl Alcohol; Relation between Structure and Catalytic Performance in O‐ vs. C‐Allylation

“…The distances of the ruthenium centre to the cyclopentadienyl group and the chloride anion are similar for all three compounds and are comparable to those of related ruthenium complexes. [14][15][16][17] The distance of the oxygen atoms O (17) and O(47) to Ru is too large [3.7932(17)-4.2351 (14) ] for all of the structures to be considered as an interaction, how-A C H T U N G T R E N N U N G ever, they are close enough to sterically block the metal centre. The two other oxygen atoms, O (27) and O (37), are relatively far away from the ruthenium atom [5.1764(15)-5.3428 (13) ].…”

A Synthetic Breakthrough into an Unanticipated Stability Regime: A Series of Isolable Complexes in which C6, C8, C10, C12, C16, C20, C24, and C28 Polyynediyl Chains Span Two Platinum Atoms

“…However, many current efforts seek to test the limits of homologous series of compounds. One 6 Pt (56 %) and PtC 10 Pt (84 %). The effect of the chain lengths in PtC x Pt upon thermal stabilities (> 200 8C for x 20), IR n CC patterns (progressively more bands), colors (yellow to orange to deep red), UV/Vis spectra (progressively redshifted and more intense bands with e > 400 000 m À1 cm…”

Refining the Interpretation of Near‐Infrared Band Shapes in a Polyynediyl Molecular Wire

“…[4b, 6,7] Charge delocalisation along the six-atom MC 4 M chain is increased in complexes of the heavier metals, e.g., {ML n } = [RuA C H T U N G T R E N N U N G (PPh 3 ) 2 Cp] (1), [8] [RuA C H T U N G T R E N N U N G (dppe)Cp*], [9] [OsA C H T U N G T R E N N U N G (dppe)Cp*], [10] and [Re(NO)A C H T U N G T R E N N U N G (PPh 3 )Cp*].…”