Syntheses of Dimetallamacrocycles by Intramolecular Oxidative Couplings of Dinuclear Bis(1,3‐butadiynyl) Complexes: A New Approach to Steric Shielding in (sp‐Carbon chain)dirhenium Complexes [(η⁵‐C₅Me₅)Re(NO)(PR₃)(C≡CC≡CC≡CC≡C)(R₃P)(ON)Re(η⁵‐C₅Me₅)]

Abstract

Reactions of the chiral racemic carbonyl complex [(η5‐C5Me5)Re(NO)(NCCH3)(CO)]+·BF4− and diphosphanes Ph2P(CH2)nPPh2 [2.4:1.0 mol ratio; n = 10 (a), 14 (b)] give the (bridging phosphane)dirhenium complexes [(η5‐C5Me5)Re(NO)(CO){μ‐[PPh2(CH2)nPh2P]‐P,P}(OC)(ON)Re(η5C5Me5)]2+·2BF4− (73−80%), which are reduced (LiAlH4) to the dimethyl complexes [(η5‐C5Me5)Re(NO)(CH3){μ‐[PPh2(CH2)nPh2P]‐P,P}(ON)(H3C)Re(η5‐C5Me5)] (92−96%). Reactions with HBF4·OEt2/C6H5Cl, HC≡CC≡CSiMe3, and tBuOK give, via π‐HC≡C adducts (89−94%), the bis(trimethylsilylbutadiynyl) complexes [(η5‐C5Me5)Re(NO)(C≡CC≡ CSiMe3){μ‐[PPh2(CH2)nPh2P]‐P,P}(Me3SiC≡CC≡C)(ON)Re(η5‐C5Me5)] (9a,b; 95−66%). Desilylation (wet nBu4NF) yields labile bis(butadiynyl) complexes, which are coupled [Cu(OAc)2/pyridine] to the μ‐octatetraynediyl complexes [(η5‐C5Me5)Re(NO){μ‐[PPh2(CH2)nPh2P]‐P,P}{μ‐(C1≡CC≡CC≡CC≡C8)‐C1,C8}(ON)Re(η5‐C5Me5)] (3a,b; 10−23% from 9a,b). These represent some of the few cases of intramolecular oxidative homocouplings of terminal alkynes in metal coordination spheres. The electrochemical properties of 3a,b, which undergo two one‐electron oxidations, are compared to nonmacrocyclic analogs that lack the diphosphane bridge. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)

Iterative Synthesis of Oligoynes Capped by a Ru2(ap)4-terminus and Their Electrochemical and Optoelectronic Properties

“…Commonly used σ-polycarbon ligands include polyynyl − and allenylidenyl/cumulenyl, as shown in Scheme , and the former dominates. As the prototype of molecular electronic wires, many {M}−C 2 k −{M} type compounds of high degree of electronic mobility were reported in recent years. − Other closely related studies include multiple alkynylated ferrocenes and cyclobutadiene(cyclopentadienyl)cobalt, cumulene-bridged biferrocene, , acetylide-capped linear trimetallic com- pounds, − metal-centered bis-allenylidene, and acetylene-bridged dimers of triruthenium basic acetate , and notable results include a recent demonstration of substantial charge mobility both across a Ru 2 unit between two ferrocenyl centers and across carbon-rich chains between two Ru 2 centers. −

1 Wire-like Metalallaynes and Metalla-cumulenes

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Synthesis and Characterization of Luminescent Rhenium(I)−Platinum(II) Polypyridine Bichromophoric Alkynyl-Bridged Molecular Rods

“…In recent years, the chemistry of metal-containing alkynyls has captured the attention of many researchers due to their rigid structures as well as the rich spectroscopic and photophysical behavior associated with some of these complexes . Complexes of rhenium alkynyls are known, but with most of the studies concentrated on the homometallic systems . Gladysz and co-workers reported a series of alkynyl-bridged dinuclear rhenium(I) alkynyls, including one that involved 20 carbon atoms in the chain spanning two redox-active [Re( η 5 -C 5 Me 5 )(NO)(PPh 3 )] moieties 2a.…”

“…Complexes of rhenium alkynyls are known, but with most of the studies concentrated on the homometallic systems . Gladysz and co-workers reported a series of alkynyl-bridged dinuclear rhenium(I) alkynyls, including one that involved 20 carbon atoms in the chain spanning two redox-active [Re( η 5 -C 5 Me 5 )(NO)(PPh 3 )] moieties 2a. Examples of heteronuclear rhenium alkynyl rods are scarce, and most of them were confined to the study of their structural and electrochemical properties.…”

Longitudinally Extended Molecular Wires Based upon PtC⋮CC⋮CC⋮CC⋮C Repeat Units: Iterative Syntheses of Functionalized Linear PtC8Pt, PtC8PtC8Pt, and PtC8PtC8PtC8Pt Assemblies

“…Many such wire-like compounds are now available, and researchers are attempting to construct multidimensional arrays that model more complex types of devices . Efforts in our laboratory have focused on the elaboration of Re(C⋮C) n Re and Pt(C⋮C) n Pt − systems. These building blocks are available with chain lengths of up to 20 carbons.…”