A surprise landing on the terra incognita of macrocyclic dibridgehead diorganoarsines: syntheses, structures, and reactivities

Abstract

Reactions of trans-[Fe(CO)2(NO)(As((CH2)n)3As)]+ BF4− (n = 10, 12, 14) and Bu4N+ Cl– afford the title compounds As((CH2)n)3As, which upon reaction (n = 14) with MCl2 (M = Pt, Ni), Rh(CO)(Cl),...

Syntheses, homeomorphic and configurational isomerizations, and structures of macrocyclic aliphatic dibridgehead diphosphines; molecules that turn themselves inside out

“…They represent very promising building blocks for both monometallic and polymetallic or polymeric systems – research directions that will be facilitated as improved syntheses are developed. 28 Monometallic adducts of in , in isomers have been termed gyroscope-like and are attractive springboards for molecular gyroscopes. 42 The dynamic properties of 3c , e have already been put to use in metal transport protocols, 5 and all of the preceding directions of inquiry are actively being extended to diarsine 36,41 and phosphine oxide analogs (EX = As, PO).…”

Square-Planar and Octahedral Gyroscope-Like Metal Complexes Consisting of Dipolar Rotators Encased in Dibridgehead Di(triaryl)phosphine Stators: Syntheses, Structures, Dynamic Properties, and Reactivity

“…As shown in Scheme , a CH 2 Cl 2 solution of 14d was treated with [Rh­(CO) 2 (μ-Cl)] 2 . Under conditions analogous with those of the aliphatic diphosphine P­((CH 2 ) 14 ) 3 P, the Rh­(CO)­(Cl) fragment was reintroduced between the phosphorus atoms, (re)­generating 1 -Cl. , Accordingly, 6d reformed in quantitative spectroscopic yield, or 87% yield after workup.…”

“…One approach to enhancing the vertical clearance is to replace phosphorus by arsenic, which increases the bond lengths to the metal by ca. 4%. , Accordingly, rotational barriers drop by several kilocalories per mole . Because most rotators of interest to date have relatively modest radii, distances associated with the first few atoms bound to each phosphorus (or arsenic) atom are of the greatest interest.…”

“…We have had a long-standing interest in the transition-metal-based rotors II (Scheme ), which feature two trans phosphorus donor atoms connected by three (CH 2 ) n bridges. − Together these comprise the cagelike stator. Such dibridgehead di­(trialkyl)­phosphine complexes are usually accessed via 3-fold ring-closing metatheses of square-planar, trigonal-bipyramidal, or octahedral precursors I .…”

“…Another driving force for this study was the potential for liberating free dibridgehead di­(triaryl)­phosphines IV (Scheme ) from the metal complexes. There are increasing numbers of avenues for preparing the aliphatic analogues P­((CH 2 ) n ) 3 P from II , , including from the rhodium adduct 1 -Cl . As detailed in the Discussion section, there is prior literature on dibridgehead di­(triaryl)­phosphines and related compounds, all with additional p -phenylene moieties in each bridge. , Importantly, as partially illustrated for IV , such compounds can potentially exist as in , in , out , out , and in , out isomers, a separate theme of great interest…”