Gyroscope like molecules consisting of trigonal or square planar osmium rotators within three-spoked dibridgehead diphosphine stators: syntheses, substitution reactions, structures, and dynamic properties

Abstract

aReactions of (NH 4 ) 2 OsX 6 (X = Cl, Br) with CO and the phosphines P((CH 2 ) m CHvCH 2 ) 3 (m = 6, a; 7, b; 8, c) give cis,cis,trans-Os(CO) 2 (X) 2 (P((CH 2 ) m CHvCH 2 ) 3 ) 2 (46-73%). These are treated with Grubbs' catalyst (7 mol%, 0.0010 M, C 6 H 5 Cl). Subsequent hydrogenations (PtO 2 ) yield the gyroscope like complexes cis,cis,trans-Os(CO) 2 (X) 2 (P((CH 2 ) n ) 3 P) (n = 2m + 2; X = Cl, 6a-c; Br, 7a-c; 5-31%) and the isomers cis,cis,trans-Os(CO) 2 (X) 2 (P(CH 2 ) n−1 CH 2 )((CH 2 ) n )(P(CH 2 ) n−1 CH 2 ) (X = Cl, 6'a-c; Br, 7'a-c; 12-51%) derived from a combination of interligand and intraligand metatheses. Reductions of 6a,c, 6'b, and 7'b with C 8 K under CO atmospheres afford trans-Os(CO) 3 (P((CH 2 ) n ) 3 P) (9a,c, 79-82%) and trans-

Non-metal-templated approaches to bis(borane) derivatives of macrocyclic dibridgehead diphosphines via alkene metathesis

“…Two signals of each set exhibited phosphorus coupling. The overall pattern was quite similar to those shown by metal complexes with cis or trans coordinating diphosphine ligands of the formula ( 6 ) [ 6 – 7 12 – 13 35 ]. This suggested the diphosphine diborane structure 6 ·2BH 3 (see Scheme 2 ), which is derived from one metathesis involving alkenyl moieties on different phosphorus atoms, and two metatheses of alkenyl moieties on identical phosphorus atoms.…”

Three-Fold Intramolecular Ring Closing Alkene Metatheses of Square Planar Complexes with cis Phosphorus Donor Ligands P(X(CH2)mCH═CH2)3 (X = −, m = 5–10; X = O, m = 3–5): Syntheses, Structures, and Thermal Properties of Macrocyclic Dibridgehead Diphosphorus Complexes

“…Here, an alternative mode of ring closing metathesis affords cis bis­(phosphacycle) chelate ligands ( fac - 12′c and fac - 13′c ). As noted above, related complexes with trans spanning chelates, such as mer , trans - 12′c , are sometimes found as byproducts in syntheses of octahedral gyroscope-like complexes. , …”

“…Halide ligands in gyroscope-like complexes are usually quite easily substituted by a variety of nucleophiles. − , In all cases, the phosphorus donor atoms remain trans . As part of this work, it was not sought to develop an extensive substitution chemistry of parachute-like complexes, but rather to verify that simple displacements can occur and the attendant stereochemistry.…”

“…The ring closing metatheses to give square planar gyroscope-like complexes in Scheme are easily extended to trigonal bipyramidal and octahedral coordination geometries. ,,,, Thus, we were curious whether the routes to parachute-like complexes in Schemes and could similarly be applied to trigonal bipyramidal or octahedral educts.…”

“…Multifold ring closing alkene (CC) metatheses can lead to a variety of fascinating molecular architectures, especially in metal coordination spheres. , Over the last 15 years, we have been especially concerned with metathesis/hydrogenation sequences of the type exemplified in Scheme . − These feature educts with trans disposed olefinic phosphine ligands of the formula P­((CH 2 ) m CHCH 2 ) 3 , such as the platinum dichloride complexes trans - 1c – e (indices code to the number of atoms between phosphorus and the vinyl group). The major products are almost always derived from 3-fold interligand metatheses, which afford triply trans spanning dibridgehead diphosphine ligands.…”