The first structural characterization and determination of the isomerization activation parameters of a chiral phosphatitanoceneElectronic supplementary information (ESI) available: X-ray structure determination. See http://www.rsc.org/suppdata/cc/b2/b208945a/

Abstract

The activation parameters (delta G++298 = 11.5 (+/- 1.0) kcal mol-1, delta H++ = 16.3 (+/- 3.0) kcal mol-1, delta S++ = 16 (+/- 11) cal mol-1 K-1) have been determined for the rac to meso isomerization of a phosphametallocene, bis(3,4-dimethyl-2-phenylphospholyl)titanium dichloride, 2, which has been structurally characterized.

Synthesis and Properties of [NiCp*(2,5‐tBu2PC4H2)], a 20‐Valence‐Electron Phosphanickelocene

“…[50] However, both in Ephritikhines [7] and our work it has been possible to observe 18 ve nickel-containing structures that are formally the products of an h 5 -to h 1 -ring shift occurring in a phosphanickelocene structure. [51][52][53] The X-ray data suggesting that the carbon atoms preferentially peel away from the metal centre upon moving from phosphaferrocene 17 to phosphanickelocene 2, and the DFT results showing the high electron density at the phosphorus atom of 2, seem to indicate that the preferred structure for a simple unencumbered "monophosphanickelocene" will be a dimer such as 18. The 20ve configuration will become stable when the hindrance in the coordination sphere rises sufficiently to prevent the phospholyl ligand from adopting an orientation favourable to bridging: a situation that clearly exists in the structure found for 4.…”

The Continuing Development of the Chemistry of Phospholes

“…These products contain a valuable, previously unknown tricyclic structure, which was confirmed by X-ray diffraction analysis on the Psulfide derivative of 1 5 3. Intramolecular Diels-Alder reactions in general are aided by the favorable entropic effect from having the reaction components in fixed proximity; that this is the case here was demonstrated by the failure of a mixture of an "activated" phosphole (149) and allyl alcohol to give even a trace of cycloadduct on heating. The lithium derivative of endo-2-vinylborneol, prepared from (+)-camphor, was also used in this process; the reaction with the cyanophosphole gave an intermediate alkoxy phosphole that cyclized so rapidly at 25° that it could not be detected by 31 …”

Phosphines and Related Tervalent Phosphorus Systems

“…823,824 Palladium 825 and gallium 826 complexes of diphosphaferrocenes, involving s-donation from phosphorus, have also been prepared. Phosphametallocenes in which the phospholide anion is p-bonded to a transition metal other than iron have also generated much interest, reports having appeared concerning the chemistry of phosphatitanocenes, 827,828 phosphazirconocenes, 829 phospharuthenocenes, 830,831 and a phosphacymantrene. 832 Main group phospholide systems have also been reported, involving sodium, potassium, rubidium and caesium, 833 and also phospholides involving the f-block elements samarium and thulium.…”