Anthony D. Woods

Synthesis of cobalt-containing cyclophanes, and the formation of an unprecedented seven-membered cyclic diyne

The acid-catalysed Nicholas reaction of the bis-propargyl complex [{Co2(CO)6(μ-η2-HOMe2CCC–)}2] 1 in the presence of a variety of nucleophiles leads in each case to [{Co2(CO)6}2{cyclo-μ-η2:μ-η2-C(CH2)CH2CMe2CC–CC}], a complex which contains an unprecedented seven-membered macrocyclic diyne ligand. The reactivity of 1 is compared to that of [{Co2(CO)6}2{μ-η2:μ-η2-1,4-C6H4(CCCMe2OH)2}] which does not cyclise on treatment with nucleophiles but instead gives the expected substitution products.

Stabilisation of an ortho-deprotonated mesityl group within the unusual [{2,4,6-Me3C6H2P}{4,6-Me2C6H2(2-CH2)P}Sn]3? stannate ionElectronic supplementary information (ESI) available: synthesis of 1. See http://www.rsc.org/suppdata/cc/b3/b303390m/

The reaction of 2,4,6-Me3C6H2PHNa with Sn(NMe2)2 (3 : 1 equivalents, respectively) results in the formation of the unusual [{2,4,6-Me3C6H2P}{4,6-Me2C6H2(2-CH2)P}Sn]3− stannate trianion in the heterometallic cage [{2,4,6-Me3C6H2P}{4,6-Me2C6H2(2-CH2)P}Sn]Na3·2TMEDA]4 (1), in which unprecedented ortho-Me deprotonation of a [2,4,6-Me3C6H2P]2− ligand has occurred.

Synthesis and structure of [{Sn(μ‒PCy)}3(Na·PMDETA)2], containing an electron-deficient [{Sn(μ‒PCy)}3]2- dianion

The reaction of CyPHNa with Sn(NMe2)2 in the presence of PMDETA (= {Me2NCH2CH2}2NMe) gives the title compound [{Sn(μ–PCy)}3(Na·PMDETA)2] (1), containing an electron-deficient [(Sn(μ–PCy)}]32− dianion with a novel two-electron, three centre (2e–3c) bonding arrangement.

Steric control in the oligomerisation of phosphazane dimers; towards new phosphorus–nitrogen macrocycles

The reaction of [ClP(mu-NtBu)]2 (1) with H2O (1 : 2 equivalents) in the presence of excess Et3N gives the new chain compound [(mu-O)[P(mu-NtBu)2P(H)=O]2] (3), consisting of two P2N2 rings linked by a mu-O atom and terminating in P(V)(H)=O groups. A similar chain species is obtained from the reaction of the lithiate of [(tBuNH)P(mu-NtBu)2P(H)=O] (5) with [ClP(mu-NtBu)2P(NHtBu)] (2), the product being [(mu-O)[P(mu-NtBu)2P(NHtBu)]2] (6). Compounds 3 and 6 are the first examples of O-bridged chain phosphazanes and potential precursors to new phosphorus-nitrogen macrocycles. The syntheses and X-ray structures of 3, 5 and 6 are reported.

Reaction of Group 15 Trichlorides ECl3 with the Anion [Mo2Cp2(CO)4(μ-PH2)]−; Synthesis and Characterization of the First Complexes Featuring a Heteroμ,η2-PE ligand (E=As, Sb)

An Me2 PE tetrahedrane framework is seen in complexes 2 a-c (E=P, As, Sb), which are prepared from the appropriate trichlorides and 1 in THF. The structures of the new antimony- and arsenic-containing compounds 2 b and 2 c have been determined-this is the first structural characterization of complexes with μ,η2 -PE heteroligands from elements of Group 15.

Synthesis and deprotonation of P–H-functionalised phosph(III)azanes; borohydride dependency on the formation of cis- or trans-[HP(μ-NtBu)2PNtBuH]

The reaction of [ClP(muNtBu)2PNtBuH] (1) with LiBsBu3H yields trans-[HP(muNtBu)2PNtBuH] (2), by contrast, reaction with LiBEt3H yields cis-[HP(mu-NtBu)2PNtBuH] (3). Compounds and represent the first examples of P-H-functionalised cyclophosph(III)azanes. Deprotonation of with BnNa (Bn=benzyl) gives the first example of a secondary phosphine-functionalised cyclodiphosph(III)azane anion [HP(mu-NtBu)2PNtBu]- (4).

Double dehydration of a diynediol promoted by a single Co2(CO)6 unit; activation of an uncoordinated propargylic centre

The acid-catalysed elimination of two molecules of water from a diynediol requires only one of the alkyne functionalities to be coordinated to a dicobalt hexacarbonyl fragment; it is proposed that the reaction proceeds via an unprecedented type of intermediate in which a carbocationic centre is stabilised by a non-adjacent dicobalt hexacarbonyl moiety.

Synthesen der ersten Komplexe mit μ,η2-PE-Heteroliganden aus ECl3 und [Mo2Cp2(CO)4(μ-PH2)]− (E = As, Sb)

Ein M2PE-Tetrahedran-Grundgerust weisen die Komplexe 2 a–c auf (E = P, As bzw. Sb), die aus den entsprechenden Trichloriden und 1 in THF hergestellt wurden. Die Strukturen der neuen Arsen- und der Antimon-haltigen Verbindungen 2 b bzw. 2 b im Kristall konnten bestimmt werden – damit liegen erstmals strukturell charakterisierte Komplexe mit μ,η2-PE-Heteroliganden aus Elementen der Gruppe 15 vor.

Reductive-elimination of phosphide units; the basis of a general approach to a range of alloys and materials

Heterometallic alkali metal/Group 15 (E = As–Bi) phosphinidene cage compounds (containing RP2− groups) are thermally unstable, decomposing via the formation of thermodynamically stable P–P single bonds into Zintl compounds containing E73− or E42− anions. This approach provides access to photoactive alkali metal antimonates and a potentially general route to a range of new and existing alloys. This short review aims to highlight the mechanism of the phosphide-coupling reaction involved and the scope of this strategy in future materials synthesis.

Reactivity of acryloyl chloride towards the anion [Cp2(CO)4Mo2(µ-PPhH)]–; synthesis of an unusual phosphaalkene

Deprotonation of the complex [Cp2(CO)4Mo2(µ-PPhH)(µ-H)] by ButLi at –78 °C and subsequent addition of acryloyl chloride affords the metallophosphaalkene complex [Cp2(CO)4Mo2(η1-η2-PhPCHMe)] in high yield; the complex exhibits cis/trans isomerism, both isomers having been crystallographically characterised.