The complex [Cp*RuCl(dippe)] reacts with 1-alkynes in MeOH in the presence of NaBPh4, yielding the metastable hydrido−alkynyl derivatives [Cp*Ru(H)(C⋮CR)(dippe)][BPh4] (R = COOMe, Ph or SiMe3), intermediates in the formation of the corresponding vinylidene complexes, to which these compounds rearrange both in solution and in the solid state. The X-ray crystal structures of the isomers [Cp*RuCCHCOOMe(dippe)][BPh4] and [Cp*RuH(C⋮CCOOMe)(dippe)][BPh4] have been determined. Kinetic studies show that the mechanism for this isomerization process seems to be dissociative and that it is inhibited in solution by strong acids. In contrast with this, no hydrido−alkynyl complex has been observed in the course of the reaction of 1-alkynes with [CpRuCl(dippe)]. Instead, the alkyne adducts have been detected, and isolated in some cases. Such species have only been observed in the Cp*Ru system for acetylene, and [Cp*Ru(η2-HC⋮CH)(dippe)]+ seems to be in equilibrium with the corresponding hydrido−alkynyl complex [Cp*RuH(C⋮CH)(dippe)]+, which isomerizes to [Cp*RuCCH2(dippe)]+ via the formation of the π-alkyne complex. The effects on these tautomerization processes of the phosphine, Cp*, and Cp ligands, as well as the R group of the alkyne, are discussed.

This review deals with the study of coordinatively unsaturated half-sandwich iron, ruthenium and osmium complexes, in particular those bearing bulky phosphane ligands. The synthesis, properties and structure of neutral complexes of the type [(C 5 R 5 )MX(L)] and their cationic derivatives+ , are described here. We will also refer to related compounds containing hydrotris(pyrazolyl)borate (Tp)

The transcriptome of the venom duct of the Atlantic piscivorous cone species Chelyconus ermineus (Born, 1778) was determined. The venom repertoire of this species includes at least 378 conotoxin precursors, which could be ascribed to 33 known and 22 new (unassigned) protein superfamilies, respectively. Most abundant superfamilies were T, W, O1, M, O2, and Z, accounting for 57% of all detected diversity. A total of three individuals were sequenced showing considerable intraspecific variation: each individual had many exclusive conotoxin precursors, and only 20% of all inferred mature peptides were common to all individuals. Three different regions (distal, medium, and proximal with respect to the venom bulb) of the venom duct were analyzed independently. Diversity (in terms of number of distinct members) of conotoxin precursor superfamilies increased toward the distal region whereas transcripts detected toward the proximal region showed higher expression levels. Only the superfamilies A and I3 showed statistically significant differential expression across regions of the venom duct. Sequences belonging to the alpha (motor cabal) and kappa (lightning-strike cabal) subfamilies of the superfamily A were mainly detected in the proximal region of the venom duct. The mature peptides of the alpha subfamily had the α4/4 cysteine spacing pattern, which has been shown to selectively target muscle nicotinic-acetylcholine receptors, ultimately producing paralysis. This function is performed by mature peptides having a α3/5 cysteine spacing pattern in piscivorous cone species from the Indo-Pacific region, thereby supporting a convergent evolution of piscivory in cones.

A number of 16e two-legged piano-stool complexes [Cp*Ru(PP)][BAr‘4] have been prepared by reaction of NaBAr‘4 with either [Cp*RuCl(PP)] (PP = (PEt3)2, iPr2PCH2CH2PiPr2 (dippe), (PPh3)2) or [Cp*RuCl(PR3)] plus PR3 (PR3 = PMeiPr2, PPhiPr2) in fluorobenzene under argon. The complexes [Cp*Ru(PEt3)2][BAr‘4], [Cp*Ru(dippe)][BAr‘4], and [Cp*Ru(PMeiPr2)2][BAr‘4] have been structurally characterized by X-ray crystallography. Attempts to isolate analogous species containing other phosphine ligands such as PiPr3, PCy3, and PMe3 led to the sandwich derivative [Cp*Ru(η6-FPh)][BAr‘4], which was also structurally characterized. Both [Cp*Ru(PPh3)2][BAr‘4] and [Cp*Ru(PPhiPr2)2][BAr‘4] are unstable and rearrange to the 18e sandwich species [Cp*Ru(η6-C6H5PR2)][BAr‘4] and to [Cp*Ru(η6-C6H5POR2)][BAr‘4] (R = Ph, iPr) under trace amounts of oxygen. The geometry of the 16e complexes as well as their affinity for an additional ligand depend on the substituents on the phosphorus. The reactivity with respect to the addition of N2, PR3, O2, H2, and HCl to form 18e derivatives has been studied. Some model systems have been analyzed using density functional theory (DFT) calculations. Also included are comparative studies on the NN counterparts. The moieties [CpRu(PP)]+ (PP = (PH3)2, H2PCH2CH2PH2) adopt typically pyramidal structures (i.e. in the absence of bulky and rigid substituents on P) versus planar structures of [CpRu(NN)]+ (NN = (NH3)2, H2NCH2CH2NH2). [CpRu(PP)]+ is more stable but has nevertheless a higher affinity of adding a σ ligand than [Cp*Ru(NN)]+.

The reaction of [CpRuCl(P) 2 ] [(P) 2 ) dippe (1,2-bis(diisopropylphosphino)ethane; (PEt 3 ) 2 ; (PMe i Pr 2 ) 2 ] with Na[BAr′ 4 ] (Ar′ 4 ) 3,5-bis(trifluoromethyl)phenyl) in fluorobenzene under argon generates the corresponding cationic 16-electron species [CpRu(P) 2 ] + , which reacts with trace amounts of dinitrogen present even in high-purity argon furnishing the dinitrogenbridged complexesthe reaction is performed under dinitrogen, the terminal dinitrogen complexes [CpRu-(N 2 )(P) 2 ][BAr′ 4 ] [(P) 2 ) dippe 2a; (PMe i Pr 2 ) 2 2c] are obtained. Compound 1b was obtained irrespectively of the atmosphere used, and no terminal dinitrogen complex has been detected. The crystal structures of 1a, 1b, and 2a have been determined. During one attempt to isolate the 16-electron complex [CpRu(PMe i Pr 2 ) 2 ][BAr′ 4 ], the 18-electron tris(phosphine) derivative [CpRu(PMe i Pr 2 ) 3 ][BAr′ 4 ], 3, was obtained instead, and it was structurally characterized. Halide abstraction from [CpRuCl(PMe i Pr 2 )(PPh 3 )] under dinitrogen using Na[BAr′ 4 ] yielded [CpRu(N 2 )(PMe i Pr 2 )(PPh 3 )][BAr′ 4 ], 2d, but under argon the complex [CpRu(PMe i Pr 2 )(PPh 3 )]-[BAr′ 4 ], 4, which contains a rare η 3 -coordinated PPh 3 ligand as shown by X-ray crystallography, was isolated.

The trihydride complex [ FeH,(dmpe),] + (dmpe = Me,PCH,CH,PMe,) is best represented as [ FeH (H,) -(dmpe),] +, with the H-H separation in the H, being ca. 0.81 A. The H, can be replaced by N, , CO, MeCN, MeNC and C2H4. The dinitrogen complex [FeH( N, ) (dmpe),] + may be deprotonated to yield the solutionstable, trigonal-bipyramidal species [Fe(N,) (dmpe),], which can be reprotonated by HCI to yield [FeCI,-(dmpe),], N, , H, and NH,. The crystal structures of [FeH(H,)(dmpe),]BPh, and [FeH(N,)(dmpe),]BPh, have been determined.

The reaction of propargyl alcohol derivatives with the complex [Cp*RuCl(dippe)] [dippe = 1,2‐bis(diisopropylphosphane)ethane] and NaBPh4 in MeOH yields hydrido(3‐hydroxyalkynyl) compounds [Cp*Ru(H){C≡CC(OH)RR′}(dippe)][BPh4] [R, R′ = Ph, Ph (1a); H, Ph (1b); H, Me (1c)]. These represent intermediates in the formation of 3‐hydroxyvinylidene species [Cp*Ru{=C=CHC(OH)RR′}(dippe)][BPh4] [R, R′ = Ph, Ph (2a); H, Ph (2b); H, Me (2c)], into which they irreversibly rearrange both in solution and in the solid state. Solution kinetic studies have been carried out on this isomerization process. Ulterior dehydration processes are feasible, resulting in the formation of allenylidene [Cp*Ru(=C=C=CRR′)(dippe)][BPh4] [R, R′ = Ph, Ph (3a); H, Ph (3b)] or vinylvinylidene [Cp*Ru{=C=CHCH(=CH2)}(dippe)][BPh4] (4) species. The X‐ray crystal structure of the novel secondary allenylidene complex [Cp*Ru(=C=C=CHPh)(dippe)][BPh4] is presented.

BackgroundDue to their great species and ecological diversity as well as their capacity to produce hundreds of different toxins, cone snails are of interest to evolutionary biologists, pharmacologists and amateur naturalists alike. Taxonomic identification of cone snails still relies mostly on the shape, color, and banding patterns of the shell. However, these phenotypic traits are prone to homoplasy. Therefore, the consistent use of genetic data for species delimitation and phylogenetic inference in this apparently hyperdiverse group is largely wanting. Here, we reconstruct the phylogeny of the cones endemic to Cabo Verde archipelago, a well-known radiation of the group, using mitochondrial (mt) genomes.ResultsThe reconstructed phylogeny grouped the analyzed species into two main clades, one including Kalloconus from West Africa sister to Trovaoconus from Cabo Verde and the other with a paraphyletic Lautoconus due to the sister group relationship of Africonus from Cabo Verde and Lautoconus ventricosus from Mediterranean Sea and neighboring Atlantic Ocean to the exclusion of Lautoconus endemic to Senegal (plus Lautoconus guanche from Mauritania, Morocco, and Canary Islands). Within Trovaoconus, up to three main lineages could be distinguished. The clade of Africonus included four main lineages (named I to IV), each further subdivided into two monophyletic groups. The reconstructed phylogeny allowed inferring the evolution of the radula in the studied lineages as well as biogeographic patterns. The number of cone species endemic to Cabo Verde was revised under the light of sequence divergence data and the inferred phylogenetic relationships.ConclusionsThe sequence divergence between continental members of the genus Kalloconus and island endemics ascribed to the genus Trovaoconus is low, prompting for synonymization of the latter. The genus Lautoconus is paraphyletic. Lautoconus ventricosus is the closest living sister group of genus Africonus. Diversification of Africonus was in allopatry due to the direct development nature of their larvae and mainly triggered by eustatic sea level changes during the Miocene-Pliocene. Our study confirms the diversity of cone endemic to Cabo Verde but significantly reduces the number of valid species. Applying a sequence divergence threshold, the number of valid species within the sampled Africonus is reduced to half.Electronic supplementary materialThe online version of this article (10.1186/s12862-017-1069-x) contains supplementary material, which is available to authorized users.