Manuel Jiménez Tenorio

The interaction of [Cp∗RuCl(dippe)] and [CpRuCl(dippe)] with alkynols: hydroxyvinylidene, allenylidene and related derivatives (dippe 1,2-bis(diisopropylphosphino)ethane)

Abstract The reactions of [Cp∗RuCl(dippe)] and [CpRuCl(dippe)] (dippe  1,2-bis(diisopropylphosphino)ethane) with several alkynols HCCC(OH)RR′ (RR′H, Me; RMe, R′Ph) have been studied. These reactions leads to the formation of the corresponding allenylidene derivatives, although in some cases hydroxyvinylidene complexes were isolated as intermediates in such process. The X-ray crystal, structure of [CpRuCCCMePh(dippe)][BPh4] was determined. In the course of the reaction of [CpRuCl(dippe)] with HCCC(OH)Me2, there is evidence for the formation of a deep bluedimeric aklynyl-carbene (or alkenyl-allenylidene) complex [{CpRu(dippe)}2(μ-C10H11)][BPh4] resulting formally from the coupling of two allenylidene moieties followed by the loss of one proton. The reaction of [Cp∗RuCCCMePh(dippe)][BPh4] with KOBu′ leads to the ene-yne derivative [Cp∗Ru(CCC(Ph)CH2)(dippe)] as result of the deprotonation of the allenylidene ligand at the δ-position. This compound was structurally characterized by single crystal X-ray crystallography. In an attempt to obtain the primary allenylidene complex [Cp∗RuCCCH2(dippe)][BPh4] by dehydration of the hydroxyvinylidene [Cp∗RuCCHCH2OH(dippe)][BPh4] using P2O5, the previously reported carbonyl complex [Cp∗Ru(CO)(dippe)][BPh4] was obtained and its crystal structure determined. This is also accessible by aerial oxidation of the hydroxy-vinylidene derivative.

Hydride, dihydrogen, dinitrogen and related complexes of ruthenium containing the ligand hydrotris(pyrazolyl)borate. X-ray crystal structure of [{HB(pz)3}Ru(η2-H2)(dippe)] [BPh4] (dippe = 1,2-bis(diisopropylphosphino)ethane)

Abstract The complex [HB(pz)3)RuCl(PPh3)2] reacts with one equivalent ofdippe in toluene toyield [(HB(pz)3)RuCl(dippe)]. This compound reacts with NaBH4 in MeOH furnishing the monohydride [(HB(pz)3)RuH(dippe)], whereas [(HB(pz)3)RuH(PPh3)2] was obtained by reaction of [RuHCl(PPh3)3] with K[HB(pz)3]. Both monohydride complexes are protonated by HBF4·OEt2 at −80°C to give the corresponding dihydrogen adducts [(HB(pz)3)Ru(H2)(dippe)]+ and [(HB(pz)3]Ru(H2)(PPh3)2]+, as inferred from longitudinal relaxation time (T1) and 1J(H,D) measurements. The latter complex is unstable and decomposes at room temperature, but the former is a stable species which does not rearrange to the dihydride form when the temperature is raised. The X-ray crystal structure of [(HB(pz)3)Ru(H2)-(dippe)][BPh4] has been determined. The dihydrogen ligand in this compound is labile, and readily replaced by a range of neutral donor molecules, yielding the corresponding complexes [(HB(pz)3)Ru(L)(dippe)][BPh4] (L = CO, CNBu1, Me2CO, thf, N2). There is also supporting evidence for the formation of a paramagnetic RuIII methoxide complex, namely [(HB(pz)3)Ru(OMe)(dippe)][BPh4]. All compounds were characterized by IR, NMR and microanalysis.

Replaying the tape: recurring biogeographical patterns in Cape Verde Conus after 12 million years

Isolated oceanic islands are excellent natural laboratories to test the relative role of historical contingency and determinism in evolutionary diversification. Endemics of the marine venomous snail Conus in the Cape Verde archipelago were originated from at least two independent colonizations of ‘small’ and ‘large’ shelled species separated by 12 million years. In this study, we have reconstructed phylogenetic relationships within large‐shelled Conus (C. ateralbus, C. pseudonivifer, C. trochulus, and C. venulatus) based on mitochondrial cox1 and nad4 haplotype sequences. The reconstructed molecular phylogeny revealed three well‐supported and relatively divergent clades (A, B, and C) that do not correspond to current species classification based on shell colour and banding patterns. Clade A grouped specimens assigned either to C. pseudonivifer or C. trochulus, clade B is composed of specimens assigned to C. venulatus, and clade C comprises specimens assigned either to C. venulatus or C. ateralbus. Geometric morphometric analyses found significant differences between the radular teeth shape of C. pseudonivifer/C. trochulus and C. venulatus/C. ateralbus. In clades A and B, northwestern Boavista and Maio specimens cluster together to the exclusion of eastern Boavista samples. In Sal, populations form a monophyletic island assemblage (clade C). The large‐shelled Conus have remarkably replicated biogeographical patterns of diversification of small‐shelled Conus. Similar selective forces (i.e. nonplanktonic lecithotrophy with limited larval dispersal and allopatric diversification) together with repeated instances of low sea level stands during glacial maxima that allowed connection between islands, have overcome the effect of historical contingency, and explain the observed recurring biogeographical patterns.

Synthesis of new half-sandwich ruthenium complexes containing 1,2-bis(diisopropylphosphino)ethane (dippe); crystal structures of [Ru(C5Me5)Cl(dippe)] and [Ru(C5Me5)(O2)(dippe)][BPh4]

The complex [Ru(C5H5)Cl(PPh3)2] reacted with 1 equivalent of dippe [dippe = 1,2-bis(diisopropylphosphino)ethane] in refluxing toluene to yield [Ru(C5H5)Cl(dippe)]1. The complex [Ru(C5Me5)Cl(dippe)]2 was obtained by reaction of [{Ru(C5Me5)(µ3-Cl)}4] with a stoichiometric amount of dippe in CH2Cl2. The crystal structure of 2 has been determined. Both 1 and 2 are non-electrolytes in non-polar solvents. In alcohols, compound 2 has a strong tendency to dissociate chloride. In the presence of air, this compound binds O2 irreversibly, yielding the dioxygen complex [RuC5Me5(O2)(dippe)]+, which is isolable as the [BPh4]– salt (3). The crystal structure of this compound has also been determined. Both 1 and 2 reacted with SnCl2 in CH2Cl2 to yield the insertion derivatives [Ru(C5R5)(SnCl3)(dippe)](R = H 4 or Me 5). All compounds were characterized by NMR spectroscopy and microanalysis.

Synthesis of cationic arene complexes of iron and ruthenium with 1,2-bis(diisopropylphosphino)ethane (dippe): X-ray crystal structures of [RuCl(η6-C6H6)(dippe)][BPh4] and [RuH(η6-C6H6)(dippe)][BPh4]

Abstract The complex [FeCl2(dippe)] (dippe = 1,2-bis(diisopropylphosphino)ethane) reacts with cyclohexadienyl-lithium in tetrahydrofuran yielding a dark mixture, from which the hydrido-arene complex [FeH(C6H6)(dippe)][BPh4] (1) can be isolated in moderate yields upon treatment with MeOHNaBPh4. 1, as well as the toluene complex [FeH(C6H5Me)(dippe)][BPh4] (2), can be prepared by reaction of [FeCl2(dippe)] with LinBu in benzene or toluene respectively, followed by MeOHNaBPh4. The ruthenium complexes [RuCl(L)(dippe)]+ (L = C6H6, p-isopropylmethylbenzene (p-cymene)) are obtained by reaction of [{Ru(L)Cl2}2] wit dippe and Ag+, and isolated as the tetraphenylborate salts 3. These compounds react with NaBH4 in acetone-ethanol furnishing the hydrido-aerene derivatives [RuH(L)(dippe)][BPh4] (L = C6H6 5, p-cymene 6). All the compounds were characterized by IR, NMR and microanalysis. The X-ray crystal structures of 3 and 4 are also reported.

Irreversible rearrangement of half-sandwich ruthenium hydrido-alkynyl complexes to their vinylidene isomers

The complex [(C5Me5)RuCl(dippe)](dippe = l,2-bis(diisopropylphosphino)ethane) reacts with alk-1-ynes in MeOH in the presence of NaBPh4 yielding the metastable hydrido-alkynyl derivatives [(C5Me5)Ru(H)(CCR)(dippe)][BPh4](R = CO2Me, SiMe3 or Ph), intermediates in the formation of the corresponding vinylidene complexes, to which these compounds rearrange both in solution and in the solid state.

Synthesis and properties of the 16-electron complex [(C5Me5)RuCl(PMeiPr2)] and of half-sandwich ruthenium hydrido complexes containing bulky monodentate phosphine ligands

Abstract The 16-electron complex [(C5Me5)RuCl(PMeiPr2)] (1) was obtained by reaction of [{(C5Me5)RuCl}4] with PMeiPr2 in petroleum. This compound appears to be in equilibrium with the dimer [{(C5Me5)Ru(PMeiPr2)}2(μ-Cl)2] as inferred from low-temperature NMR studies. The 18-electron complex [(C5Me5)RuCl(PMeiPr2)2] was formed upon addition of PMeiPr2 to 1. The related species [(C5H5)RuCl(PMeiPr2)2] (2) was obtained by reaction of [(C5H5)RuCl(PMeiPr2)(PPh3)] with PMeiPr2, followed by column chromatography. A range of RuIV dihydrides [(C5R5)RuH2(PR3)2][BPh4] (R=Me, H; PR3=PMeiPr2, PEt3) have been prepared and characterised. The corresponding monohydrido complexes [(C5R5)RuH(PR3)2] were obtained by deprotonation of the cationic dihydrides. Protonation at low temperature of either of these monohydrido complexes yielded back the corresponding dihydrido derivative, except in the case of [(C5Me5)RuH(PEt3)2], for which the metastable cationic dihydrogen complex [(C5Me5)Ru(H2)(PEt3)2]+ was obtained and characterised by NMR spectroscopy. This compound rearranges to its dihydrido tautomer as the temperature is raised, and a kinetic study of such process was accomplished. Interestingly, the only isolable dinitrogen adduct of the type [(C5R5)Ru(N2)(PR3)2][BPh4] among all possible combinations of phosphines and cyclopentadienyl ring substituents was [(C5Me5)Ru(N2)(PEt3)2][BPh4].

Ruthenium–dihydrogen complexes via C–H cleavage in alk-1-ynes. Crystal structure of [Ru(H2)(CCPh}(dippe)2][BPh4][dippe = 1,2-bis(diisopropylphosphino)ethane]

The reaction of the monohydride complex [RuH(dippe)2]+ with alk-1-ynes yields the dihydrogen complexes [Ru(H2)(CCR)(dippe)2]+(R = Ph or CO2Me); the X-ray crystal structure of [Ru(H2)(CCPh)(dippe)2][BPh4] has been determined, and represents the first structural report of an alkynyl–dihydrogen complex.

Evolution at a Different Pace: Distinctive Phylogenetic Patterns of Cone Snails from Two Ancient Oceanic Archipelagos

Ancient oceanic archipelagos of similar geological age are expected to accrue comparable numbers of endemic lineages with identical life history strategies, especially if the islands exhibit analogous habitats. We tested this hypothesis using marine snails of the genus Conus from the Atlantic archipelagos of Cape Verde and Canary Islands. Together with Azores and Madeira, these archipelagos comprise the Macaronesia biogeographic region and differ remarkably in the diversity of this group. More than 50 endemic Conus species have been described from Cape Verde, whereas prior to this study, only two nonendemic species, including a putative species complex, were thought to occur in the Canary Islands. We combined molecular phylogenetic data and geometric morphometrics with bathymetric and paleoclimatic reconstructions to understand the contrasting diversification patterns found in these regions. Our results suggest that species diversity is even lower than previously thought in the Canary Islands, with the putative species complex corresponding to a single species, Conus guanche. One explanation for the enormous disparity in Conus diversity is that the amount of available habitat may differ, or may have differed in the past due to eustatic (global) sea level changes. Historical bathymetric data, however, indicated that sea level fluctuations since the Miocene have had a similar impact on the available habitat area in both Cape Verde and Canary archipelagos and therefore do not explain this disparity. We suggest that recurrent gene flow between the Canary Islands and West Africa, habitat losses due to intense volcanic activity in combination with unsuccessful colonization of new Conus species from more diverse regions, were all determinant in shaping diversity patterns within the Canarian archipelago. Worldwide Conus species diversity follows the well-established pattern of latitudinal increase of species richness from the poles towards the tropics. However, the eastern Atlantic revealed a striking pattern with two main peaks of Conus species richness in the subtropical area and decreasing diversities toward the tropical western African coast. A Random Forests model using 12 oceanographic variables suggested that sea surface temperature is the main determinant of Conus diversity either at continental scales (eastern Atlantic coast) or in a broader context (worldwide). Other factors such as availability of suitable habitat and reduced salinity due to the influx of large rivers in the tropical area also play an important role in shaping Conus diversity patterns in the western coast of Africa.

Formation of Platinum–Tin Bond by Tin(II)Chloride Insertion

The first 119Sn NMR evidence for the presence of direct platinum–tin bond in solution has been obtained for PtCl(SnCl3)(bdpp) complex (bdpp = (2S,4S)-2,4-bis(diphenylphosphino)pentane). Various PtCl2(L2) complexes (L2 = heterobidentate P−P, P−O, P−N, P−S chelating ligands) have been reacted with tin(II)chloride resulting in the formation of the corresponding PtCl(SnCl3)(L2) derivatives. Tin(II)chloride has been inserted into the Pt−Cl bond transto the harder donor atom of the L2 ligand.