Cluster 4a Research Articles

Distinct Clusters of HIV-1 CRF01_AE in Zhejiang, China: High-Risk Transmission Cluster 4 Requires Heightened Surveillance.

HIV-1 CRF01_AE is becoming the predominant HIV-1 subtype among patients in China. The distribution and characteristics of transmission clusters of HIV-1 CRF01_AE in Zhejiang, Eastern China remains unclear. This study analyzed the epidemiologic characteristics and transmission clusters of HIV-1 CRF01_AE in Zhejiang. Plasma samples obtained from 152 patients of HIV-1 CRF01_AE not undergoing ART were used to amplify HIV-1 pol and env gene. CRF01_AE drug resistance mutations (DRM) prevalence was analysed using Stanford University's HIV Drug Resistance Database. A phylogenetic tree was constructed using FastTree (version 2.1.11) based on the GTR nucleotide substitution model and visualized using Figtree (version 1.4.4) and The Interactive Tree of Life; the Chinese HIV Gene Sequence Data Platform was used to construct genetic transmission networks. Majority samples could be grouped into CRF01_AE transmission Clusters 1 (11.2%), 4 (64.5%), and 5 (7.2%). The CD4+ T-cell counts in Cluster 1, 4a, 4b are lower than 5 were 15, 38, 30, and 248 cells/mm3, respectively (P < 0.05). The high X4 tropism rates were 13.2%, 11.8%, 20.0%, and 0.0% in Clusters 1, 4a, 4b, and 5, respectively. DRM rates in Clusters 4a and 4b were 17.6%, and 25.45% respectively (P < 0.05), whereas they were 17.6% and 18.2% in Clusters 1 and 5, respectively. In total, 24 transmission genetic networks, comprising 72 sequences and 61 links, were discovered; of them, 61.2%, 11.7%, and 18.2% were from Clusters 4, 1, and 5, respectively (P < 0.05). In Zhejiang, different CRF01_AE clusters displayed unique clinic features. Cluster 4, particularly Cluster 4b, was considered a high-risk transmission cluster. The surveillance of epidemiology of HIV-1 should be enhanced to minimize its transmission.

Genetic Characteristics of Human Parainfluenza Virus Types 1-4 From Patients With Clinical Respiratory Tract Infection in China.

Human parainfluenza viruses (HPIV1–4) cause acute respiratory tract infections, thereby impacting human health worldwide. However, there are no current effective antivirals or licensed vaccines for infection prevention. Moreover, sequence information for human parainfluenza viruses (HPIVs) circulating in China is inadequate. Therefore, to shed light on viral genetic diversity and evolution, we collected samples from patients infected with HPIV1–4 in China from 2012 to 2018 to sequence the viruses. We obtained 24 consensus sequences, comprising 1 for HPIV1, 2 for HPIV2, 19 for HPIV3, and 2 for HPIV4A. Phylogenetic analyses classified the 1 HPIV1 into clade 2, and the 2 HPIV4 sequences into cluster 4A. Based on the hemagglutinin-neuraminidase (HN) gene, a new sub-cluster was identified in one of the HPIV2, namely G1c, and the 19 HPIV3 sequences were classified into the genetic lineages of C3f and C3a. The results indicated that HPIV1–4 were co-circulated in China. Further, the lineages of sub-cluster C3 of HPIV3 were co-circulated in China. A recombination analysis indicated that a putative recombination event may have occurred in the HN gene of HPIV3. In the obtained sequences of HPIV3, we found that two amino acid substitution sites (R73K in the F protein of PUMCH14028/2014 and A281V in the HN protein of PUMCH13961/2014) and a negative selection site (amino acid position 398 in the F protein) corresponded to the previously reported neutralization-related sites. Moreover, amino acid substitution site (K108E) corresponded to the negative selection site (amino acid position 108) in the 10 F proteins of HPIV3. However, no amino acid substitution site corresponded to the glycosylation site in the obtained HPIV3 sequences. These results might help in studying virus evolution, developing vaccines, and monitoring HPIV-related respiratory diseases.

Genetic Characterization of a Novel HIV-1 Second-Generation Recombinant Form (CRF01_AE/CRF07_BC) Identified in Yan'an City, China.

Owing to co-epidemic of CRF01_AE and CRF07_BC in China, increasing numbers of the second-generation recombinants between them have been identified especially among sexual population. In this study, we identified a unique CRF01_AE/CRF07_BC recombinants from a male HIV-1 positive individual (18YA004) infected by heterosexual contact in Yan'an city, Shaanxi province. The near full-length genome analyses showed 18YA004 was divided into six fragments by five breakpoints located in the pol, vpr, vpu, and nef gene, respectively. Three CRF01_AE segments (segments I, III, and V) were all clustered within the cluster 4a lineage, exclusively circulating among MSM in the northern China. Coupled with our previous finding of CRF01_AE/C recombinant in Yan'an city, the emergence of CRF01_AE/CRF07_BC strain further suggested coexistence of multiple HIV-1 genotypes here. Therefore, it is necessary to continue monitoring the molecular epidemiology of HIV-1 among high-risk groups to obtain a better understanding of the genetic complexity and transmission of HIV-1 in this region.

Origin and Transport Pathway of Dust Storm and Its Contribution to Particulate Air Pollution in Northeast Edge of Taklimakan Desert, China

The Taklimakan Desert in Northwest China is the major source of dust storms in China. The northeast edge of this desert is a typical arid area which houses a fragile oasis eco-environment. Frequent dust storms cause harmful effects on the oasis ecosystem and negative impacts on agriculture, transportation, and human health. In this study, the major source region, transport pathway, and the potential contribution of dust storms to particulate air pollution were identified by using both trajectory analysis and monitoring data. To assess the source regions of dust storms, 48 h backward trajectories of air masses arriving at the Bugur (Luntai) County, which is located at the northeast edge of Taklimakan Desert, China on the dusty season (spring) and non-dusty month (August, representing non-dusty season) in the period of 1999–2013, were determined using Hybrid Single Particle Lagrangian Integrated Trajectory model version 4 (HYSPLIT 4). The trajectories were categorized by k-means clustering into 5 clusters (1a–5a) in the dusty season and 2 clusters (1b and 2b) in the non-dusty season, which show distinct features in terms of the trajectory origins and the entry direction to the site. Daily levels of three air pollutants measured at a station located in Bugur County were analyzed by using Potential Source Contribution Function (PSCF) for each air mass cluster in dusty season. The results showed that TSP is the major pollutant, with an average concentration of 612 µg/m3, as compared to SO2 (23 µg/m3) and NO2 (32 µg/m3) in the dusty season. All pollutants were increased with the dust weather intensity, i.e., from suspended dust to dust storms. High levels of SO2 and NO2 were mostly associated with cluster 1a and cluster 5a which had trajectories passing over the anthropogenic source regions, while high TSP was mainly observed in cluster 4a, which has a longer pathway over the shifting sand desert area. Thus, on strong dust storm days, not only higher TSP but also higher SO2 and NO2 levels were observed as compared to normal days. The results of this study could be useful to forecast the potential occurrence of dust storms based on meteorological data. Research focusing on this dust-storm-prone region will help to understand the possible causes for the changes in the dust storm frequency and intensity, which can provide the basis for mitigation of the negative effects on human health and the environment.

MOLECULAR IDENTIFICATION OF MEMBERS OF THE FAMILY PASTEURELLACEAE FROM THE ORAL CAVITY OF KOALAS (PHASCOLARCTOS CINEREUS) AND THEIR RELATIONSHIP WITH ISOLATES FROM KOALA BITE WOUNDS IN HUMANS.

A total of 22 Pasteurellaceae isolates obtained from the oral cavity of koalas (Phascolarctos cinereus) at different wildlife centers in Australia were investigated using amplification and sequencing of two housekeeping genes, rpoA and recN. The available sequences from the Lonepinella koalarum type strain (ACM3666T) and the recent isolates of Lonepinella-like bacteria obtained from human infected wounds associated with koala bites were also included. Phylogenetic analysis was performed on the concatenated rpoA-recN genes and genome relatedness was calculated based on the recN sequences. The oral cavity isolates, the koala bite wound isolates, and L. koalarum ACM3666T resulted in four clusters (Clusters 1-4). Clusters 1-3 were clearly not members of the genus Lonepinella. Cluster 1 was closely related to the genus Fredericksenia, and Clusters 2 and 3 appeared to be novel genera. Cluster 4 consisted of three subclusters: Cluster 4a with one koala bite wound isolate and L. koalarum ACM3666T, Cluster 4b with three oral cavity isolates and two Lonepinella-like wound isolates, and Cluster 4c with three nearly identical oral cavity isolates that may represent a different species within the genus Lonepinella. The rich Pasteurellaceae population, including potential novel taxa in the oral cavity of koalas supports an important role of these highly adapted microorganisms in the physiology of koalas. Moreover, the pathogenic potential of Lonepinella-like species is an important consideration when investigating infected koala bites in humans.

A DNA Microarray-based Analysis of the Host Response to a Nonviral Gene Carrier: A Strategy for Improving the Immune Response

The purpose of this study was to investigate the host response to systemically administered lipid nanoparticles (NPs) encapsulating plasmid DNA (pDNA) in the spleen using a DNA microarray. As a model for NPs, we used a multifunctional envelope-type nano device (MEND). Microarray analysis revealed that 1,581 of the differentially expressed genes could be identified by polyethylene glycol (PEG)-unmodified NP using a threefold change relative to the control. As the result of PEGylation, the NP treatment resulted in the reduction in the expression of most of the genes. However, the expression of type I interferon (IFN) was specifically increased by PEGylation. Based on the microarray and a pathway analysis, we hypothesize that PEGylation inhibited the endosomal escape of NP, and extended the interaction of toll-like receptor-9 (TLR9) with CpG-DNA accompanied by the production of type I IFN. This hypothesis was tested by introducing a pH-sensitive fusogenic peptide, GALA, which enhances the endosomal escape of PEGylated NP. As expected, type I IFN was reduced and interleukin-6 (IL-6) remained at the baseline. These findings indicate that a carrier design based on microarray analysis and the manipulation of intracellular trafficking constitutes a rational strategy for reducing the host immune response to NPs.

Proton‐Transfer Reactions on Hexanuclear Platinum Clusters: Reversible Heterolytic Cleavage of H2 and CH Activation Affording a Linear, Cluster‐Containing Polymer

The hexanuclear cluster {Pt(6)}H(2) (2) contains a sterically hindered and chemically stable {Pt(6)} = Pt(6)(mu-PtBu(2))(4)(CO)(4) core, with the six metals forming an edge-bridged tetrahedron. The two hydrides are the reactive sites of the cluster and lie on opposite sides of the cluster, terminally bonded to the two "apical" edge-bridging platinum centres. Indeed, cluster 2 reacts with acids of different acidity (HA = CF(3)SO(3)H, HBF(4), p-CH(3)-C(6)H(4)-SO(3)H, CF(3)COOH, PhCOOH and CH(3)COOH), affording, after evolution of two equivalents of dihydrogen, the corresponding anion-substituted clusters {Pt(6)}A(2) (4). We suggest that the reaction proceeds through a mechanism similar to the one generally accepted for the analogous protonation of mononuclear hydrides, with some of the intermediates partially characterised at low temperature. Interestingly, the reverse reaction, the heterolytic splitting of H(2) by clusters 4, occurs readily under mild conditions. The anions in clusters 4a and 4b (4a: A = CF(3)SO(3), 4b: A = BF(4)) are bonded in the solid state but very easily dissociate in solution and may be substituted under mild conditions by weak ligands, such as CH(2)Cl(2) or CH(3)CN. With dialkyl ethers, the reaction proceeds further with the heterolytic splitting of a C-H bond of the ethereal ligand. This process allowed us to isolate the polymer [{Pt(6)}(CH(2)OCH(2)CH(2)OCH(2))](x) (8), in which the {Pt(6)} cluster units are connected by insulating spacers arising from dimethoxyethane. The results of single-crystal X-ray diffraction studies on 4a and 8 are also reported.

Bimetallic Ru–Cu tellurido complexes: controlled synthesis and electrochemical studies of copper halide–TeRu5 and Te2Ru4clusters

When [TeRu(5)(CO)(14)](2-) () was treated with 1 equiv. of CuX (X = Cl, Br, I) in THF, mono-CuX-TeRu(5) clusters [TeRu(5)(CO)(14)CuX](2-) (X = Cl, ; Br, ; I, ) were obtained. Clusters consist of an octahedral TeRu(5) core, in which one triangular Ru(3) plane is capped by a mu(3)-CuX fragment. For CuX (X = Cl, Br), the reaction of complex with 2 equiv. of CuX in THF at room temperature formed Cu(4)X(2)-linked di-TeRu(5) clusters [{TeRu(5)(CO)(14)}(2)Cu(4)X(2)](2-) (X = Cl, ; Br, ), while the same reaction in MeCN at -35 degrees C produced bis-CuX-TeRu(5) complexes [TeRu(5)(CO)(14)(CuX)(2)](2-) (X = Cl, ; Br, ). X-Ray analysis showed that displays a TeRu(5) core with two adjacent Ru(3) triangles each capped by a mu(3)-CuBr ligand while has two TeRu(5) cores that are linked by a mu(6)-Cu(4)Br(2) moiety. Clusters and underwent coupling reactions in THF to yield clusters and , and easily transformed to bis-CuX-Te(2)Ru(4) clusters [Te(2)Ru(4)(CO)(10)(CuX)(2)](2-) (X = Cl, ; X = Br, ) in MeCN. On the other hand, the reaction of with 2 equiv. of CuI in THF directly produced the bis-CuI-Te(2)Ru(4) cluster [Te(2)Ru(4)(CO)(10)(CuI)(2)](2-) (). The nature, stability, stepwise cluster transformation, and electrochemistry of these CuX-incorporated TeRu(5)- and Te(2)Ru(4)-based complexes are discussed systematically. In particular, the effects of CuX and the metal cores (TeRu(5)vs. Te(2)Ru(4)) on the resultant Te-Ru-Cu clusters are further elucidated by molecular orbital calculations at the B3LYP level of the density functional theory.

Copper Halide-Incorporated Tellurium−Iron Carbonyl Complexes: Transformation, Electrochemical Properties, and Theoretical Calculations

When the tellurium-capped tri-iron carbonyl cluster [Et(4)N](2)[TeFe(3)(CO)(9)] was treated with 1 equiv of CuX in THF at 0 degrees C, CuX-incorporated clusters [Et(4)N](2)[TeFe(3)(CO)(9)CuX] (X = Cl, [Et(4)N](2)[1a]; Br, [Et(4)N](2)[1b]; I, [Et(4)N](2)[1c]) were formed, respectively. X-ray analysis showed that 1a-1c each exhibited a TeFe(3) core with one Fe-Fe bond bridged by one CuX fragment. When the reactions were carried out at a molar ratio of 1:2 (X = Cl, Br) or 1:3 (X = I) in tetrahydrofuran (THF) or MeCN at 0 degrees C, Cu(2)X(2)-incorporated clusters [Et(4)N](2)[TeFe(3)(CO)(9)Cu(2)X(2)] (X = Cl, [Et(4)N](2)[2a]; Br, [Et(4)N](2)[2b]; I, [Et(4)N](2)[2c]) were obtained, respectively. Cluster 2a was structurally characterized by X-ray analysis to display a TeFe(3) core, in which one TeFe(2) plane was asymmetrically bridged and capped by one mu(3)-CuCl and another mu(4)-CuCl with two Cu atoms bonded. Complexes 1a-1c underwent skeleton expansion to form Cu(3)X-incorporated di-TeFe(3) clusters [{TeFe(3)(CO)(9)}(2)Cu(3)X](2-) (X = Cl, 3a; Br, 3b; I, 3c), respectively, upon treatment with 1 equiv of [Cu(MeCN)(4)][BF(4)] at 0 degrees C. X-ray analysis showed that 3b and 3c each consisted of two TeFe(3) clusters that were linked by a Cu(3)X moiety. However, a similar reaction for 1a and 1b with 1 equiv of [Cu(MeCN)(4)][BF(4)] at room temperature produced Cu(4)X(2)-linked di-TeFe(3) clusters [{TeFe(3)(CO)(9)}(2)Cu(4)X(2)](2-) (X = Cl, 4a; Br, 4b). Cluster 4a was shown by X-ray analysis to have two TeFe(3) cores linked by a Cu(4)Cl(2) moiety. Clusters 4a and 4b were also produced directly from the reaction of [Et(4)N](2)[TeFe(3)(CO)(9)] with 4 equiv of CuX (X = Cl, Br) in THF. Furthermore, the nature, the formation, the cluster transformation, and the electrochemistry of the CuX-incorporated mono- or di-TeFe(3) clusters are explained in terms of the effects of tellurium, copper halide, and the size of the metal skeleton, all of which are elucidated by molecular calculations at the B3LYP level of density functional theory.

Construction of Copper Halide-Triiron Selenide Carbonyl Complexes: Synthetic, Electrochemical, and Theoretical Studies

A new family of CuX-, Cu(2)X(2)-, and Cu(4)X(2)-incorporated mono- or di-SeFe(3)-based carbonyl clusters were constructed and structurally characterized. When the selenium-capped triiron carbonyl cluster [Et(4)N](2)[SeFe(3)(CO)(9)] was treated with 1-3 equiv of CuX in tetrahydrofuran (THF) at low or room temperatures, CuX-incorporated SeFe(3) complexes [Et(4)N](2)[SeFe(3)(CO)(9)CuX] (X = Cl, [Et(4)N](2)[1a]; Br, [Et(4)N](2)[1b]; I, [Et(4)N](2)[1c]), Cu(2)X(2)-incorporated SeFe(3) clusters [Et(4)N](2)[SeFe(3)(CO)(9)Cu(2)X(2)] (X = Cl, [Et(4)N](2)[2a]; Br, [Et(4)N](2)[2b]), and Cu(4)X(2)-linked di-SeFe(3) clusters [Et(4)N](2)[{SeFe(3)(CO)(9)}(2)Cu(4)X(2)] (X = Cl, [Et(4)N](2)[3a]; Br, [PPh(4)](2)[3b]) were obtained, respectively, in good yields. SeFe(3)CuX complexes 1a and 1b were found to undergo cluster expansion to form SeFe(3)Cu(2)X(2) complexes 2a and 2b, respectively, upon the addition of 1 equiv of CuX (X = Cl, Br). Furthermore, complexes 2a and 2b can expand further to form Cu(4)X(2)-linked di-SeFe(3) clusters 3a and 3b, upon treatment with 1 equiv of CuX (X = Cl, Br). [Et(4)N](4)[{SeFe(3)(CO)(9)(CuCl)(2)}(2)] ([Et(4)N](4)[4a]) was produced when the reaction of [Et(4)N](2)[SeFe(3)(CO)(9)] with 2 equiv of CuCl was conducted in THF at 40 degrees C. The Cu(2)Cl(2)-linked di-SeFe(3)CuCl cluster 4a is a dimerization product derived from complex 2a. Further, it is found that complex 4a can convert to the Cu(4)Cl(2)-linked di-SeFe(3) cluster 3a upon treatment with CuCl. The nature, formation, stepwise cluster expansion, and electrochemical properties of these CuX-, Cu(2)X(2)-, and Cu(4)X(2)-incorporated mono- or di-SeFe(3)-based clusters are elucidated in detail by molecular calculations at the B3LYP level of the density functional theory in terms of the effects of selenium, iron, copper halides, and the size of the metal skeleton.

Alkylthio Bridged 44 cve Triangular Platinum Clusters: Synthesis, Oxidation, Degradation, Ligand Substitution, and Quantum Chemical Calculations

Acetylplatinum(II) complexes trans-[Pt(COMe)Cl(L)2] (L = PPh3, 2a; P(4-FC6H4)3, 2b) were found to react with dialkyldisulfides R2S2 (R = Me, Et, Pr, Bu; Pr = n-propyl, Bu = n-butyl), yielding trinuclear 44 cve (cluster valence electrons) platinum clusters [(PtL)3(mu-SR)3]Cl (4). The analogous reaction of 2a-b with Ph2S2 gave SPh bridged dinuclear complexes trans-[{PtCl(L)}2(mu-SPh)2] (5), whereas the addition of Bn2S2 (Bn = benzyl) to 2a ended up in the formation of [{Pt(PPh3)}3(mu3-S)(mu-SBn)3]Cl (6). Theoretical studies based on the AIM theory revealed that type 4 complexes must be regarded as triangular platinum clusters with Pt-Pt bonds whereas complex 6 must be treated as a sulfur capped 48 ve (valence electrons) trinuclear platinum(II) complex without Pt-Pt bonding interactions. Phosphine ligands with a lower donor capability in clusters 4 proved to be subject to substitution by stronger donating monodentate phosphine ligands (L' = PMePh2, PMe2Ph, PBu3) yielding clusters [(PtL')3(mu-SR)3]Cl (9). In case of the reaction of clusters 4 and 9 with PPh2CH2PPh2 (dppm), a fragmentation reaction occurred, and the complexes [(PtL)2(mu-SMe)(mu-dppm)]Cl (12) and [Pt(mu-SMe)2(dppm)] (13) were isolated. Furthermore, oxidation reactions of cluster [{Pt(PPh3)}3(mu-SMe)3]Cl (4a) using halogens (Br2, I2) gave dimeric platinum(II) complexes cis-[{PtX(PPh3)}2(mu-SMe)2] (14, X = Br, I) whereas oxidation reactions using sulfur and selenium afforded chalcogen capped trinuclear 48 ve complexes [{Pt(PPh3)}3(mu3-E)(mu-SMe)3] (15, E = S, Se). All compounds were fully characterized by means of NMR and IR spectroscopy, microanalyses, and ESI mass spectrometry. Furthermore, X-ray diffraction analyses were performed for the triangular cluster 4a, the trinuclear complex 6, as well as for the dinuclear complexes trans-[{Pt(AsPh3)}2(mu-SPh)2] (5c), [{Pt(PPh3)}2(mu-SMe)(mu-dppm)]Cl (12a), and [{{PtBr(PPh3)}2(mu-SMe)2] (14a).

Luminescent Hydrido-Carbonyl Clusters of Rhenium Containing Bridging 1,2-Diazine Ligands

The reaction of the electronically unsaturated (56 valence electrons, ve) tetrahedral cluster [Re4(mu3-H)4(CO)12] (1) with pyridazine (pydz) gives as the main initial product the tetranuclear cluster [Re4(mu-H)4(mu-pydz)(pydz)2(CO)12] (2a), with 64 ve and four hydrogen-bridged metal-metal interactions, with a spiked-triangle geometry. One of the three pydz ligands bridges, in a cis configuration, the cluster edge opposite to the vertex bearing the spike, as indicated by the X-ray single-crystal analysis. This species slowly decomposes, affording the dinuclear unsaturated (32 ve) complex [Re2(mu-H)2(mu-pydz)(CO)6] (3a) and two isomers of the tetranuclear cluster [Re4(mu-H)4(mu-pydz)2(CO)12] (64 ve), sharing an unusual square cluster geometry and differing in the trans (major, 85%, 4a) or cis (4a') configuration of the bridging pydz ligands. The structures of 3a and 4a have been ascertained by X-ray analysis, while the characterization of 4a' was hampered by its instability (slowly transforming into 3a in THF solution). Both the dimer and the square cluster 4a are also formed directly (and quickly) from 1, being present in solution since the beginning of the reaction. Cluster 4a is the main final reaction product. The reaction with phthalazine follows a similar course, with some differences in the relative amount of the final products 3b and 4b. Most of the novel complexes are able to emit light in solution at room temperature, and photophysical measurements were performed in CH2Cl2 solution on the main stable reaction products (i.e., the dinuclear species 3a and 3b and the trans square clusters 4a and 4b). The emission was in the range of 580-645 nm, from MLCT excited states, with lifetimes on the order of a hundred nanoseconds (50-473 ns). The quantum yields were 1 order of magnitude higher for the squares (1.7 and 1.3% for 4a and 4b, respectively, in CH2Cl2) than for the dinuclear complexes ( approximately 0.1%). In the case of 4a, a blue shift and an increase of the emission intensity were observed upon decreasing the solvent polarity.

Chemical transformations on diols anchored to a triosmium cluster

Clusters of the general formula Os3(μ-H)(CO)10(μ-O–OH), 2, have been synthesised from the reaction of Os3(μ-H)(CO)10(μ-OH) with the appropriate glycol. The free –OH function of the glycol derivative, Os3(μ-H)(CO)10(μ-OCH2CH2OH), 2a, can be elaborated by esterification with benzoyl chloride to give Os3(μ-H)(CO)10(μ-OCH2CH2OC(O)Ph), 3, and partially oxidised to give Os3(μ-H)(CO)10(μ-OCH2CHO), 4a. Cluster 4a itself can undergo allylation to give Os3(μ-H)(CO)10(μ-OCH2CH(OH)CH2CHCH2), 5, or react with PhMgBr to give Os3(μ-H)(CO)10(μ-OCH2CH(OH)Ph), 2e. Cluster 2a can also be functionalised at the cluster metal core with PPh3 as Os3(μ-H)(CO)9(μ-OCH2CH2OH)(PPh3), 6.

Reactions of 1,8-Nonadiyne with Co2(CO)8 and Mo2(C5H4R)2(CO)4 and Crystal Structures of [M2L2(CO)4][μ-HC2(CH2)5C2H-μ][Mo2(C5H4R)2(CO)4] (M = Co, L = CO; M = Mo, L = C5H4R, R = H, COCH3, COOC2H5)

The treatment of 1,8-nonadiyne with Co2(CO)8 in hexane at room temperature gives a new complex [Co2(CO)6][μ-HC2(CH2)5C2H-μ][Co2(CO)6] (1) followed by regioselective exchange reactions with Na[Mo(C5H4R)(CO)3] (R = H, COCH3, COOC2H5) to afford the hetero-tetranuclear clusters [Co2(CO)6][μ-HC2(CH2)5C2H-μ][CoMo(C5H4R)(CO)5] (2a, R = H; 2b, R = COCH3; 2c, R = COOC2H5) and [CoMo(C5H4R)(CO)5][μ-HC2(CH2)5C2H-μ][CoMo(C5H4R)(CO)5] (3a, R = H; 3b, R = COCH3; 3c, R = COOC2H5), respectively. The reaction of Mo2(C5H4R)2(CO)4 with 1,8-nonadiyne produces the homo-dinuclear clusters [HC2(CH2)5C2H-μ][Mo2(C5H4R)2(CO)4] (4a, R = H; 4b, R = COCH3; 4c, R = COOC2H5) and homo-tetranuclear clusters [Mo2(C5H4R)2(CO)4][μ-HC2(CH2)5C2H-μ][Mo2(C5H4R)2(CO)4] (5a, R = H; 5b, R = COCH3; 5c, R = COOC2H5), respectively. The clusters 4a, 4b, and 4c reacted with Co2(CO)8 to form the novel tetranuclear clusters [Co2(CO)6][μ-HC2(CH2)5C2H-μ][Mo2(C5H4R)2(CO)4] (6a, R = H; 6b, R = COCH3; 6c, R = COOC2H5). The structures of 5a, 5b, and 6a have been determined by single-crystal X-ray diffraction, and the regioselective exchange reactions have been briefly discussed.

Heterometallic Osmium−Mercury Chain Structures Linking Two {Os3(CO)10(μ-X)} Subunits (X = Cl, Br, I): Syntheses and Molecular Structures of [{Os3(CO)10(μ-X)}2(μ4-Hg)] (X = Cl, I), [{Os3(CO)10(μ-Cl)}2{μ-HgOs(CO)4}2], andcis-[Os(CO)4{(μ-Hg)Os3(CO)10(μ-Cl)}2

Treatment of RHgCl (R = Me, Et, Ph, Fc) with the activated cluster [Os(3)(CO)(10)(NCMe)(2)] produces the osmium-mercury mixed-metal clusters [{Os(3)(CO)(10)(&mgr;-Cl)}(2)(&mgr;(4)-Hg)] (1a) and [{Os(3)(CO)(10)(&mgr;-Cl)}(2){&mgr;-HgOs(CO)(4)}(2)] (2a) in low yields. Cluster 1a bears a central wingtip mercury atom simultaneously bridging two {Os(3)(CO)(10)(&mgr;-Cl)} units. Cluster 2a comprises an unprecedented decanuclear osmium-mercury framework in which there is a central linear "Hg-{Os(CO)(4)}(2)-Hg" molecular backbone with the two Os(CO)(4) fragments arranged in a staggered conformation. Cluster 2a is thermally unstable and converts slowly to cis-[Os(CO)(4){(&mgr;-Hg)Os(3)(CO)(10)(&mgr;-Cl)}(2)] (4a) via the extrusion of an Os(CO)(4) moiety under ambient conditions. Cluster 4a comprises two {(&mgr;-Hg)Os(3)(CO)(10)(&mgr;-Cl)} subcluster units bonded to a central Os(CO)(4) moiety in a cis configuration. Similar reactions with PhHgBr and MeHgI have also been investigated. Cluster 1a crystallizes in the triclinic space group P&onemacr; with a = 9.112(2) Å, b = 12.314(2) Å, c = 15.501(4) Å, alpha = 84.92(2), degrees beta = 88.26(3), degrees gamma = 79.52(2) degrees and Z = 2. Cluster 2a crystallizes in the triclinic space group P&onemacr; with a = 13.306(2) Å, b = 20.768(5) Å, c = 9.771(4) Å, alpha = 96.36(3), degrees beta = 90.50(2), degrees gamma = 98.81(2) degrees and Z = 2. Cluster 4a crystallizes in the triclinic space group P&onemacr; with a = 18.356(2) Å, b = 19.100(3) Å, c = 14.478(2) Å, alpha = 89.783(2), degrees beta = 113.19(2), degrees gamma = 113.70(2) degrees and Z = 4.

The reaction of ( μ3-CCO 2R)Co 2M(CO) 8L (M = Co, Mo, W; L = CO, MeCp; R = Me, Et) with Na 2[Fe(CO) 4]. X-ray crystal structure analysis of (EtO 2CCCCO 2Et)Co 4(CO) 10 and (MeO 2CCCCO 2Me)FeCo 2(CO) 9

The reactions of clusters [(μ 3- CCO 2 Et) Co 2 M( CO) 8( MeCp)][ M = Mo ( 2 a ), W ( 2 b )] , derived from the reactions of ( μ 3-CCO 2Et)Co 3(CO) 9 with Na[M(CO) 3(MeCp)], with Na 2[Fe(CO) 4] in THF at reflux not only gave the expected metal fragment exchange products [(μ 3- CCO 2 Et) FeCoM(CO) 8( MeCp) H][ M = Mo ( 3 a ), W ( 3 b )] , but also gave the unexpected compounds [(μ 3- CCO) FeCoM(CO) 8( MeCp)][ M = Mo ( 4 a ), W ( 4 b ) . It is suggested that the formation of two kinds of compounds resulted from two competitive reactions of the intermediates [( μ 3-CCO 2Et)FeCoM(CO) 8(MeCp)] − with acidic treatment: the one is the protonic reaction of the intermediate giving the clusters 3a and 3b; the other is the intermolecular nucleophilic substitution reaction of the intermediate by the catalysis of H +, giving the clusters 4a and 4b. Under the different reaction temperature and molar ratio of the starting materials, the reactions of (μ 3- CCO 2 R) Co 3( CO) 9[ R = Me ( 1 1 ), Et ( 1 b )] [ R = Me ( 6 a ) , Et ( 6b)] abd (RO 2CCCCO 2R)FeCo 2(CO) 9[R = Me ( 7a), Et ( 7b)] besides the expected exchange products (μ 3- CCO 2 R) FeCo 2( CO) 9 H[ R = Me ( 5 a ), Et ( 5 b )] . This is the first example that the reaction of 6a and 6b with Na 2[Fe(CO) 4] could produce the clusters 7a and 7b. The clusters (EtO 2CCCCO 2Et)Co 4(CO) 10 and (RO 2CCCCO 2R)FeCo 2(CO) 9 were determined structurally by X-ray diffraction.

Phylogeny of the pasteurellaceae as determined by comparison of 16S ribosomal ribonucleic acid sequences

Previously, virtually complete 16S ribosomal ribonucleic acid sequences were determined for 54 strains of species in the family Pasteurellaceae. The sequences for 16 additional strains have been determined, bringing the total number of strains sequenced to 70. The additional strains include: Actinobacillus hominis, A. muris, A. salpingitis, Pasteurella bettyae, P. mairii, P. testudinis, and Bisgaard taxa 2, 3, 5, 6, 7, 8, 9, 13, and 14 (2 strains). A phylogenetic tree was constructed based upon sequence similarity using the Neighbor-Joining method. The additional sequence information and phylogenetic analysis generally supported our previously described phylogenetic structure for the family Pasteurellaceae. Cluster 1, containing Haemophilus sensu stricto, was unchanged. P. mairii was closely related to P. aerogenes and Bisgaard taxon 6 was related to H. somnus in Cluster 2. A. salpingitidis and Bisgaard taxa 2, 3, 7, and 13 fell in Cluster 3 which contains Pasteurella sensu stricto. A. hominis was closely related to Actinobacillus sensu stricto species in Cluster 4A. Bisgaard taxa 5, 8, 9 and P. bettyae fell in Cluster 4B. A. muris was related to P. pneumotropica in Cluster 5. Haemophilus parainfluenzae strains branched deeply as a 6th cluster. Bisgaard taxon 14 and P. testudinis formed a 7th cluster which branched deeper than any previously described clusters in the family Pasteurellaceae. The branching was extremely complex and taxonomic division of the family into phylogenetically and phenotypically coherent genera will be difficult.