Ancestry-linked stromal variations impact breast epithelial cell invasion.

Breast cancer is a significant health challenge worldwide, and disproportionately affects women of African ancestry (AA) who experience higher mortality rates relative to other racial/ethnic groups. Several studies have pointed to biological factors that affect breast cancer outcomes. A recently discovered stromal cell population that expresses P ROCR, Z EB1 and P DGFRα (PZP cells) was found to be enriched in normal healthy breast tissue from AA donors, and only in tumor adjacent tissues from donors of European ancestry (EA).

Synthesis and exploration of a 1-germol-1-ide/pyridine bidentate ligand.

The synthesis of an anionic [Ge,N]-bidentate ligand based on the combination of an amidopyridinato group with an anionic germolide ring is reported. The potential of the germolide part of this ligand to switch between η-( Ge) and η-( CGe) coordination modes makes this ligand an interesting synthetic target. Salt metathesis reactions of the potassium salt of this ligand with GeCl dioxane and SnCl allow the synthesis of bis-germolyl-substituted germylenes and stannylenes with the tetrel atoms in a distorted square pyramidal coordination environment.

Synthesis, characterization and functionalization of titanium κ amidinato complexes from carbodiimides.

A series of titanium amidinato complexes were synthesized by stoichiometric insertion reactions of carbodiimides into bis(π-η:σ-η-pentafulvene)titanium complexes. NMR studies and single-crystal X-ray diffraction showed κ coordination of the former carbodiimides to the metal center. DFT calculations were performed, confirming the clear preference for a single nitrogen atom coordinating to the metal center with a high energy transition state for the formation of a chelating heteroallyl ligand.

Synthesis of Optically Active Spirocycles by a Sequence of Decarboxylative Asymmetric Allylic Alkylation and Heck Reaction.

Optically active spirocycles were prepared in a sequence of two palladium-catalyzed reactions. In the first step, racemic α-(-iodophenyl)-β-oxo allyl esters were submitted to the palladium-catalyzed decarboxylative asymmetric allylic alkylation reaction, furnishing the α-allylated products with a quaternary stereocenter with good yields and enantioselectivities. Subsequently, these intermediate products were converted in a Heck reaction yielding the spirocyclic structures as a mixture of - and -cyclic regioisomers.

Metal ion-driven formation of 2-silolides and -germolides.

The synthesis of potassio-1-silolides and -germolides substituted with an amidinate-stabilized silylene is reported. Both anions undergo a thermal rearrangement to the 2-isomer yielding cyclic sila- and germavinyl anions. The reaction is driven by complex formation with metal ions.

Phospha-bicyclohexene-germylenes exhibiting unexpected reactivity.

Introducing phospha-bicyclohexene (BCH)-germylenes (BCHGe's) as a novel, multifunctional compound class: the title compounds 15-18 are obtained from simple salt metathesis reactions of dipotassium germacyclopentadienediides K[1] with phosphorusdichlorides. The BCHGe's 15-18 are stabilized by homoconjugation of the germanium(ii) centre with the remote C[double bond, length as m-dash]C double bond. Despite substantial thermodynamic stabilization, phospha-BCHGe's are reactive and undergo a reductive elimination of elemental germanium to give the corresponding phospholes.

From Coordination to Noncoordination: Syntheses and Substitution Lability Studies of Titanium Triflato Complexes.

A new concept for obtaining cationic complexes with triflate counteranions from coordinating triflato ligands was developed. Various routes are leading to titanium(IV) and titanium(III) triflato complexes efficiently. The reactions of pentafulvene titanium complexes with either triflic acid or silver triflate give the corresponding titanium(IV) triflato complexes in excellent yields.

Syntheses, Characterization, and Redox Activity of Ferrocene-Containing Titanium Complexes.

The chemistry of bis(π-η:σ-η-pentafulvene)titanium complexes is characterized by a broad range of E-H activation and Ti-C functionalization reactions, whereas ferrocene derivatives are easily accessible and redox-active compounds. The reaction of ferrocenealdehyde and -ketones with bis(π-η:σ-η-pentafulvene)titanium complexes result in the formation of bimetallic complexes via insertion of the C=O double bond of the aldehyde/ketone into the Ti-C bond of the pentafulvene moiety. The reaction of bis(π-η:σ-η-pentafulvene)titanium complexes with ferrocenyl alcohols leads to alcoholate complexes via deprotonation of the OH group by the pentafulvene ligand.

A Bis(silylene)silole - synthesis, properties and reactivity.

A 1,1-bis(silylene)silole has been synthesised by a double salt-metathesis reaction from potassium silacyclopentadienediide, K[1], and an amidinato-stabilized silylene chloride in a 1 : 2 ratio. The red colour of the title compound is due to the lp(Si)/π*(silole) transition. This band is bathochromically shifted compared to that of other 1,1-bissilylsiloles suggesting enhanced conjugation between the silole π-system and the newly formed Si(II)-Si(IV)-Si(II) group.

Germaaluminocenes-Masked Heterofulvenes.

Germaaluminocenes are formed by salt metathesis reactions of dipotassium germacyclopentadienediides with pentamethylcyclopentadienylaluminum dichloride. The reactivity pattern of these sandwich complexes is determined by the electrophilic central aluminum atom and by the nucleophilic dicoordinated germanium center. Surprisingly, the products formed by reactions with Lewis acids, Lewis bases, amphiphiles and compounds with polar double bonds are those expected from the reaction of a hypothetical aluminagermapentafulvene with these types of reagents.

Aluminagerma[5]pyramidanes-Formation and Skeletal Rearrangement.

The salt metathesis reaction of dipotassium germacyclopentadienediide with aluminum(III) dichlorides provides either half-sandwich alumole complexes of germanium(II) or aluminylene germole complexes. Their molecular structure and the delocalized bonding situation, revealed by density functional theory (DFT) calculations, are equally described as isomeric aluminagerma[5]pyramidanes with either the germanium or the aluminum atom in the apical position of the pentagonal pyramid. The product formation and the selectivity of the reaction depends on the third substituent of the aluminum dichloride.

Selective Manipulation of Well-Defined Trinuclear Pd(II)-Complexes.

Several strategies are available to design well-defined multimetallic molecular entities bearing functional ligands. Substoichiometric exchange reactions in the coordination sphere of pre-existing multinuclear precursors are relatively underexploited in this context. Palladium(II) acetate is not a mononuclear compound in the solid state but rather exists as a trimer, i.

Syntheses, Characterization, and Multifaceted Coordination Chemistry of Hydrazonido Titanium Complexes.

The reaction of hydrazones with bis(π-η:σ-η-pentafulvene)titanium complexes leads to both hydrazonido and hydrazido complexes depending on the interaction of the hydrazone with the fulvene ligand of the metal complex. The molecular structures mostly reveal κ, side-on coordination of the hydrazonido ligand due to the deprotonation of the N-H bond by one of the fulvene moieties. Instead of deprotonation, the reaction of the bis(adamantylidene fulvene)titanium complexes with cinnamon aldehyde phenylhydrazone leads to κ coordination.

Extracellular Vesicles: Biological Packages That Modulate Tumor Cell Invasion.

Tumor progression, from early-stage invasion to the formation of distal metastases, relies on the capacity of tumor cells to modify the extracellular matrix (ECM) and communicate with the surrounding stroma. Extracellular vesicles (EVs) provide an important means to regulate cell invasion due to the selective inclusion of cargoes such as proteases and matrix proteins into EVs that can degrade or modify the ECM. EVs have also been shown to facilitate intercellular communication in the tumor microenvironment through paracrine signaling, which can impact ECM invasion by cancer cells.

Geometrically Deformed and Conformationally Rigid Phosphorus Trisamides Featuring an Unsymmetrical Backbone.

Nonclassical P(III) centers have attracted much attention in recent years. Incorporating a P(III) center in a rigid bicyclic platform offers a particularly attractive way to invoke significant geometric distortion of the phosphorus atom that may in turn induce unusual reactivity. Although still relatively scarcely explored, phosphorus centers enforced in a non-C symmetry have gained significant traction lately.

Density Functional Theory Calculations for Multiple Conformers Explaining the Regio- and Stereoselectivity of Ti-Catalyzed Hydroaminoalkylation Reactions.

Hybrid Density Functional Theory (DFT) calculations for multiple conformers of the insertion reactions of a methylenecyclopropane into the Ti-C bond of two differently α-substituted titanaaziridines explain the experimentally observed differences in regioselectivity between catalytic hydroaminoalkylation reactions of methylenecyclopropanes with α-phenyl-substituted secondary amines and corresponding stoichiometric reactions of a methylenecyclopropane with titanaaziridines, which can only be achieved with α-unsubstituted titanaaziridines. In addition, the lack of reactivity of α-phenyl-substituted titanaaziridines as well as the diastereoselectivity of the catalytic and stoichiometric reactions can be understood.

Phosphanyl-substituted tin half-sandwich complexes.

Phosphanyl-substituted tin(ii) half sandwich complexes are reported. Due to the Lewis acidic tin center and Lewis basic phosphorous atom they form head-to-tail dimers. Their properties and reactivities were investigated both experimentally and theoretically.

Elemental Magnesium as an Early Transition Metal Substitute: From Pentafulvene Coordination to Deprotonation of Amines.

The reaction of magnesium turnings and 6,6-di-para-tolylpentafulvene was investigated. Under mild conditions, the magnesium dissolves, forming the Mg complex 1 with a π-η  : σ-κ coordinating ligand of the dimerized pentafulvene, analyzed by NMR and XRD investigations. As a magnesium pentafulvene complex was a possible intermediate, amines were employed as intercepting agents.

Vanadium Pentafulvene Complexes: Synthon for Unprecedented Vanadocene Derivatives.

The benzene ligand at CpV(η -C H ) (1) is exchanged for pentafulvenes. Using sterically demanding pentafulvenes gives a clean exchange reaction, yielding vanadium pentafulvene (2 a and 2 b) and benzofulvene complexes (3 a and 3 b). The molecular structures of the target compounds suggest a π-η :σ-η coordination mode with a vanadium center.

Light-induced dissolution and concomitant crystallization of a Keggin-type polyoxometalate mimicking a naturally occurring phenomenon.

A suspension of a yellow polycrystalline compound [PPh][PMoO] in -methylformanilide (NMF) (in which it is not soluble), on irradiation with sunlight, initiates dissolution its reduction followed by its crystallization leading to the isolation of single crystals of compound [PPh][PMoMoO]·3CH(CH)NCHO (1). Compounds [PPh][PMoO]·1.75 CH(CH)NCHO (2) and [PPh][PMoO]·2CH(CH)NCHO (3), each containing an oxidized Keggin anion, are obtained at two different temperatures when the corresponding mother liquor is kept in the dark.

(Carbazol-9-ido-κ)di-chlorido-(η:η-2,3,4,5-tetra-methyl-penta-fulvene)tantalum(V).

The reaction of (η:η-2,3,4,5-tetra-methyl-penta-fulvene)tantalum(V) dicarbazolide chloride () with etheric HCl results in the formation of the title compound (), [Ta(CH)(CHN)Cl]. The Ta atom has a distorted tetra-hedral coordination environment in a three-legged piano-stool fashion. The conformation of the penta-fulvene exocyclic C atom to the three other ligands is staggered and not eclipsed, as found in the crystal structure of .

Crystal structures of the Lewis acid-base adducts {[(CH)N]Ti-}[MeB(CF)]·1.5CH; LB = (CH)PO (1), -F-CHCN (2).

The reaction of [(CH)N]Ti-CH with the Lewis acid B(CF), followed by addition of the Lewis bases (CH)PO and -F-CHCN led to the complex salts tris-(di-cyclo-hexyl-amido)(tri-phenyl-phosphine oxide)titanium methyl-tris(penta-fluoro-phen-yl)borate toluene sesquisolvate, [Ti(CHN)(CHOP)](CHFB)·1.5CH, (), and tris-(di-cyclo-hexyl-amido)(4-fluoro-benzo-nitrile)-titanium methyl-tris-(penta-fluoro-phen-yl)borate toluene sesquisolvate, [Ti(CHN)(CHFN)](CHFB)·1.5CH, (), both crystallizing with 1.

A niobium pentafulvene ethylene complex: synthesis, properties and reaction pathways.

The π-η:σ-η coordination mode of early transition metal pentafulvene ligands yields a strongly nucleophilic exocyclic carbon atom (C). The substitution of the chlorido ligand of bis(η:η-(di--tolyl)pentafulvene)niobium chloride (1) by reaction with ethyl magnesium bromide is subsequently followed by a β-C-H activation employing this C, forming the pentafulvene niobium ethylene complex 2. The intermediately formed ethyl complex can be intercepted with water, protonating both pentafulvene moieties and thereby retaining the ethyl moiety to give the terminal oxo complex 3.

Covalent triflates as synthons for silolyl- and germolyl cations.

The synthesis of 1-silolyl and 1-germolyl triflates from the corresponding chlorides by salt metathesis reaction is reported. These covalent triflates are ideal starting materials for the preparation of ionic silolyl- and germolyl-imidazolium triflates by their reaction with N-heterocyclic carbenes. Similarily, ionic silolyl- and germolyl-oxophosphonium triflates are obtained by substitution of the triflate group by triethylphosphane oxide EtPO.