The Bis(ferrocenyl)phosphenium Ion Revisited

The bis(ferrocenyl)phosphenium ion, [Fc2P]+, reported by Cowley et al. (J. Am. Chem. Soc. 1981, 103, 714–715), was the only claimed donor‐free divalent phosphenium ion. Our examination of the molecular and electronic structure reveals that [Fc2P]+ possesses significant intramolecular Fe⋅⋅⋅P contacts, which are predominantly electrostatic and moderate the Lewis acidity. Nonetheless, [Fc2P]+ undergoes complex formation with the Lewis bases PPh3 and IPr to give the donor–acceptor complexes [Fc2P(PPh3)]+ and [Fc2P(IPr)]+ (IPr=1,3‐bis(2,6‐diisopropylphenyl)imidazole‐2‐ylidene)

RESEARCH ON THE CHEMICAL CONTROL OF THE INVASIVE SPECIES AILANTHUS ALTISSIMA FROM PASTURES

The present paper presents the results of the chemical control research of the species Ailanthus altissima, an invasive species that damages the lands on which it appears spontaneously, in the form of restricted areas. The total systemic herbicide Roundup, based on glyphosate, 360 g/l was used. Two methods of application were investigated, namely, by brushing on a 30 cm height of the tree trunk and by injection into holes made in the tree trunk. Undiluted herbicide was applied. The first method of application had almost no effect on Ailanthus altissima trees due to the fact that the herbicide cannot be absorbed through the mature bark of the trees. The second method of application gave very good results

Silyl Cations Stabilized by Pincer Type Ligands with Adjustable Donor Atoms

Novel E,C,E'-pincer supported silyl cations (E, E' = O, S, Se, Au) were prepared in three steps starting from 2,6-F2C6H3SiMe2H (1a) and 2,6-Br2C6H3SiMe2H (1b), which were first converted in two complementary ways into 2,6-(Ph2P)(2)C6H3SiMe2H (2). The oxidation of 2 with H2O2 center dot urea, S-8, and Se-8 afforded 2,6-(Ph2PE)(2)C6H3SiMe2H (3a, E = O; 3b, E = S; 3c, E = Se) and 2-(Ph2PE)-6-(Ph2P)-C6H3SiMe2H (4b, E = S; 4c, E = Se), which were reacted to the E,C,E-supported silyl cations [2,6-(Ph2PE)(2)C6H3SiMe2](+) (5a, E = O, counterion Br-3(-); 5b, E = S, counterion B(C6F5)(4)(-); 5c, E = Se, counterion B(C6F5)(4)(-)), the E,C-supported silyl cations [2-(Ph2PE)-6-(Ph2P)C6H3SiMe2](+) (6b, E = S, not isolated; 6c, E = Se, not isolated), the O,C,S-supported silyl cation [2-(Ph2PS)-6-(Ph2PO)C6H3SiMe2](+) (7, counterion B(C6F5)(4)(-)) as well as the E,C,Au-supported silyl cations [2-(Ph2PAuC6F5)-6-(Ph2PE)C6H3SiMe2](+) (8b, E = S, counterion [B{3,5-(CF3)(2)C6H3}(4)](-); 8c, E = Se, [B{3,5-(CF3)(2)C6H3}(4)](-)) using Br-2, O-2, S-8, (tht)AuC6F5, Ph3C[B(C6F5)(4)] and Ph3C[B{3,5-(CF3)(2)C6H3}(4)]. All compounds were characterized by multinuclear (H-1, C-13, F-19, Si-29, P-31, Se-77) NMR spectroscopy, ESI MS spectrometry and X-ray crystallography (2, 3a center dot H2O, 3b, 3c, 4b, 5a, 5c, 7, 8b, 8c). The gas phase structures of 2, 3a-c, 5a-c (fully optimized) and 8b, 8c (single-point calculations) were studied at the B3PW91/6-311+G(2df,p) level of theory. A set of real-space bonding indicators (RSBIs) derived from the theoretically calculated electron and pair densities were analyzed utilizing the atoms-in molecules (AIM) and electron-localizability indicator (ELI-D) space partitioning schemes

Intramolecular Reaction of Transient Phosphenium and Arsenium Ions Giving Rise to Isolable 9-Phospha- and 9-Arsena-Fluorenium Ions

Transient phosphenium and arsenium ions, generated by fluoride abstraction from bis(m-terphenyl)fluoropnictogens, underwent intramolecular electrophilic attack prior to methyl group migration and gave rise to isolable 9-phospha- and 9-arsena-fluorenium ions

FOLIAR AND STEM CHEMICAL CONTROL OF THE INVASIVE SPECIES AILANTHUS ALTISSIMA FROM PASTURES

The present paper presents the results of the chemical foliar control research of the species Ailanthus altissima. In the shrubs sprayed on the foliar apparatus, the effect was 100%, only where the solution reached the leaves, and in the tops of the trees where the solution did not spread, the leaves were not affected, having a normal vegetation. It should be noted that this method applied by spraying the foliar apparatus did not affect other shrubs in the vicinity, only the treated herbicide had an effect on those treated. In conclusion, the herbicide had its effect only where it came in contact with the leaves, the rest of the leaves not being affected. In those injected with a herbicide dose of 4 ml / cm in the diameter of the tree (15 cm in diameter corresponds to a dose of 60 ml pure herbicide) at a distance of 30 cm above the ground, the herbicide made its effect 100%, these shrubs drying completely. They were also affected, in addition to those injected a no. of 10 and 12 trees, respectively, on a perimeter of 10 m2, but not entirely, the foliar apparatus being affected 70-80% of the foliage and at the same time new shoots of approx. 30-40 cm long, and the tendency of herbicidal trees to regenerate after approx. 35 days

2′-Iodo-2,2′′,3,3′′,4,4′′,5,5′′,6,6′′-deca­methyl-1,1′:3′,1′′-terphenyl chloro­form monosolvate

The title compound, C28H33I·CHCl3, forms dimers through C—I⋯π inter­actions. The crystal structure is consolidated by the presence of C—H⋯π inter­actions between the chloro­form solvent and the main mol­ecule

(2,4,6-Trimethyl­phen­yl)boronic acid–triphenyl­phosphine oxide (1/1)

In the crystal structure of the title compound, C9H13BO2·C18H15OP, there are O—H⋯O hydrogen bonds between the O atom of triphenyl­phosphine oxide and one hy­droxy group of the boronic acid. Boronic acid mol­ecules form inversion-related hydrogen-bonded dimers in an R 2 2(8) motif. The structure is consolidated by inter­molecular C—H⋯O bonds and C—H⋯π inter­actions

A New Approach of Some Contractive Mappings on Metric Spaces

In this paper, we introduce a new contraction-type mapping and provide a fixed-point theorem which generalizes and improves some existing results in the literature. Thus, we prove that the Boyd and Wong theorem (1969) and, more recently, the fixed-point results due to Wardowski (2012), Turinici (2012), Piri and Kumam (2016), Secelean (2016), Proinov (2020), and others are consequences of our main result. An application in integral equations and some illustrative examples are indicated

A New Contraction-Type Mapping on a Vectorial Dislocated Metric Space over Topological Modules

One recent and prolific direction in the development of fixed point theory is to consider an operator T:X→X defined on a metric space (X,d) which is an F—contraction, i.e., T verifies a condition of type τ+F(d(T(x),T(y))≤F(d(x,y)), for all x,y∈X, T(x)≠T(y), where τ>0 and F:(0,∞)→R satisfies some suitable conditions which ensure the existence and uniqueness for the fixed point of operator T. Moreover, the notion of F-contraction over a metric space (X,d) was generalized by considering the notion of (G,H)—contraction, i.e., a condition of type G(d(Tx,Ty))≤H(d(x,y)), for all x,y∈X, Tx≠Ty for some appropriate G,H:(0,∞)→R functions. Recently, the abovementioned F-contraction theory was extended to the setup of cone metric space over the topological left modules. The principal objective of this paper is to introduce the concept of vectorial dislocated metric space over a topological left module and the notion of A-Cauchy sequence, as a generalization of the classical Cauchy sequence concept. Furthermore, based on the introduced concept, a fixed point result is provided for an operator T:X→X, which satisfies the condition (G,H)—contraction, where G,H are defined on the interior of a solid cone