Uncommon Twist: Femoral Neck Stress Fracture in a High-Performance Athlete With an Incidental Diagnosis of Femoroacetabular Impingement.

Femoral neck stress fractures (FNSFs) are rare but significant injuries, often leading to delayed diagnosis due to nonspecific symptomatology. This case report presents a 30-year-old professional surfer who experienced acute groin pain during a half marathon, ultimately diagnosed with a left intertrochanteric line femur stress fracture and with femoroacetabular impingement (FAI) in the opposite hip. Despite being physically fit, his presentation challenges the prevailing notion that FNSFs predominantly occur in military personnel or the elderly. The patient underwent surgical left hip osteosynthesis without complications. This case highlights the importance of early suspicion of FNSFs in young, active individuals and emphasizes the need for comprehensive evaluation to prevent complications like osteonecrosis and malunion. It underscores the value of a broad differential diagnosis and timely intervention in optimizing outcomes, especially in the context of rising high-impact sports participation.

A Case Report of a 17 cm Retropharyngeal Well-Differentiated Liposarcoma With Bilateral Neck Extension.

Liposarcomas, malignant adipocytic tumors, primarily manifest in the lower extremities and retroperitoneum, with a strikingly low incidence in the head and neck region. Symptomatology typically remains absent until the tumor attains significant size, leading to cosmetic concerns or compression-related complications. This report presents a unique case of well-differentiated retropharyngeal liposarcoma in an 81-year-old male, emphasizing diagnostic challenges, management strategies, and the crucial role of Mouse double minute 2 (MDM2) fluorescence in situ hybridization (FISH) analysis in confirmation. The patient exhibited dysphagia attributed to a retropharyngeal mass, prompting suspicion of malignancy. Diagnostic assessments, including flexible laryngoscopy and percutaneous tru-cut biopsy, highlighted unique features such as atypical nuclear features in adipocytes. MDM2 FISH analysis definitively confirmed the diagnosis by detecting MDM2 gene amplification. The rarity of retropharyngeal liposarcomas complicates diagnosis, often leading to confusion with benign lesions. Surgical excision, the mainstay of treatment, varies based on tumor size and extension. In this case, a left neck dissection via a hockey stick incision successfully resected a 17 cm well-differentiated liposarcoma. Pathologic analysis revealed focal involvement of resection margins, with no complications or vocal cord damage. In conclusion, retropharyngeal liposarcomas pose diagnostic challenges, warranting reliance on MDM2 FISH analysis for accurate confirmation. Early surgical intervention, guided by tumor size and extension, is paramount for optimal outcomes in managing these rare tumors. This case underscores the significance of a detailed surgical approach in achieving successful outcomes for retropharyngeal liposarcomas.

Enantioselective Synthesis, DFT Calculations, and Preliminary Antineoplastic Activity of Dibenzo 1-Azaspiro[4.5]decanes on Drug-Resistant Leukemias.

The addition of 2-bromobenzylmagnesium bromide to chiral N- tert-butanesulfinyl imines derived from tetralone-type ketones proceeds with high levels of diastereocontrol. The resulting sulfinamide derivatives were transformed into dibenzoazaspiro compounds after a palladium-catalyzed intramolecular N-arylation. DFT calculations have been performed to rationalize the stereochemical course of the reaction. Similar results have been obtained considering either diethyl ether or toluene as a solvent, in both cases in an excellent agreement with experimental findings. NCI topological calculations have also been used to evidence crucial noncovalent interactions. In addition, the azaspiro compounds reduced the viability of chronic myeloid leukemia cells in the micromolar range. Notably, both the halogen-substituted ( R)- and ( S)-8g and -8h as well as ( R)-8j were at least two times more effective on a multidrug-resistant derivative than on the parental cell line, exerting a collateral sensitivity effect.

Stereoselective Coupling of N-tert-Butanesulfinyl Aldimines and ß-Keto Acids: Access to ß-Amino Ketones.

The reaction of chiral N-tert-butanesulfinyl aldimines with ß-keto acids under basic conditions at room temperature proceeds with high levels of diastereocontrol, leading to ß-amino ketones in high yields. Based on DFT calculations, an eight-membered cyclic transition state involving coordination of the lithium atom to the oxygens of carboxylate and sulfinyl units was proposed, being in agreement with the observed experimental diastereomeric ratios. The synthesis of the piperidine alkaloid (-)-pelletierine was successfully undertaken in order to demonstrate the utility of this methodology.

Selective palladium(ii)-mediated oxidation of homoallylic N-tert-butanesulfinyl amine derivatives.

The palladium(ii)-catalyzed oxidation of homoallylic amine derivatives resulting from the allylation of N-tert-butanesulfinyl imines with allyl bromide led to the formation of the corresponding terminal allylic acetates in a regioselective fashion in moderate yields. In the case of the homoallylic amine derivatives obtained using cyclohexenyl bromide as the allylating reagent, the allylic oxidation took place with high regio- and diastereoselectivity and yields ranging from 40 to 85%.

Stereoselective Synthesis of 1,3-Diaminotruxillic Acid Derivatives: An Advantageous Combination of C-H-ortho-Palladation and On-Flow [2+2]-Photocycloaddition in Microreactors.

The stereoselective synthesis of ε-isomers of dimethyl esters of 1,3-diaminotruxillic acid in three steps is reported. The first step is the ortho-palladation of (Z)-2-aryl-4-aryliden-5(4H)-oxazolones 1 to give dinuclear complexes 2 with bridging carboxylates. The reaction occurs through regioselective activation of the ortho-CH bond of the 4-arylidene ring in carboxylic acids. The second step is the [2+2]-photocycloaddition of the CC exocyclic bonds of the oxazolone skeleton in 2 to afford the corresponding dinuclear ortho-palladated cyclobutanes 3. This key step was performed very efficiently by using LED light sources with different wavelengths (465, 525 or 625 nm) in flow microreactors. The final step involved the depalladation of 3 by hydrogenation in methanol to afford the ε-1,3-diaminotruxillic acid derivatives as single isomers.

Efectividad de una intervención para reducir el miedo a caer en las personas mayores / Effectiveness of an Intervention to Reduce the Fear of Falling in Elderly Persons / Efetividade de uma intervenção para reduzir o medo de cair nas pessoas idosas

Objetivo: las caídas y el miedo a caerse se relacionan entre sí, siendo cada uno de ellos factor de riesgo del otro. Este trabajo pretende analizar la efectividad de una intervención para reducir el miedo a caer y sus consecuencias dado que la aplicación de este tipo de tratamientos ha mostrado resultados satisfactorios. Método: mediante un diseño cuasi-experimental, con medidas pre-pos, se evaluó a 53 sujetos, con edades comprendidas entre 65 y 89 años y que habían sufrido una caída anterior. La muestra fue dividida en grupo control y tratamiento, poniéndose en marcha un método combinado de ejercicios y educación sanitaria para la prevención de caídas. Resultados: se obtuvieron resultados significativos en la calidad de vida relacionada con la salud, el equilibrio y el miedo a caer, observándose mejoras en el grupo tratamiento. Conclusión: la aplicación de intervenciones para la reducción del miedo a caerse en población anciana se plantea como un tratamiento cuyos efectos serían dobles, pues no solo se reduciría el propio miedo sino que, dada la asociación existente, se reduciría la posible caída por repetición.

Objective: Falling and the fear of falling are interrelated, with each being a risk factor of the other. This study is an attempt to analyze the effectiveness of an intervention to reduce the fear of falling and its consequences, since treatments of this type have demonstrated satisfactory results. Method: A quasi-experimental study with pre-post measurements was used to evaluate 53 subjects between the ages of 65 and 89 who had suffered a prior fall. The sample was divided into a control group and a treatment group. The latter was subject to treatment featuring a combination of exercises and health education to prevent falling. Results: The results obtained with respect to quality of life were significant for health, balance and fear of falling, with the treatment group showing progress. Conclusion: The application of interventions to reduce the fear of falling in the elderly population is proposed as a treatment with a twofold effect, not only on reducing fear itself, but also - given the association that exists - on reducing the potential for falling through repetition.

Objetivo: as quedas e o medo de cair se relacionam entre si, sendo cada um deles fator de risco do outro. Este trabalho pretende analisar a efetividade de uma intervenção para reduzir o medo de cair e suas consequências, já que a aplicação desse tipo de tratamentos vem mostrando resultados satisfatórios. Método: mediante um desenho quase experimental, com medidas pré e pós, avaliaram-se 53 sujeitos, na faixa de 65 a 89 anos, que sofreram uma queda. A amostra foi dividida em grupo controle e tratamento, iniciando-se um método combinado de exercícios e educação sanitária para a prevenção de quedas. Resultados: obtiveram-se resultados significativos na qualidade de vida relacionada com a saúde, o equilíbrio e o medo de cair, e observaram-se melhoras no grupo tratamento. Conclusão: a aplicação de intervenções para a redução do medo de cair em população idosa se propõe como tratamento cujos efeitos seriam duplos, uma vez que não só se reduziria o próprio medo, mas também, dada a associação existente, se reduziria a possível queda por repetição.

Cyclopalladation and reactivity of amino esters through C-H bond activation: experimental, kinetic, and density functional theory mechanistic studies.

The orthopalladation, through C-H bond activation, of a large number of amino esters and amino phosphonates derived from phenylglycine, and having different substituents at the aryl ring and the C-α atom, as well as on the N-amine atom, has been studied. The experimental observations indicated an improvement in the yields of the orthopalladated compounds when the N-amine and/or the C-α atom are substituted, when compared with the unsubstituted methyl phenylglycinate derivatives. In contrast, substitutions at the aryl ring do not promote significant changes in the orthometalation results. Furthermore, the use of hydrochloride salts of the amino esters has also been shown to have a remarkably favorable effect on the process. All these observations have been fully quantified at different temperatures and pressures by a detailed kinetic study in solution in different solvents and in the presence and absence of added Brønsted acids and chloride anions. The data collected indicate relevant changes in the process depending on these conditions, as expected from the general background known for cyclopalladation reactions. An electronic mechanism of the orthopalladation has been proposed based on DFT calculations at the B3LYP level, and a very good agreement between the trends kinetically measured and the theoretically calculated activation barriers has been obtained. The reactivity of the new orthopalladated amino phosphonate derivatives has been tested and it was found that their halogenation, alkoxylation and carbonylation resulted in formation of the corresponding functionalized ortho-haloaminophosphonates, ortho-alkoxyaminophosphonates and oxoisoindolinylphosphonates.

Cycloruthenated complexes from imine-based heterocycles: synthesis, characterization, and reactivity toward alkynes.

Novel cycloruthenated complexes 2 a-c, 4 a-c, and 6 a, b based on heteroaromatic cores have been synthesized by reaction of a series of heterocycle-based imines with [{RuCl(η(6)-p-cymene)}(2)(µ-Cl)(2)] and Cu(OAc)(2). This approach has proved efficient for the cyclometalation of thiophene, benzothiophene, furan, benzofuran, pyrrole, and indole derivatives. In addition, even a double cyclometalation process over the same heterocyclic ring is possible, yielding unprecedented bimetallic complexes. These ruthenacycles react with 3-hexyne through an unexpected pathway, which involves the coupling of the original imino heterocycle and acetylene followed by dearomatization to afford fused hetero-hydropyridyl ligands bonded to the {Ru(p-cymene)} organometallic moiety (i.e., 7 a-c and 8 a-c). These complexes represent, as far as we know, the first examples of this type of compound within the context of cyclometalation, and an exhaustive analysis of their structure was carried out in solution and solid state. Furthermore, these unique species react with CuCl(2), which promotes the rearomatization and the release of highly valuable aromatic fused bis-heterocycles (i.e., 9 a-c, 10 a-c, 11 a, and 12 a/12 a'), providing a novel and appealing synthetic route to this extraordinary family of molecules.

Regioselective orthopalladation of (Z)-2-aryl-4-arylidene-5(4H)-oxazolones: scope, kinetico-mechanistic, and density functional theory studies of the C-H bond activation.

Orthopalladated complexes derived from (Z)-2-aryl-4-arylidene-5(4H)-oxazolones have been prepared by reaction of the oxazolone with palladium acetate in acidic medium. The reaction is regioselective, only the ortho C-H bond of the arylidene ring being activated, producing a six-membered ring. The scope and reaction conditions of the orthopalladation are dependent on the acidity of the solvent. In CF(3)CO(2)H a large number of oxazolones can be metalated under mild conditions. As acidity decreases a lesser number of oxazolones can be efficiently palladated and harsher conditions must be used to achieve similar yields. The C-H bond activation in acidic medium agrees with an ambiphilic mechanism, as determined from kinetic measurements at variable temperature and pressure for different oxazolones substituted at the arylidene ring. The mechanism has been confirmed by density functional theory (DFT) calculations, where the formation of the six-membered ring is shown to be favored from both a kinetic and a thermodynamic perspective. In addition, the dependence of the reaction rate on the acidity of the medium has also been accounted for via a fine-tuning between the C-H agostic precoordination and the proton abstraction reaction in the overall process occurring on coordinatively saturated [Pd(κ(N)-oxazolone)(RCO(2)H)(3)](2+).

Novel cyclopalladated imino-thiophenes: synthesis and reactivity toward alkynes and carbon monoxide.

ortho-palladated complexes based on thiophene and benzothiophene ligands 1a and 1b have been synthesized by direct C-H activation under mild conditions. These species were fully characterized, including single-crystal X-ray diffraction analysis. The reactions of these novel complexes with internal alkynes afforded a variety of thieno[3,2-c]pyridinium salts substituted at the 6- and 7-positions. The thiophene-based complex 2a also reacts with carbon monoxide, in the presence of different alcohols, forming the corresponding esters by tandem alkoxycarbonylations. This latter reaction can be exploited for the unexpected, but straightforward, formation of the monomeric bis-cyclometallated complexes 6a and 6b from 2a or 2b, whose syntheses do not require the employment of transmetallating agents. The structures of these monomeric palladacycles were also fully elucidated by means of X-ray diffraction studies.

Novel thiophene-based cycloruthenated compounds: synthesis, characterization, and reactivity.

The reactions between a series of thiophene-based imines with [(η(6)-C(6)H(6))RuCl(µ-Cl)](2), in a basic medium, and in MeCN give a family of ruthenacycles of stoichiometry [Ru(C^N)(NCMe)(4)]PF(6) (C^N = orthometalated thiopheneimine). In these species, the C-H activation process is produced in most cases at the thiophene ring. When two C-H bonds are competing (thiophene vs aryl), the cyclometalation can be driven regioselectively to the thiophene unit or to the aryl ring as a function of the location of the iminic C=N bond. Cyclometalation can also be oriented to positions 2 or 3 of the thiophene depending on the situation of the imine in the heterocycle (3 or 2, respectively). In all studied cases, the η(6)-C(6)H(6) ligand was substituted by acetonitrile. The X-ray structures of two representative complexes have been determined. These thiophene-based metallacycles react with iodine under very mild conditions affording, after hydrolysis, substituted 3-iodo-2-formyl(benzo)thiophenes or substituted 2-iodo-3-formyl(benzo)thiophenes, as a function of the organometallic precursor.

Regioselective functionalization of iminophosphoranes through Pd-mediated C-H bond activation: C-C and C-X bond formation.

The orthopalladation of iminophosphoranes [R(3)P=N-C(10)H(7)-1] (R(3) = Ph(3) 1, p-Tol(3) 2, PhMe(2) 3, Ph(2)Me 4, N-C(10)H(7)-1 = 1-naphthyl) has been studied. It occurs regioselectively at the aryl ring bonded to the P atom in 1 and 2, giving endo-[Pd(µ-Cl)(C(6)H(4)-(PPh(2=N-1-C(10)H(7))-2)-κ-C,N](2) (5) or endo-[Pd(µ-Cl)(C(6)H(3)-(P(p-Tol)(2)=N-C(10)H(7)-1)-2-Me-5)-κ-C,N](2) (6), while in 3 the 1-naphthyl group is metallated instead, giving exo-[Pd(µ-Cl)(C(10)H(6)-(N=PPhMe(2))-8)-κ-C,N](2) (7). In the case of 4, orthopalladation at room temperature affords the kinetic exo isomer [Pd(µ-Cl)(C(10)H(6)-(N=PPh(2)Me)-8)-κ-C,N](2) (11exo), while a mixture of 11exo and the thermodynamic endo isomer [Pd(µ-Cl)(C(6)H(4)-(PPhMe=N-C(10)H(7)-1)-2)-κ-C,N](2) (11endo) is obtained in refluxing toluene. The heating in toluene of the acetate bridge dimer [Pd(µ-OAc)(C(10)H(6)-(N=PPh(2)Me)-8)-κ-C,N](2) (13exo) promotes the facile transformation of the exo isomer into the endo isomer [Pd(µ-OAc)(C(6)H(4)-(PPhMe=N-C(10)H(7)-1)-2)-κ-C,N](2) (13endo), confirming that the exo isomers are formed under kinetic control. Reactions of the orthometallated complexes have led to functionalized molecules. The stoichiometric reactions of the orthometallated complexes [Pd(µ-Cl)(C(10)H(6)-(N=PPhMe(2))-8)-κ-C,N](2) (7), [Pd(µ-Cl)(C(6)H(4)-(PPh(2)[=NPh)-2)](2) (17) and [Pd(µ-Cl)(C(6)H(3)-(C(O)N=PPh(3))-2-OMe-4)](2) (18) with I(2) or with CO results in the synthesis of the ortho-halogenated compounds [PhMe(2)P=N-C(10)H(6)-I-8] (19), [I-C(6)H(4)-(PPh(2)=NPh)-2] (21) and [Ph(3)P=NC(O)C(6)H(3)-I-2-OMe-5] (23) or the heterocycles [C(10)H(6)-(N=PPhMe(2))-1-(C(O))-8]Cl (20), [C(6)H(5)-(N=PPh(2)-C(6)H(4)-C(O)-2]ClO(4) (22) and [C(6)H(3)-(C(O)-1,2-N-PPh(3))-OMe-4]Cl (24).

Synthesis, structure, and reactivity of N-benzoyl iminophosphoranes ortho lithiated at the benzoyl group.

Ortho lithiation of N-benzamido-P,P,P-triaryliminophosphoranes through deprotonation with alkyllithium bases was achieved with ortho-C═O and ortho-P═N chemoselectivity. However, the synthetic scope of these processes was rather limited. Ortho-lithiated N-benzamido-P,P,P-triphenyliminophosphorane 8 was efficiently prepared via lithium/halogen exchange of the corresponding ortho-brominated precursor with s-BuLi in THF at -90 °C. The reaction of 8 with a variety of electrophiles provides an easy and mild method for the regioselective synthesis of ortho-modified iminophosphoranes via C-C (alkylation and hydroxyalkylation) and C-X (X = I, Si, P, Sn, and Hg) bond-forming reactions. NMR characterization of 8 in THF solution showed that 8 exists as an equilibrium mixture of one monomer and two dimers. The Li atoms of these species become members of five-membered rings through chelation by the ortho-metalated carbon and the carbonyl oxygen. The dimers differ in the relative orientation of the two chelates with respect to the plane defined by the C(2)Li(2) core. The equilibrium between all species is established by splitting the dimers into monomers and subsequent recombination with formation of a different dimer.

Functionalization of methyl (R)-phenylglycinate through orthopalladation: C-Hal, C-O, C-N, and C-C bond coupling.

The ortho functionalization of methyl R-phenylglycinate has been easily achieved using the known orthopalladated complex [Pd(mu-Cl){R-C(6)H(4)(CH(CO(2)Me)NH(2))-2}](2) (1) as synthetic tool. Different functional groups have been introduced at the ortho position of the aryl ring. The reaction of (R)-1 with X(2) or PhI(OAc)(2) gives XC(6)H(4)(CH(CO(2)Me)NH(2))-2 (X = I, Br, OMe, OEt) through oxidative coupling, while the reaction with CO gives an isoindolone. (R)-1 also reacts with one, two, or three alkyne molecules to give different metal-containing or metal-free heterocycles. The resulting functionalized amino esters or heterocycles retain the chirality of (R)-1, according with the values of the optical rotation and the obtained ee values ranging from 22%-87%. The X-ray structures of six representative compounds have also been determined.

Unexpected [2 + 2] C-C bond coupling due to photocycloaddition on orthopalladated (Z)-2-aryl-4-arylidene-5(4H)-oxazolones.

A [2 + 2] photocycloaddition has been observed in regioselectively orthopalladated 2-aryl-4-arylidene-5(4H)-oxazolones, leading to unprecedented cyclobutane-bis(oxazolones).

Experimental and computational study of the bonding properties of mixed bis-ylides of phosphorus and sulfur.

The reactivity of the known ylide-sulfonium salt [Ph(3)P=CHC(O)CH(2)SMe(2)]Br 1 and the new ylide-sulfide [Ph(3)P=CHC-(O)CH(2)SMe] 2 toward Pd(II) complexes has been studied. Compound 1 reacts with PdCl(2)(NCMe)(2) and NEt(3) to give cis-[PdCl(2)[Ph(3)PCHC(O)CHSMe(2)-kappa-C,C]] 3, which is obtained selectively as the meso diastereoisomer (RS/SR). The reactivity of 3 has been studied, and shows the stability of the bis-ylide unit. However, reflux in NCMe of [PdCl(PPh(3))-[Ph(3)PCHC(O)CHSMe(2)-kappa-C,C]]ClO(4) 6 promotes orthopalladation and affords [PdCl(PPh(3))(C(6)H(4)-2-PPh(2)CHC(O)CH(2)SMe(2)-kappa-C,C)]ClO(4) 12, which is characterized by X-ray methods. Density functional theory (DFT) and Bader's Atoms in Molecules (AIM) studies on S-ylides, mixed P-S bis-ylides, and the corresponding Pd complexes have been performed. Free S-ylides show strong conformational preferences, which lies with the establishment of a set of cooperative intramolecular interactions of weak strength: the 1,4 S...O interactions and the 1,6-C-H...O H-bonds between the protons of the methyl substituents and the carbonyl oxygen was fully characterized for the first time. For free mixed P-S bis-ylides, an additional 1,4-P...O intramolecular interaction of moderate strength was characterized. These interactions play a key role in determining the preferred conformations, which then are transferred to the complexes, explaining the observed diastereoselectivity in complex 3. The ylide-sulfide 2 reacts with PdCl(2)(NCMe)(2) and NEt(3) affording [Pd(Cl)[Ph(3)PCHC(O)CHSMe]](2) 9, which in turn reacts with PPh(3) giving [Pd(Cl)(PPh(3))[Ph(3)PCHC(O)CHSMe-kappa-C,C]] 10. The X-ray structure of 10 shows the anion [Ph(3)PCHC(O)CHSMe](-) acting as a C,C-chelate. The bonding in 10 is produced with complete diastereoselectivity but, instead of the expected meso form, the d,l pair (RR/SS) is formed. This inversion is observed for the first time.

Disorder and pseudo-symmetry in octakis(trivinylsilyl)octasilicate.

Octakis(trivinylsilyl)octasilicate was prepared by capping octaspherosilicate cubes, [Si(8)O(20)](8-), with trivinylsilyl groups in methanol solution. Crystals grown from CCl(4) crystallize in the tetragonal space group I4(1). Systematic absences are consistent with the space group I4(1)/amd, although the R(int) values clearly indicate 4/m rather than 4/mmm Laue symmetry. Structure solution and refinement show that the pseudo a-glide results from the approximate m\bar 3m symmetry of the core (Si(8)O(12))O(8)(8-) unit. The positions of the molecules conform to a {110} d-glide that is broken by the small rotations of all the molecules in the same direction about [001]. Crystals grown from toluene give a diffraction pattern consisting of sharp peaks that can be indexed on the same ca 7200 A(3) unit cell, but with h + k even, and l even only. The l = odd layers contain no Bragg spots, but instead exhibit diffuse sheets of intensity. Within the sheets of diffuse scattering are streaks parallel to r* = 110* that cross at the h + k odd Bragg positions. This diffuse scattering pattern arises from well ordered rods of molecules parallel to c with frequent faults in the stacking sequence of molecules parallel to 110, with displacement vectors of [00(1/2)].

Synthesis and structure of tetranuclear orthometallated Pd(II) complexes derived from bis-iminophosphoranes.

The reaction of Pd(OAc)2 with bis-iminophosphoranes Ph3P=NCH2CH2CH2N=PPh3 (1a), [C6H4(C(O)N=PPh3)2-1,3] (1b) and [C6H4(C(O)N=PPh3)2-1,2] (1c), gives the orthopalladated tetranuclear complexes [{Pd(mu-Cl){C6H4(PPh2=NCH2-kappa-C,N)-2}}2CH2]2 (2a) [{Pd(mu-OAc){C6H4(PPh2=NC(O)-kappa-C,N)-2}}2C6H4-1',3']2 (2b) and [{Pd(mu-OAc){C6H4(PPh2=NC(O)-kappa-C,N)-2}}2C6H4-1',2']2 (2c). The reaction takes place in CH2Cl2 for 1a, but must be performed in glacial acetic acid for 1b and 1c. The process implies in all cases the activation of a C-H bond on a Ph ring of the phosphonium group, with concomitant formation of endo complexes. This is the expected behaviour for 1a, but for 1b and 1c reverses the exo orientation observed in other ketostabilized iminophosphoranes. The influence of the solvent in the orientation of the reaction is discussed. The dinuclear acetylacetonate complexes [{Pd(acac-O,O'){C6H4(PPh2=NCH2-kappa-C,N)-2}}2CH2] (3a), [{Pd(acac-O,O'){C6H4(PPh2=NC(O)-kappa-C,N)-2}}2C6H4-1',3'] (3b) and [{Pd(acac-O,O'){C6H4(PPh2=NC(O)-kappa-C,N)-2}}2C6H4-1',2'] (3c) have been obtained from the halide-bridging tetranuclear derivatives. The X-ray crystal structure of [3c.4CHCl3] is also reported.

Orthopalladation of iminophosphoranes: synthesis, structure and study of stability.

The reaction of Pd(OAc)(2) with polyfunctional iminophosphoranes Ph(3)P=NCH(2)CO(2)Me (1a), Ph(3)P=NCH(2)C(O)NMe(2) (1b), Ph(3)P=NCH(2)CH(2)SMe (1c) and Ph(3)P=NCH(2)-2-NC(5)H(4) (1d), gives the orthopalladated dinuclear complex [Pd(mu-Cl){C(6)H(4)(PPh(2)=NCH(2)CO(2)Me-kappa-C,N)-2}](2) (2a) and the mononuclear derivatives [PdCl{C(6)H(4)(PPh(2)=NCH(2)CONMe(2)-kappa-C,N,O)-2}] (2b), [PdCl{C(6)H(4)(PPh(2)=NCH(2)CH(2)SMe-kappa-C,N,S)-2}] (2c) and [PdCl{C(6)H(4)(PPh(2)=NCH(2)-2-NC(5)H(4)-kappa-C,N,N)-2}] (2d). The reaction implies the activation of a C-H bond in a phenyl ring of the phosphonium group, this fact being worthy of note due to the strongly deactivating nature of the phosphonium unit. The palladacycle containing the metallated carbon atom is remarkably stable toward the coordination of incoming ligands, while that formed by the iminic N atom and another heteroatom (O, 2a and 2b; S, 2c; N, 2d) is less stable and the resulting complexes can be considered as hemilabile. The X-ray crystal structures of the cyclopalladated [Pd(mu-Cl){C(6)H(4)(PPh(2)=NCH(2)CO(2)Me-kappa-C,N)-2}](2) (2a), [PdCl{C(6)H(4)(PPh(2)=NCH(2)-2-NC(5)H(4)-kappa-C,N,N)-2}] (2d), [Pd{C(6)H(4)(PPh(2)=NCH(2)CONMe(2)-kappa-C,N,O)-2}(NCMe)](ClO(4)) (7b) and [Pd{C(6)H(4)(PPh(2)NCH(2)CONMe(2)-kappa-C,N,O)-2}(py)](ClO(4)) (3b), and the coordination compound cis-[Pd(Cl)(2)(Ph(3)P=NCH(2)CH(2)SMe-kappa-N,S)] (8) are also reported.