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Mobile cloud computing combines mobile devices, cloud computing, and wireless technology. It is an important technology today but faces challenges like storage, security, privacy, and connectivity issues. This technology helps solve these problems, especially in education, business, and healthcare. Security is a major concern in mobile cloud computing due to risks in different sectors. Ensuring data protection and privacy is essential for its success. Connectivity issues can also affect performance. More research is needed to find solutions to these challenges. The future of mobile cloud computing relies on overcoming these obstacles. Continuous improvement will enhance its efficiency and security. [ABSTRACT FROM AUTHOR]

The synthesis and characterization of 14 Zn [X.sub.2] (X = Cl or Br) complexes containing aryl-oxazoline (ox) ligands is reported. Eleven of these derivatives have been structurally elucidated in the solid state by single crystal X-ray diffraction methods. The ligands used are 2-(3-R-phenyl)-2-oxazoline (R = Cl or Me), 2-(4-R-phenyl)-2-oxazoline (R = Cl, F, Me or -OMe), and 2-(anisol-2-yl)-4,4-dimethyl-2-oxazoline (7a). All oxazolines, with the exception of 7a, lead to the formation of materials identified as Zn [X.sub.2][(ox).sub.2] upon reaction with Zn [X.sub.2]. A distorted tetrahedral coordination motif around the Zn metal centre is displayed in nine examples that have been characterized by single crystal X-ray diffraction methods. In the case of ligand 7a, an unusual dimeric species (X-ray) of formula [Zn [Cl.sub.2] (7a)].sub.2] (7b) is formed upon reaction with Zn [Cl.sub.2]. Compound 7b displays a rare (formally neutral) µ-[(Cl).sub.2]-[(Zn[L]Cl).sub.2] (L = neutral donor ligand) unit in addition to secondary bonding interactions between the Zn centres and the O-atom of the -OMe group (Zn *** O distance of ~2.56 Å). In contrast, reactions of 7a with Zn [Br.sub.2] lead to the formation of a monomeric species containing a chelating molecule of 7a with binding through the oxazoline N-atom and the methoxy (Zn-O distance of ~2.14 Å) group, i.e., Zn [Br.sub.2](7a-[κ.sup.2] N, [O.sub.OMe]). These complexes are discussed in terms of structurally related Zn species and some comment is made as to the direction to be explored within this series of materials that may lead to further unusual structural diversity. Key words: oxazoline, oxazole, zinc, X-ray crystal structure, coordination complex, Zn(II) halide. 379 On rapporte la synthese et la caracterisation de quatorze complexes de Zn [X.sub.2] (X = Cl ou Br) contenant des ligands aryloxazoline (ox). On a elucide les structures de onze de ces derives en faisant appel a des methodes de diffraction des rayons X a l'etat solide. Les ligands utilises comprennent des 2-(3-R-phenyl)-2-oxazolines (R = Cl ou Me), des 2-(3-4-phenyl)-2-oxazolines (R = Cl, F, Me ou OMe) et la 2-(anisoly-2-yl)-4,4-dimethyl-2-oxazoline (7a). Par reaction avec du Zn [X.sub.2], toutes les oxazolines, a l'exception du compose 7a, conduisent a la formation de produits identifies par la formule generale Zn [X.sub.2][(ox).sub.2]. Dans neuf exemples caracterises par des methodes de diffraction des rayons-X par un cristal unique presentent un motif de coordination de tetraedre deforme autour du centre metallique Zn. Dans le cas du ligand 7a, il se forme une espece dimere inhabituelle (aux rayons X) de formule [Zn [Cl.sub.2](7a)]2 (7b). Le compose 7b comporte une unite rare (formellement neutre) µ-([Cl.sub.2])-[(Zn[L]Cl).sub.2] (L = ligand donneur neutre) en plus des interactions de liaisons secondaires entre les centres Zn et l'atome d'oxygene du groupe -OMe (distance Zn *** O de ~2,56 Å). Par opposition, les reactions du compose 7a avec le Zn [Br.sub.2] conduit a la formation d'especes monomeres contenant une molecule chelatante de 7a qui donne des liaisons par le biais de l'atome d'azote de l'oxazoline et du groupe methoxy (distance Zn-O de ~2,14 Å), c'est-a-dire Zn [Br.sub.2](7a-[κ.sup.2] N, [O.sub.OMe]). On discute de ces complexes en fonction d'especes de Zn reliees d'un point de vue structural et on fait quelques commentaires concernant la direction qui devrait etre explorer dans cette serie de produits qui pourrait conduire a une plus grande diversite structurale. Mots-cles : oxazoline, oxazole, structure cristalline par diffusion des rayons X, complexe de coordination, halogenure de Zn(II). [Traduit par la Redaction] Gossage et al., Introduction Despite the stability of only a single cationic oxidation state, zinc displays rich and diverse coordination chemistry in both the natural and artificial (i.e., synthetic) settings (1). The formal [...]

The synthesis and characterization of a new and readily synthesized class of potentially anionic pincer ligands with [C.sub.1] point group symmetries is described. These materials can be made via amide coupling of a 2-(2'anilinyl)-2-oxazoline unit with picolinic acid; the incorporation of enantiopure oxazoline fragments facilitates the construction of chiral [C.sub.1] pincers. Treatment of the free ligands with Pd metal sources leads to the formation of amido-Pd pincer complexes in good yield. One of these Pd complexes has been characterized by single crystal X-ray diffraction methods, which confirms the proposed tridentate binding mode of the ligand and the formation of an amido N--Pd bond. The metal complexes have been shown to be suitable precusors for catalytically active Pd species that are useful for C--C bond forming reactions, notably the Heck reaction under standard conditions. Key words: oxazoline, 4,5-dihydro-2-oxazole, palladium, pincer ligand, amido, Heck reaction. Resume : On decrit la synthese facile et la caracterisation d'une nouvelle classe de ligands anioniques a pinces ayant des groupes de symetrie ponctuelle [C.sub.1]. Ces produits peuvent etre obtenus par couplage d'amide d'une unite 2-(2'-anilinyl)-2-oxazoline avec de l'acide picolinique; l'incorporation de fragments oxazolines enantiopurs facilite la formation de ligands a pince de symetrie [C.sub.1]. Le traitement des ligands libres avec des sources de palladium metallique conduit a la formation, avec de bons rendements, de complexes amido-Pd pincer. On a caracterise un de ces complexes du Pd par diffraction des rayons X par un cristal unique et on a ainsi pu confirmer le mode de liaison tridentate du ligand et la formation d'une liaison N--Pd amido. On a montre que les complexes metalliques sont des precurseurs appropries pour des especes catalytiquement actives de Pd qui sont utiles dans les reactions de formation de liaisons C--C, particulierement dans la reaction de Heck dans des conditions standards. Mots cles : oxazoline, 4,5-dihydro-2-oxazole, palladium, ligand h pince, amido, reaction de Heck.