MoCl(5), 1a, and WCl(6), 1b, activate 1,3-dioxolane at room temperature in chlorinated solvents: the compound [MoOCl(3){O=C(H)OCH(2)CH(2)Cl}](2), 2, has been isolated from MoCl(5)/dioxolane. The mixed oxo-chloro species WOCl(4), 1c, reacts with 1,3-dioxolane, selectively giving the coordination adduct WOCl(4)(kappa(1)-C(3)H(6)O(2)), 3. Dimethoxymethane, CH(2)(OMe)(2), undergoes activation including C-H bond cleavage when reacted with 1a to give the molybdenum complexes [MoOCl(3){O=C(H)OMe}](2), 4, and Mo(2)Cl(5)(OMe)(5), 5. The reactions of 1b with CH(2)(OR)(2) (R = Me, Et) proceed via O-abstraction with formation of the oxo-derivatives WOCl(4)[O(R)CH(2)Cl] (R = Me, 6a; R = Et, 6b) in admixture with equimolar amounts of RCl. The reactions of 1a,b with CMe(2)(OMe)(2) lead to mesityl oxide, MeC(O)CH=C(Me)(2). A series of simple diethers of general formula ROCH(2)(CHR')OR'' are activated by 1a,b in CDCl(3), usually via cleavage of C-O bonds at high temperature. The complex WCl(5)(OCH(2)CH(2)OMe), 7, has been detected in solution as an intermediate species in the course of the degradation of 1,2-dimethoxyethane (dme) by 1b. The activation of CH(OMe)(3) by 1 is limited to C-O bonds and selectively gives methyl chloride and methylformate, which has been found coordinated in WOCl(4)[O=C(H)OMe], 8. The organic fragments produced in the reactions have been detected by GC-MS and NMR analyses, upon hydrolysis of the reaction mixtures. Compounds 2 and 5, which have had their molecular structures ascertained by X-ray diffraction, represent rare examples of crystallographically-characterized dinuclear Mo(V) species containing both halides and oxygen ligands.

Several experimental techniques have been used to investigate the chemical physical properties of new functionalized ultra-small iron oxide nanoparticles (USPION), which are of interest for biomedical applications. Methods: The chemical composition of oleate-coated iron oxide (OA-NPs) and cystine-coated iron oxide (Cy-NPs) nanoparticles was investigated by means of analytical methods and Fourier Transform Infrared (FT-IR) spectroscopy. Atomic Force Microscopy (AFM) and Transmission Electron Microscopy (TEM) investigations, at high and low resolutions, on both OA-NPs and Cy-NPs, were performed to investigate their morphology. The magnetization and susceptibility behavior of OA-NPs and Cy-NPs were studied by SQUID magnetometry. Results: The combination of different experimental techniques was of help in characterizing the chemical structure of both magnetic core and surface-coating of OA-NPs and Cy-NPs. AFM/TEM images and magnetic measurements were analyzed in terms of crystallinity, polidispersity, average magnetic core size and coating effects of these nanoparticles. Conclusions: These results show that the preparations reported in the present paper are effective in obtaining nanoparticles of 4 nm magnetic core size and the procedure is highly reproducible. The presence of the external cystine shell, fundamental for biomedical applications, does not affect the polidispersity, the crystallinity or the average core size. Moreover, similar values of the average core dimensions have been obtained by three different techniques (AFM and TEM images, magnetic measurements

WCl6, 1, reacted with two equivalents of HC(O)NR2 (R = Me, Et) in CH2Cl2 to afford the W(VI) oxo-derivatives WOCl4(OCHNR2) (R = Me, 2a; R = Et, 2b) as main products. The hexachlorotungstate(V) salts [{O=C–N(Me)CH2CH2CH2}2(μ-H)][WCl6], 3, and [PhNHC(Me)N(Ph)C(O)Me][WCl6], 4, were isolated in moderate yields from the 1:2 molar reactions of 1 with N-methyl-2-pyrrolidone (in CH2Cl2) and acetanilide (in CDCl3), respectively. The additions of two equivalents of ketones/aldehydes to 1/CH2Cl2 yielded the complexes WOCl4[OC(R)(R′)] (R = Me, R′ = Ph, 5a; R = R′ = Ph, 5b; R = R′ = Me, 5c; R = R′ = Et, 5d; R = H, R′ = 2-Me-C6H4, 5e) and equimolar amounts of C(R)(R′)Cl2. Analogously, WOCl3[κ(2)-{1,2-C6H4(O)(CHO)}], 5f, and 1,2-C6H4(OH)(CHCl2) were obtained from 1 and salicylaldehyde. The 1:1 reaction of 1 with acetone in CH2Cl2 resulted in the clean formation of WOCl4 and 2,2-dichloropropane. Compounds 5a,b,f were isolated as crystalline solids, whereas 5c,d,e could be detected by solution NMR only. The interaction of 1/CH2Cl2 with isatin, in a 1:1 molar ratio, revealed to be a new, convenient route for the synthesis of 3,3-dichloro-2,3-dihydro-1H-indol-2-one, 6. The 1:1 reactions of 1 with R′OCH(R)CO2Me (R = H, R′ = Me; R = Me, R′ = H) in a chlorinated solvent afforded the tungsten(V) adducts WCl4[κ(2)-OCH(R)CO2Me] (R = H, 7a; R = Me, 7b). 1/CH2Cl2 reacted sluggishly with equimolar quantities of trans-(CO2Et)CH=CH(CO2Et) and CH2(CO2Me)2 to give, respectively, the W(IV) derivatives WCl4[κ(2)-CH2(CO2Me)2], 8a, and [WCl4-κ(2)-{trans-(CO2Et)CH=CH (CO2Et)}]n, 8b, in about 70% yields. The molecular structures of 2a, 3, 4, 5a, 5f, 7a and 7b were ascertained by X-ray diffraction studies.

Super Paramagnetic Iron-Oxide Nanoparticles (SPION) are currently used as magnetic resonance imaging (MRI) contrast agents. The functionalization of their surface with organic and biocompatible molecules has the purpose to produce carriers selective for different tissues and organs. In this paper, we present the preparation of new cystine-coated ultra small super paramagnetic iron-oxide nanoparticles (USPION) of different core size, from 4 nm to 11 nm. The physical-chemical characterization of these nanoparticles was performed by using several experimental techniques, such as atomic force microscopy (AFM), high resolution transmission electron microscopy (HRTEM) and magnetic measurements. 1H NMR relaxation times at different magnetic field strengths have been measured for several waterdispersions of cystine-coated iron-oxide nanoparticles of the smallest dimensions (4 nm). These preliminary results confirm their potentialities as molecular imaging probes and MRI contrast agents