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Abstract: The rare example of protonated aldehyde salt [4-(OH)-3-(OCH3)C6H3CH( O H)][4-(OH)-3-(OCH3)C6H3CHO][TaF6], 1, was isolated in the solid state by the reaction of 4-hydroxy-3-methoxybenzaldehyde (vanillin) with TaF5 in dichloromethane. The product 1 was characterized by X-ray diffraction and IR spectroscopy. The 1:1 reaction of TaF5 with N,N-dimethylaniline in CH2Cl2 cleanly afforded [TaF4(NMe2C6H5)2][TaF6], 2, which was identified by NMR spectroscopy. Attempts of crystallization of 2 resulted in the isolation of the ammonium salt [NHMe2C6H5][TaF6], 3. [Copyright &y& Elsevier]

Abstract: Niobium and tantalum pentahalides, MX5 (1), react with acetic acid and halo-substituted acetic acids, in 1:1 ratio, to give the dinuclear complexes [MX4(μ-OOCMe)]2 [M=Nb, X=Cl, 2a; M=Ta, X=Cl, 2b; Br, 2c] and [MCl4(μ-OOCR)]2 [M=Nb, R=CH2Cl, 4a; CHCl2, 4c; CCl3, 4e; CF3, 4g; CHBr2, 4i; CH2I, 4j; M=Ta, R=CH2Cl, 4b; CHCl2, 4d; CCl3, 4f; CF3, 4h]. The solid state structures of 2b and 4e have been ascertained by X-ray diffraction studies. The reactions of 1 with acetic anhydride and halo-substituted acetic anhydrides result in C–O bond activation and afford 2 and 4, respectively, with concomitant formation of acetyl halides. Moreover, the complexes MCl5[OC(Cl)Me] [M=Nb, 3a; M=Ta, 3b] have been detected in significant amounts within the mixtures of the reactions of MCl5 with acetic anhydride. TaI5 is unreactive, at room temperature, towards both MeCOOH and (MeCO)2O. MF5 react with RCOOH (R=Me, CH2Cl) in 1:1 molar ratio, to afford the ionic compounds [MF4(RCOOH)2][MF6], 5a–d, in high yields. The additions of (RCO)2O (R=Me, CH2Cl) to MF5 give 5, suggesting that anhydride C–H and C–O bonds activation is operative during the course of these reactions. [Copyright &y& Elsevier]

Abstract: Copper(I) acylpyrazolonate derivatives of formula [Cu(Q)(PPh3)2] (HQ=HQC2F5 = 1-phenyl-3-methyl-4-pentafluoropropanoylpyrazol-5-one, HQCF3,CF3 =1-(4-trifluoromethyl)phenyl-3-methyl-4-trifluoroacetylpyrazol-5-one, HQnaph =1-phenyl-3-methyl-4-(1-naphthoyl)pyrazol-5-one, HQfur =1-phenyl-3-methyl-4-furylpyrazol-5-one, HQthi =1-phenyl-3-methyl-4-thienoylpyrazol-5-one, HQCF3,py =1-(2-pyridyl)-3-methyl-4-trifluoromethylpyrazol-5-one) have been synthesized and characterized, both in the solid state and in solution. The isomorphous crystal structures of [Cu(Qfur)(PPh3)2] and [Cu(Qthi)(PPh3)2] and of [Cu(QC2F5)(PPh3)2] show their copper atoms in distorted tetrahedral environments. Apart from the derivative [Cu(Qnaph)(PPh3)2], they are fluxional in chloroform solution, dissociating partially to the [Cu(Q)(PR3)] fragment and free PR3, or existing in solution as [Cu(O2–Q)(PR3)2] or [Cu(O–Q)(PR3)2] species, with CuO2P2 or CuOP2 metal environments, in equilibrium with each other. By contrast, in [Cu(QCF3,py)(PPh3)2] the QCF3,py ligand is coordinated to copper through the nitrogen atoms of the pyrazole and pyridine rings. The latter compound reacts with Zn(BF4)2 · xH2O and [Ru(p-cymene)Cl2]2 affording ionic heterobimetallic adducts. [Copyright &y& Elsevier]

A comprehensive survey of the syntheses and of spectroscopic, analytical and structural data of silver(I), copper(I), and copper(II) complexes containing scorpionate and related ligands and prepared by this group has been reported. This review outlines the possible strategies that can be used in this field for the synthesis of analogous complexes. Statistical analyses of structural features are reported as a function of (1) the steric and electronic properties of the scorpionate ligand, (2) the steric and electronic properties of eventual ancillary ligands, and (3) the nature of the counter-ion. The most important results obtained in this field have been also summarized. [Copyright &y& Elsevier]