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From the interaction of organotin(iv) halides SnR₂Cl₂ with 1,4-bis(5-hydroxy-1-phenyl-3-methyl-1H-pyrazol-4-yl)butane-1,4-dione (Q2QH₂) in methanol in the presence of base the complexes [SnR₂(Q2Q)] (1: R = isobutyl (Bui); 2: R = n-octyl (Ot); 3: R = n-dodecyl (Do)) have been synthesised. The reaction between equimolar quantities of R₂SnO and Q2QH₂ in toluene yields the dinuclear derivatives [SnR₂(Q2Q)]₂ 4 (R = Me) and 5 (R = Bun) which have a cis-R₂Sn configuration in solution whereas from the reaction of Q2QH₂ with SnMe₂Cl₂ in CH₃OH in the presence of KOH, an insoluble probably polynuclear isomeric form of 4 formed. The reaction between Q2QH₂ and (R₃Sn)₂O produces the derivative [(SnR₃)₂(Q2Q)] (6: R = Bun; 7: R = Ph). 6 reacts with water yielding the aquo complex [(SnBun₃)₂(Q2Q)(H₂O)] 8. The X-ray crystal structures of [SnBun₂(Q2Q)]₂ 5, [(SnBun₃)₂(Q2Q)] 6 and [(SnPh₃)₂(Q2Q)] 7 have been determined. Compound 5 is a binuclear species with the tin atoms in a distorted octahedral Sn-cis-C₂O₄ environment (skewed trapezoidal bipyramidal) with the C–Sn–C angles ranging from 107.28(14) to 112.4(2)°. The two different carbonyl groups coordinate the metal with different donor abilities (the Sn–O bond lengths range from 2.132(2) to 2.209(2) Å). Compounds 6 and 7 contain a dianionic ligand (Q2Q)2− bridged to two triorganotin(iv) fragments with the tin atoms in a strongly distorted trigonal bipyramidal environment. 1H, 13C and 119Sn NMR (rt and −55 °C) data indicate that the diorganotin(iv) derivatives 1–5 are not fluxional in solution whereas 6–8 slowly undergo disproportionation reaction, affording SnR₄ and [SnR₂(Q2Q)]₂.

By reaction of 4-tert-butylacetyl-3-methyl-1-phenylpyrazol-5-one (HQ) with metallic Ba in MeOH the dinuclear derivative [{BaQ2(H2O)2}2] 1 has been synthesized. It contains two barium atoms each eight-co-ordinated by a terminal bidentate Q ligand, two bridging double chelating Q ligands and two molecules of water. When the reaction of HQ with Ba was carried out in the presence of mono-, bi- or poly-dentate O- or N-donor ligands, derivatives of formula BaQ2Ln(H2O)m have been obtained, depending on the nature of the ancillary ligand and reaction conditions employed [L 4;= 4;2,5,8,11,14-pentaoxapentadecane (tetraglyme), 2,5,8,11-tetraoxadodecane (triglyme), 2,5,8-trioxanonane (diglyme), 2,2′∶6′,2″-terpyridine (terpy), 2,3-bis(2-pyridyl)pyrazine (Pypy), n 4;= 4;1, m 4;= 4;0 or 1; L 4;= 4;imidazole (Him), 1-methylimidazole (1-MeIm), 2-methylimidazole (2-MeImH), 1,10-phenanthroline (phen), 2,2′-bipyridyl (bipy), 2,9-dimethyl-1,10-phenanthroline (Cupr) and triphenylphosphine oxide (PPh3O), n 4;= 4;2, m 4;= 4;0 or 1]. In the nine-co-ordinated [BaQ2(tetraglyme)] the Ba atom is co-ordinated by all the five oxygen atoms of tetraglyme and by four oxygen atoms of two bidentate Q whereas the co-ordination number of barium in [BaQ2(phen)2] is eight due to four oxygen atoms of the two Q ligands and four nitrogen atoms of the two 1,10-phenanthrolines. The derivative [{BaQ2(Him)2}2] is dinuclear with the Ba atoms linked by two double chelating Q ligands. The imidazoles complete the co-ordination number of Ba to 8. The compound [(BaQ2)n] has been obtained by heating derivative 1 in vacuo at 100 4;°C, whereas the 1∶1 adduct [BaQ2(phen)] was obtained only when [(BaQ2)n] was treated in diethyl ether with an equimolar solution of phen. When a methanol solution of [BaQ2(Pypy)] reacts with an equimolar methanol solution of CdCl2 scrambling of the ligand occurs and derivatives 1 and [(CdCl2)2(Pypy)] are obtained. All the compounds obtained have been characterised by IR and far-IR data, conductivity and vaporimetric molecular weight measurements, 1H NMR and in some cases also variable temperature 1H NMR spectra. Comparison was made with structural and spectroscopic data reported for related barium(II) compounds.

From the interaction between [(DPPF )Pt(az)2] [DPPF 4;= 4;1,1′-bis(diphenylphosphino)ferrocene; azH 4;= 4;pyrazole (pzH), 3,5-dimethylpyrazole (3,5-Me2pzH) or 4-methylpyrazole (4-MepzH)] and several MX2 acceptors (M 4;= 4;Zn, X 4;= 4;Cl, Br, I or BF4; M 4;= 4;Cd, X 4;= 4;Cl, Br, I or ClO4, M 4;= 4;Hg, X 4;= 4;Cl, Br or I; M 4;= 4;Ba, X 4;= 4;I) 16 novel heteropolymetallic compounds were synthesized and characterized by IR, far-IR, 1H and 31P, and in some cases also with 113Cd, NMR spectroscopy. Heterotrinuclear adducts [(DPPF )Pt(µ-az)2MX2] were obtained when X 4;= 4;halide, whereas ionic heteropentanuclear complexes [{(DPPF )Pt(µ2-az)2}2M]2+[X]22– were afforded when X is a weak nucleophile (ClO4 or BF4). Scrambling of the ligands occurred when the reaction between [(DPPF )Pt(az)2] and Cu(II)X2 salts (X 4;= 4;Cl or Br) was carried out in methanol, [(DPPF )PtX2] being always obtained. X-Ray crystallography confirms the mononuclear structure of [(DPPF )Pt(az)2] (azH 4;= 4;pyrazole or 3,5-methylpyrazole), in which the Pt atom is in a distorted cis square planar coordination with the two cyclopentadienyl rings in a staggered conformation. In the heterotrinuclear [(DPPF )Pt(µ-pz)2CdI2], the cadmium atom is strongly distorted tetrahedral, coordinated by two N-atoms of pyrazolate rings and two iodine atoms.