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Despite the generally accepted inertness of platinum(IV) complexes towards nucleophilic substitution, the title compound promptly reacts with nucleophiles L (L = pyridine, quinoline, isoquinoline, benzothiazole, o-, m-, p-toluidine) affording the corresponding acetonitrile substitution products. To follow the reaction spectroscopically, a series of platinum(IV) standards were prepared by bridge splitting of trans-[Pt(μ-Cl)Cl(PPh3)]2, followed by oxidation by PhICl2. All the new platinum(II) and platinum(IV) complexes were fully characterized, and, in some cases, the structure was studied by single crystal X-ray diffraction. Even when protic o-, m- and p-toluidines were used, chemoselectivity towards substitution was observed, with addition products formed in less than 10% extent.

Neutral complexes with generic formula [PtCl2(PPh3)(L)] were efficiently oxidized to [PtCl4(PPh3)(L)] (L = dibenzylamine, p-toluidine, diethanolamine, pyridine and acetonitrile) using PhICl2 The anionic complex [TBA][PtCl3(PPh3)] (TBA = Tetrabutylammonium) was also oxidized to [TBA][PtCl5(PPh3)] with this method. The obtained products were fully characterized by 1H, 13C, 31P and 195Pt NMR, IR-ATR spectroscopy, elemental analysis and, for complexes cis-([PtCl4(PPh3)(p-toluidine)]·CHCl3 and trans-[PtCl4(PPh3)(NCCH3)]·CH3CN, also by single crystal X-ray diffraction.

[Y(O 2 CNBu 2 ) 3 ], has been prepared by extraction of the Y 3+ ions from aqueous solution into heptane by the NHBu 2 /CO 2 system. Exhaustive hydrolysis of [Y(O 2 CNBu 2 ) 3 ] produced the yttrium carbonate [Y 2 (CO 3 ) 3 ⋅n H 2 O] (n = 2–3), that was converted to Y 2 O 3 by thermal treatment at 550 °C for 12 h. The exhaustive hydrolysis of [Y(O 2 CNBu 2 ) 3 ] and [Al(OBu) 3 ] (Y/Al molar ratio = 3/5) carried out at room temperature yielded an intermediate mixed carbonate, that, upon heating at 950 °C for 12 h, was converted to Y 3 Al 5 O 12 . The exhaustive hydrolysis of [Y(O 2 CNBu 2 ) 3 ] and [Al(OBu) 3 ] was repeated in the presence of [Nd(O 2 CNBu 2 ) 3 ] (Nd/Y molar ratio = 0.07;(Nd + Y)/Al molar ratio = 3:5). The neodymium doped garnet Nd:Y 3 Al 5 O 12 was obtained, through the intermediate formation of a mixed hydroxo-carbonate. For comparison, the neodymium doped garnet was prepared also starting from N,N -dialkylcarbamato complexes of all three metals, [Y(O 2 CNBu 2 ) 3 ], [Nd(O 2 CNBu 2 ) 3 ] and [Al 2 (O 2 CN i Pr 2 ) 6 ] (Nd/Y molar ratio = 0.07;(Nd + Y)/Al molar ratio = 3:5). Also in this case the intermediate mixed hydroxo-carbonate, after heating at 950 °C for 12 h, evolved to Nd:Y 3 Al 5 O 12 . FTIR, XRD, SEM, TGA measurements were used for the characterization of the obtained materials. Preliminary studies of the photoluminescent emission properties were carried out on Nd:Y 3 Al 5 O 12 . Photoluminescence dynamics have been investigated by means of femtosecond laser pulses and nanosecond temporal resolution up to the millisecond range after excitation. All the luminescence traces have shown a decay time of the order 200 microseconds indicating its potential as a laser medium for infrared emission at 1064 nm.

Exhaustive hydrolysis of a mixture of [La4(CO3)(O2CNBu2)10] and [Cu(O2CNBu2)(py∗)2] (py∗ = 4-dimethylamino pyridine) in molar ratio 1/2 corresponding to a La/Cu molar ratio 2/1 was carried out in toluene at room temperature. The carbamato derivatives of lanthanum and copper can be easily prepared by extraction of the metal ions from aqueous solution into heptane by the NHBu2/CO2 system, according to a method previously reported. The copper precursor was selected amongst a number of derivatives in respect of its easy tractability. The tetragonal modification T′ of La2CuO4 was obtained by treatment at 600 °C of the intermediate mixed carbonate. The thermal treatment of T′-La2CuO4 at 850 °C, followed by cooling down to room temperature, afforded the orthorhombic modification of the mixed oxide.

Red crystals of [TBA]2[Pt5Cl20] were obtained by reacting [TBA]2[PtCl6] with an excess of AlCl3 at room temperature in CH2Cl2. The salt [PPN]2[Pt5Cl20] containing the same anion was prepared by reaction of platinum tetrachloride with a small excess of [PPN]Cl in 1,2-dichloroethane at room temperature. Single crystal X-Ray diffraction studies confirmed that both species contained the mixed-valence [Pt5Cl20]2− anion with two dinuclear platinum(IV) Pt2Cl10 fragments organized around a central square planar platinum(II) in a chair arrangement.

We present an approach toward sequence-dependent materials based on a stepwise assembly on a silica surface of rare earth cations (RE: Y3+, Eu3+ and Tb3+) and the 1,4-benzenedicarboxylate (terephthalate, T2-) ligand, organized in an ordered sequence RE1-T-RE2. The first RE was grafted to silica through a reaction of its N,N-dibutylcarbamato derivative, [RE1(O2CNBu2)(3)], with the surface silanols. The residual carbamato groups in the metal coordination sphere were then substituted by HT- through a reaction with H2T in pyridine. The BrOnsted acidity of the pendant COOH groups was successively exploited for the anchorage of the second metal ion (RE1 = Eu, RE2 = Tb; RE1 = Y, RE2 = Tb). The choice of pyridine as the solvent, able to dissolve both H2T and the secondary product [NH2Bu2](2)[T]H2T, was crucial for achieving success with this method. The emission properties of the materials were modulated by modifying the order of the synthetic steps. Metal complexes and materials were characterized by IR, EDX, ICP and photoluminescence. We used Tb3+ to Eu3+ energy transfer (ET) to study the RE3+ spatial distribution and intermetal distances to prove the formation of a RE1-T-RE2 sequence. Photoluminescence was used as a multi-tool technique to characterize the functional properties of the materials and to obtain structural information supporting the sequence growth.

The reaction of a lanthanide precursor with 2,5-dihydroxyterephthalic acid (H4L) yields different MOFs, having [H2L]2− and [L]4− as anionic spacers, in different synthetic conditions. The interconversion conditions have been established for some of them. The known gadolinium coordination polymer (CP) {[Gd2(H2L)3(DMF)4]·2DMF}n (DMF = N,N-dimethylformamide), 1, was prepared in DMF, either at 90 °C or also at room temperature, if assisted by a base diffusion. NMR monitoring for the synthesis of the analogous yttrium system (DMF, 90 °C) showed that the reaction progress relates with the formation of NHMe2 by DMF decomposition. {[Y2(H2L)3(DMF)4]·2DMF}n, 2, isotypic with 1, was obtained. The new structurally characterized CP {[Gd2(H2L)3(H2O)6]·2H2O}n 3, has been prepared by initial thermal (T = 170 °C) desolvation of 1 in vacuo (P = 1·10−3 Torr), followed by a hydrothermal treatment. Interestingly, 3 reverted back to 1 by treatment in DMF at 90 °C. Moreover 3 has been obtained starting from the metal nitrate and H4L in hydrothermal conditions (140 °C; 12 h) in the presence of the stoichiometric amount of NaOH. Long reaction times produced the intermediate formation of a mixture where it was possible to identify the new structurally characterized {[Gd2(H2L)3]·2H2O}n, 4, the known {[Gd2(H2L)2(L)0.5(H2O)3]·4H2O}n, 5 and {[Gd2(H2L)(L)(H2O)5]·2H2O}n, 6, while at higher temperature (160 °C; 24 h) the pure 6 was obtained. The observed transformations of 1 into 6 in H2O involve H4L elimination. On the other hand, it was found that the treatment of 6 in DMF in the presence of H4L leads back to 1. Single Crystal X Ray Diffraction (SCXRD) studies were carried out on the new species 2, 3 and 4.

The coordination chain {[Dy(dbm)3bpy]·C7H8}n (1) having only 4,4′-bipyridine as connector has been prepared in high yield and its structural and magnetic properties have been investigated. It is isostructural with the terbium analogue {[Tb(dbm)3bpy]·C7H8}n (2) and features units repeating in a 1D-zigzag fashion, where the metal is octa-coordinated in a distorted square antiprism geometry. Despite the 1D structure, the absence of paramagnetic connectors prevents the direct magnetic intrachain interaction among the lanthanide ions. In zero magnetic field, only a small fraction of the magnetization of 1 displayed slow dynamics with no dependence on temperature. Upon application of a 1 kOe magnetic field, a relaxation process appears, compatible with a mixed Raman/Direct mechanisms. Magnetic dilution in the diamagnetic Y(III)-based analogue revealed that actually two distinct relaxation processes are active for 1, whose temperature dependence can be interpreted again with a mixed Raman/Direct relaxation model. Compound 2 displayed only in-field slow relaxation, compatible with the models employed for 1.

The coordination polymers [ Ln ( β - dik ) 3 bpy ] ∞ 1 ·C7H8 (Ln = Eu, β-dik = dbm, tta, hfac; Ln = Tb; β-dik = dbm; Hdbm = dibenzoylmethane, Htta = thenoyltrifluoroacetone, Hhfac: hexafluoroacetylacetone) were easily assembled in mild conditions and high yields starting from the anhydrous lanthanide β-diketonates as nodes and 4,4′-bipyridine (bpy) as connector. X-ray single crystal studies have shown zigzag extended chains where lanthanide centres are 8-coordinated in a distorted square-antiprismatic geometry. Photoluminescence studies show bright red europium emission and spectral features dependent on the topology of the polymeric chains.

Partial hydrolysis (H2O/Ln molar ratio = ¼) of lanthanum di-iso-propylcarbamato complex, [La(O2CNiPr2)3], 1, afforded the tetranuclear μ-oxo derivative [La4O(O2CNiPr2)10], 2, which was structurally characterized by single crystal X-ray diffraction studies. The carbonato–carbamato derivative of lanthanum, [La4(CO3)(O2CNBu2)10], 3, was prepared by extraction of lanthanum ions from aqueous solution into heptane by the NHBu2/CO2 system. Partial hydrolysis (H2O/Ln molar ratio = ½) of N,N-di-iso-propylcarbamato complexes of neodymium, europium, gadolinium and terbium, [Ln(O2CNiPr2)3], yielded the derivatives [Ln2(CO3)(O2CNiPr2)4] (Ln = Nd, 4, Eu, 5, Gd, 6). Exhaustive hydrolysis of [Ln(O2CNR2)3] (Ln = Nd, Tb, R = Bu; Ln = Eu, Gd, R = iPr, Bu) produced hydrated lanthanide carbonates, Ln2(CO3)3·nH2O. For sake of comparison with a block d metal, the exhaustive hydrolysis of two copper(II) carbamato complexes, [Cu(O2CNEt2)2(NHEt2)]2 and [Cu(O2CNiPr2)2], was carried out with formation in both cases of the hydrated basic carbonate Cu2(OH)2(CO3)·nH2O. The exhaustive hydrolysis of mixtures of cerium and lanthanum or cerium and terbium N,N-dibutylcarbamato complexes allowed the preparation of mixed oxides containing the two metals in the desired molar ratio, via the intermediate formation of the corresponding mixed carbonates.

trans -[Pt(μ-Cl)Cl(PPh 3 )] 2 reacted with arylaldoximes in 1,2-dichloroethane to afford [PtCl 2 (PPh 3 ){N(OH) CHAr}] (Ar = 3,4-dimethoxyphenyl, 1-naphthyl, 9-anthryl) where aldoxime ligands are N-coordinated to platinum. The obtained complexes are soluble in chlorinated solvents, where they afford equilibrium mixtures of cis,trans and/or ( E ),( Z ) isomers. Equilibria in solution were studied by 31 P-NMR spectroscopy and solid state structural data were obtained by single crystal X ray diffraction studies. The reactivity of [PtCl 2 (PPh 3 ){N(OH) CHAr}] complexes with basic aqueous solutions was studied, under liquid-liquid phase transfer catalysis conditions. The outcome of the reaction depends on the stereochemistry of the precursors: cis, ( Z )-isomers promptly undergo cyclization to the corresponding dinuclear derivatives [Pt{μ-(κ 2 -N,O)}-{N(O) CHAr}Cl(PPh 3 )] 2 , where two aldoximate ligands symmetrically bridge two metal centers.

The simple but rarely used heterotopic divergent ligand N-oxide-4,4′-bipyridine (bipyMO) has been exploited, for the first time, for the preparation of heterometallic derivatives, showing the ability to selectively use its two potential coordination sites in dependence of the metal ion nature. By reacting in refluxing acetonitrile ∞ 1 [Cu(hfac) 2 (bipyMO)] with ∞ 1 [Mn(hfac) 2 (bipyMO)] (herein completely characterized), the heterometallic self-assembled monodimensional coordination polymer containing the two regularly alternated moieties Cu(hfac) 2 [N] 2 and Mn(hfac) 2 [O] 2 was obtained in high yield and purity and structurally characterized. On the other hand, a molecular heterometallic compound was obtained using, as a ligand, the here prepared mononuclear complex trans -[PtCl 2 (bipyMO)(PPh 3 )], with the hypodentate bipyMO ligand coordinated to platinum through the nitrogen atom. Reaction with [Zn(hfac) 2 (DME)] afforded the heterometallic trinuclear complex trans [Zn(hfac) 2 { trans -PtCl 2 (PPh 3 )(bipyMO)} 2 ] that was structurally characterized.

The reactivity of ( cis - + trans -)[Pt(μ-Cl){(κ 2 -P,C)P(OC 6 H 4 )(OPh) 2 }] 2 ( 1 ) towards several ligands L (L = RCN, P(OMe) 3 , DMSO, NHEt 2 , py, CO, C 2 H 4 , C 8 H 16 ) has been studied. Ethylene and 1-octene do not react while the other reactions proceed with cleavage of the halide bridge and formation of one or both geometrical isomers of [PtCl{(κ 2 -P,C)P(OC 6 H 4 )(OPh) 2 }L] ( 2 – 8 ) depending on the nature of the entering ligand. In some cases equilibrium reactions (L = RCN, DMSO, CO, py) were observed. The structures of [SP4-3]-[PtCl{(κ 2 -P,C)P(OC 6 H 4 )(OPh) 2 }(S)DMSO] ([SP4-3]- 4 ) and [SP4-4]-[[PtCl{(κ 2 -P,C)P(OC 6 H 4 )(OPh) 2 }py] ([SP4-4]- 6 ) are reported.

The reactivity of mixed complexes [PtCl2(L)(L′)] (L = MeCN, EtCN, CO), L′ = PPh3; L = η2-C2H4, CO; L′ = MeCN, EtCN) towards diethylamine has been investigated. The processes are chemo- (substitution versus addition) and stereo-selective in dependence of the stereochemistry of the precursor. The structures of [SP4-4]-[PtCl(CONEt2)(NHEt2)(PPh3)], [SP4-4]-1, trans-[PtCl2(NHEt2)(PPh3)], trans-2, and cis-[PtCl2{(E-)HN C(NEt2)Me}(PPh3)], cis-3a, are reported.

Ionic platinum(II) complexes [PtCl(PPh3)(L∧L)][BF4] {L∧L = 2,2′-bipyridyl (1) 1,10-phenanthroline (2)} and [PtCl(PPh3)(L)2][BF4] {L = pyridine (3), dimethyl sulfoxide (4)} were synthesized by dehalogenation of cis-[PtCl2(PPh3)(NCMe)], followed by reaction with the suitable ligand. Chelating nitrogen ligands L∧L afforded single products, which were structurally characterized. In the other cases mixtures of geometric (L = pyridine) and/or coordination (L = dimethyl sulfoxide) isomers were observed in solution. In these cases the structures of the less soluble isomers were obtained via single crystal X-ray diffraction. All the complexes were tested in vitro for their antiproliferative activity on three human tumor cell lines: MSTO-211H, HeLa and HepG2.

Dinuclear platinum(II) complexes [{PtCl2(PPh3)}2(μ-N–N)], where N–N is a divergent bidentate nitrogen ligand, were prepared by reacting cis-[PtCl2(PPh3)(NCMe)] with N–N in a Pt/N–N molar ratio 2. The (trans,trans)-isomers were obtained as kinetic products and recovered in good yields and high purity {1, N–N = pyrazine (pyrz); 2, N–N = 4,4′-bipyridyl (bipy); 3, N–N = piperazine (pipz); 4, N–N = p-xylylendiamine (xylN2)}. Cis-[PtCl2(PPh3)(NCMe)] was also reacted with the tridentate divergent ligand 2,4,6-tris-(pyrid-4′-yl)1,3,5-triazine (py3TRIA) in molar ratio 3 with formation of the trinuclear (trans,trans,trans)-[{PtCl2(PPh3)}3(μ-py3TRIA)], 5. On the other hand, the treatment of cis-[PtCl2(PPh3)(NCMe)] with the monodentate pyridine (py) produced a mixture of both trans-[PtCl2(PPh3)(py)] (6a) and cis-[PtCl2(PPh3)(py)] (6b). The reactions of cis-[PtCl2(PPh3)(NCMe)] with N–N = pyrz, bipy, pipz, carried out with a Pt/N–N molar ratio 1, were monitored by 31P NMR spectroscopy. Equilibria were observed in solution, involving dinuclear (trans–trans)-[{PtCl2(PPh3)}2(μ-N–N)], mononuclear [PtCl2(PPh3)(N–N)] and free N–N. The addition of an excess of the divergent ligand allowed the complete conversion to the corresponding mononuclear complexes. With the heteroaromatic ligands both geometric isomers were observed (7a, 7b and 8a, 8b, for pyrz and bipy derivatives, respectively) while with pipz the trans-isomer only was detected, 9. In the system involving bipy, the scarcely soluble dinuclear (cis,cis)-[{PtCl2(PPh3)}2(μ-bipy)], 2b, was also obtained. Products 2, 2b, 3·2(CHCl3) and 6a·0.5(C2H4 Cl2) were structurally characterized by single crystal X-ray diffraction methods.

Neodymium and terbium pentafluorophenolates, containing 1,10-phenanthroline as ancillary ligand, [Ln(OC6F5)3(phen)3], (1 Ln = Nd, 2 Ln = Tb) have been synthesized by reacting the N,N-dibutylcarbamato complexes, [Ln(O2CNBu2)3], easily obtained from aqueous solutions of lanthanide salts, with C6F5OH in the presence of 1,10-phenanthroline. The formation of the sparingly soluble hydrated compound [Tb(OC6F5)3(phen)2(H2O)·phen], 3, was observed, due to fortuitous presence of water. Single crystal X-ray diffraction studies on compounds 1, 3 and 3·DME (DME = dimethoxyethane) showed coordination numbers (CN) 9 for neodymium in 1 and 8 for terbium in 3 and 3·DME, where only two 1,10-phenanthroline ligands are coordinated to terbium, the third forming two hydrogen bonds with the coordinated water. The structural characterisation of [NH2Bu2][C6F5O], 4, showed the organisation of the product in ionic quartets. The photoluminescence spectra of 1 and 2 displayed the typical emissions related to the lanthanide centre in the NIR and visible region, respectively.

Systematic studies on symmetric twin molecules composed of two bent-core mesogenic units are reported for the first time. It is shown that the formation of mesophases mainly depends on the chemical structure of the spacer. A sufficiently flexible spacer containing dimethylsiloxane units allows a decoupling of the mesogenic moieties; the related compounds exhibit a ferroelectric SmCP phase proved by electro-optical measurements. On the basis of X-ray data, a plausible structure model is presented. The connection of two bent-core mesogenic units by means of a tetraethylene glycol spacer results in dimers, which are able to form columnar phases. For twins containing a simple hydrocarbon chain as spacer, in most cases liquid-crystalline behavior could not be detected. These general tendencies remain valid if the bent-core unit is changed, e.g., by increasing the number of aromatic rings, by lateral substitution, and by inversion of the direction of one of the connecting groups between the aromatic rings, resp...

Fast oxidations of the iron(II)N,N-dialkylcarbamato complexes [Fe(II)(O2CNR2)(2)](n) (R = Et, n = 6, 1; R = Pr-i, 2) and [Fe(II)(8)(mu(4)-O)(2)((O2CNPr2)-Pr-i)(12)], 3, by dioxygen were carried out both in an anhydrous hydrocarbon and in the solid state affording [Fe(III)(2)(O)(O2CNR2)(4)](x), 7 and 8 for R = Et and Pr-i, respectively, and [Fe(III)(4)(O)(3) ((O2CNPr2)-Pr-i)(6)](y), 9. The stoichiometric O-2 uptake was not accompanied by oxidation of the ligand. Recovery of unchanged starting material was observed when the manganese(II) derivatives [Mn(II)(O2CNR2)(2)](n) (R = Et, n = 6, 4; R = Pr-i, 5) were treated with O-2. Nevertheless, when [Mn(II)(8)(mu(4)-O)(2)((O2CNPr2)-Pr-i)(12)], 6, prepared in situ by reaction of 5 with water (Mn/H2O molar ratio = 4), was reacted with O-2, complete oxidation occurred to a product where manganese showed an average. oxidation number III, [Mn(III)(4)(O)(3) ((O2CNPr2)-Pr-i)(6)](y), 10. The product [Mn(II)(6)Mn(III)(2)(mu(4)-O)(2)(mu(3)-O)((O2CNPr2)-Pr-i)(12)], 11, obtained by partial oxidation of 6 by 02, has been characterised by X-ray diffraction methods. (C) 2013 Elsevier Ltd. All rights reserved.

Convenient one-pot reduction-complexation reactions of hexachloroplatinato(IV) anions to (η4-alkadiene)dichloroplatinum(II) complexes (η4-alkadiene = COD, DAE, DCPD, NBD) under suitable phase-transfer catalysis conditions are reported. Reduction to zerovalent platinum alkene complexes has been obtained in the presence of an excess of alkene, potassium formate and 18-crown-6 as phase-transfer catalyst (alkene = COD, NB, dba). The crystal and molecular structure of [Pt1.03(dba)3]·CH2Cl2 has been studied by X-ray diffraction methods: it can be described as a solid solution of Pt(dba)3 and Pt2(dba)3, the mononuclear complex being largely prevailing.

The homoleptic [M(MeCN)4]2+ cations (M = Pd, Pt) as the tetrafluoroborato derivatives were reacted with NHEt2. The platinum species affords the amidino derivative {Pt[(E)-HN C(NEt2)Me]4}[BF4]2, 1, as the only detected product of the addition of the amine to the coordinated nitrile. On the contrary, for [Pd(MeCN)4][BF4]2 competition between the substitution of the nitrile and addition of the amine to the nitrile group is operative: by carrying out the reaction in acetonitrile as solvent, complete conversion was obtained to the crystallographically defined {Pd[(E)-HN C(NEt2)Me]4}[BF4]2. Consistent with these findings, PdCl2(MeCN)2 reacts with NHEt2 in acetonitrile yielding the substitution complex PdCl2(NHEt2)2, whereas the amidino complex cis-PtCl2[(E)-HN C(NEt2)Me]2, 3 was obtained from PtCl2(MeCN)2. Complex 3 was characterized by X-ray diffractometry.

In this review we summarize some recent literature data concerning synthetic procedures, properties, structure, reactivity and applications of halo-carbonyl complexes of palladium, platinum and gold, taking into consideration that the organometallic chemistry of these metals, with a particular attention to the halo-carbonyls, has been reviewed 20 years ago [F. Calderazzo, J. Organomet. Chem. 400 (1990) 303]. A brief overview of the early studies is provided.