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Platinum amidine complexes represent a new class of potential antitumor drugs that contain the imino moiety HN=C(sp(2)) bonded to the platinum center. They can be related to the iminoether derivatives, which were recently shown to be the first Pt(II) compounds with a trans configuration endowed with anticancer activity. The chemical and biological properties of platinum amidine complexes, and more generally of platinum imino derivatives, can be rationally modified through suitable synthetic procedures with the aim of improving their cytotoxicity and antitumor activity. The addition of protic nucleophiles to nitriles coordinated to platinum in various oxidation states can offer a wide variety of complexes with chemical, structural, and physical properties specifically tuned for a more efficacious biological response.

Baeyer–Villiger oxidation of cyclic ketones with 35 % hydrogen peroxide as a green oxidant mediated by monomeric PtII complexes bearing alkyl diphosphines greatly benefits from the employment of water with anionic surfactants as reaction medium. Under such conditions, the reaction shows enhanced catalytic activity compared to that with organic solvents. For more acid sensitive substrates, hydrolysis of the lactone product to the corresponding hydroxy acid occurs. Mild experimental conditions, such as moderate temperature and low catalyst loading (≤2 % mol), enabled moderate to good yields.

The Baeyer–Villiger oxidation of ketones to the corresponding esters or lactones is a valuable transformation that has been upgraded several times over the last century, from the original use of monopersulfuric acid as oxidant to more atom efficient and environmentally friendly oxidants such as hydrogen peroxide. The latter requires activation with organometallic complexes to explicate its oxidizing power. The catalytic version of the reaction can be achieved with several transition metal catalysts, but major differences are present among the various catalysts proposed in terms of scope of the reaction. In particular, most of the catalytic systems are active towards four-membered ring ketones leading to the corresponding substituted γ-butyro-lactones. Pt II complexes characterized by the employment of chelating diphosphines turned out to be the most efficient in catalyzing the BV oxidation of a wider range of substrates, in particular cyclohexanones are suitable substrates and acyclic ketones can be converted into the corresponding esters, albeit with low turnover. As long as organometallic catalyzed BV reaction is concerned, Pt II catalysts show the most versatile activity and selectivity. Such peculiar features are the result of the unique electronic properties of such metal combined with an easily tailored soft Lewis acid character modulated by the proper choice of the ancillary ligands. The enantioselective version of the reaction benefits from these properties and the compatibility of Pt II species with water enabled the development of asymmetric catalytic BV reactions in water aided by the presence of micelles as dynamic self-assembled environments.

The reactivity of the cyclic primary aliphatic amines cyclopropyl-, cyclopentyl- and cyclohexylamine with cis- and trans-[PtCl 2 (NCMe) 2 ], under the same experimental conditions, is compared. Whereas cis-[PtCl 2 (NCMe) 2 ] yields the neutral diamidine compounds, the reactions with trans-[PtCl 2 (NCMe) 2 ] take place either with addition or substitution processes yielding the neutral diamidine complexes trans-[PtCl 2 (Amidine) 2 ], the monocationic trans-[PtCl(Amine)(Amidine) 2 ]Cl and the dicationic trans-[Pt(Amine) 2 (Amidine) 2 ]Cl 2 salts. An NMR and ESI study indicate that the main species formed is the monocationic trans-[PtCl(Amine)(Amidine) 2 ]Cl complex. The X-ray structure of trans{PtCl 2 {N(H)=C(CH 3 )NHCHCH 2 CH 2 } 2 ] is reported and its supramolecular arrangement is described.

Synergy in flame retardancy of polyurethane foams between phosphorus-based flame retardant (aluminium phosphinate) and layered silicates has been investigated. We used pristine montmorillonite as well as ammonium modified clay (commercially available) and diphosphonium modified clay, which were synthesised by the intercalation of the quaternary diphosphonium salt according to a procedure reported here. The morphology of the foams was characterised through X-ray diffraction (XRD), while thermal properties were characterised by oxygen index test, cone calorimeter and thermogravimetric analysis (TGA). The morphological characterisation showed that pristine and diphosphonium modified clays are almost slightly intercalated, while ammonium modified one is very well dispersed. The results of thermal characterisation showed that in the presence of phosphinate enhancements of oxygen index, fire behaviour, measured by cone calorimeter, and thermal stability have been achieved. Phosphinate is therefore an efficient flame retardant for polyurethane foams and its flame retardancy action takes place in both condensed and gas phases. Pristine and ammonium modified layered silicate bring some enhancements of thermal stability while having no important effect in decreasing peak heat release rate (PHRR) and total heat evolved (THE) when used in conjunction with phosphinate; their main advantage is related to the enhancement of compactness of the char layer formed. Diphosphonium clay is instead effective in further improving the fire behaviour of the foams because of the flame retardancy action of phosphonium: both PHRR and THE were decreased. The analysis of cone calorimeter data showed that clays act through physical effect constituting a barrier at the surface which is effective in preventing or slowing the diffusion of volatiles and oxygen, while phosphinate and phosphonium are more effective owing to their combined action in both condensed and gas phases.

The reaction of cis - and trans -[PtCl 2 (NCCH 2 Ph) 2 ] with a 5-fold excess of MeNH 2 and Me 2 NH in CH 2 Cl 2 at −10 °C affords in high yield the bis-amidine derivatives cis - and trans -[PtCl 2 { Z -N(H) C(NHMe)CH 2 Ph} 2 ] ( 1a , 2a ) and cis - and trans -[PtCl 2 { E -N(H) C(NMe 2 )CH 2 Ph} 2 ] ( 3a , 4a ), respectively. The complexes were characterized by means of elemental analysis, multinuclear NMR and FT-IR techniques. The X-ray diffraction analysis was carried out for trans -[PtCl 2 { Z -N(H) C(NHMe)CH 2 Ph} 2 ] ( 2a ). Moreover, the in vitro cytotoxicity for the new derivatives was evaluated in a wide panel of human tumor cell lines.

A series of platinum(II) amidine complexes were previously prepared with the aim of obtaining a new class of platinum-based antitumour drugs. This series includes compounds of the type cis-[PtCl2{Z-HN=C(NHMe)Me}2] and trans-[PtCl2{Z-HN=C(NHMe)Me}2] (1, 2 ), cis-[PtCl2{E-HN=C(NMe2)Me}2] and trans-[PtCl2{E-HN=C(NMe2)Me}2] (3 , 4), cis-[PtCl2{Z-HN=C(NHMe)Ph}2] and trans-[PtCl2{Z-HN=C(NHMe)Ph}2] (5 , 6), and cis-[PtCl2{HN=C(NMe2)Ph}2] and trans-[PtCl2{HN=C(NMe2)Ph}2] (7 , 8 ). The reactions with dimethyl sulfoxide were studied for complexes 5 - 8 ; the formation of cationic species con-taining coordinated dimethyl sulfoxide was demon-strated by NMR experiments and electrospray ionization mass spectrometry. In this work, the ami-dine platinum(II) complexes were tested for their in vitro cytotoxicity on a panel of various human cancer cell lines. The results indicate that the benzamidine complex 8 was the most effective derivative also cir-cumventing acquired cisplatin resistance as demon-strated by chemosensitivity tests performed on cisplatin-sensitive and cisplatin-resistant cell lines. The studies concerning the cellular DNA damage on both parental chemosensitive and resistant sublines suggest for the new trans-amidine complex a different mecha-nism of action compared with that exhibited by cis-platin.

The synthesis and spectroscopic characterization of the new hydroxo-bridged platinum(II) complex [P(μ-OH)(Pom-Pom)] 2 [BF 4 ] 2 ( 3 ) containing the electron-poor P–P ligand 1,2-bis(dimethoxyphosphino)ethane, (OMe) 2 PCH 2 CH 2 P(OMe) 2 (Pom-Pom), is reported. This compound has been used in the Baeyer–Villiger oxidation of a series of cyclic ketones using 35% hydrogen peroxide as oxidant. The reactions were performed at 25 °C and at 70 °C in chlorinated solvent/H 2 O biphasic system. The catalytic activity and the Lewis acidity of the complex ( 3 ) has been compared to other Pt(II) complexes previously investigated.

The synthesis, transition metal coordination and reactivity of the functional isocyanides o-(CH2Y)C6H4−N C (Y = OSiMe3, OH; N3; AsR 3 + ) to afford N-heterocyclic carbenes is shortly reviewed.

The synthesis and characterization of new hydroxo-bridged platinum(II) complexes of the type [P(μ-OH)(P−P)]2[BF4]2 (1−4), where P−P = (C6H5-nFn)2PCH2CH2P(C6H5-nFn)2 (n = 2 (2Fdppe) (1), 3 (3Fdppe) (2), 4 (4Fdppe) (3), 5 (dfppe) (4), are reported. These compounds have been used in the Baeyer−Villiger oxidation of 2-methylcyclohexanone using 35% hydrogen peroxide as oxidant. The reactions were performed at 25, 50, and 70 °C in a chlorinated solvent/H2O two-phase system. Among the fluorinated catalysts, complex 4 was found to be the best one in the oxidation of cyclic ketones; however, it is ineffective toward acyclic ketones. The Lewis acidity of the platinum(II) complexes with coordinated fluorinated diphosphines was investigated through the determination of the wavenumber shift Δν = ν(C⋮N)coord − ν(C⋮N)free of the isocyanide group in complexes of the type [PtCl(CN-2,6-(CH3)2C6H3)(P−P)][BF4] (P−P = 2Fdppe, 3Fdppe, 4Fdppe, dfppe, dppe). This latter parameter, which represents a measure of the electrophil...

2-(Azidomethyl)phenyl isocyanide, 2-(CH2N3)C6H4NC (AziNC), coordinates to some cationic Pt(II) and Pd(II) species to afford isocyanide complexes of the type trans-[MCl(AziNC)(PPh3)2][BF4] (M=Pt, l; Pd, 2). AziNC is coordinated also in some neutral Pt(II) and Pd(II) species such as [MCl2(AziNC)2] (M=Pt, 3; Pd, 4) derived from the reactions of 2 equiv. of AziNC with [PtCl2(COD)] and [PdCl2(MeCN)2], respectively. Complexes 1 and 2 react with 1 equiv. of PPh3 affording the heterocyclic carbene complexes trans-[MCl{ (H)}(PPh3)2][BF4] (M=Pt, 5; Pd, 6). Complexes 3 and 4 react with 1 equiv. of PPh3 displacing the isocyanide with the formation of the complexes cis-[MCl2(AziNC)(PPh3)] (M=Pt, 7; Pd, 8). These latter ones react with 2 equiv. of PPh3 affording as the final products the cationic carbene species trans-[MCl{ (H)}(PPh3)2][Cl] (M=Pt, 9; Pd, 10). Complex 5 was also characterized by single crystal X-ray diffraction. The carbene complex is square-planar and the angle formed between the platinum square plane and the heterocyclic carbene ligand is 87.9(2)°. The C(1)–N(1) and C(1)–N(2) bond distances in the latter of 1.32(2) and 1.30(2) A, respectively, are short for a single bond and indicate extensive π-bonding between the nitrogen atoms and the carbene carbon.

2-(Azidomethyl)phenyl isocyanide, 2-(CH 2 N 3 )C 6 H 4 NC (AziNC), coordinates to {M(CO) 5 } (M=W, Cr) fragments to afford the corresponding isocyanide complexes [M(CO) 5 (AziNC)] (M=W ( 1 ), Cr ( 2 )). AziNC coordinates also to some Au(I) species such as [AuCl(AziNC)] ( 3 ), derived from the reaction of [AuCl(Me 2 S)] with AziNC, and [Au(AziNC) 2 ][BF 4 ] ( 4 ), obtained from the reaction of 3 with AgBF 4 , followed by treatment with AziNC. Complexes 1 and 2 undergo the Staudinger reaction with PPh 3 affording the phosphinimine-isocyanide derivatives [M(CO) 5 {CNC 6 H 4 -2-(CH 2 NPPh 3 )}] (M=W ( 5 ), Cr ( 6 )). Complex 6 reacts with H 2 O affording a mixture of the amino–isocyanide [Cr(CO) 5 {CNC 6 H 4 -2-(CH 2 NH 2 )}] ( 7 ) and the carbene [Cr(CO) 5 { CN(H)C 6 H 4 -2-CH 2 N (H)}] ( 8 ) species. Complexes 3 and 4 react with 1 or 2 equiv. of PPh 3 displacing the isocyanide with the formation of the complexes [AuCl(PPh 3 )] ( 9 ) and [Au(PPh 3 ) 2 ][BF 4 ] ( 10 ), respectively. The halogeno–isocyanide complexes [W(CO) 5 (CNC 6 H 4 -2-CH 2 Cl)] ( 11 ) and [W(CO) 5 (CNC 6 H 4 -2-CH 2 I)] ( 12 ) show different reactivity towards amines so that only 12 reacts with MeNH 2 to afford in low yield the N -heterocyclic carbene species [W(CO) 5 { CN(H)C 6 H 4 -2-CH 2 N (Me)}] ( 13 ).

In the di(organocyanamide) complexes trans-[PtCl2(NCNR2)2] (R = Me 1a, Et 1b), prepared by reaction of PtCl2 with the appropriate NCNR2, the cyanamide ligands, activated by coordination, undergo an unprecedented nucleophilic addition, at room temperature, of an haloalcohol (ClCH2CH2OH/LiBun) or of an alcohol (MeOH) to give the corresponding 2-amino-2-oxazoline cis-[PtCl2{NC(OCH2CH2)NR2}2] (R = Me 2a, Et 2b) or trialkylisourea trans-[PtCl2{NHC(OMe)NR2}2] (R = Me 3a, Et 3b) complexes. The X-ray crystal structure of 2b is also reported, indicating a π-bond delocalization along the NCN group of the aminooxazoline ligands.

The improved preparation and the new synthesis of the hydroxo complexes [Pt(Me)(OH)(PP)] (PPPh2PCH2CH2PPh2 (1), Ph2PCHCHPPh2 (2)), abbreviated as [Pt]OH, is reported. The chemical behavior of 1 towards bases, organic and organometallic halides has been tested. There was no NMR spectroscopic evidence for the formation of a reactive oxo intermediate [Pt]O− upon reaction with a strong base. In the presence of an electrophilic organic reagent such as an alkyl halide RX (R=Me, CH2Ph, Et, t-Bu; X=Cl, Br, I), the OH for X exchange process takes place with the formation of the organometallic derivative [Pt(Me)(X)(PP)] and the corresponding alcohols ROH. Similar reactions carried out in the presence of an electrophilic organometallic species such as the neutral complexes [PtCl2(CNC6H4p-OMe)(PPh3)] and [PtCl2(COD)] or the cationic derivative trans-[PtCl(CNMe)(PPh3)2][BF4] indicate primarily OH for Cl exchange with formation of the chloro species [Pt(Me)(Cl)(PP)] and unstable hydroxo complexes, which decompose under the experimental conditions. In the case of the cationic complex also OH for PPh3 exchange is observed. A possible mechanism for the observed reactivity is described.

Magnetic Fluid Hyperthermia uses magnetic nanoparticle and time-varying magnetic field to heat tissue. A study on the correlation between synthetic parameters and morphological structure of magnetic iron nanoparticles was performed using a one-pot water-dispersible-NP synthetic method. Magnetization and thermic measurements confirm their potential use for hyperthermia therapy.

Purpose – Magnetic fluid hyperthermia experiment requires a uniform magnetic field in order to control the heating rate of a magnetic nanoparticle fluid for laboratory tests. The automated optimal design of a real-life device able to generate a uniform magnetic field suitable to heat cells in a Petri dish is presented. The paper aims to discuss these issues. Design/methodology/approach – The inductor for tests has been designed using finite element analysis and evolutionary computing coupled to design of experiments technique in order to take into account sensitivity of solutions. Findings – The geometry of the inductor has been designed and a laboratory prototype has been built. Results of preliminary tests, using a previously synthesized and characterized magneto fluid, are presented. Originality/value – Design of experiment approach combined with evolutionary computing has been used to compute the solution sensitivity and approximate a 3D Pareto front. The designed inductor has been tested in an experimental set-up.

The reaction of 2-(chloromethyl)phenyl formamide, 2-(CH2Cl)C6H4NHCHO, with NaN3 in DMSO at room temperature affords 2-(azidomethyl)phenyl formamide, 2-(CH2N3)C6H4NHCHO (1), which is then dehydrated to 2-(azidomethyl)phenyl isocyanide, 2-(CH2N3)C6H4NC, (2) upon reaction with SOCl2 in DMF at low temperature. The coordination ability of the isocyanide 2 has been tested towards some Pt(II), Pd(II) and W(0) metal complexes to yield derivatives of the type [PtCl2(CNC6H4-2-CH2N3)2], [PdCl2(CNC6H4-2-CH2N3)(PPh3)] and [W(CO)5(CNC6H4-2-CH2N3)], respectively.

The phenyl-platinum(II) organocyanamide trans-[Pt(Ph)(NCNR2)(PPh3)2][BPh4] (R=Me 1a, Et 1b) or cyanoguanidine cis-[Pt(Ph){NCNC(NH2)2}(PPh3)2][BPh4] (2) complexes have been prepared by treatment of cis-[PtCl2(PPh3)2] in THF with NCNR2 or NCNC(NH2)2, respectively, in the presence of Na[BPh4], whereas the cyanoguanidine chloro-complex cis-[PtCl{NCNC(NH2)2}(PPh3)2][BF4] (3) has been obtained by using Tl[BF4] instead of Na[BPh4]. Complex 3 reacts further with cyanoguanidine, in the presence of Na[BPh4], to produce the di(cyanoguanidine) cis-[Pt{NCNC(NH2)2}2(PPh3)2][BPh4]2 complex 5, whereas the amine complex cis-[PtCl(NH2R′)(PPh3)2][BF4] (R′=CH2C6H4Me-4, 4) is formed on reaction of the former with NH2R′ in CH2Cl2. The X-ray structure of 1a is also reported.

The reactions of cis-[PtCl2(NCMe)2] with a fivefold excess of the primary aliphatic amines RNH2 (R=Me, Et, Pri, But) in CH2Cl2 at −10 °C afford in high yield the bis-amidine complexes cis-[PtCl2{ZN(H)C(NHR)Me}2], where both amidine ligands assume the Z configuration. The corresponding reactions of trans-[PtCl2(NCMe)2] with RNH2 (R=Me, Et, But) give a mixture of the bis-amidine trans-[PtCl2{ZN(H)C(NHR)Me}2] and the mono-amidine trans-[PtCl2(NCMe){ZN(H)C(NHR)Me}] derivatives, which could be isolated as pure products operating with a platinum nitrile complex:amine molar ratio of 1:50 or 1:1, respectively. The reaction of trans-[PtCl2(NCMe)2] with a 50-M excess of PriNH2 affords the bis-amidine bis-amine dicationic complex trans-[Pt(H2NPri)2{ZN(H)C(NHPri)Me}2]Cl2, which has been characterized also by X-ray diffraction analysis. The reactions of cis- and trans-[PtCl2(NCMe)2] with the secondary aliphatic amines R′R″NH yield the bis-amidine complexes cis- and trans-[PtCl2{EN(H)C(NR′R″)Me}2] (R′, R″=Et) and/or cis- and trans-[PtCl(NCMe){EN(H)C(NR′R″)Me}2] (R′, R″=Et; R′=Me, R″=But), where the amidine ligands have the E configuration. The compound trans-[PtCl2(NCMe){EN(H)C(NMeBut)Me}] has been characterized by single crystal X-ray diffraction. All the complexes have been characterized by IR, 1H and 13C NMR spectroscopies. The Z or E configuration of the amidine ligand can be readily deduced by 1H NMR data.

When binding a low-valent electron-rich metal centre, isocyanides can be activated towards β-electrophilic attack at the N atom to give aminocarbyne complexes. The syntheses, structural and electronic properties of these compounds are reviewed, as well as their reactions, in particular, proton-induced CC coupling to form diaminoacetylene complexes, deprotonation, dehydrogenation and addition of electrophiles across the metal–carbon triple bond. The kinetic and mechanistic studies performed on these systems are also described.

Isocyanides ligating medium to high-valent electron-poor metal centers can undergo activation toward α-nucleophilic addition to afford a variety of aminocarbene complexes with either heterocyclic or acyclic aminocarbene ligands. These reactions as well as the structural and electronic properties of such products are reviewed.

The reaction of cis-[PtCl2(NCMe)2] with a 5-fold excess of Me2NH in CH2Cl2 at −10°C affords in high yield the bis-amidine complex cis-[PtCl2{E-N(H)C(NMe2)Me}2] (E,E-2), where both the amidine ligands assume the E configuration. E,E-2 was characterized by X-ray structure analysis, NMR spectroscopy and electrospray ionization mass spectrometry (ESI-MS). The corresponding reactions of trans-[PtCl2(NCMe)2] with Me2NH gave the bis-amidine complex trans-[PtCl2{E-N(H)C(NMe2)Me}2] (E,E-3) and the mono-amidine derivative trans-[PtCl2{E-N(H)C(NMe2)Me}(NCMe)] (E-4).

The dialkylcyanamide complexes cis-[PtCl(NCNR(2))(PPh(3))(2)][BF(4)] 1 and cis-[Pt(NCNR(2))(2)(PPh(3))(2)][BF(4)](2) 2 (R = Me or Et) have been prepared by treatment of a CH(2)Cl(2) solution of cis-[PtCl(2)(PPh(3))(2)] with the appropriate dialkylcyanamide and one or two equivalents of Ag[BF(4)], respectively. Compounds 2 can also be obtained from 1 by a similar procedure. Their reaction with oximes, HON=CR'R' ' (R'R' ' = Me(2) or C(4)H(8)), in CH(2)Cl(2) and in the presence of Ag[BF(4)] or Cu(CH(3)COO)(2), leads to the novel type of azametallacycles cis-[Pt(NH=C(ON=CR'R")-NR2)(PPh3)2][BF4]2 4 upon an unprecedented coupling of the organocyanamides with oximes, in a process that proceeds via the mixed oxime-organocyanamide species cis-[Pt(NCNR(2))(HON=CR'R' ')(PPh(3))(2)][BF(4)](2) 3, and is catalyzed by either Ag(+) or Cu(2+) which activate the ligating organocyanamide by Lewis acid addition to the amide group. In contrast, in the organonitrile complexes cis-[Pt(NCR)(2)(PPh(3))(2)][BF(4)](2) 5 (R = C(6)H(4)OMe-4 or Et), obtained in a similar way as 2 (but by using NCR instead of the cyanamide), the ligating NCR is not activated by the Lewis acid and does not couple with the oximes. The spectroscopic properties of those complexes are reported along with the molecular structures of 2b (R = Et), 4a1 (R = Me, R'R' ' = Me(2)), and 4b1 (R = Et, R'R' ' = Me(2)), as established by X-ray crystallography which indicates that in the former complex the amide-N-atoms are trigonal planar, whereas in the latter (4a1 and 4b1) the five-membered rings are planar with a localized N=C double bond (imine group derived from the cyanamide) and the exocyclic amide and alkylidene groups (in 4b1) are involved in two intramolecular H-bonds to the oxygen atom of the ring.

The chemistry of alkynyl and alkyne ligands in platinum complexes of different oxidation states is described. The review focuses on the synthetic aspects of mono- and polynuclear compounds and on the reactivity of σ-alkynyl and π-alkyne species in different stoichiometric reactions such as insertion, addition of nucleophiles and electrophiles, rearrangements and isomerization processes and also some catalytic additions of heteroatoms (B, Si, S) across the CC triple bond. The relevant features of polynuclear complexes bearing the CC group in dendrimers and organometallic polymers are briefly reported.

The complexes trans-[FeH(NCR)(dppe)2][BF4] (1) (R=NH2, NMe2, NEt2 or NC(NH2)2; dppe=Ph2PCH2CH2PPh2) and trans-[FeL(NCR)(depe)2]Yn (R=NH2, NMe2, NEt2 or NC(NH2)2; depe=Et2PCH2CH2PEt2; Y=BF4 or BPh4; (2), L=Br, n=1; (3), L=NCR, n=2) have been prepared by treatment of trans-[FeHCl(dppe)2] (in THF and in the presence of Tl[BF4]) or trans-[FeBr2(depe)2] (in MeOH and in the presence of [NBu4][BF4] or Na[BPh4]), respectively, with the appropriate cyanamide. NMR and Mossbauer spectral, as well as FAB mass spectrometric data are reported. Mossbauer partial isomer shift (PIS) and partial quadrupole splitting (PQS) parameters have been estimated for the cyanamide and dppe ligands and rationalised, with the overall IS and QS, in terms of π- and σ-electronic effects, the cyanamides behaving as more effective σ-donors and weaker π-acceptors than organonitriles. FAB MS fragmentation patterns are also proposed. The crystal structures of 1 (R=NH2) and 3 (R=NEt2, Y=BF4) are reported.

The cationic solvento species trans -[Pt(Me)(PPh 3 ) 2 (solv)][BF 4 ] (solv = CH 2 Cl 2 , Et 2 O) reacts with 1.5 equiv. of p -tolylacetylene in the presence of a 10-fold excess of the hydroxylated compounds HOCH 2 CH 2 X (X = Br, I, OH) to give the corresponding (alkoxy)alkyl carbene complexes trans -[Pt(Me)=C(OCH 2 CH 2 X)CH 2 ( p -tolyl)(PPh 3 ) 2 ][BF 4 ( 1–3 ). Complexes 1–3 were also obtained by reaction of the acetylide complex trans -[Pt(Me)(CCR)(PPh 3 ) 2 ] (R = p -tolyl) in the presence of 1 equiv. of HBF 4 with an excess of HOCH 2 CH 2 X. The carbene complex trans -[Pt(Me)=C(OCH 2 CH 2 Cl)CH 2 R(PPh 3 ) 2 ][BF 4 ] (R = p -tolyl) can be readily deprotonated by NEt 3 to afford the vinyl complex trans -[Pt(Me)C(OCH 2 CH 2 Cl)CH(R)(PPh 3 ) 2 ] ( 4 ). A similar behavior is observed also for 1–3 when treated with a base.

The coordination and organometallic chemistry of P- and As-carbonyl stabilized ylides is reviewed. As a general feature, the coordination chemistry of R3ECHCOR′-type (E=P, As) ligands appears to be dominated by C(ylide) metal coordination, although a few examples of O(ylide)-bound complexes are known. The factors addressing C(ylide)-vs. O(ylide)-coordination in Pt(II) and Pd(II) systems are examined. The Ni(II) complexes containing P,O-chelate ylide ligands are also discussed, with a special emphasis on their catalytic activity. The synthesis and reactivity of phosphonium functionalized isocyanides and their corresponding ylides, which provide a new route to metal coordinated indole systems, are described. Finally, the reactivity of Ph3PCCO towards metal substrates is summarized including the formation of ketenyl complexes.

Reactions at ambient temperature of the solvento cationic trifluoromethyl complex trans-[Pt(CF3)(PPh3)2(solv)][BF4] with 1.5 equiv of 1-alkynes RC⋮CH (R = Ph, p-tolyl) and 2-chloroethanol afford in high yield the β-alkoxyalkenyl complexes trans-[Pt{C(H)C(R)OCH2CH2Cl}(CO)(PPh3)2][BF4] (R = Ph (1), p-tolyl (2)). In these reactions the CF3 group is also converted to a CO ligand. Complexes 1 and 2 were characterized by spectroscopic techniques and 1 also by an X-ray diffraction analysis. Reaction of the alkynyl complex trans-[Pt(CF3)(C⋮C-p-tolyl)(PPh3)2] with 2-chloroethanol and 1 equiv of HBF4 gives the acetylide-carbonyl derivative trans-[Pt(C⋮C-p-tolyl)(CO)(PPh3)2][BF4] (3), which was also formed by reaction of trans-[Pt(CF3)(C⋮C-p-tolyl)(PPh3)2] with aqueous HBF4. Possible mechanisms of these reactions are discussed.

The cyanoguanidine complex cis-[Pt(NCNC(NH2)2)2(PPh3)2][BPh4]2, prepared by reacting cis-[PtCl2(PPh3)2] with cyanoguanidine in the presence of Na[BPh4], readily reacts with methanol to give cis-[(PPh3)2PtNHC(OMe) = NC(NH2) = NH)] [BPh4] containing a novel type of azametallcycle whose molecuar structure is established by X-ray crystallography. Its formation involves metal-promoted nucleophilic addition of the alcohol to the cyano group of a cyanoguanidine ligand, combined with deprotonation of the guanidine unit which then chelates the Pt(II) centre.

The carbonyl stabilized P and As Ph3PHCOR (RCH3, Ph, OCH3) and Ph3ASCHCOR (RCH3, PH, OCH3) have been reacted with some platinum(II) complexes bearing ancillary ligands with different steric hindrance, in order to determine the factors that influence the C- versus O-coordination mode of the ylides. Thus, the reactions of [(dppe)PtCl2] and [(dppv)PtCl2] with Ph3PCHCOR (R^z.dbnd;CH3, Ph) give the O-coordinated complexes, while with Ph3PCHCOOCH3 they give the corresponding C-coordinated derivatives. The reactions of trans-[PPh3)2(CF3)Pt(solv)]+BF−4 yieldd the O-coordinated compounds and the reactions with [Pt(C3H5)Cl]4 give selectivity the C-coordinated derivatives as well as the reactions with the dimer [ PlCl(P(Bu 2 ) 2 C(Me) 2 C H 2 }] 2 . The derivative trans-[Pt(PPh3)2(CF3){OC(OCH3)=C(H)(PPh3)}][BF4]] crystallizes in the triclinic group P1 (No. 2), a = 10.385(4), b = 14.844(5), c = 18.511(6) →A , α = 96.46(2), β=99.79(2), γ = 97.00(2)°, V = 2765(1) a A 3 , Z = 2 . The values of coordination distances and of the PtOC angle appear influenced by steric factors.

The cyclic five-membered platinum(II) oxycarbene complex trans-[Pt(Me){CCH(p-tolyl)CH2CH2O}(PPh3)2][BF4] (1) can be prepared in good yield under very mild conditions either by reaction of trans-[Pt(Me)(C⋮C-p-tolyl)(PPh3)2] with oxirane in the presence of 1 equiv of HBF4 or by reaction of the cationic solvato complex trans-[Pt(Me)(PPh3)2(solv)][BF4] with oxirane and 1.5 equiv of p-tolylacetylene. The X-ray crystal structure of 1 is reported.

Hexakist 4-formylphenoxy cyclophosphazene (1) reacts with six equivalents of cyanomethylenetriphenylphosphorane to give hexakist 4-cinnamonitrile cyclotriphosphazene bearing 12 functional groups tsix nitriles and six olefins' able to coordinate up to 12 metals. In this way a series of polynuclear phosphazene metal derivatives (8–12) was prepared with different transition metals and in different oxidation states. Pt(0), Pt(II) and Rh(I). The analogous cinnamonitrile derivatives (3–7) were prepared and used as models for the characterization of corresponding phosphazene compounds. The redox properties of the complexes3–5 and8–10 as well as of the free cinnamonitrile2 and the free substituted cyclophosphazene1 have been investigated by cyclic voltammetry (CV) and controlled potential electrolysis (CPE) in aprotic media (THF, CH2Cl2, or NCMe 0.2M [NBu4][BF4]), at Pt electrodes. Cathodic processes have been detected only when the unsaturated C=C bond of the cinnamonitrile group is uncoordinated: hence, for compounds1. 4. and9. they are irreversible occur at potentialsE p red ca. −1.3 to ca. −1.9V vs SCE which are less cathodic than that exhibited by the free cinnamonitrile (2:E p red ca. −2.0 V vs SCE), and are believed to be centered at the electron-acceptor emptyπ * (C=C) orbital of each of the cinnamonitrile groups present in the molecule. Anodic processes are displayed only by complexes3. 5. 8. and10 with at least one Pt(0) site: they are irreversible, conceivably centered at such a metal center, and occur at potentials (E p bv ca. 0.7 1.2 V vs SCE) which are dependent on the electronic effects of the ligands, in particular the strong electron-withdrawing ability of the cyclophosphazene group. Complex10 undergoes dissociation in NCMe to form9 and possibly solvated [Pt(PPh3)2] species which adsorb at the electrode surface. No evidence for any redox process centered at the phosphazene ring has been found.

The conversion of a nitrile to an oxazoline group in an amino acid side chain promoted by platinum(II) was investigated. While benzyloxycarbonyl-β-cyano-alanine (Z-Ala(CN)OH) did not give any evidence of coordination of the nitrile group to Pt(II) in different complexes, the corresponding methyl ester Z-Ala(CN)OCH 3 readily afforded the Pt(II)-nitrile complex trans -[Pt(CF 3 ){Z-Ala(CN)OCH 3 }(PPh 3 ) 2 ][BF 4 ] in good yield by reaction with the cationic derivative trans -[Pt(CF 3 ) 2 (solv)][BF 4 ] (solv = CH 2 Cl 2 ). The reactivity of the CN group in the complex trans -[Pt(CF 3 ){Z-Ala(CN)OCH 3 }(PPh 3 ) 2 ][BF 4 ] with ClCH 2 CH 2 O − to the oxazoline ligand 2 was examined. The presence of the oxazoline ring in the final products was evidenced by IR, 1 H and 13 C NMR data and confirmed by FAB and MALDI mass spectra, but its isolation was hampered by the cleavage of the oxazoline ring under the chromatographic conditions applied.

Reaction of 3-bromo-1-propanol with Et4N(CN) in CH2Cl2 at room temperature gives in high yield 4-hydroxybutyronitrile, HO(CH2)3CN (1), which upon reaction with Na2PdCl4 affords [PdCl2{N(H)CCH2CH2CH2O}2] (2), containing two 2-iminotetrahydrofuran ligands derived from intramolecular cyclization of 1. Substitution of one imino ligand for an entering nucleophile L leads to the complexes [PdCl2{N(H)CCH2CH2CH2O}(L)] (L = PPh3 (3), py (4), DMF (5)) . Similarly, the reaction of 2 with 1 equiv of cis-Ph2PCHCHPPh2 results in the displacement of the two iminolactone ligands and formation of [PdCl2(Ph2PCHCHPPh2)]. The ligand 1 and the complexes 2−5 were characterized by analytical and spectroscopic techniques. IR data suggest that 2 and 3 are present as a mixture of cis and trans isomers, while 4 and 5 have a trans stereochemistry. Complex 3 gave crystals of the cis form, as evidenced by an X-ray structural determination.

The reaction chemistry of nitriles, RCN, where R is usually an organyl group, with transition metal complexes is reviewed. The review surveys data published during the period 1977-early 1994 on new reaction processes such as insertion into metal-hydrogen and -carbon bonds, coupling between one nitrile and an unsaturated metal fragment or between two nitriles, reduction to amines, attack by protic and aprotic nucleophiles and electrophilic attack as well as some catalytic transformations, which result from the ability of nitriles to coordinate to transition metal centres with a consequent change in the electrophilicity or nucleophilicity of the coordinated ligand.

The reactions of the nitrile complexes cis- and trans-[PtCl2(NCR)2] (R = Me, Et, CH2Ph, Ph) with an excess of ethanethiol, EtSH, in the presence of a catalytic amount of n-BuLi in tetrahydrofuran (THF), afforded in good yield the bis-imino thioether derivatives cis-[PtCl2{E-N(H)?C(SEt)R}2] (R = Me (1), Et (2), CH2Ph (3), Ph (4)) and trans-[PtCl2{E-N(H)?C(SEt)R}2] (R = Me (5), Et (6), CH2Ph (7), Ph (8)). The imino thioether ligands assumed the E configuration corresponding to a cis addition of the thiol to the nitrile triple bond. The spectroscopic properties of these complexes have been reported along with the molecular structures of 1, 2, and 7 as established by X-ray crystallography which indicated that these compounds exhibit square-planar coordination geometry around the platinum center. Four N-H···Cl intermolecular contacts (N-H···Cl ca. 2.5-2.7 Å) between each chlorine atom and the N-H proton of the imino thioether ligand gave rise to "dimers" Pt2Cl4L4 (L = imino thioether) formed by two PtCl2L2 units. The cytotoxic properties of these new platinum(II) complexes were evaluated against various human cancer cell lines. Among all derivatives, trans-[PtCl2{E-N(H)?C(SEt)CH2Ph}2] showed the greatest in vitro cytotoxic activity being able to decrease cancer cell viability roughly 3-fold more effectively than cisplatin.

Bisphosphonates (BPs) are key drugs for the treatment of bone resorption diseases like osteoporosis, Paget's disease and some forms of tumors. Recent findings underlined the importance of lipophilic N-containing BPs to ensure high biological activity. Herein we present some unprecedented results concerning the low toxicity and good anti-osteoclast activity of low molecular weight hydrophilic S-containing BPs. A series of S and N-containing BPs bearing aromatic and aliphatic substitution were prepared through Michael addition reaction between vinylidenebisphosphonate tetraethyl ester and the proper nucleophile under basic catalysis. S-containing BPs showed a generally low toxicity, determined with the neutral-red assay using the L929 cell line, and, in particular for an aliphatic one, a good biological activity assessed on primary cultures of human osteoclasts. © 2013 Elsevier Masson SAS. All rights reserved.

A series of novel diisocyanide ligands (o-CNC6H 4O)2Y (diNC-1: Y = P(O)Ph; diNC-2: Y = o-C(O)C 6H4C(O); diNC-3: Y = m-C(O)C6H4C(O); diNC-4: Y = C(O)C2H4C(O); diNC-5: Y = trans-C(O)C 2H2C(O)) was successfully synthesized by reaction of lithium 2-isocyanophenate (generated in situ from benzoxazole and n-BuLi) and a diacylic or phosphonic dichloride. The corresponding platinum(II) complexes of general formula [PtX2(diNC)]1,2 (X = Cl, Me; diNC = diisocyanide ligand) were isolated by simple substitution of 1,5-cyclooctadiene in the starting [PtX2(COD)] complexes. The structure of the complexes, mononuclear or dinuclear, was confirmed by single-crystal X-ray analysis. A dinuclear complex of formula {(?-diNC)[cis-PtCl 2(PPh3)]2} could also be obtained with the diisocyanide ligand having a rigid fumaryl bridge and consequently the isocyanide moieties pointing in opposite directions. All the complexes were employed as catalysts in the hydroarylation of alkynes, showing generally good activity and selectivity toward the trans-hydroarylation product. With N-methylindole as aromatic substrate the major product was instead a heterocycle:alkyne 2:1 adduct.

The chloro complexes trans-[Pt(Me)(Cl)(PPh3)2], after treatment with AgBF4, react with 1-alkynes HCCR in the presence of NEt3 to afford the corresponding acetylide derivatives trans-[Pt(Me) (CCR) (PPh3)2] (R = p-tolyl (1), Ph (2), C(CH3)3 (3)). These complexes, with the exception of the t-butylacetylide complex, react with the chloroalcohols HO(CH2)nCl (n = 2, 3) in the presence of 1 equiv. of HBF4 to afford the alkyl(chloroalkoxy)carbene complexes trans-[Pt(Me) {C[O(CH2)nCl](CH2R) } (PPh3)2][BF4] (R = p-tolyl, n = 2 (4), n = 3 (5); RPh, n = 2 (6)). A similar reaction of the bis(acetylide) complex trans-[Pt(CCPh)2(PMe2Ph)2] with 2 equiv. HBF4 and 3-chloro-1-propanol affords trans-[Pt(CCPh) {C(OCH2CH2CH2Cl)(CH2Ph) } (PMe2Ph)2][BF4] (7). T alkyl(chloroalkoxy)-carbene complex trans-[Pt(Me) {C(OCH2CH2Cl)(CH2Ph) } (PPh3)2][BF4] (8) is formed by reaction of trans-[Pt(Me)(Cl)(PPh3)2], after treatment with AgBF4 in HOCH2CH2Cl, with phenylacetylene in the presence of 1 equiv. of n-BuLi. The reaction of the dimer [Pt(Cl)(μ-Cl)(PMe2Ph)]2 with p-tolylacetylene and 3-chloro-1-propanol yields cis-[PtCl2{C(OCH2CH2CH2Cl)(CH2C6H4-p-Me}(PMe2Ph)] (9). The X-ray molecular structure of (8) has been determined. It crystallizes in the orthorhombic system, space group Pna21, with a = 11.785(2), b = 29.418(4), c = 15.409(3) A, V = 4889(1) A3 and Z = 4. The carbene ligand is perpendicular to the Pt(II) coordination plane; the PtC(carbene) bond distance is 2.01(1) A and the short C(carbene)-O bond distance of 1.30(1) A suggests extensive electronic delocalization within the PtC(carbene)O moietry.

A monomeric bis-cationic complex bearing a small bite angle PNP ligand allows for highly selective alkyne hydration in water/surfactant media.

The synthesis, reactivity, and catalytic activity of Pt(II) phosphine complexes containing σ-metal-bound fluoroalkyl and fluoroaryl ligands are surveyed. The increased Pt–C(RF) chemical stability has allowed the isolation and investigation of a series of stable transition-metal hydride, hydroxo, and peroxo complexes. The relative inertness of these complexes coupled with an increased Lewis acidity of the metal center led to the catalytic oxidation of organic substrates (e.g., epoxidation and hydroxylation) in the presence of hydrogen peroxide.

Highly active monomeric bis-cationic platinum(II) catalysts bearing small bite angle diphosphinamine [N,N-bis(diarylphosphino)amine] ‘PNP’ ligands efficiently catalyze Markovnikov hydration of terminal and internal alkynes to the corresponding ketones in water. Catalyst solubilization in water is achieved via ion pairing with anionic micelles formed by surfactant addition. The micelles ensure dissolution of apolar alkynes and promote the intimate contact between reagents and catalyst, while in organic-water media in the absence of surfactants the reaction is sluggish. Hydration products can be isolated by means of extraction with an apolar solvent and the catalyst, that remains confined in the aqueous phase, can be recycled up to four times without loss of catalytic activity.

The synthesis, reactivity, and catalytic activity of Pt(II) phosphine complexes containing σ-metal-bound fluoroalkyl and fluoroaryl ligands are surveyed. The increased Pt–C(RF) chemical stability has allowed the isolation and investigation of a series of stable transition-metal hydride, hydroxo, and peroxo complexes. The relative inertness of these complexes coupled with an increased Lewis acidity of the metal center led to the catalytic oxidation of organic substrates (e.g., epoxidation and hydroxylation) in the presence of hydrogen peroxide.

The 1,3-oxazine complexes cis- and trans-[PtCl2{ N C(R)OCH2CH2C}H22] (cis: RCH3 (1a), CH2CH3 (2a), (CH3)3C (3a), C6H5 (4a); trans:R CH3 (1b), C6H5 (4b)) were obtained in 51-71% yield by reaction in THF at 0 °C of the corresponding nitrile complexes cis- and trans-[PtCl2(NCR)2] with 2 equiv. of −OCH2CH2CH2Cl, generated by deprotonation of 3-chloro-1-propanol with n-BuLi. The cationic nitrile complexes trans-[Pt(CF3)(NCR)(PPh3)2]BF4 (RCH3, C6H5) react with 1 equiv, of − OCH2CH2CH2Cl to give a mixture of products, including the corresponding oxazine derivatives trans-[Pt(CF3){ NC(R)OCH2CH2C CH2}(PPh3)2]BF4 (5 and 6), the chloro complex trans- [Pt(CF3)Cl(PPh3)2] and free oxazine NC(R)OCH 2 CH 2 C H2. For short reaction times (c. 5–15 min) the oxazine complexes 5 and 6 could be isolated in modest yield (37–49%) from the reaction mixtures and they could be separated from the corresponding chloro complex (yield 40%) by taking advantage of the higher solubility of the latter derivative in benzene. For longer reaction times (> 2 h), trans-[Pt(CF3)Cl(PPh3)2] was the only isolated product. Complex 6 was crystallographically characterized and it was found to contain also crystals of trans- [PtCl{ NC(R)OCH 2 CH 2 C H2}(PPh3)2]BF4, which prevented a more detailed analysis of the bond lengths and angles within the metal coordination sphere. The 1,3-oxazine ring, which shows an overall planar arrangement, is characterized by high thermal values of the carbon atoms of the methylene groups indicative of disordering in this part of the molecule in agreement with fast dynamic ring processes suggested on the basis of 1H NMR spectra. It crystallizes in the trigonal space group P 3 , with a=22.590(4), b=15.970(3) A, γ=120°, V=7058(1) A3 and Z=6. The structure was refined to R=0.059 for 3903 unique observed (I⩾3σ(I)) reflections. A mechanism is proposed for the conversion of nitrile ligands to oxazines in Pt(II) complexes.

Platinum amidine complexes represent a new class of potential antitumor drugs that contain the imino moiety HN=C(sp(2)) bonded to the platinum center. They can be related to the iminoether derivatives, which were recently shown to be the first Pt(II) compounds with a trans configuration endowed with anticancer activity. The chemical and biological properties of platinum amidine complexes, and more generally of platinum imino derivatives, can be rationally modified through suitable synthetic procedures with the aim of improving their cytotoxicity and antitumor activity. The addition of protic nucleophiles to nitriles coordinated to platinum in various oxidation states can offer a wide variety of complexes with chemical, structural, and physical properties specifically tuned for a more efficacious biological response.