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The reaction between [NnBu4][(C6F5)2PtII(μ-PPh2)2PtIV(C^N)(I)2] (C^N = κ2-N,C-benzoquinolinate, 1) and (i) bidentate S^S, N^S and O^O anionic ligands or (ii) monodentate S- N- or O-based anionic ligands was studied in order to investigate the factors that may guarantee the stability of Pt(II),Pt(IV) mixed-valence dinuclear phosphanido complexes. While reactions of 1 with S^S or N^S ligands afforded stable Pt(II),Pt(IV) species of general formula [(C6F5)2PtII(μ-PPh2)2PtIV(C^N)(L^S)]x− [(L^S)(x−1) = 2-mercaptopyrimidinate (pymS−), 2-mercaptopyridinate (pyS−), dimethyldithiocarbamate (Me2NCS2−), ethyl xanthogenate (EtOCS2−) and 1,2-benzenedithiolate (PhS22−)], the reaction of 1 with the O^O ligand sodium acetylacetonate gave several products, and no pure Pt(II),Pt(IV) complex could be isolated. The reaction of monodentate ligands such as PhS−, OH− or N3− with 1 led to a stable Pt(II),Pt(IV) complex only in the case of N3−. The reaction with OH− afforded the Pt(II),Pt(II) complex [(C6F5)2PtII(μ-PPh2)(κ2-O,P-μ-O–PPh2)PtII(C^N)]− (8) deriving from reductive coupling of a diphenylphosphanide and an O-donor ligand coordinated to the Pt(IV) centre, while the reaction with PhS− produced the unstable Pt(II),Pt(IV) complex [NnBu4][(C6F5)2PtII(μ-PPh2)2PtIV(C^N)(PhS)2] (11) that evolved in solution to the Pt(II),Pt(II) species [NnBu4][(C6F5)2PtII(μ-PPh2)2PtII(C^N)] (9) by elimination of diphenyldisulfide. Thus, the stability of mixed valence Pt(II),Pt(IV) phosphanide complexes is affected by several concurrent factors, including the chelating effect of the ligands and the type of ligating atoms. [ABSTRACT FROM AUTHOR]

The outcome of the reaction of the Pt(III),Pt(III) complex [(C6F5)2PtIII(μ-PPh2)2PtIII(C6F5)2](Pt-Pt) (1) with the S-based anions thiophenoxide (PhS-), ethyl xanthogenate (EtOCS2-), 2-mercaptopyrimidinate (pymS-), and 2-mercaptopyridinate (pyS-) was found to be dependent on the reaction solvent. The reactions carried out in acetone led to the formation of [NnBu4][(RF)2PtII(μ-PhS-PPh2)(μ-PPh2)PtII(RF)2] (2), [NnBu4][(RF)2PtII(μ-EtOCS2-PPh2)(μ-PPh2)PtII(RF)2] (3), [NnBu4][(RF)2PtII(μ-pymS-PPh2)(μ-PPh2)PtII(RF)2] (4), and [NnBu4][(RF)2PtII(μ-pyS-PPh2)(μ-PPh2)PtII(RF)2] (5), respectively (RF = C6F5). Complexes 2-5 display new Ph2P(SL) ligands exhibiting a κ2-P,S bridging coordination mode, which is derived from a reductive elimination of a PPh2 group and the S-based anion. Carrying out the reaction in dichloromethane afforded, in the cases of EtOCS2- and pymS-, the monobridged complexes [NnBu4][(PPh2RF)(RF)2PtII(μ-PPh2)PtII(EtOCS2)(RF)] (6) and [NnBu4][(PPh2RF)(RF)2PtII(μ-PPh2)PtII(pymS)(RF)] (7), respectively, which are derived from reductive elimination of a PPh2 group with a pentafluorophenyl ring. The reaction of 1 with EtOCS2K in acetonitrile yielded a mixture of 3 and 6 as a consequence of the concurrence of two processes: (a) the formation of 3 by a reaction that parallels the formation of 3 by 1 plus EtOCS2K in acetone and (b) the transformation of 1 into the neutral complex [(PPh2RF)(CH3CN)(RF)PtII(μ-PPh2)PtII(RF)2(CH3CN)] (8), which, in turn, reacts with EtOCS2K to give 6. The 1 to 8 transformation was found to be fully reversible. In fact, dissolving 8 in acetone or dichloromethane afforded pure 1 after solvent evaporation or crystallization with n-hexane. The XRD structures of 2-4 and 6-8 were determined, and the behavior in solution of the new complexes is discussed. [ABSTRACT FROM AUTHOR]

The reaction of [NBu4] [(C6F5)2Pt(μ-PPh2)2Pt(μ-PPh2)2Pt(O,O-acac)] (48 VEC) with [HPPh3][Cl04] gives the 46 VEC unsaturated [(C6F5)2Pt¹ (μ-PPh2)2Pt²(μ-PPh2)2Pt³(PPh3)](Pt²-Pt³) (1), a trinuclear compound endowed with a Pt--Pt bond. This compound displays amphophilic behavior and reacts easily with nucleophiles L, yielding the saturated complexes [(C6F5)2Pt11(μ-PPh2)2Pt11(μ-PPh2)2Pt11(PPh3)L] [L = PPh3 (2), py (3)]. The reaction with the electrophile [Ag(OClO3)PPh3] affords the adduct 1-AgPPh3, which evolves, even at low temperature, to a mixture in which [(C6F5)2PtIII(μ-PPh2)2PtIII(μ-PPh2)2PtII(PPh3)2]2+(PtIII-PtIII>) and 2 (plus silver metal) are present. The nudeophilic nature of 1 is also demonstrated through its reaction with cis-[Pt-(C6F5)2(THF)2] which results in the formation of [Pt4(μ-PPh2)4(C6F5)4(PPh3)] (4). The structure and NMR features indicate that 1 can be better considered as a PtII--PtIII--PtI complex instead of a PtII--PtII--PtII derivative. Theoretical calculations (density functional theory) on similar model compounds are in agreement with the assigned oxidation states of the metal centers. The strong intermetallic interactions resulting in a Pt²--Pt³ metal--metal bond and the respective bonding mechanism were verified by employing a multitude of computational techniques (natural bond order analysis, the Lapladan of the electron density, and localized orbital locator profiles). [ABSTRACT FROM AUTHOR]

The reaction of the neutral binuclear complexes [(RF)2Pt(μ-PPh2)2M(phen)] (phen = 1,10-phenanthroline, RF = C6F5; M = Pt, 1; M = Pd, 2) with AgClO4 or [Ag(OClO3)(PPh3)] affords the trinuclear complexes [AgPt2(μ-PPh2)2(RF)2(phen)(OClO3)] (7a) or [AgPtM(μ-PPh2)2(RF)2(phen)(PPh3)][ClO4] (M = Pt, 8; M = Pd, 9), which display an "open-book" type structure and two (7a) or one (8, 9) Pt-Ag bonds. The neutral diphosphine complexes [(RF)2Pt(μ-PPh2)2M(P-P)] (P-P = 1,2-bis(diphenylphosphino)methane, dppm, M = Pt, 3; M = Pd, 4; P-P = 1,2-bis(diphenylphosphino)ethane, dppe, M = Pt, 5; M = Pd, 6) react with AgClO4 or [Ag(OClO3)(PPh3)], and the nature of the resulting complexes is dependent on both M and the diphosphine. The dppm Pt-Pt complex 3 reacts with [Ag(OClO3)(PPh3)], affording a silver adduct 10 in which the Ag atom interacts with the Pt atoms, while the dppm Pt-Pd complex 4 reacts with [Ag(OClO3)(PPh3)], forming a 1:1 mixture of [AgPdPt(μ-PPh2)2(RF)2(OClO3)(dppm)] (11), in which the silver atom is connected to the Pt-Pd moiety through Pd-(μ-PPh2)-Ag and Ag-P(k1-dppm) interactions, and [AgPdPt(μ-PPh2)2(RF)2(OClO3)(PPh3)2][ClO4] (12). The reaction of complex 4 with AgClO4 gives the trinuclear derivative 11 as the only product. Complex 11 shows a dynamic process in solution in which the silver atom interacts alternatively with both Pd—μPPh2 bonds. When P-P is dppe, both complexes 5 and 6 react with AgClO4 or [Ag(OClO3)(PPh3)], forming the saturated complexes [(PPh2C6F5)(RF)Pt(μ-PPh2)(μ-OH)M(dppe)][ClO4] (M = Pt, 13; Pd, 14), which are the result of an oxidation followed by a PPh2/C6F5 reductive coupling. Finally, the oxidation of trinuclear derivatives [(RF)2PtII(μ-PPh2)2PtII(μ-PPh2)2PtIIL2] (L2 = phen, 15; L = PPh3, 16) by AgClO4 results in the formation of the unsaturated 46 VEC complexes [(RF)2PtIII(μ-PPh2)2PtIII(μ-PPh2)2PtIIL2][ClO4]2 (17 and 18, respectively) which display Pt(III)-Pt(III) bonds. [ABSTRACT FROM AUTHOR]

The reaction of [NBu4]2[(C6F5)2Pt(μ-PPh2)2Pd(μ-PPh2)2Pt(C6F5)2] (1a) with [AgPPh3]+ results in the oxidation of two bridging diphenylphosphanides to give the 46e species [(PPh3)(C6F5)2Pt2(μ-P2Ph2)Pd(μ-PPh2)(μ-Ph2P4-P3Ph2)Pt1(C6F5)2] (3). Complex 3 displays two tetracoordinated terminal platinum centers and a central Pd atom that is bonded to three P atoms and that completes its coordination sphere by a rather long (3.237 Å) dative Pt2 → Pd bond. Complex 3 is also obtained when [(RF)2Pt(μ-PPh2)Pd(μ-PPh2)(μ-Ph2P-PPh2)Pt(RF)2] (2) is reacted with PPh3. Analogously, the addition of PPh2Et, CO or pyridine to 2 affords the 46e complexes of general formula [(L)(C6F5)2Pt2(μ-P2Ph2)Pd(μ-PPh2)(μ-Ph2P4-P3Ph2)Pt1(C6F5)2] (L = PPh2Et, 4; L = CO, 6; L = pyridine, 7). The geometry around Pt2 is determined by the bulkiness of L bonded to Pt. Thus, in complexes 3 (L = PPh3) and 4 (L = PPh2Et), the ligand L occupies the trans position with respect to μ-P2, and in 6 (L = CO), the ligand L occupies the cis position with respect to μ-P2. Interestingly, for 7 (L = py), both isomers 7-trans and 7-cis, could be isolated. Although 4 did not react with an excess of PPh2Et, the reaction with the less sterically demanding CH3CN ligand resulted in the opening of the Pt2—P2—Pd cycle with formation of the saturated 48e species [(PPh2Et)(C6F5)2Pt(μ-PPh2)Pd(MeCN)(μ-PPh2)(μ-Ph2P-PPh2)Pt(C6F5)2] (8). The saturated 48e complex [(CO)(C6F5)2Pt(μ-PPh2)Pd(MeCN)(μ-PPh2)(μ-Ph2P-PPh2)Pt(C6F5)2] (9) was obtained by acetonitrile addition to 6. Beside the hindered rotation of the pentafluorophenyl groups and a flip-flop motion of the Pd—P—Pt1—P—P ring observed at low T, a rotation about the Pt2—P2 bond and a P—C oxidative addition/reductive elimination process occur for 3 and 4 at room temperature. A "through-space" 19F—31P spin—spin coupling between an ortho-F and the P4 is observed for complexes 3 and 4, having the C6F5 groups bonded to Pt2 in mutually trans position. The XRD structures of complexes 3, 6, 7-trans, 7-cis, 8, and 9 are described. [ABSTRACT FROM AUTHOR]

Reaction of unsaturated (44e- skeleton) [PdPt2(μ-PPh2)2(μ-P2Ph4)(RF)4] 4 with Br- produces the saturated (48e- skeleton) complex [NBu4][(RF)2Pt(μ-PPh2)(μ-Br)Pd(μ-PPh2)(μ-P2Ph4)Pt(RF)2] 5 without any M-Mʹ bond. Attempts to eliminate Br- of 5 with Ag+ in CH2CI2 as a solvent gives a mixture of [(RF)2PtIII(μ-PPh2)2PtIII(RF)2] and some other unidentified products as a consequence of oxidation and partial fragmentation. However, when the reaction of 5 with Ag+ is carried out in CH3CN, no oxidation is observed but the elimination of Br- and the formation of [(RF)2(CH3CN)Pt(μ-PPh2)Pd(μ-PPh2)(μ-P2Ph4)Pt(RF)2] 6 (46e- skeleton), a complex with a Pt-Pd bond, takes place. It is noteworthy that the reaction of 5 with TIPF6 in CH2CI2 does not precipitate TIBr but forms the adduct [(RF)2PtTI(μ-PPh2)(μ-Br)Pd(μ-PPh2)(μ-P2Ph4)Pt(RF)2] 7 with a Pt-TI bond. Likewise, 5 reacts with [AgOClO3(PPh3)] in CH2CI2 forming the adduct [AgPdPt2(μ-Br)(μ-PPh2)2(μ-Ph2P-PPh2)(RF)4(PPh3)] 8, which contains a Pt-Ag bond. Both adducts are unstable in a CH3CN solution, precipitating TIBr or AgBr and yielding the unsaturated 6. The treatment of [NBu4]2[(RF)2Pt(μ-PPh2)2Pd(μ-PPh2)2Pt(RF)2] in CH3CN with I2 (1:1 molar ratio) at 233 K yields a mixture of 4 and 6, which after recrystallization from CH2CI2 is totally converted in 4. If the reaction with I2 is carried out at room temperature, a mixture of the isomers [NBu4][(RF)2Pt(μ-PPh2)(μ-I)Pd(μ-PPh2)(μ-P2Ph4)Pt(RF)2] 9 and [NBu4][(RF)(PPh2RF)Pt(μ-PPh2)(μ-l)Pd(μ-PPh2)2Pt(RF)2] 10 are obtained. The structures of the complexes have been established on the bases of NMR data, and the X-ray structures of 5-8 have been studied. The relationship between the different complexes has been studied. [ABSTRACT FROM AUTHOR]

Reaction of the trinuclear PtIII-PtIIIPt-II [(C6F5)2PtIII(μ-PPh2)2PtIII(μ-PPh2)2Pt(C6F5)2] (2) derivative with NBu4Br or NBu4I results in the formation of the trinuclear PtII complexes [NBu4][(PPh2C6F5)(C6F5)Pt(μ-PPh2)(μ-X)Pt(μ-PPh2)2-Pt(C6F5)2] [X = I (3), Br (4)] through an intramolecular PPh2/C6F5 reductive coupling and the formation of the phosphine PPh2C6F5. The trinuclear PtII complex [(PPh2C6F5)(C6F5)Pt(μ-PPh2)Pt(μ-PPh2)2Pt(C6F5)2] (5), which displays two Pt-Pt bonds, can be obtained either by halide abstraction in 4 or by refluxing of 2 in CH2Cl2. This latter process also implies an intramolecular PPh2/C6F5 reductive coupling. Treatment of complex 5 with several ligands (Br-, H-, and CO) results in the incorporation of the ligand to the cluster and elimination of one (X = H-) or both (X = Br-, CO) Pt-Pt bonds, forming the trinuclear complexes [NBu4][(PPh2C6F5)(C6F5)Pt(μ-PPh2)(μ-X)Pt(μ-PPh2)2- Pt(C6F5)2] [X = Br (6), H (7)] or [(PPh2C6F5)(C6F5)Pt(u-PPh2)2Pt(μ-PPh2)(CO)Pt(C6F5)2(CO)] (8). The structures of the complexes have been established on the basis of ¹H, 19F, and 31P NMR data, and the X-ray structures of the complexes 2, 3, 5, and 7 have been established. The chemical relationship between the different complexes has also been studied. [ABSTRACT FROM AUTHOR]

The addition of [NBu4]Br or [NBu4][BH4] to solutions of [Pt4(μ-PPh2)4(C6F5)4(CO)2] (3) yields the complexes [NBu4]2 [Pt4(μ-PPh2)4(μ-X)2(C6F5)4] (X = Br, 4; H, 5) in which the two CO groups have been replaced by two anionic, bridging X ligands. The total valence electron counts are 64 and 60, respectively; thus, complex 4 does not require Pt-Pt bonds, while two metal-metal bonds are present in 5, as their NMR spectra confirm. Also, the NMR spectra indicate a nonsymmetrical "Pt(μ-PPh2)22Pt(μ-PPh2)(μ-X)Pt(μ-PPh2)(μ-X)Pt" disposition for 4 and 5. Treatment of 5 with HX (X = Cl, Br) yields the complexes [NBu4]2[Pt4(μ-PPh2)4(μ-H)2(C6F5)3X] (X = Cl, 6; Br, 7). These complexes react with [Ag(OClO3)PPh3] with displacement of the halide and formation of [NBu4][Pt4(μ-PPh2)4(μ-H)2(C6F5)3PPh3] (8). Complexes 6-8 maintain the same basic skeleton as 5, with two Pt-Pt bonds. Complex 4 is, however, an isomer of the symmetric [NBu4]2[{(C6F5)4Pt(μ-PPh2)2Pt(μ-Br)}2] (9), which has been prepared by a metathetical process from the well-known [NBu4]2[{(C6F5)2Pt(μ-PPh2)2Pt(μ-Cl)}2] (1). The comparison of the X-ray structures of 4 and 9 confirms the different disposition of the bridging ligands, and their main structural differences seem to be related to the size of Br- and its position in the skeleton. [ABSTRACT FROM AUTHOR]

• Oxidative coupling of PPh 2 – with terminally bonded anionic ligands (L–) takes place onto polynuclear Pt or Pd systems. • The formation of P–E bonds with E = C, N, O, P, S is easily achieved. • High-valent M(IV) centres (M = Pd, Pt) are involved in most cases. The coupling of bridging diphenylphosphanides (PPh 2 –) with terminally bonded anionic ligands (L–) that takes place onto polynuclear Pt or Pd systems is reviewed. The two-electron reduction that accompanies the PPh 2 /L coupling generally implicates a M(IV) centre but there are examples where the redox process involves a M(II),M(II) system that is transformed into a M(I),M(I) containing product (M = Pd, Pt). The discussed coupling reactions end up with formation of new ligands which, depending on the nature of L–, display P–E bonds with E=C, N, O, P, S and I. [ABSTRACT FROM AUTHOR]

The reactions of [Ag(OClO3)(PPh3)] with [NBu4][(C6F5)2Pt(μ-PPh2)2M(hq)], [NBu4][(C6F5)2Pt(μ-PPh2)2M(bq)], [NBu4][(C6F5)2Pt(μ-PPh2)2M(pic)] and [NBu4][(C6F5)2Pt(μ-PPh2)2Pt(C6F5)(tht)] (M = Pt, Pd; hq = 8-hydroxyquinolinate, bq = benzoquinolinate, pic = picolinate, tht = tetrahydrothiophene) afford the corresponding neutral adducts [(C6F5)2Pt(μ-PPh2)2(μ-AgPPh3)M(bq)] (M = Pt, 1; Pd, 2), [(C6F5)2Pt(μ-PPh2)2(μ-AgPPh3)M(hq)] (M = Pt, 3; Pd, 4) [(C6F5)2Pt(μ-PPh2)2(μ-AgPPh3)Pt(C6F5)(tht)] ( 5) and [(C6F5)2Pt(μ-PPh2)2M(pic-AgPPh3)] (M = Pt, 6; Pd, 7) as yellow solids. The XRD structures of 1- 5, in which a [AgPPh3]+ moiety bridges the metal centres, were confirmed in solution at low temperature. At room temperature, a dynamic process for the [AgPPh3]+ moiety, which passes from the top to the bottom part of the molecules 1- 5, was ascertained. For 6 and 7, the XRD analyses revealed structures in which the [AgPPh3]+ moiety is linked to the picolinate oxygen atom bonded to the M centre; however, although such a structure was confirmed in solution for the Pt-Pd species 7, the stable form of the Pt-Pt species 6 in solution is that with the [AgPPh3]+ moiety bridging the metal centres. [ABSTRACT FROM AUTHOR]

The reactivity of the dinuclear platinum(III) derivative [(RF)2 PtIII(μ-PPh2)2PtIII(RF)2](Pt-Pt) (RF = C6F5) (1) toward OH-, N3-, and NCO- was studied. The coordination of these nucleophiles to a metal center evolves with reductive coupling or reductive elimination between a bridging diphenylphosphanido group and OH-, N3-, and NCO- or C6F5 groups and formation of P-O, P-N, or P-C bonds. The addition of OH- to 1 evolves with a reductive coupling with the incoming ligand, formation of a P-O bond, and the synthesis of [NBu4]2[(RF)2PtII(μ-OPPh2)(μ-PPh2)PtII(RF)2] (3). The addition of N3- takes place through two ways: (a) formation of the P-N bond and reductive elimination of PPh2N3 yielding [NBu4]2[(RF) 2PtII(μ-N3)(μ-PPh2)PtII(RF)2] (4a) and (b) formation of the P-C bond and reductive coupling with one of the C6F5 groups yielding [NBu4][(RF)2PtII(μ-N3)(μ-PPh2)PtII(RF)(PPh2RF)] (4b). Analogous behavior was shown in the addition of NCO- to 1 which afforded [NBu4]²[(RF)2PtII(μ-NCO)(μ-PPh2)PtII(RF)2] (5a) and [NBu4][(RF)2PtII(μ-NCO)(μ-PPh2)PtII(RF)(PPh2RF)] (5b). In the reaction of the trinuclear complex [(RF)2PtIII(μ-PPh2)2PtIII(μ-PPh2)2PtII(RF)2](PtIII-PtIII) (2) with OH- or N3-, the coordination of the nucleophile takes place selectively at the central platinum(III) center, and the PPh2/OH- or PPh2/N3- reductive coupling yields the trinuclear [NBu4]2[(RF)2PtII(μ-Ph2PO)(μ-PPh2)PtII(μ-PPh2)2PtII(RF)2] (6) and [NBu4][(RF)2Pt¹(μ3-Ph2PNPPh2)(μ-PPh2)Pt²(μ-PPh2)Pt³(RF)2](Pt²-Pt³) (7). Complex 7 is fluxional in solution, and an equilibrium consisting of Pt-Pt bond migration was ascertained by 31P EXSY experiments. [ABSTRACT FROM AUTHOR]

Highlights: [•] Di- and trinuclear phosphanido synthons to tetra- and hexanuclear platinum complexes. [•] Polynuclear complexes with only P and N (or O) donors bridging the platinum centres. [•] The first X-ray characterized “Pt(μ-1,1-N3)Pt” and “Pt(μ-C2O4-κ2 O,O′:κ2 O″,O‴)Pt” systems. [•] Tetra and hexanuclear complexes with the Pt centres in a linear arrangement. [ABSTRACT FROM AUTHOR]

The dinuclear anionic complexes [NBu4]-[(RF)2MII(ü-PPh2)2M'II(NAO)] (RF = C6F5. NAO = 8-hydrox-yquinolinate, hq; M = M' = Pt 1; Pd 2; M = Pt, M' = Pd, 3. NAO = o-picolinate, pic; M = Pt, M' = Pt, 4; Pd, 5) are synthesized from the tetranuclear [NBu4]2[{(RThe dinuclear anionic complexes [NBu4]-[(RF)2MII(Ā-PPh2)2M'II(NAO)] (RF = C6F5. NAO = 8-hydrox-yquinolinate, hq; M = M' = Pt 1; Pd 2; M = Pt, M' = Pd, 3. NAO = o-picolinate, pic; M = Pt, M' = Pt, 4; Pd, 5) are synthesized from the tetranuclear [NBu4]2[{(RF)2Pt(Ā-PPh2)2M(Ā-Cl)}2] by the elimination of the bridging CI as AgCl in acetone, and coordination of the corresponding N,0-donor ligand (1, 4, and 5) or connecting the fragments "cis-[(RF)2M(Ā-PPh2)2]2-" and "M'(NAO)w (2 and 3). The electrochemical oxidation of the anionic complexes 1--5 occurring under HRMS(+) conditions gave the cations [(RF)2M-(Ā-PPh2)2M'(NA0)]+, presumably endowed with a M(III),M'(III) core. The oxidative addition of I2 to the 8-hydroxyquinolinate complexes 1--3 triggers a reductive coupling between a PPh2 bridging ligand and the N,0-donor chelate ligand with formation of a P--O bond and ends up in complexes of platinum (II) or palladium(II) of formula [(RF)2MII(Ā-I)(Ā-PPh2)M'II(P,N-PPh2hq)], M = M' = Pt 7, Pd 8; M = Pt, M' = Pd, 9. Complexes 7-9 show a new PhjP-OCHftN (Ph2P-hq) ligand bonded to the metal center in a P,N-chelate mode. Analogously, the addition of I2 to solutions of the o-picolinate complexes 4 and 5 causes the reductive coupling between a PPh2 bridging ligand and the starting N,0-donor chelate ligand with formation of a P--O bond, forming Ph2P-OC6H4NO (Ph2P-pic). In these cases, the isolated derivatives [NBu4][(Ph2P-pic)(RF)PtII(μ-I)(μ-PPh2)MII(RF)I] (M = Pt 10, Pd 11) are anionic, as a consequence of the coordination of the resulting new phosphane ligand (Ph2P-pic) as monodentate P-donor, and a terminal iodo group to the M atom. The oxidative addition of I2 to [NBu4](RF)PtII(μ-I)(μ-PPh2)PtII(Ph2P-acac>) (6) (acac = acetylacetonate) also results in a reductive coupling between die diphenylphosphanido and the acetylacetonate ligand with formation of a P--O bond and synthesis of the complex [NBu4](RF)2PtII(μ-I)(μ-PPh2)PtII(Ph2P-acac)l] (12). The transformations of the starting complexes into the products containing the P--O ligands passes through mixed valence M(II),M'(IV) intermediates which were detected, for M = M' = Pt, by spectroscopic and spectrometric measurements. [ABSTRACT FROM AUTHOR]

The rational synthesis of dinudear asymmetric phosphanido derivatives of palladium and platinum(II), [NBu4][(Rp)2M(μ-PPh2)2M'(k2,N,C-C13H8N)] (Rp = C6F5; M = M' = Pt, 1; M = Pt, M' = Pd, 2; M = Pd, M' = Pt, 3; M = M' = Pd, 4), is described. Addition of I2, to 1-4 gives complexes [(RF),MIII(μ-PPh2)(μ-I)PdII{PPh2(C13H5N)}] (M = M' = Pt, 6; M = Pt, M' = Pd, 7; M = M' = Pd, 8; M = Pd, M' = Pt 10) which contain the aminophosphane PPh2(C13H5N) ligand formed through a Ph2P/CN reductive coupling on the mixed valence M(II)-M'(IV) [NBu4][(Rp)2MIIμ-PPh2);M'IV(k2,N,C- C13H8N)I2] complexes, which were identified for MII = Pd, M'IV = Pt (9), and isolated for MII = Pt, M'IV = Pt (5). Compl ex 5 showed an unusual dynamic behavior consisting in the exchange of two phenyl groups bonded to different P atoms, as well as a "through space" spin--spin coupling between ortho-F atoms of the pentafluorophenyl rings. [ABSTRACT FROM AUTHOR]

The reaction between the unsaturated 30-valence-electron-count [(C6F5)2Pt(μ-PPh2)2M(PPh3)] (M = Pt, Pd) and [M'(OCIO3)PPh3] (M'=Ag, Au) yield the cationic trinuclear [(C6F5)2Pt(μ-PPh2)2M(PPh3)(M'PPh3)][CIO4] (M = Pt, Pd; M' = Ag, Au), which displays Pt —M and M —M' bonds. Te X-ray structures of the complexes reveal that the core of the molecules is planar and the Pt—M and M—M' distances point to the presence of Pt—M and M—M' bonds. A computational study on the formation of these complexes and the analysis of the interaction between the binuclear fragment [(C6F5)2Pt(μ-PPh2)2Pt(PPh3)] and the cation [Ag PPh3]+ has been carried out on the basis of density functional theory and shows that the Ag center interacts weakly with M and P (PPh2ligand) atoms of the binuclear fragment. [ABSTRACT FROM AUTHOR]

Reaction of the trinuclear [NBu4]2[(RF)2Pt(μ-PPh2)2Pt(μ-PPh2)2Pt(RF)2] (1, RF = C6F5) with HCI results in the formation of the unusual anionic hexanuclear derivative [NBU4]2[{(RF)2Pt(μ-PPh2)2Pt(μ-PPh2)2Pt(μ-Cl)}2] (4, 96 e- skeleton) through the cleavage of two Pt-C6F5 bonds. The reaction of 4 with Tl(acac) yields the trinuclear [NBu4][(RF)2Pt-(μ-PPh2)2Pt(μ-PPh2)2Pt(acac)] (5, 48 e- skeleton), which is oxidized by Ag+ to form the trinuclear compound [(RF)2Pt(μ-PPh2)2Pt(μ-PPh2)2Pt(acac)][ClO4] (6, 46 e- skeleton) in mixed oxidation state Pt(lll)-Pt(lll)-Pt(ll), which displays a Pt-Pt bond. The reduction of 6 by [NBu4][BH4] gives back 5. The treatment of 6 with Br- (1:1 molar ratio) at room temperature gives a mixture of the isomers [(PPh2RF)(RF)Pt(μ-PPh2)(μ-Br)Pt(μ-PPh2)2Pt(acac)], having Br trans to RF (7a) or Br cis to RF (7b), which are the result of PPh2/C6F5 reductive coupling. The treatment of 5 with 12 (1:1 molar ratio) yields the hexanuclear [{(PPh2RF)(RF)Pt(μ-PPh2)(μ-l)Pt(μ-PPh2)2Pt(μ-l)}2] (8, 96 e- skeleton), which is easily transformed into the trinuclear compound [(PPh2RF)(RF)Pt(μ-PPh2)(μ-l)Pt(μ-PPh2)2Pt(l)(PPh3)] (9, 48 e- skeleton). Reaction of [(RF)2Pt(μ-PPh2)2Pt(μ-PPh2)2Pt(NCMe)2] (10) with l2 at 213 K for short reaction times gives the trinuclear platinum derivative [(RF)2Pt(μ-PPh2)2Pt(μ-PPh2)2Pt(l)2] (11, 46 e- skeleton) in mixed oxidation state Pt(lll)-Pt(lll)-Pt(ll) and with a Pt-Pt bond, while the reaction at room temperature and longer reactions times gives 8. The structures of the complexes have been established by multinuclear NMR spectroscopy. In particular, the 195Pt NMR analysis, carried out also by 19F-195Pt heteronuclear multiple-quantum coherence, revealed an unprecedented shielding of the 195Pt nuclei upon passing from Pt(ll) to Pt(lll). The X-ray diffraction structures of complexes 4, 5, 6, 9, and 11 have been studied. A detailed study of the relationship between the complexes has been carried out. [ABSTRACT FROM AUTHOR]

Abstract: The elimination of the NCMe ligand in [(C6F5)2Pt(μ-PPh2)2M(NCCH3)2] (M=Pd, Pt) results in the formation of the tetranuclear clusters [Pt2Pd2(μ-PPh2)3(C6F5)3(PPh2C6F5)] 1 and [Pt4(μ-PPh2)4(C6F5)4] 2. The structure of 1 indicates that one of the palladium centres is connected to the rest of the centres through two M–M bonds and two weaker η2-C6H5 and η2-P–C interactions. [Copyright &y& Elsevier]

Multinuclear (31P, 195Pt, 19F) solid-state NMR experiments on (nBu4N)2[(C6F5)2Pt(µ-PPh2)2Pt(C6F5)2] (1), [(C6F5)2Pt(µ-PPh2)2Pt(C6F5)2](Pt-Pt) (2), and cis-Pt(C6F5)2(PHPh2)2 (3) were carried out under cross-polarization/magic-angle-spinning conditions or with the cross-polarization/Carr-Purcell Meiboom-Gill pulse sequence. Analysis of the principal components of the 31P and 195Pt chemical shift (CS) tensors of 1 and 2 reveals that the variations observed comparing the isotropic chemical shifts of 1 and 2, commonly referred to as "ring effect", are mainly due to changes in the principal components oriented along the direction perpendicular to the Pt2P2 plane. DFT calculations of 31P and 195Pt CS tensors confirmed the tensor orientation proposed from experimental data and symmetry arguments and revealed that the different values of the isotropic shieldings stem from differences in the paramagnetic and spin-orbit contributions. [ABSTRACT FROM AUTHOR]

Treatment of [{(C6F5)(PPh3)Pt(μ-PPh2)(μ-H)}2Pt] (1) with I2 results in a complicated reaction from which [{(C6F5)(PPh3)Pt(μ-PPh2)(μ-I)}2Pt] (2) is obtained. The X-ray structure and 19F and 31P NMR spectra are given. Density functional theory (DFT) at the B3LYP level, using the LANL2DZ basis set, provides a satisfactory description of structural, bonding, electronic and related properties of [{(CF3)(PH3)Pt(μ-PH2)(μ-H)}2Pt] and [{(CF3)(PH3)Pt(μ-PH2)(μ-I)}2Pt] model compounds. The results unambiguously justify the predictions of the through-ring bonding required by the number of framework electrons and threw light on the bonding mechanism in the “{Pt(μ-X)(μ-PH2)}2Pt” (X=H, I) nuclear framework of the compounds. [Copyright &y& Elsevier]