Tellurium(II) and tellurium(IV) complexes of phosphine chalcogenide ligands,synthesis and X-ray structures

Reaction of TeX₄ (X = Cl or Br) with 2 mol. equiv. of OPR₃ (R = Me, Et or Ph) gives the distorted octahedral cis-[TeX₄(OPR₃)₂], while the bidentates Ph₂P(E)(CH₂)_nP(E)Ph₂ (E = O, n = 1 or 2; E = S, n = 1) give the six-coordinate [TeX₄{Ph₂P(E)(CH₂)_nP(E)Ph₂}]. These species have been characterised spectroscopically (via ¹H and ³¹P{¹H} NMR and IR) and by crystallographic analyses on cis-[TeBr₄(OPPh₃)₂], [TeCl₄{Ph₂P(O)CH₂P(O)Ph₂}] and [TeBr₄{Ph₂P(S)CH₂P(S)Ph₂}]. The TeX₄ (X = Cl or Br) are reduced by Ph₂P(S)(CH₂)₂P(S)Ph₂ and Ph₂P(Se)CH₂P(Se)Ph₂, giving the planar, four-coordinate Te(II) species [Te{Ph₂P(S)(CH₂)₂P(S)Ph₂}₂]²⁺ (isolated as [(TeCl₅)₂{μ-Ph₂P(S)(CH₂)₂P(S)Ph₂}]^2? and [TeBr₆]^2? salts) and [TeBr₂{Ph₂P(Se)CH₂P(Se)Ph₂}], all of which have also been identified crystallographically. On the basis of the structural data the Te-based lone pair associated with the Te(IV) species is assumed to occupy the 5s orbital, whereas in the Te(II) complexes the planar coordination is consistent with the two stereochemically active lone pairs occupying the axial sites.     

The preparation and characterisation of a series of cationic bimetallic linear triphos-bridged complexes of the type [Mo (CO) (L,L′ or L″–P) (η2-RC2R′)Cp] [BF4] {L,L′ or L″= [WI2 (CO){PhP(CH2CH2PPh2)2–P,P′} (η2-RC2R′)] (L,R=R′=Me; L′,R=R′=Ph; L″,R=Me,R′=Ph}

Equimolar quantities of [Mo (CO) (η²-RC₂R′)₂Cp] [BF₄] (R=R′=Me Ph R=Me R′=Ph) and L L′ or L″ {L L′ or L″= [WI₂ (CO){PhP(CH₂CH₂PPh₂)₂-PP′} (η²-RC₂R′)]} (L R=R′=Me L′ R=R′=Ph L″ R=Me R′=Ph) react in CH₂Cl₂ at room temperature to give the new bimetallic complexes[Mo (CO) (L L′ or L″–P) (η²-RC₂R′)Cp] [BF₄] (1–9) via displacement of the alkyne ligand on the molybdenum centre The complexes have been characterised by elemental analysis IR and ¹ H NMR spectroscopy and in selected cases by ³¹ P NMR spectroscopy.     

Computational Analysis of Mesomerism in para-Substituted mer-NCN Pincer Platinum(II) Complexes,Including its Relationships with Hammett σp Substituent Parameters

Density Functional Theory studies of square-planar Pt^II pincer structures, (4-Z-NCN)PtCl ([4-Z-NCN]⁻=[4-Z-2,6-(Me₂NCH₂)₂C₆H₂-N,C,N]⁻, Z=H, NO₂, CF₃, CO₂H, CHO, Cl, Br, I, F, SMe, SiMe₃, tBu, OH, NH₂, NMe₂), enable characterisation of mesomerism for the pincer-Pt interaction. Relationships between Hammett σ_p substituent parameters of Z and DFT data obtained from NBO6 and AOMix computation are used to probe the interaction of the 5d_yz orbital of platinum with π-orbitals of the arene ring. Analogous computation for 2,6-(Me₂CH₂)₂C₆H₃Z (Z=H, CF₃, CHO, Cl, Br, I, F, SMe, SiMe₃, tBu, OH, NH₂) and (4-H-NCN)PtZ allows an estimation of the relative substituent effects of “(CH₂NMe₂)₂PtZ” on π-delocalisation in the pincer system.     

Synthesis and spectral studies on platinum complexes with mono- and bidentate N-donor organic ligands

Platinum(II) complexes of types PtLX₂, PtL₂X₂, PtLX″ and the Pt(IV) complexes PtLXY (where L = mono- or bidentate organic ligand containing nitrogen donor atoms; X = Cl or Br; X′ = oxalate or malonate and Y = Br) have been synthesized and characterized from their elemental analysis, IR and X-ray photoelectron spectral data. The Pt 4f_7/2 binding energies indicate that 1,8-naphthalene-diamine ligand is a better donor of electron density to the metal than other ligands studied here. The Cl 2p_3/2 binding energies in the square planar Pt(II) complexes are observed in the range 198.8 ± 0.8 eV. The ν (PtCl) vibrations (ca 335 and 320 cm^?1) corresponding to two cis-Cl ligands were observed in the IR spectra.The extent of the interaction between cis-dichloro-bis-(theophylline)platinum(II) with calf thymus DNA has beenstudied. The UV difference spectra resulting from aquated Pt^II(theoph)₂-DNA interaction exhibit bands at 282 and 292 nm attributable to the change in the electron distribution of the base moieties induced by binding with platinum and due to the loss of base stacking. Melting profiles for the DNA samples treated with Pt-complex showed decrease in the melting temperature. Binding of the guanine residues of the DNA, involving probably (N7)-0(6) positions to the metal is implied.     

Stereospecific synthesis and redox properties of ruthenium(II) carbonyl complexes bearing a redox-active 1,8-naphthyridine unit

Two stereoisomers of cis-[Ru(bpy)(pynp)(CO)Cl]PF₆ (bpy = 2,2′-bipyridine, pynp = 2-(2-pyridyl)-1,8-naphthyridine) were selectively prepared. The pyridyl rings of the pynp ligand in [Ru(bpy)(pynp)(CO)Cl]⁺ are situated trans and cis, respectively, to the CO ligand. The corresponding CH₃CN complex ([Ru(bpy)(pynp)(CO)(CH₃CN)]²⁺) was also prepared by replacement reactions of the chlorido ligand in CH₃CN. Using these complexes, ligand-centered redox behavior was studied by electrochemical and spectroelectrochemical techniques. The molecular structures of pynp-containing complexes (two stereoisomers of [Ru(bpy)(pynp)(CO)Cl]PF₆ and [Ru(pynp)₂(CO)Cl]PF₆) were determined by X-ray structure analyses.     

Thermodynamics of vinyl ethers—XV : Halogen-containing vinyl ethers

Thermodynamics of geometrical and prototropic isomerization reactions on some halogen-containing vinyl ethers of the types ROCH–CHX (X = Cl, Br), ROC(CH₂X)CH₂ (X = F, Cl, Br), and ROC(CHMeCl)CH₂ (R = Me, Et, Et₂CH) have been studied. In ROCH_αCH_βX the cis (or Z) isomer is thermodynamically the more stable isomer, the higher stability of the Z isomer being due to its lower enthalpy. The relative stability of the E and Z forms is, however, reversed if the α H atom is replaced by a Me group. In systems like OCCX the double-bond stabilizing ability of the halogen atom decreases in the order Cl > Br > F, in contrast to the case in haloalkenes, where the corresponding order is F > Cl > Br.     

Addition of protic molecules to coordinated 2-pyridinecarboxaldehyde in gold(III), palladium(II), and platinum(II) complexes

The reactions of Au^III, Pt^II and Pd^II complexes with 2-pyridinecarboxaldehyde (2CHO-py) have been examined in protic (H₂O, MeOH, EtOH) and aprotic (DMF, CH₂Cl₂) solvents. Compounds in which the pyridine ligand is N-coordinated, either in the original aldehydic form or in a new form derived from addition of one or two protic molecules, have been isolated, namely: [Au(2CHO-py · H₂O)Cl₃], [Au(2CHO-py · MeOH)Cl₃], [Au(2CHO-py · 2EtOH)Cl₃], cis-[Pt(2CHO-py)₂Cl₂], trans-[Pd(2CHO-py)₂Cl₂], trans-[Pt(dmso)(2CHO-py)Cl₂], [Pt{C₅H₄N-(CH₂SMe)}Cl(2CHO-py)](ClO₄), [Pt(terpy)(2CHOpy)](ClO₄)₂, [Pt(terpy)(2CHO-py · H₂O)](ClO₄)₂ (terpy = 2,2′:6′,2′′-terpyridine). ¹H-n.m.r. experiments show that the addition of the protic molecule(s) to the Pt^II and Pd^II complexes is reversible. The effects of the nature of the metal ion and the ancillary ligands as well as of the total charge of the complexes on the relative stability of the addition products are discussed. This revised version was published online in June 2006 with corrections to the Cover Date.     

Preparation and characterization of some mixed ligand complexes of platinum(II)

The mixed ligand complexes PtX₂(ER₃)L and PtXY(ER₃)L (where ER₃ = PR₃ or AsMe₃; L = phosphine, arsine; X = Cl; Y = Cl, H or Me) have been prepared and characterized. Reaction of PtMe₂(ER₃)L with HCl yields PtMeCl(ER₃)L, in exclusively one of three possible isomeric forms. Excess tetramethyltin reacts with Pt₂Cl₂(μ-Cl)₂(PMe₂Ph)₂ giving both cis and trans Pt₂(μ-Cl)₂(PMe₂Ph)₂, as identified from the NMR spectra. Cleavage of Pt₂(μ-Cl)₂Me₂(PMe₂Ph)₂ with donor ligands such as AsPh₃, PMe₂ or pyridine, was useful as a synthetic route to the unsymmetrical methylchloro Pt^II derivatives. The reaction of cis-[PtMe₂(PPh₃)(AsPh₃)] with excess dimethylacetylenedicarboxylate (DMA) yielded only one product, which was of the formula trans-[Pt{C(COOCH₃)C(COOCH₃)CH₃}₂(PPh₃)(AsPh₃)], with the alkenyl groups having the same geometry about the CC bond. The use of diethylacetylene-dicarboxylate (DEA) rather than DMA gave a similar product. However, when cis-[PtMe₂(PEt₃)(AsPh₃)] was allowed to react with DMA, two products of the formula trans-[Pt{C(COOCH₃)C(COOCH₃)CH₃}₂(PEt₃)(AsPh₃)] were obtained, with the stereochemistry of both alkenyl groups being either cis or trans.     

Ligandverhalten von P‐funktionellen Organozinnhalogeniden: Nickel(II)‐, Palladium(II)‐ und Platin(II)‐halogenid‐Komplexe mit Me2(Cl)SnCH2CH2PPh2

Ligand Behaviour of P‐functional Organotin Halides: Nickel(II), Palladium(II), and Platinum(II) Complexes with Me₂(Cl)SnCH₂CH₂PPh₂ Me₂(Cl)SnCH₂CH₂PPh₂ ( 1 ) reacts with Ni^II, Pd^II, and Pt^II halides in molar ratio 2 : 1 forming the complexes [MX₂{PPh₂CH₂CH₂Sn(Cl)Me₂}₂] (M = Ni, Pd, Pt; X = Cl, Br) ( 3 – 6 , 9 , 10 ) ( 7 , 8 : M = Ni; Br instead of Cl). The nickel complexes were isolated and characterized both as the planar ( 3 , 5 , 7 ) and the tetrahedral ( 4 , 6 , 8 ) isomer. Crystal structure analyses and NMR data indicate for the planar nickel complexes 3 , 5 , 7 and [MCl₂{PPh₂CH₂CH₂Sn(Cl)Me₂}₂] ( 9 : M = Pd; 10 : M = Pt) the existence of intra and intermolecular M–Hal…Sn bridges. In a ligand : metal molar ratio of 3 : 1 the complexes [M^éCl{PPh₂CH₂CH₂Sn^⊖Cl₂Me₂}{PPh₂CH₂CH₂Sn(Cl)Me₂}₂] ( 11 : M = Pd; 12 : M = Pt) are formed which represent intramolecular ion pairs. By dehalogenation of [PdCl₂{PPh₂CH₂CH₂Sn(Cl)Me₂}₂] ( 9 ) with sodium amalgam and graphite potassium (C₈K), respectively, the palladacycles cis‐[Pd{PPh₂CH₂CH₂SnMe₂}₂] ( 13 ) and trans‐[Pd(Cl)PPh₂CH₂CH₂SnMe₂{PPh₂CH₂CH₂Sn(Cl)Me₂}] ( 14 ) are formed. From the compounds 1 , 3 , 9 , 11 , and 12 the crystal structures are determined. All compounds are characterized by ¹H, ³¹P, and ¹¹⁹Sn NMR spectroscopy.     

Magnetic Relaxation Studies on Trigonal Bipyramidal Cobalt(II) Complexes

We report the preparation and the full characterization of a novel mononuclear trigonal bipyramidal Co^II complex [Co(NS₃^iPr)Br](BPh₄) ( 1 ) with the tetradentate sulfur‐containing ligand NS₃^iPr (N(CH₂CH₂SCH(CH₃)₂)₃). The comparison of its magnetic behaviour with those of two previously reported compounds [Co(NS₃^iPr)Cl](BPh₄) ( 2 ) and [Co(NS₃^tBu)Br](ClO₄) ( 3 ) (NS₃^tBu=N(CH₂CH₂SC(CH₃)₃)₃) with similar structures shows that 1 displays a single‐molecule magnet behaviour with the longest magnetic relaxation time (0.051 s) at T=1.8 K, which is almost thirty times larger than that of 3 (0.0019 s) and more than three times larger than that of 2 (0.015 s), though its effective energy barrier (26 cm^?1) is smaller. Compound 1 , which contains two crystallographically independent molecules, presents smaller rhombic parameters (E=1.45 and 0.59 cm^?1) than 2 (E=2.05 and 1.02 cm^?1) and 3 (E=2.00 and 0.80 cm^?1) obtained from theoretical calculations. Compounds 2 and 3 have almost the same axial (D) and rhombic (E) parameter values, but present a large difference of their effective energy barrier and magnetic relaxation which may be attributed to the larger volume of BPh₄^? than ClO₄^? leading to larger diamagnetic dilution (weaker magnetic dipolar interaction) for 2 than for 3 . The combination of these factors leads to a much slower magnetic relaxation for 1 than for the two other compounds.     

The use of chloroalkyldichloroarsines in hybrid ligand synthesis. The preparation of but-3-enylbis(3-dimethylarsinopropyl)arsine and 3-dimethylarsinopropylbis(but-3-enyl)arsine,and their reaction with nickel(II) salts to form pentacoordinate complexes. Novel nickel(II)—olefin bonds

Routes have been developed to the hitherto unobtainable arsine-olefin ligands (CH₂CHCH₂CH₂)_nAs(CH₂CH₂CH₂AsMe₂)_3-n (n = 1, tasol, but-3-enylbis(3-dimethylarsinopropyl)arsine; n = 2, dasdol, 3-dimethylarsinopropylbis(but-3-enyl)arsine) by making use of the difference in reactivity between the ClC and AsCl bonds in the precursor Cl(CH₂)_mAsCl₂ (m = 2,3) molecules. Thus, the triarsine obtained by reaction of 2-chloroethyldichloroarsine with the Grignard reagent of 3-chloropropyldimethylarsine yields 2-chloroethylbis(3-dimethylarsinopropyl)arsine, from which tasol is obtainable by subsequent reaction with either the Grignard reagent of vinyl bromide or, preferably, with vinyllithium. Similarly, 3-chloropropyldichloroarsine reacts with the Grignard reagent of 4-chlorobut-1-ene to form 3-chloropropylbis(but-3-enyl)arsine which, on reaction with sodium dimethylarsenide yields dasdol. The tasol ligand reacts with nickel(II) salts to form [NiX(tasol)]⁺ (X = Cl, Br) and [NiI₂(tasol)], the former are trigonal bipyramidal and contain a nickel(II)—olefin bond, and the latter are square pyramidal containing a [NiI₂As₃] coordination sphere. In addition, tasol forms a number of polynuclear complexes with nickel(II). The dasdol ligand acts as a bidentate arsine to form only [NiX(dasdol)₂)]⁺ The formation of novel nickel(II)—olefin bonds in the [NiX(tasol)]⁺ cations is discussed.     

Nickel(II)-dppa-arylazoimidazole complexes: Synthesis and detailed spectroscopic study

The reaction of [Ni(dppa)(Cl)₂] or [Ni(dppa)(Br)₂] with AgOTf gives [Ni(dppa)(OTf)₂], which then form [Ni(dppa)(RaaiR)](OSO₂CF₃)₂ under the action of arylazoimidazole(RaaiR) in a dichloromethane medium [RaaiR′ = p-R-C₆H₄-N=N-C₃H₂-NN-1-R′, (I–III), abbreviated as N,N′-chelating agent, where N(imidazole) and N(azo) represent N and N’, respectively; R = H (a), Me (b), Cl (c) and R′ = Me (I), CH₂CH₃ (II), CH₂Ph (III), OSO₂CF₃ is the triflate anion]. The ¹H NMR spectral measurements suggest that a bound azoimine is responsible for a number of signals of phenyl protons in the aromatic region. The molecules of the complexes contain a number of different carbon atoms which gives a number of different peaks in the ¹³C (¹H) NMR spectrum. The text was submitted by the author in English. The text was submitted by the author in English.     

Cobalt(II), nickel(II), copper(II), zinc(II) and uranyl(VI) complexes of acetylacetone bis(4-phenylthiosemicarbazone)

Summary Reaction of one mole of acetylacetone with two moles of 4-phenylthiosemicarbazide yields the unusual Schiff base, MeC(=N-NHCSNHPh)CH₂C(=NNHCSNHPh)Me. APT = H₂L) acetylacetone bis(4-phenylthiosemicarbazone). The complexes of Co^II, Ni^II, Cu^II, Zn^II and U^VIO₂ have been prepared and characterized by analytical, i.r., electronic spectral and magnetic measurements. The Co^II, Ni^II and Cu^II complexes have been assigned square-planar stereochemistry on the basis of magnetic and spectroscopic studies. The ligand is a neutral or dibasic quadridentate SNNS donor as revealed by i.r. spectral studies.     

Osmium(II)-Phthalocyanine: Darstellung und Eigenschaften von Di(acido)phthalocyaninatoosmaten(II)

Osmium(II) Phthalocyanines: Preparation and Properties of Di(acido)phthalocyaninatoosmates(II) “H[Os(X)₂Pc^2?]” (X = Br, Cl) reacts in basic medium or in the melt with (ⁿBu₄N)X forming less stable, diamagnetic, darkgreen (ⁿBu₄N)₂[Os(X)₂Pc^2?]. Similar dicyano and diimidazolido(Im) complexes are formed by the reaction of “H[Os(Cl)₂Pc^2?]” with excess ligand in the presence of [BH₄]^?. The cyclic voltammograms show up to three quasireversible redoxprocesses: E_1/2(I) = 0.13 V (X = CN), ?0.03 V (Im), ?0.13 V (Br) resp. ?0.18 V (Cl) is metal directed (Os^II/III), E_1/2(II) = 0.69 V (Cl), 0.71 V (Br), 0.83 V (CN), 1.02 V (Im) is ligand directed (Pc^2?/?) and E_1/2(III) = 1.17 V (Cl) resp. 1.23 V (Br) is again metal directed (Os^III/IV). Between the typical “B” (～16.2 kK) and “Q” (～29.4 kK), “N regions” (～34.1 kK) up to seven strong “extra bands” of the phthalocyanine dianion (Pc^2?) are observed in the uv-vis spectrum. Within the row CN > Im > Br > Cl, most of the bands are shifted slightly, the “extra bands” considerably more to lower energy in correlation with E_1/2(I). The vibrational spectra are typical for the Pc^2? ligand with D_4h symmetry. M.i.r. bands at 514, 909, 1 173 and 1 331 cm^?1 are specific for hexa-coordinated low spin Os^II phthalocyanines. In the resonance Raman (r.r.) spectra polarized, depolarized or anomalously polarized deformation and stretching vibrations of the Pc^2? ligand will be selectively enhanced, if the excitation frequency coincides with “extra bands”. With excitation at ～19.5 kK the intensity of the symmetrical Os? X stretching vibration at 295 cm^?1 (X = Cl), 252 cm^?1 (X = Im) and 181 cm^?1 (X = Br) is r.r. enhanced, too. The asymmetrical Os? X stretching vibration is observed in the f.i.r. spectrum at 345 cm^?1 (X = CN), 274 cm^?1 (X = Cl), 261 cm^?1 (X = Im) and 200 cm^?1 (X = Br).     

Formation and crystal structures of [(alkoxy)bis(pyridin-2-yl)methanolato-N,O,N]tin(IV) complexes

Reactions of bis(pyridin-2-yl)ketone with tin tetrahalides, SnX₄ (X = Cl or Br), or organotin trichlorides, R^′SnCl₃ (R^′ = Ph, Bu or CH₂CH₂CO₂Me), in ROH (R = Me or Et) readily produces RObis(pyridin-2-yl)methanolato)tin complexes, [5: RO(py)₂C(OSnX₃)] (5: R,X = Me,Cl; Et,Cl; Et,Br) or [6: MeO(py)₂C(OSnCl₂R^′)] (R^′ = Ph, Bu, CH₂CH₂CO₂Me). In addition, halide exchange reaction between SnI₄ and (5: R,X = Me,Cl) occurred to give (5: R,X = Me,I). The crystal structures of six tin(IV) derivatives indicated, in all cases, a monoanionic tridentate ligand, [RO(py)₂C(O⁻)-N,O,N], arranged in a fac manner about a distorted octahedral tin atom. The Sn–O and Sn–N bonds lengths do not show much variation amongst the six complexes despite the differences in the other ligands at tin.     

Ligating properties oftert-phosphine/arsine sulphides or selenides,Part IX. Preparation and spectroscopic studies of copper(I)/copper(II) complexes with bis(—phosphine chalcogenides)

Summary The analytical, molar conductance and spectroscopic studies of new complexes of copper(I) and copper(II) with bis(—phosphine chalcogenides), Ph₂P(E)(CH₂)_n-P(E)Ph₂(L-L) are reported. The complexes are of the types: (a) [CuX(L-L)](X, n, E: Cl, 2–4, Br, 2, S; Cl, Br, 1, Se); (b) [Cu₂X₂(L-L)] (X, n, E: Cl, Br, 2, 3, Se) and (c) [CuCl₂(L-L)] (n, E: 2, 3, S). Possible structures have been derived.     

1,3-diaryltriazenido complexes of ruthenium(I), (II) and (III), and of osmium(III), rhodium(III) and iridium(III)

The synthesis and characterization of the platinum metal—1,3-diaryltriazenido complexes [Ru(ArNNNAr)(CO)₃]₂, [Ru(ArNNNAr)₂]₂, cis-Ru(ArNNNAr)₂(CO)₂, MX₂(ArNNNAr)(PPh₃)₂ (M = Ru, Os; X = Cl, Br) and M′(ArNNNAr)₃ (M′= Ru, Os, Rh and Ir) are reported. Axial ligand substitution in [Ru(ArNNNAr)(CO)₃]₂ and adduct formation by [Ru(ArNNNAr)₂]₂ are described. In contrast to other known Ru(II)/Ru(II) “lantern” molecules, the species [Ru(ArNNNAr)₂]₂ have measured magnetic moments equivalent to ca one unpaired electron per dimer, which are presumably due to population of the spin states σ²π⁴δ²π^*4 and σ²π⁴δ²π^*3σ^*1.     

Ruthenium(II)-Phthalocyanine: Darstellung und Eigenschaften von Di(halogeno)phthalocyaninatoruthenat(II)

Ruthenium(II) Phthalocyanines: Preparation and Properties of Di(halo)phthalocyaninatoruthenate(II) [Ru(Py)₂Pc^2?] reacts with molten (ⁿBu₄N)X forming stable, green (ⁿBu₄N)₂[Ru(X)₂Pc^2?] (X = Cl, Br). The cyclovoltammogram shows a quasireversible redoxprocess for the metal oxidation at E_1/2(I) = ?0.02 V (X = Cl) resp. 0.05 V (X = Br) and for the first ringoxidation at E_1/2(II) = 0.70 V. The typical π-π*-transitions (B < Q < N) of the phthalocyanine dianion (Pc^2?) are observed in the uv-vis spectrum. With respect to Ru^III phthalocyanines B is shifted significantly to higher, Q, N to lower energy. The strong extra-band at 24.2 kK is diagnostic for these Ru^II phthalocyanines. The vibrational spectra are typical for the Pc^2? ligand with D_4h symmetry, too, and bands at 513, 909, 1 171 und 1 329 cm^?1 in the m.i.r. spectrum are specific for hexa-coordinated low spin Ru^II. In the Raman spectrum with excitation at ～480 nm the intensity of the totally symmetrical Ru? X stretching vibration at 266 cm^?1 (X = Cl) resp. 168 cm^?1 (X = Br) together with a progression of up to three overtones is selectively resonance Raman enhanced. The asymmetrical Ru? X stretching vibration is observed in the f.i.r. spectrum at 272 cm^?1 (X = Cl) resp. 215 cm^?1 (X = Br).     

Photochemistry of some alkoxycarbonylplatinum(II) complexes

Alkoxycarbonylplatinum(II) complexes trans-Pt(CO₂CH₂R)Cl(PPh₃)₂, where R = H, Me and Ph, were synthesized in two steps and were characterized by infrared and ultraviolet absorption, proton and phosphorus-31 nuclear magnetic resonance, and mass spectral techniques, and by elemental analysis. Irradiation of the complexes in the solid state or in fluid solution with 254 nm light causes a steady decrease in the intensities of the infrared absorptions in the 1650 and 1070 cm^?1 regions, which is interpreted as signifying labilization of the alkoxycarbonyl ligand. In dichloromethane solution, irradiation causes dissociation of the alkoxycarbonyl ligand, which then decomposes into carbon monoxide and an alkoxide ion. The carbon monoxide is thought to re-coordinate to afford the stable product trans-PtCl(CO)(PPh₃)₂⁺. In the presence of oxygen, triphenylphosphine which dissociates from the metal, is photooxidized to form triphenylphosphine oxide in a parallel photoreaction. Disappearance quantum yields for the alkoxycarbonyl complexes are quite small, Φ ～ 10^?4?10^?3 mol/einstein, and follow the trend H > Me > Ph.     

Mixed ligand complexes of platinum(0) containing diphosphines

The reaction of PtCl₂L (L = diphosphine) with the appropriate diphosphine L′ in ethanol followed by reduction with aqueous sodium borohydride leads to either disproportionation to give mixtures of the bis(diphosphine) complexes PtL₂ and PtL′₂ or to the formation of the mixed ligand complex PtLL′ depending on the diphosphines. Mixed ligand complexes are obtained when L=Ph₂P(CH₂)₂PPh₂, L′ = Ph₂P(CH₂PPh₂cis-Ph₂PCH CHPPh₂, Ph₂P(CH₂)₂AsPh₂, Ph₂- P(CH₂)₄PPh₂, o-Ph₂PC₆H₄PPh₂; and L=(C₆H₁₁)₂P(CH₂₂P(C₆H₁₁)₂, L′= Ph₂P(CH₂)PPh₂, Ph₂P(CH₂)₂PPh₂cis-Ph₂PCHCHPPh₂, (2S,3S)-Ph₂PCH- (CH₃)CH(CH₃)PPh₂, (R)-Ph₂PCH(CH₃)CH₂PPh₂. When L=Ph₂P(CH₂)₄PPh₂ L′= Ph₂P(CH₂₃PPh₂ or cis-Ph₂PCHCHRPh₂ the mixed ligand complexes are obtained but extensive disproportionation also occurs.