195Pt, 119Sn and 31P NMR studies of alkyl,aryl and acyl trichlorostannate complexes of platinum(II). The crystal structure of trans-[Pt(SnCl3)(COC6H5)(PEt3)2]

¹⁹⁵Pt, ¹¹⁹Sn and ³¹P NMR characteristics of the complexes trans-[Pt(SnCl₃)(carbon ligand)(PEt₃)₂] (1a-1e) are reported, (carbon ligand = CH₃ (1a), CH₂Ph (1b), COPh (1c), C₆Cl₅ (1d), C₆Cl₄Y (e); Y = meta- and para-NO₂, CF₃, Br, H, CH₃, OCH₃, or Pt(SnCl₃)(PEt₃)₂. The values of ¹J(¹⁹⁵Pt, ¹¹⁹Sn) vary from 2376 to 11895 Hz with the COPh ligand having the smallest and the C₆Cl₅ ligand the largest value, making a total range for this coupling constant, when the dimer syn-trans-[PtCl(SnCl₃)(PEt₃)]₂ is included, of ca. 33000 Hz. In the meta- and para-substituted phenyl complexes ¹J(¹⁹⁵Pt, ¹¹⁹Sn) (a) is greater for electron-withdrawing substituents, (b) varies more for the meta-substituted derivatives (5634 to 7906 Hz) than for the para analogues (6088 to 7644 Hz) and (c) has the lowest values when the Pt(SnCl₃)(PEt₃)₂ group is the meta- or para-substituent. The direction of the change in ¹J(¹⁹⁵Pt, ¹¹⁹Sn) is opposite to that found for ¹J(¹⁹⁵Pt, ¹¹⁹P). For the aryl complexes linear correlations are observed between δ(¹¹⁹Sn), ¹J(¹⁹⁵Pt, ¹¹⁹Sn), ¹J(¹⁹⁵Pt, ³¹P), ¹J(¹¹⁹Sn, ³¹P) and the Hammett substituent constant σⁿ. δ(¹¹⁹Sn) and ¹J(¹⁹⁵Pt, ¹¹⁹Sn) are related linearly to v(Pt-H) in the complexes trans-[PtH(C₆H₄Y)(PEt₃)₂]; δ(¹¹⁹Sn) and δ(¹H) (hydride) are also linearly related. Based on ¹J(¹⁹⁵Pt, ¹¹⁹Sn), the acyl ligand is suggested to have a very large NMR trans influence. The differences in the NMR parameters for (1a-e) are rationalized in terms of differing σ- and π-bonding abilities of the carbon ligands.The structure of 1c has been determined by crystallographic methods. The complex has a slightly distorted square planar geometry with trans-PEt₃ ligands. Relevant bond lengths (Å) and bond angles (°) are: PtSn, 2.634(1), PtP, 2.324(4) and 2.329(4), PtC, 2.05(1); PPtP, 170.7(6), SnPtC, 173.0(3), SnPtP, 92.1(1), 91.7(1), PPtC, 88.8(4) and 88.3(4). The PtSn bond separation is the longest yet observed for square-planar platinum trichlorostannate complexes, and would be consistent with a large crystallographic trans influence of the benzoyl ligand. The PtSn bond separation is shown to correlate with ¹J(¹⁹⁵Pt, ¹¹⁹Sn).     

31P-, 119Sn- and 195Pt-NMR. Studies of Trichlorostannate Complexes of Pt(II) and Pd(II). 2J(119Sn, 117Sn)-Values

The synthesis and solution structures of new four- and five-coordinate phosphine and arsine complexes of Pt and Pd containing the trichlorostannate ligand are described. Complexes containing two and three SnCl^?₃-ligands have been identified from their ³¹P-, ¹¹⁹Sn- and ¹⁹⁵Pt-NMR. spectra. The complexes trans-[M (SnCl₃)₂L₂] (M = Pt, L-PEt₃, PPr₃, AsEt₃; M = Pd, L = AsEt₃) show unexpectedly large ²J(¹¹⁹Sn, ¹¹⁷Sn)-values (34,674–37,164 Hz) with the trans-orientation of these spins playing an important role. The heteronuclear coupling constant ²J(¹¹⁹Sn, ³¹P) in the five-coordinate cationic complexes [Pt(SnCl₃)(P(o-AsPh₂? C₆H₄)₃)]⁺ and [Pt(SnCl₃)(As(o-PPh₂? C₆H₄)₃)]⁺ also shows a geometric dependence. New five-coordinate anionic complexes of type [M (SnCl₃)₃L₂]^? (M = Pd, Pt; L = PEt₃, AsEt₃) may be prepared via addition of three mol-equiv. of SnCl₂ and one mol-equiv. of (PPN)Cl to [MCl₂L₂] in acetone.     

119Sn- and 31P-NMR. Spectroscopy of the 5-coordinate complexes [Rh (SnClnBr(3−n)) (norbornadiene) (tertiary phosphine)2]

The products of the reaction of [RhCl (NBD)]₂ (NBD = norbornadiene), with four equivalents tertiary phosphine and two equivalents of tin (II) bromide have been studied by ¹¹⁹Sn- and ³¹P-NMR. spectroscopy. The solution data suggest that halogen scrambling occurs during the preparation and results in a mixture of complexes containing SnBr₃, SnClBr₂, and SnCl₂Br and SnCl₃ ligands, and this is confirmed by independent synthesis of the SnCl₃ and SnBr₃ complexes. The metalmetal coupling constants, ¹J (¹¹⁹Sn, ¹⁰³Rh), vary from 452 to 580 Hz and are linearly related to: (a) δ(¹¹⁹Sn) in the complexes [Rh (SnCl_nBr_(3-n))NBD (PEtPh₂)₂] and (b) the sum of the Pauling electronegativities for the halogens on tin.     

The preparation and 119Sn and 19F NMR spectra of some trifluoromethylphenyltin(IV) compounds

The preparation of a series of new trifluoromethylphenyltin(IV) compounds, Bu_nSn(C₆H₄CF₃-3)_4-n, (C₆H₄CF₃-3)SnCl₃, (C₆H₄CF₃-2)SnCl₃, and some related adducts with 2,2¹-bipyridyl and 1,10-phenanthroline, is described. ¹¹⁹Sn and ¹⁹F chemical shifts have been determined, together with values of J(¹¹⁹Sn=F) and ³J(¹¹⁹Sn=H_itortho), and the possibility of a “through space” tinfluorine coupling mechanism is also discussed.     

Double deoxygenation of PPN(NO2) using metal carbonyl clusters of cobalt,rhodium, and iridium

The reaction of PP(NO₂) with M₄(CO)₁₂ (M = Co, Rh) gives the nitrido clusters [M₆N(CO)₁₅]^? in 13 and 21% yields, respectively. A high yield synthesis (77%) of [Rh₆N(CO)₁₅)]^? directly from Rh₆(CO)₁₆ and PPN(NO₂) is also presented. PPN(NO₂) reacts with Ir₄(CO)₁₂ to give the new isocyanato cluster, [Ir₄(NCO)(CO)₁₁]^? in 34% yield, while the direct synthesis of this isocyanate product occurs in 77% yield from PPN(N₃) and Ir₄(CO)₁₂. Modifications of published procedures for the preparation of [N(C₂H₅)₄]₂ [Ir₆(CO)₁₅] and Ir₆(CO)₁₆ are reported that allow shorter reaction times and give higher yields. The reaction of Ir₆(CO)₁₆ with one equivalent of PPN(NO₂) generates a new cluster, PPN[Ir₆(CO)₁₅(NO)], in 57% yield which is proposed to contain a bent nitrosyl ligand. An additional equivalent of PPN(NO₂) gives (PPN)₂[Ir₆(CO)₁₅] in 84% yield with the evolution of N₂O as well as CO₂.     

Über polystannane: II. I(t-Bu2Sn)4I,ein 1,4-difunktionelles tetrastannan

The compound I(t-Bu₂Sn)₄I has been synthesized by controlled cleavage of the related cyclotetrastannane (t-Bu₂Sn)₄ with iodine in toluene. Both compounds have been investigated by mass, NMR and vibrational spectra. I(t-Bu₂Sn)₄I: δ(¹¹⁹Sn_terminal) 67.7, δ(Sn_central) 17.4 ppm; ¹J(SnSn) 2199 (terminal-central) and 1575 (central-central), ²J(SnSn) 20 (terminal-central), ³J (SnSn) 307 Hz (terminal-terminal); ν(SnSn) 119, ν(SnI) 167 cm^?1. (t-Bu₂Sn)₄: δ(Sn) 87.4 ppm; ν(SnSn) 125 cm^?1. The crystal structure of I(t-Bu₂Sn)₄I has been determined (R = 0.071): bond lengths SnSn 289.5(1) (terminal-central) and 292.4(1) (central-central), SnI 275.3(1) pm. The conformation of the chain ISn₄I is all trans.     

Oxidative addition reactions of [Pt(CN)4]2−; A 13C and 195Pt NMR study

¹³C and ¹⁹⁵Pt NMR measurements show that complexes of the type trans-[Pt(CN)₄X₂]^2? are formed on addition of X₂ (X = Br, Cl, I) to M₂[Pt(CN)₄] (M = K or NBu₄) in aqueous and chloroform solution respectively. Addition of ICN to K₂[Pt(CN)₄] (60% ¹³CN^?) in aqueous solution results in the formation of potassium pentacyanoiodoplatinate(IV) with complete¹³CN^?/¹²CN^?scrambling. The reaction of equi-molar amounts of trans-[PtX₂(CN)₄]^2? (X = Br and Cl), which was previously claimed to result in complete transformation into trans-[PtBrCl(CN)₄]^2?, is instead shown to result in an approximately statistical redistribution of halogens. A progressive shift of δ_Pt to high field is observed on successive replacement of ¹²CN^? by ¹³CN^? in [Pt(CN)₄]^2?.     

13C- und 199Sn-NMR untersuchungen an alkinylstannanen

Chemical shifts δ(¹³C), δ(¹¹⁹Sn) and coupling constants J(¹¹⁹Sn¹³C) for alkynylstannanes of the type R_4-nSn(CCR′)_n (n = 1–4) are reported. The values of ¹J(¹¹⁹Sn¹³C) and ²J(¹¹⁹SnC¹³C) depend upon the nature of the substituent R′. ¹J(¹¹⁹Sn¹³C) in Sn(CCCH₃)₄ is 1168 Hz, much larger than a value predicted in the literature of ca. 700 Hz. The comparison of δ(¹¹⁹Sn) for (CH₃)₂Sn(CCR′)₂ and 1,1,4,4-tetramethyl-1-stannacyclohexadi-2,5-ene suggests that the δ(¹¹⁹Sn) of alkynylstannanes are determined only to a small extent by the diamagnetic anisotropic effect of the CC-triple bond.     

NMR (195Pt and 13C) contribution to the study of some Pt(II), Pt(IV) and mixed-valence thioamido complexes

The ¹⁹⁵Pt and ¹³C chemical shifts (δ_Pt and δ_c) are reported for platinum(II), platinum(IV) and class II mixed-valence complexes, with general formula [PtL₄]X₂, cis- and trans-PtL₂X₂, PtL₂X₄ and Pt₂L₄X₆ (where L may be thiourea, 2-imidazolidine-thione, tetrahydro 2-pyrimidinethione, thiocaprolactam, pyridine-2-thione and tetramethylthiourea, and X may be Cl or Br). The ¹⁹⁵Pt chemical shifts can be understood in view of ¹³C data in terms of variations of electronegativities and σ-donor abilities of ligands attached to platinum.     

Anionic and neutral rhodium(I) complexes containing trichlorostannato ligands

The complexes Et₄N[Rh(SnCl₃)₂(diolefin)(PR₃)] (diolefin = COD or NBD) have been isolated and their reactions studied. Reaction with arylic tertiary phosphines led to SnCl₃⁻ displacement and isolation of neutral pentacoordinated Rh(SnCl₃)(diolefin)(PR₃)₂ complexes. Reaction with carbon monoxide involved diolefin displacement when the diolefin was COD, thus giving Et₄N[Rh(SnCl₃)₂(CO)₂(PR₃)] compounds, but SnCl₃⁻ displacement when it was NBD, thus yielding Rh(SnCl₃)(CO)(NBD)(PR₃) complexes. The complexes [Rh(diolefin)Cl]₂ were found to react with triarylphosphines in the presence of SnCl₂ and with CO bubbling through the solution to give Rh(SnCl₃)(CO)(NBD)(PR₃) when the diolefin was NBD but Rh(Cl)(CO)(PR₃)₂ when the diolefin was COD.     

The hydrogenphosphate complex of (1,5-cyclooctadiene)iridium(I), {[Bu4N][(1,5-COD)Ir · HPO4]}n: synthesis, spectroscopic characterization, and ES-MS of a new, preferred precursor to HPO4 and Bu4N stabilized Ir(0)n nanoclusters

The synthesis and characterization of a previously unknown, rare organometallic-phosphate complex, {[Bu₄N][(1,5-COD)Ir · HPO₄]}_n (1), is described. Characterization of 1 was accomplished by elemental analysis, electrospray mass spectrometry (ES-MS), and ¹H and ¹³C NMR which established the symmetry of the product as at least C₂ or C_s. The ES-MS reveals an interesting, Ir(I) to Ir(III) oxidative process with intense peaks displaying the ¹⁹¹Ir/¹⁹³Ir isotopic distribution patterns expected for the fragments [(1,5-COD)Ir^III(HPO₄)₂]⁻, [(C₈H₁₁)₂(Ir^III)₂(PO₄)(HPO₄)(H₂O)]⁻, and [(C₈H₁₁)₂(Ir^III)₂(PO₄)(HPO₄)(H₂O)₂]⁻. These fragments, in turn, provide evidence for a structure with two HPO₄²⁻ groups attached to a single Ir, for example ring structures (of at least such C₂ or C_s symmetry) such as {[Bu₄N][(1,5-COD)Ir · HPO₄]}₂. Complex 1 is significant since it is known to be the preferred, compositionally precise precursor to the prototype example of a recently discovered class of novel, HPO₄²⁻ and Bu₄N⁺ stabilized nanoclusters, (Bu₄N)_2n²ⁿ⁺[Ir(0)_n · (HPO₄)_n]²ⁿ⁻. Such nanoclusters are being extended, via their analogous hydrogenphosphate-organometallic precursors (1,5-COD)M^{+ or 2+}/HPO₄²⁻ (M=Rh(I), Ru(II), Pt(II)) to their corresponding, catalytically active [M(0)_n · (HPO₄)_n]²ⁿ⁻ nanoclusters.     

Synthesis, spectroscopic characterization and in vitro antimicrobial activity of diorganotin(IV) dichloride adducts with [1,2,4]triazolo-[1,5-a]pyrimidine and 5,7-dimethyl-[1,2,4]triazolo-[1,5-a]pyrimidine

The heterocyclic ligands [1,2,4]triazolo-[1,5-a]pyrimidine (tp) and 5,7-dimethyl-[1,2,4]triazolo-[1,5-a]pyrimidine (dmtp), react with diorganotin dichlorides giving the addition compounds Me₂SnCl₂(tp)₂, Et₂SnCl₂(tp)₂, Me₂SnCl₂(dmtp)₂, Et₂SnCl₂(dmtp)₂, Bu₂SnCl₂(dmtp), Ph₂SnCl₂(dmtp). The organotin:ligand stoichiometry goes from 1:2 to 1:1 by increasing the steric hindrance of the organic groups bound to tin. The compounds have been characterized by means of infrared, ¹¹⁹Sn Mössbauer and ¹H AND ¹³C NMR spectroscopy.The ligands presumably coordinate to tin classically through the nitrogen atom at the position 3. The 1:1 complexes adopt trigonal bipyramidal structures, with the organic groups on the equatorial plane and the ligand in the apical position. All-trans octahedral structures are inferred for the 1:2 complexes, except for Et₂SnCl₂(tp)₂, characterized by a skew-trapezoidal structure.¹¹⁹Sn Mössbauer measurements, at room temperature, in concomitance with DFT calculations, performed on isomeric structures of R₂SnCl₂(tp)₂ (R = Me, Et), allowed us to conclude that the all-trans octahedral coordination induces self-assembly in the solid state, possibly accomplished through π-π stacking interactions among the planar ligands coordinated to the organotin(IV) compound, while the skew-trapezoidal structure attributed to Et₂SnCl₂(tp)₂, induces the formation of monomeric adducts in the solid state.In vitro antimicrobial tests showed that [n-Bu₂SnCl₂(dmtp)] has interesting properties as anti Gram-positive and antibiofilm agent.     

Tin(IV) and organotin(IV) derivatives of bis(pyrazolyl)acetate: Synthesis, spectroscopic characterization and behaviour in solution.: X-ray single crystal study of bis(pyrazol-1-yl)acetatotri-iodotin(IV) [SnI3(bdmpza)]

Novel heteroscorpionate-containing tin and organotin(IV) complexes, [SnR_nX_3 − n(L)], R = Me, Buⁿ, Ph, or cy; X = Cl, Br or I, n = 0, 1, 2 or 3; L = bis(pyrazol-1-yl)acetate (bpza) or bis(3,5-dimethylpyrazol-1-yl)acetate (bdmpza), have been synthesized and characterized by spectral (IR, ¹H, ¹³C and ¹¹⁹Sn NMR, ^119mSn Mössbauer) and analytical data. In [SnI₃(bdmpza)], the ligand is fac-N,N′,O-tridentate, the three iodine atoms thus also fac about the six-coordinate tin(IV) atom. Neutral bpzaH reacts with BuⁿSnCl₃, PhSnCl₃ and SnCl₄ in Et₂O in the absence of base, yielding 1:1 adducts [XSnCl₃(bpzaH)] (X = R or Cl).     

Stannylene complexes of manganese,iron, and platinum

A number of stannylene complexes with different M: Sn ratios were obtained using various metals and substituents at the tin atom. The structures of the complexes were examined. A reaction of CpMn(CO)₂THF with (Ph₄As)⁺(SnCl₃)^? gave the ionic complex [Ph₄As]⁺[CpMn(CO)₂SnCl₃]^? (I). The action of C₆F₅MgBr on the complex C₅H₅Mn(CO)(NO)SnCl₃ produced C₅H₅Mn(CO)(NO)Sn(C₆F₅)₃ (II). Replacement of the Cl ions in the complex [CpFe(CO)₂]₂SnCl₂ by phenylacetylenide groups gave rise to the neutral complex [CpFe(CO)₂]₂Sn(C≡CPh)₂ (III). A reaction of (Dppm)PtCl₂ (Dppm is 1,1-bis(diphenylphosphino)methane) with SnCl₂ · 2H₂O in the presence of diglyme yielded the ionic complex [η³-CH₃O(CH₂)₂O(CH₂)₂OCH₃)SnCl]⁺[(η ²-Dppm)Pt(SnCl₃)₃]^? (IV). Transmetalation in a reaction of [(Dppe)₂CoCl][SnCl₃] · PhBr (Dppe is 1,2-bis(diphenylphosphino)ethane) with (Dcpd)PtCl₂ (Dcpd is dicyclopentadiene) in the presence of SnCl₂ afforded the ionic complex [Pt(Dppe)₂]₃[Pt(SnCl₃)₅]₂ (V). Structures I–V were identified by X-ray diffraction. In these structures, the formally single bonds between the atoms of transition metals M (Mn, Fe, and Pt) and Main Group heavy elements (Sn and P) having vacant d orbitals are appreciably shortened. The M-Sn bond length in complexes II and III are virtually independent of the substituents at the tin atom and the Pt-Sn bond length in complexes IV and V is virtually independent of the Pt: Sn ratio.     

Novel bicyclic hexanuclear copper(I) aggregate: Structure and solid state P CPMAS NMR spectra of [(Cu3L3)2] and [Cu(PPh3)2L] complexes of N-(diisopropoxythiophosphinyl)-N′-phenylthiourea (HL)

A new complex of N-thiophosphorylthiourea PhNHC(S)NHP(S)(OiPr)₂ (HL) of formula [(Cu₃L₃)₂] has been synthesized and characterized by single crystal X-ray diffraction, FT-IR, ¹H, ³¹P NMR in solution and by ³¹P CPMAS NMR spectroscopy in the solid state. A comparison of the structure and the spectral parameters of [(Cu₃L₃)₂] with those of the mononuclear analogue [Cu(PPh₃)₂L] was performed. In the solid state the aggregate [(Cu₃L₃)₂] represents the first example of a spontaneous “side-by-side” association of two neutral cyclic [Cu₃L₃] moieties using two Cu-S-Cu bridges formed by the sulfur atoms of the PS-groups. The values of the ¹J(³¹P-^63,65Cu) and ²J(³¹P-³¹P) coupling constants of the [Cu(PPh₃)₂]⁺ moiety in the solid state spectra are reported.     

(η6-Arene)(η4-cycloocta-1,5-diene)ruthenium(0) complexes as homogeneous hydrogenation catalysts

Ru(η⁶-arene)(η⁴-COD) complexes (COD = cycloocta-1,5-diene) have been found to be catalytic precursors for the homogeneous hydrogenation of α-olefins and cycloolefins under mild conditions (room temperature, P(H₂) 1–20 atm).     

Four-coordinated palladium(II) and platinum(II) complexes containing the Lewis-acid {M(S2CNHR)(PR3′)} group combined with a variety of other ligands

A new series of four-coordinated Pd(II) and Pt(II) complexes in which the Lewis-acid (14-electron) {M(S₂CNHR)(PR₃′)} group is combined with a variety of other ligands (such as RHNCS₂^?, I^?, SCN^?, SnCl₂I^?) has been synthesised and studied. The structures of the new compounds are discussed in relation to their specroscopic, magnetic and thermal properties. In the case of [M(S₂CNHR)₂(PR₃′)] complexes both the spectroscopic data (IR, ¹H NMR, UV-Vis) and their thermal behaviour strongly suggest the coexistence of two kinds of gem-disulphide ligands, one acting as a bidentate ligand and the other one as a unidentate. Also it was confirmed that the chemical behaviour of the bis(N-alkyldithiocarbamato) complexes of Pd(II) and Pt(II) towards tertiary phosphines is similar to that of the isoelectronic xanthate complexes rathe than to the bis(N,N-dialkyldithiocarbamato) complexes.     

119Sn mössbauer,IR, 1H NMR spectroscopic and thermal decomposition studies on organotin(IV) adducts with glycylglycine

The complexes R₂SnCl₂·(H₂glygly), (H₂glygly = glycylglycine) (R = Me, Buⁿ, Octⁿ, Ph) and RSnCl₃·(H₂glygly)     

Synthesis,Raman and NMR spectroscopy of the trimetallic complexes [IrCl(SnCl3)(HgCl)(CO)(PR3)2]

Synthesis, Raman and NMR studies are presented for the new octahedral trimetallic complexes with composition [IrCl(SnCl₃)(HgCl)(CO)(PR₃)₂], R = p-XC₆H₄; X = H, CH₃O, F, Cl. Only the isomer containing the Cl₃SnIrHgCl fragment and trans phosphine ligands is observed. Force constants for the IrSn and IrHg bonds as well as ³¹P, ¹¹⁹Sn and ¹⁹⁹Hg NMR data are reported. The presence of a spin-spin coupling constant of more than 40,000 Hz between the ¹⁹⁹Hg and ¹¹⁹Sn atoms is shown to originate from a two-bond and not a one-bond interaction.     

Mixed Halide Tin(IV) Complexes with NN-dimethylformamide and dimethylsulfoxide

By oxidative-addition reactions of Br₂ and I₂ to SnCl₂ in the presence of NN-dimethylformamide (DMF) and dimethylsulphoxide (DMSO), the mixed halide complexes SnCl₂Br₂L₂ (L ? DMF, DMSO) and SnCl₂I₂(DMSO)₂ are obtained. The IR, Raman and ¹¹⁹Sn Mössbauer spectra suggest that the ligands coordinate in cis position through the oxygen atom, a C₁ symmetry being found for SnCl₂I₂(DMSO)₂. SnCl₂Br₂(DMSO)₂ crystallizes in the triclinic space group P1 with two molecules per unit cell. The lattice constants are a = 752.4, b = 1350.6, c = 820.3 pm, α = 89.60, β = 117.31 and γ = 90.83°. 2317 independent observed reflexions were used for refinement: R = 8.4%. The structure is disordered and our results are again consistent with a C₁ molecular symmetry. Mixtures of products were obtained by reaction of SnCl₂ with I₂ in the presence of DMF and by reaction of SnBr₂ with I₂ in the presence of DMSO.