Dithiophosphate Complexes Research Articles

Synthesis and characterization of some binuclear alkylene dithiophosphate complexes of bis(acetylacetonato)aluminium(III)-di-(μ-isopropoxo)di-isopropoxoaluminium(III) and sol-gel synthesis of nanosized θ-alumina

Reactions of bis(acetylacetonato)aluminum(III)-di-(μ–isopropoxo)-di-isopropoxoaluminum(III) (A) with a variety of alkylenedithiophosphoric acids in different molar ratio yield products of the type [(CH3COCHCOCH3)2Al(μ-OPri)2Al{S(S)P(O-G-O)n(OPri)2-n] (1-9) {where G = C(CH3)2C(CH3)2, n=1[1], n=2[2]; -CH2CH(C2H5), n=1[3], n=2[4]; CH2CH(CH3), n=1[5], n=2[6];C(CH3)2CH2CH(CH3), n=1[7]; CH(CH3)CH(CH3) n=1[8], n=2[9]}. Progress of the reactions was monitored by estimating liberated 2-propanol in benzene-2-propanol azeotrope by oxidimetric method. All pale coloured viscous products were soluble in common organic solvents and were characterized by elemental analyses, FT-IR and NMR (1H and 13C{1H} NMR) spectral studies. Molecular weight measurements in refluxing anhydrous benzene indicated binuclear nature of the complexes. 27Al NMR spectra of two of the derivatives, (1) and (2), suggested the presence of aluminium(III) atoms in different coordination states. 31P NMR spectra of the representative derivatives (1) and (2) exhibited only a single peak at 95.71 and 90.59 ppm, respectively suggesting tetra-coordination around phosphorus atom and a bidentate mode of chelation of the dithio ligand. Sol-gel transformation of Al(OPri)3 and [(CH3COCHCOCH3)2Al(μ-OPri)2Al(OPri)2] (A) followed by sintering at ~850°C yield alumina (a) and (b), respectively. The powder X-ray diffraction patterns, SEM images and FT-IR spectral studies of (a) and (b) indicated formation of nano-crystallites of θ -Al2O3 [PDF # 110517] in both the cases. The energy band gaps of 4.78 eV and 5.01 eV for (a) and (b), respectively were obtained from the absorption spectra.

Construction of a whole-cell biohybrid catalyst using a Cp*Rh(III)-dithiophosphate complex as a precursor of a metal cofactor

A whole-cell biohybrid catalyst where a (pentamethylcyclopentadienyl)rhodium(III) (Cp*Rh(III)) complex was covalently incorporated into the cavity of nitrobindin (NB), a β-barrel protein, was prepared on an E. coli cell surface to produce isoquinolines via C(sp2)–H bond activation. In this whole-cell biohybrid system, the Cp*Rh(III)-dithiophosphate complex with latent catalytic activity was utilized as a precursor of the metal cofactor. Strong chelation of the dithiophosphate ligands protects the rhodium complex from being deactivated by abundant nucleophiles in cellular environments during conjugation of the cofactor with the protein scaffold. The whole-cell biohybrid catalyst was then activated upon addition of Ag+ ion to dissociate the dithiophosphate ligands and promoted cycloaddition of acetophenone oxime with diphenylacetylene. Furthermore, the activity of the Cp*Rh(III)-linked whole-cell biohybrid catalyst was enhanced 2.1-fold by introducing glutamate residues at positions adjacent to the Cp*Rh(III) cofactor. These results indicate that the use of the Cp*Rh(III)-dithiophosphate complex with switchable activity from a “latent” form to an “active” form provides a new strategy for generating whole-cell biohybrid catalysts.

Coordinationversusspodium bonds in dinuclear Zn(ii) and Cd(ii) complexes with a dithiophosphate ligand

Two new d10-metal dithiophosphate complexes have been synthesized in purely aqueous media and characterized by elemental and spectral analyses. DFT calculations, QTAIM and NCI Plot index methods are preformed to differentiate the coordination and spodium bonds in the complexes.

Seed free high yield gold nanorods synthesis from single precursor gold(I) dithiophosphate complex

In this work, we demonstrate a simple, one pot and seed free synthetic route for the formation of gold nanorods (Au NRs) via thermal decomposition of gold(I) dithiophosphate {[Au2{S2P(OiPr)2}2]n,} 1 complex as a molecular precursor in presence of 4′‐amino‐biphenyl‐4‐carboxylic molecule. Here [Au2{S2P(OiPr)2}2]n, complex functioned as gold (Au) source and 4′‐amino‐biphenyl‐4‐carboxylic molecule stabilized gold (Au) nanorods (NRs) through the unidirectional coating of Au surface during its growth in the reaction medium.

Experimental and theoretical studies of acetatodi(methylcyano)bis(O,O′-dialkyl and alkylene dithiophosphate)gadolinium(III) novel adducts

Seven novel Gd(OAc)[S2P(OR)2]2·2CH3CN and Gd(OAc)[S2P(OR′)2]2·2CH3CN gadolinium complexes where R=Et, n-Pr, n-Bu and Ph and R′=CH2CMe2CH2, CH2CEt2CH2, and CMe2CMe2 were synthesized and characterized by elemental analyses, Molecular weight determinations, IR and UV Visible spectroscopy. Micro analytical data revealed a 1:2 metal–ligand (O,O′-dialkyl and alkylene dithiophosphate) molar ratio in all complexes. Geometries were fully optimized at the Semi Empirical Sparkle PM6 level of theory and geometrical structures and electronic properties of the complexes were evaluated. The optimized geometries were confirmed to be minima on the potential energy surfaces through frequency calculations. Linear and nonlinear static optical susceptibilities for all complexes were calculated at the same level of theory. The absorption spectra of the complexes have been established using ORCA2.9 package utilizing the predicted optimized wave functions. The polarizability invariants were, in general, well-correlated with the molecular volume and the number of carbon atoms within the alkyl moieties. The largest electric properties were exhibited by the phenyl dithiophosphate complex.

Spectroscopic and Thermogravimetric Characterization of Pb(II) Dinonyldithiophosphate: Removal of Pb(II) from Aqueous Solution

Dinonyldithiophosphoric acid (DNDTPA) was prepared by adding phosphorus pentasulfide to nonyl alcohol. The lead dinonyl dithiophosphate complex Pb(DNDTP) 2 was prepared by mixing a solution of lead(II) with a solution of DNDTPA in ethanol at room temperature. The recovered Pb(DNDTP) 2 was crystallized in ethanol, and fi ne colorless needles were obtained. The complex was characterised by elemental analysis and IR, UV–vis and atomic absorption spectroscopy. The thermal behavior of Pb(DNDTP) 2 was investigated by thermogravimetric analysis under a nitrogen atmosphere. Removal of Pb(II) from aqueous media by DNDTPA solutions was investigated. The optimum conditions for extraction, such as the organic solvent, pH of the aqueous phase, time of equilibration, concentration, and effect of anions, were investigated. It was found that DNDTPA is an effective substance for removing Pb(II) from aqueous solution.

Synthesis and Spectroscopic Characterization of Mononuclear Oxomolybdenum(IV)O,O′-Ditolyl Dithiophosphate Complexes and Their Adducts With 2,2′-Bipyridyl and 1,10-Phenanthroline

A series of mononuclear oxomolybdenum(IV) O,O′-ditolyldithiophosphate complexes, of the type MoO[S2P(OR)2]2 (R = o-,m-,p-C6H4Me), were synthesized by refluxing of the reaction mixture containing triphenylphosphine and binuclear oxomolybdenum(V)O,O′-ditolyldithiophosphate, Mo2O3[S2P(OR)2]4 (R = o-,m-,p-C6H4Me), in equimolar ratio in dichloromethane. The desired pink colored Mo(IV) complexes were separated out by dissolving in cold n-hexane. The equimolar adducts of mononuclear oxomolybdenum(IV) O,O′-ditolyldithiophosphates with heterocyclic amines, MoO[S2P(OR)2]2.L (R = o-,m-,p-C6H4Me; L = 2,2′-bipyridyl and 1,10-phenanthroline), have been prepared by reacting the corresponding oxomolybdenum(IV) complexes with an excess of 2,2′-bipyridyl and 1,10-phenanthroline in a 1,1 molar ratio. The complexes have been characterized by elemental analysis, IR, 1H. and 31P NMR spectroscopy. Based on these, a square pyramidal structure incorporating bidentate dithiophosphate moieties is suggested and a six-coordinated distorted octahedral structure for the entire base adducts complexes. It appears that oxomolybdenum(IV) is preferentially stabilized by sulfur donors.

Vanadium(III) dithiophosphate complex [V(S2P(O-iso-Pr)2)3]: synthesis and structure

The reaction of [VO(OPr)3] with (iso-PrO)2P(S)SH (Pr is n-propyl, and iso-Pr is isopropyl) followed by the treatment with hexamethyldisilthiane (Me3SiSSiMe3) affords the vanadium(III) dithiophosphate complex [V(S2P(O-iso-Pr)2)3]. The structure of the complex is determined by X-ray diffraction analysis (CIF file CCDC 986354).

Synthesis and semi-empirical sparkle PM6 study of substituted dithiophosphoric compounds of gadolinium(III)

Seven gadolinium(III) derivatives containing dialkyl and alkylene dithiophosphate chelating ligands [S2P(OR)2]3·2CH3CN (R = Et, n-Pr, n-Bu and Ph) and [S2POR′O]3·2CH3CN (R′ = CH2CMe2CH2, CH2CEt2CH2 and CMe2CMe2) have been synthesized. The metal complexes have been characterized by elemental analyzes, molecular weight determinations, IR, and UV–Visible spectroscopy. Microanalytical data revealed a 1 : 3 metal–ligand ratio in all complexes. Geometries were fully optimized at the semi-empirical sparkle PM6 level of theory using MOPAC2009 and geometrical structures and electronic properties of the complexes have been evaluated. The optimized geometries were confirmed to be minima on the potential energy surfaces through frequency calculations. Absorption spectra of the complexes have been calculated using ORCA2.9 package utilizing the predicted optimized wave functions. Linear and nonlinear static optical susceptibilities for all complexes were calculated at the same level of theory. The polarizability invariants were, in general, well correlated with the molecular volume and the number of carbons within the alkyl moieties. The largest electric properties were exhibited by the phenyl dithiophosphate complex.

The diethyl dithiophosphate complex of tetraphenylantimony(V) and its solvated form, [Sb(C6H5)4{S2P(OC2H5)2}] · 1/2 C6H6: Synthesis, crystal structure, and 13C, 31P CP/MAS NMR study. an example of monodentate coordination of dithio ligands

The O,O′-diethyl dithiophosphate complex of tetraphenylantimony(V) [Sb(C6H5)4{S2P(OC2H5)2}] (I) and its benzene-solvated form I · 1/2C6H6 (II) were synthesized and studied by high-resolution solid-state 13C and 31P NMR (MAS NMR). The diethyl dithiophosphate (Dtph) groups in I and II were quantitatively characterized by the 31P chemical shift anisotropy (δaniso), the asymmetry parameter (η), and the principal values of chemical shift tensors (δxx, δyy, δzz). The calculation of the anisotropy parameters included construction of χ2 statistic diagrams from full 31P MAS NMR spectra. In both complexes, the Dtph groups were found to have mainly axially symmetric 31P chemical shift tensors (for δzz < δxx ≈ δyy) with similar anisotropy parameters (δaniso and η), which is due to their identical S-monodentate function. According to X-ray diffraction data, II has a trigonal bipyramidal (TBP) molecular structure with Smonodentate coordination of Dtph in the TBP axial position and outer-sphere position of the benzene molecule. The desorption of the outer-sphere benzene solvent molecules from structure II, which was noted in MAS NMR experiment, passes through the formation of three intermediate solvated forms with benzene content n < 1/2.

Binding of Au3+ from solutions by nickel(II) and cadmium diisopropyl dithiophosphates: MAS 31P NMR, structure and thermal behavior of the polynuclear complex [Au2{S2P(O-iso-C3H7)2}2] n

The paper deals with reactions of freshly precipitated diisopropyl dithiophosphate (Dtph) complexes of nickel(II), [Ni{S2P(O-iso-C3H7)2}2] and cadmium, [Cd2{S2P(O-iso-C3H7)2}4], with the [AuCl4]− in 2M HCl, resulting in gold transition from the solution to the precipitate as polymeric gold(I) diisopropyl dithiophosphate. The reduction of gold(III) to gold(I) noted in both cases is due to oxidation of the relevant part of the Dtph group to bis(O,O′-di-(iso)-propoxythiophosphoryl) disulfide, (iso-C3H7O)2P(S)S-S(S)P(O-iso-C3H7)2. The polynuclear gold(I) complex [Au2{S2P(O-iso-C3H7)2}2] n (I) was isolated on a preparative scale from the chemisorption system and studied by MAS 31P NMR and X-ray diffraction. The key structural unit of I is the non-centrosymmetric binuclear molecule [Au2{S2P(O-iso-C3H7)2}2] in which the gold atoms are connected by two bridging Dtph groups. The structure contains two types of non-equivalent binuclear molecules related as conformational isomers. Owing to the relatively weak Au-Au contacts, the neighboring binuclear [Au2{S2P(O-iso-C3H7)2}2] molecules are involved in an infinite polymeric chain with conformer alternation along the chain. To elucidate the conditions for the recovery of bound gold(I), the precipitates formed in the sorption systems were studied by simultaneous thermal analysis under argon. As the final product, thermolysis gives reduced metallic gold. The ability of dithiophosphate complexes to bind gold from a solution is much lower than that of dithiocarbamate complexes, which is due to oxidation of some Dtph groups to disulfide.

Synthesis and characterization of 3-picoline adducts of bis(O,O′-ditolyl/dibenzyl/diphenyl dithiophosphato)cobalt(II) complexes: crystal structure of 3-picoline adducts Co{S2P(OC6H4Me-p)2}2(NC5H4Me-3)2

Bis(O,O′-ditolyl/dibenzyl/diphenyl dithiophosphato)cobalt(II) (1–5) with 3-picoline, Co{S2P(OR)2}2(NC5H4Me-3)2 (R = o-, m-, p-C6H4Me, CH2Ph, Ph) have been synthesized by in situ reaction of 3-picoline and CoCl2·6H2O in aqueous medium followed by the addition of aqueous solution of NH4S2P(OR)2. The single crystal structure of Co{S2P(OC6H4Me-p)2}2(NC5H4Me-3)2 shows that geometry around cobalt(II) is distorted octahedral with two 3-picoline molecules in trans positions. These Co(II) dithiophosphate complexes (1–5) have been characterized by elemental analyses, spectroscopic techniques (UV-Vis, IR), and magnetic moment measurements.

A 31P CP/MAS NMR study of PbS surface [formula omitted]-dialkyldithiophosphate lead(II) complexes

31P CP/MAS NMR spectroscopy was used to study the adsorption of six different O , O ′ -dialkyldithiophosphate ions on the surface of synthetic galena (PbS). The 31P CP/MAS NMR spectra of the surface lead(II) dithiophosphates were compared with the 31P CP/MAS NMR spectra of polycrystalline lead(II) dithiophosphate complexes of the same ligands. Surface complexation of the dialkyldithiophosphate ions was established on the surface of PbS. A terminal S , S ′ -chelating coordination is suggested for the surface complexes. The bulkier alkyl groups lead to surface precipitation in addition to the surface adsorption. Derivatives of monothiophosphoric and phosphoric acids were displayed as hydrolysis products of dialkyldithiophosphates on the synthetic PbS, the amount of which depends on the type of alkyl group.

Synthesis and characterization of binuclear oxomolybdenum(V) and dioxomolybdenum(VI) O, O′-ditolyl dithiophosphate complexes. : Crystal structures of Mo 2O 3[S 2P(OC 6H 4Me- o) 2] 4, Mo 2O 3[S 2P(OC 6H 4Me- m) 2] 4 and MoO 2[S 2P(OC 6H 4Me- p) 2] 2

A series of binuclear oxomolybdenum(V) O, O′-ditolyl dithiophosphate complexes, Mo 2O 3[S 2P(OR) 2] 4 (R = o-, m-, p-C 6H 4Me) were synthesized by drop wise addition of aqueous solution of the ammonium salt of O, O′-ditolyl dithiophosphoric acid into an acidic solution of sodium molybdate with constant stirring to yield purple solids. Dioxomolybdenum(VI) O, O′-ditolyl dithiophosphate complexes, MoO 2[S 2P(OR) 2] 2 (R = o-, m-, p-C 6H 4Me and CH 2C 6H 5) were also synthesized by reducing Mo 2O 3[S 2P(OR) 2] 4 with OPPh 3 in benzene to yield yellow solids. These complexes were characterized by elemental analysis and IR, 1H and 31P NMR spectroscopy and, in three cases, by X-ray crystallography. In Mo 2O 3[S 2P(OC 6H 4Me- o) 2] 4 and Mo 2O 3[S 2P(OC 6H 4Me- m) 2] 4, the environment around each molybdenum atom can be described as the expected distorted octahedral, consisting of one terminal and one bridging oxygen along with the four chelating sulfur atoms of the dithio ligands, with one Mo–S distance being significantly longer than the other three. In MoO 2[S 2P(OC 6H 4Me- p) 2] 2 the geometry around the Mo atom is again distorted octahedral with two cis terminal oxygen atoms and two anisobidentate dithiophosphate ligands.

Solid-state 31P CP/MAS and static 65Cu NMR characterization of polycrystalline copper(I) dialkyldithiophosphate clusters

Polycrystalline tetra-nuclear Cu4[S2P(O-i-C3H7)2]4, hexa-nuclear Cu6[S2P(OC2H5)2]6, and octa-nuclear Cu8[S2P(O-i-C4H9)2]6(S) complexes were synthesized and analyzed by means of solid-state 31P CP/MAS and 65Cu static NMR spectroscopy. The symmetries of the electronic environments around each P-site were estimated from the 31P chemical shift anisotropy (CSA) parameters, Deltaaniso and eta. The 65Cu chemical shift and quadrupolar splitting parameters obtained from the experimental 65Cu NMR spectra of the polycrystalline Cu(I)-complexes are presented. A solid-state NMR approach for the elucidation of the stereochemistry of poly-nuclear Cu(I) dithiophosphate complexes, when the structural analysis of the systems by single-crystal X-ray diffraction is not readily available, is proposed.

Extraction of arsenic as the diethyl dithiophosphate complex with supercritical fluid and quantitation by cathodic stripping voltammetry

The separation of arsenic based on in situ chelation with ammonium diethyl dithiophosphate (ADDTP) has been carried out using methanol-modified supercritical CO 2. Aliquots of extract were added to an electroanalytical cell and arsenic was determined by square wave cathodic stripping voltammetry (SWCSV) at a hanging mercury drop electrode (HMDE). Quantitative extractions of As(DDTP) 3 were achieved when the experiments were carried out at a pressure of 2500 psi, a temperature of 90 °C, 2.0 mL of methanol, 20.0 min of static extraction and 5.0 min of dynamic extraction in the presence of 18 mg of ADDTP. Analysis of arsenic was made using 150 mg L −1 of Cu(II) in 1 M HCl solution as supporting electrolyte in the presence of ADDTP as ligand. Preconcentration was carried out by deposition at a potential of −0.50 V and the intermetallic compound Cu x As y was reduced at a potential of −0.77 to −0.82 V, depending on ligand concentration. The results showed that the presence of ligand plays an important role, increasing the method's sensitivity and preventing the oxidation of As(III). The calibration graph of the As(DDTP) 3 solution was linear from 0.8 to 12.5 μg L −1 of arsenic (LOD 0.5 μg L −1, R = 0.9992, t acc = 60 s). The method was validated using carrot pulp spiked with arsenic solution. This method was applied to the determination of arsenic in samples of carrots, beets and irrigation water. Arsenic in beets was: skin 4.10 ± 0.18 mg kg −1; pulp 3.83 ± 0.19 mg kg −1 and juice 0.71 ± 0.09 mg L −1; arsenic in carrots was: skin 2.15 ± 0.09 mg kg −1; pulp 0.59 ± 0.11 mg kg −1 and juice 0.71 ± 0.03 mg L −1. Arsenic in water were: Chiu-Chiu 0.08 mg L −1, Inacaliri 1.12 mg L −1, and Salado river 0.17 ± 0.07 mg L −1.

Synthesis Properties and Characterization of Di Cyclopentadienyl Vanadium Bis Dialkyl and Alkylene Dithiophosphate Complexes

The reaction of dichloro bis cyclopentadienyl vanadium with O,O dialkyl and alkylene dithiophosphoric acids proceed in 1:2 molar ratio in refluxing benzene to yield di cyclopentadienyl vanadium bis O,O dialkyl and alkylene dithiophosphates, [Cp 2 V(S 2 P(OR) 2 ) 2 ], where R = Et, Pr i , Pr n , Bu i , Ph and [Cp 2 V (S 2 POGO) 2 ] where G = CMe 2 CMe 2 , CH 2 CEt 2 CH 2 , CH 2 CMe 2 CH 2 . These complexes are semi solids or solids soluble in common organic solvents. Elemental analysis, molecular weight determination, magnetic susceptibility, UV-vis spectrophotometer, IR, 1 H, 13 C, and 31 P NMR spectra indicate a hexa coordinated octahedral structure.

Synthesis and structure of [M3(µ3-Se)(µ-SeS)3]4+ core compounds (M = Mo, W): a less-common type of linkage isomerism for the µ-SSe ligand

The M3(μ3-Se)(μ-Se)34+ clusters (written also as M3Se44+) show a strong tendency to add sulfur to the μ-Se bridges giving new chalcogen-rich clusters with M3(μ3-Se)(μ-SeS)34+ cores i.e. Mo3Se4S34+. They are isolated as dithiophosphate complexes [M3(μ3-Se)(μ-SeS)3((RO)2PS2)3]Cl (1a, M = Mo, R = Et; 1b, R = i-Pr; 2a, M = W, R = Et, 2b, R = i-Pr) upon treatment of solutions of [M3Se4(H2O)9]4+ in 2 M HCl with a large excess of P4S10/ROH reagent. The structures of 1a and 2a have been determined by single crystal X-ray analysis. The sulfur atom forms a part of the μ-SeS ligand, which is asymmetrically coordinated to two metal atoms, so that the sulfurs are almost coplanar with the M3 triangle (equatorial positions) and the Se atoms are strongly out of the plane (axial positions). This represents a rare kind of linkage isomerism since the opposite bridging mode is observed for the SeS ligand in the clusters M3(μ3-S)(μ-SeS)34+ in which the Se is equatorial and the S occupies the axial positions. As an alternative the pure dithiophosphate salts KS2P(OR)2 (R = Et, i-Pr) do not lead to sulfur addition and allow isolation of [Mo3Se4((RO)2PS2)3(μ-CH3COO)(C5H5N)] (3) upon recrystallyzation from a CH3CN–CH3COOH–pyridine mixture. Both 3 and its sulfur analogue abstract sulfur from propylene sulfide at room temperature to give Mo3Se4S34+ and Mo3S74+ clusters, respectively.

Separation of uranium(VI) from Fe(II), Ni(II), Co(II) and Cu(II) by electrophoresis using diethyldithiophosphoric acid

Paper electrophoresis has been used for uranium(VI) separation from Fe(II), Co(II), Ni(II) and Cu(II). The background electrolyte (0.1M HNO3-NaNO3) at different pH values contains diethyldithiophosphoric acid as complexing agent. A plot of mobility versus pH is used to obtain information on the formation of dithiophosphate complexes and to compute the stability constant of an uranyldiethyldithiophosphate complex.

Synthesis, fluxional behavior and structures of diethyldithiophosphate molybdenum complexes: crystal structures of [Et 4N][Mo(CO) 4{η 2-S 2P(OEt) 2}] and [Mo(CH 3CN)(η 3-C 3H 5)(CO) 2{η 2-S 2P(OEt) 2}

The air-sensitive dithiophosphate complexes [Et 4N][M(CO) 4{η 2-S 2P(OEt) 2}] ( 1, M=Mo; 2, M=W) are accessible by the reaction of M(CO) 4(pip) 2 (pip=piperidine) (M=Mo, W) with NH 4S 2P(OEt) 2 in refluxing acetonitrile in the presence of Et 4NBr. Complex 1 reacts with allyl bromide in CH 3CN to give the complex [Mo(CH 3CN)(η 3-C 3H 5)(CO) 2{η 2-S 2P(OEt) 2}] ( 3). The single-crystal structures of complexes 1 and 3 have been determined by X-ray diffraction analyses. Crystal data for 1: space group, C2/ c with a=13.088(7), b=16.271(4), c=11.366(7) Å, β=93.88(5)°, V=2414.9(21) Å 3, Z=4. The structure was refined to R=0.031 and Rw=0.031; Crystal data for 3: space group, Pna2 1 with a=15.979(3), b=8.613(2), c=12.720(3) Å, V=1750.6(6) Å 3, Z=4. The structure was refined to R=0.026 and Rw=0.028. Treatment of 3 with piperidine results in the formation of the complex [Mo(η 3-C 3H 5)(CO) 2{η 2-S 2P(OEt) 2}(C 5H 10NH)] ( 4), in which the labile CH 3CN ligand was substituted by C 5H 10NH. The rotational behaviors of complex 3 and 4 in solution state were detected by variable-temperature 1H-NMR spectroscopy. The mechanism can be described as a trigonal twist, which involves the rotation of the triangular face formed by the nitrogen ligand and the two sulfur atoms relative to the face formed by the allyl and the two carbonyl groups. The 16-electron dithiocarbamate complex [Mo(η 3-C 3H 5)(CO) 2(η 2-S 2CNC 5H 10)] ( 5) is produced by S 2P(OEt) 2 − ligand replacement of 4 with C 5H 10NC(S)SH or the insertion reaction of CS 2 into the MoN bond of 4 with releasing of the (EtO) 2P(S)SH ligand.