Mono- and bi-metallic complexes based on redox-active tris(3,5-dimethylpyrazolyl)borato-molybdenum nitrosyls,part III.(1) Complexes containing meta-substituted benzene- and naphthalenediols or -diamines

Summary The complexes [MoL^*(NO)Cl(YC₆H₄YH-m)] (Y = O or NH), [MoL^*(NO)Cl(YC₁₀H₆YH-1,5)], (Y = O or NH), [MoL^*(NO)Cl(OC₁₀H₆OH-2,7)], [{MoL^*(NO)Cl}₂(XC₆H₄Y-m)] (X=Y=O, NH or S; X=O, Y=NH), [{MoL^*(NO)-C1}₂(YC₁₀H₆Y-1,5)] (Y=O or NH) and [{MoL^*(NO)Cl₂-(OC₁₀H₆-2,7)] have been prepared and studied by cyclic voltammetry. The monometallic species undergo a reversible oneelectron reduction, whereas the bimetallics undergo two oneelectron reductions. A comparison of E_1/2 (E_1/2(1)-E_1/2(2)) values for those new species with those obtained frompara- substituted analogues and bimetallics containing extended bridges YC₆H₄ZC₆H₄Y (e.g. Z = S or CH₂CH₂) established that the interaction between the redox centres in these new species is intermediate (YC₆H₄Y-m; NHC₁₀H₆NH-1,5) or weak (OC₁₀H₆O).In earlier papers^1,2 we have described the synthesis and electrochemical properties of a series of mono- and bi-metallic complexes of the type [MoL^*(NO)X(YC₆H₄YH)], [MoL^*(NO)X}₂(YC₆H₄Y)] and [{MoL^*(NO)X}₂(YC₆H₄-ZC₆H₄Y)] [L^*=tris(3,5-dimethylpyrazolyl)borate, HB(Me₂C₃HN₂)₃] where the arene ring ispara-substituted (X=Cl or I while Y=O, S or NH and Z = nothing, CH₂, CH₂CH₂, S, SO₂ or O). We have shown that the E_1/2-values of these species are dependent on X and Y, and that the bimetallic species undergo two one-electron reduction processes.We have established that there is strong interaction between the redox centres in bimetallics bridged byp-YC₆H₄Y, but that weak-to-negligible interaction occurs in those species containing YC₆H₄ZC₆H₄Y bridges. In this paper we describe our investigations ofmete-substituted bridging systems,m-YC₆H₄Y, and comparable systems containing naphthalene bridges,e.g. 1,5- or 2,7-YC₁₀H₂Y. From these studies we hoped to establish the extent of interaction between the two redox centres and how this compared to thepara-substituted arene counterparts.     

The effect of cation size on ion pairing of methyl orange dye with tetraalkylammonium and benzyltrialkylammonium ions in aqueous solution

Formation constants have been measured by a solvent distribution method for the ion pairing of an arene sulfonate, methyl orange dye, with two series of quaternary ammonium ions: R₄N⁺(R=Et,n-Pr,n-Bu, andn-Pent) and C₆H₅CH₂R₃N⁺ (R=Me, Et,n-Pr,n-Bu,n-Pent, andn-Hex). Ion pairing increases dramatically as the length of the R group increases beyond butyl. Using a hard-sphere model for contact ion pairs, it is estimated that coulombic attraction contributes about –kT to the binding free energy and decreases slightly with increasing size of R₄N⁺. Other factors related to solvation effects, of which cosphere overlap predominates, contribute from –2kT to –7kT of binding energy. Plots of logK for association as a function of cation size show an inflection with decreasing slope between R=propyl and R=butyl. Possible causes for the inflection are considered.     

Stabilization of a Silaaldehyde by its η2 Coordination to Tungsten

Treatment of pyridine‐stabilized silylene complexes [(η⁵‐C₅Me₄R)(CO)₂(H)W?SiH(py)(Tsi)] (R=Me, Et; py=pyridine; Tsi=C(SiMe₃)₃) with an N‐heterocyclic carbene ^MeIⁱPr (1,3‐diisopropyl‐4,5‐dimethylimidazol‐2‐ylidene) caused deprotonation to afford anionic silylene complexes [(η⁵‐C₅Me₄R)(CO)₂W?SiH(Tsi)][H^MeIⁱPr] (R=Me ( 1‐Me ); R=Et ( 1‐Et )). Subsequent oxidation of 1‐Me and 1‐Et with pyridine‐N‐oxide (1 equiv) gave anionic η²‐silaaldehydetungsten complexes [(η⁵‐C₅Me₄R)(CO)₂W{η²‐O?SiH(Tsi)}][H^MeIⁱPr] (R=Me ( 2‐Me ); R=Et ( 2‐Et )). The formation of an unprecedented W‐Si‐O three‐membered ring was confirmed by X‐ray crystal structure analysis.     

Substitution of Secondary Benzylic Phosphates with Diarylmethyl Anions

Substitution of diethyl and diphenyl benzylic phosphates, Alk-CH(Ar¹)OP(O)(OR)₂ (R = Et, Ph; Alk = Me, Et, i-Pr; Ar¹ = aryl), with the anions derived from Ar²CH₂ (Ph₂CH₂,9H-xanthene and fluorene) and n-BuLi at –15 °C was studied. For phosphates with Me as an Alk, diethyl phosphates produced Me-CH(Ar¹)CH(Ar²)₂ (Ar¹ = 4-halo-, 4-CN, 4-Me-, 2-Me, 2-Br-, 3-MeO-phenyl and 2-naphthyl). However, an unwanted substitution at the Et group competed with phosphates of Alk = Et- and i-Pr. Fortunately, the corresponding diphenyl phosphates cleanly underwent the desired substitution. Two enantioenriched phosphates, MeCH(Ph)OP(O)(OEt)₂ and EtCH(Ph)OP(O)(OPh)₂, proceeded with complete inversion of the stereochemistry.     

Reactions of cationic rhodium(I) carbonyl compounds with nucleophiles to form alkoxo,carboalkoxy and carboxylato complexes. Part II

Summary The rhodium(I) carbonyl compounds [Rh(CO)L₂2] [BF₄]. 1/2CH₂Cl_nn2 (L = PPh₂ or AsPh₃) react with the nucleophiles OMe⁻, RCOO⁻ (R = Me, Et) under nitrogen to form [Rh(OR)(CO)L₂] (1)–(2) and [Rh(OOCR)(CO)L₂] (7)–(₁₀), respectively. Addition of [Rh(CO)₂(PPh₃)₂]-[BF ₄] to OMe⁻ under nitrogen produces [Rh(COOMe)-(CO) (PPh₃)₂]-MeOH (3), whilst reactions of [Rh(CO)-(PPh₃)₂] [BF₄]·1/2CH₂Cl₂ and [Rh(CO)₂(PPh₃)₂] [BF₄] with OR_- (R = Me, Et or n-Pr) in the presence of CO produce [Rh(COOR)(CO)₂(PPh₃)₂] (4)–(6). The products have been characterised by i.r., ¹H, ³¹P, ¹³Cn.m.r. spectroscopy and elemental analysis.     

Synthesis and spectroscopic characterization of bis(N-alkyldithiocarbamato)nickel(II) complexes: crystal structures of [Ni(S2CNH(n-Pr))2] and [Ni(S2CNH(i-Pr))2]

Bis(N-alkyldithiocarbamato)nickel(II) complexes (1–5) [Ni(S₂CNHR)₂] (where R?=?Me, Et, n-Pr, i-Pr, n-Bu) were synthesized by the reaction of NiCl₂?·?6H₂O and the corresponding sodium salt of N-alkyldithiocarbamate in 1?:?2 molar ratio in aqueous medium. These bis(N-alkyldithiocarbamato)nickel(II) complexes (1–5) were characterized by elemental analysis, UV-Visible, IR, and ¹H/¹³C-NMR spectroscopy. The crystallographic investigation of [Ni(S₂CNH(n-Pr))₂] (3) and [Ni(S₂CNH(i-Pr))₂] (4) revealed distorted square-planar geometry around nickel(II). The dithiocarbamates have anisobidentate coordination with nickel and the dithiocarbamates are trans.     

Chiral dienolates : Stereoselective formation and α-alkylation of the lithium dienolates derived from (RS)-Z-[(n5-C5H5)Fe(CO)(PPh3)COCHCHCH2R] (RMe,Et,n-pr) and (RS)-[(n5-C5H5)Fe(CO)(PPh3)(COCHCMme2)]

The acyl ligands Z-(COCHCHCH₂-R)(RMe,Et,$\text{n}$-Pr) and (COCH-CMe₂) bound to the chiral auxiliary [(n⁵ -C₅H₅)Fe(CO)(PPh₃)] undergo exclusive γ-deprotonation to form the corresponding dienolates which react with electrophiles regio- and stereoselectively at the α-position to give in most cases single diastereoisomers of the corresponding α-substituted-βγ-unsaturated acyl complexes, together with in the former cases complete control over the β,γ-double bond geometry (E).     

The antispermatogenic activity of some phenylbismuth(III) O,O′‐dialkyldithiophosphates

Ten dialkyldithiophosphate derivatives of phenylbismuth(III) of the type, Ph_(3–n)Bi[S(S)P(OR)₂]_n [where n = 1; R = Me( 1 ), Et( 2 ), Pri( 3 ), Prⁿ( 4 ) and Buⁿ( 5 ); n = 2; R = Me( 6 ), Et( 7 ), Prⁱ( 8 ), Prⁿ( 9 ) and Buⁿ( 10 )] have been synthesized by the reactions of triphenylbismuth(III) with corresponding dialkyldithiophosphoric acids in 1:1 and 1:2 stoichiometric ratios, respectively, in stirred benzene solution. The newly synthesized brown colored compounds, 1–10 have been characterized by elemental analyses, molecular weight measurements, IR and NMR (¹H, ¹³C and ³¹P) spectral studies. The ligand diethyldithiophosphoric acid, [(C₂H₅O)₂P(S)SH], and its organobismuth(III) derivatives, compounds 2 and 7 were administered to adult male rats by oral gavage at the dose of 25 mg per kg body weight per day, for 60 days, and their effects were evaluated and compared for changes in testicular morphology, circulatory concentrations of testosterone, FSH and LH, sperm dynamics, fertility index and testicular cell population dynamics. Copyright © 2007 John Wiley & Sons, Ltd.     

Photochemical reactions of chromium hexacarbonyl with tetraalkyldiphosphine disulfides

New complexes [Cr(CO)₄(R₂P(S)P(S)R₂)] and [Cr₂(CO)₁₀(-R₂P(S)P(S)R₂)] (R = Me, Et, Pr ⁿ , Bu ⁿ ), (1a)–(1d) and (2a)–(2d) [(1a), R = Me; (1b), R = Et; (1c), R = Pr ⁿ ; (1d), R = Bu ⁿ ; (2a), R = Me; (2b), R = Et; (2c), R = Pr ⁿ ; (2d), R = Bu ⁿ ] have been prepared by the photochemical reaction of Cr(CO)₆ with R₂P(S)P(S)R₂ (R = Me, Et, Pr ⁿ and Bu ⁿ ) and characterized by elemental analyses, FT-i.r., ³¹P-[¹H]-n.m.r. spectroscopy and FAB-mass spectrometry. The spectroscopic data suggest cis-chelate bidentate coordination of the ligand in [Cr(CO)₄(R₂P(S)P(S)R₂)] and cis-bridging bidentate coordination of the ligand between two metals in [Cr₂(CO)₁₀(-R₂P(S)P(S)R₂)] (R = Me, Et, Pr ⁿ and Bu ⁿ ).     

Crystal structure oftrans-ethyl(1,5,6-trimethylbenzimidazole)-bis(dimethylglyoximato)cobalt(III). Relationships between structural and spectroscopic properties in compounds of the general formulae [Co(dmgH)2(R)(1,5,6-Me3Bzm)]

Summary The synthesis and x-ray crystal structure oftrans-[Co(dmgH)₂(Et)(1,5,6-Me₃Bzm)] where dmgH=dimethylglyoximate(–1), and 1,5,6-Me₃Bzm=1,5,6-trimethylbenzimidazole, is reported. The compound C₁₉H₂₆N₆O₄Co is monoclinic, space group P2₁/n;a=11.700(4);b=24.205(6);c=8.500(3) Å and =101.63(3)°. D(calcd) 1.299 g cm^–3; Z=4 and R=0.066 for 2359 independent reflections. Comparison of Co-N(axial ligand) bond lengths for compounds of general formulaetrans-[Co(dmgH)₂(R)(L)], with L=pyridine or 1,5,6-trimethylbenzimidazole and R=CH(CN)Cl, CH₂NO₂, Me, Et,i-Pr, cyclo-hexyl or adamantyl is made. The Co–N(1,5,6-Me₃Bzm) bond lengths of the trimethylbenzimidazole derivatives show a fairly linear relationship with the electronic parameter of the axial R group, derived from the¹³C-n.m.r. spectra of their pyridine analogues. The influence of steric effects on the properties of these Co^III compounds is discussed.     

Mass spectra of new heterocycles: X. Fragmentation of the molecular ions of 1-alkyl(cycloalkyl,aryl)-3-alkoxy(aryl)-2-methylsulfanyl-1<Emphasis Type="Italic">H</Emphasis>-pyrroles

The mass spectra of previously unknown 1-alkyl(cycloalkyl, aryl)-3-alkoxy(aryl)-2-methylsulfanyl-1H-pyrroles were studied. Fragmentation of all 3-alkoxy-substituted pyrroles under electron impact (70 eV) follow both ether and sulfide decomposition paths; In particular, 1-R-substituted 3-methoxy-2-methylsulfanyl-1H-pyrroles (R = Me, Et, i-Pr, s-Bu, cyclo-C₅H₉, cyclo-C₆H₁₁, Ph) lose methyl radical group from both methoxy and methylsulfanyl groups. The mass spectra of 1-sec-butyl- and 1-cycloalkylpyrroles also contained a strong peak (10–49%) from odd-electron [M — C _n H_2n ]^+· ion formed via cleavage of the N-R bond with synchronous hydrogen transfer. Cleavage of the O-Alk bond in the fragmentation of 3-alkoxy-1-isopropyl-2-methylsulfanyl-1H-pyrroles (Alk = Et, i-Pr, t-Bu) was accompanied by rearrangement process leading to the corresponding alkene and odd-electron 1-isopropyl-2-methylsulfanyl-1H-pyrrol-3-ol ion. The main fragmentation path of 1-alkyl-2-methylsulfanyl-3-phenyl-1H-pyrroles (Alk = Me, i-Pr) under electron impact involves dissociation of the S-Me bond with formation of rearrangement 1H-[1]benzothieno[2,3-b]pyrrol-8-ium ion.     

Preparation of complexes formed in the reaction between diironnanocarbonyl and tetraalkyl(phenyl)diphosphine disulfides,R2P(S)P(S)R2 (R=Et,n -Pr,n -Bu,Ph)

Fe₂(CO)₉ and R₂P(S)P(S)R₂ (R = Et, n-Pr, n-Bu, Ph) react to form two types of cluster complexes Fe₃(CO)₉(μ₃-S)₂ (1), Fe₂(CO)₆(μ-SPR₂)₂ (2A)–(2D), [2A, R = Et; 2B, R = n-Pr; 2C, R = n-Bu; 2D, R = Ph]. The complexes result from phosphorus–phosphorus bond scission; in the former sulfur abstraction has also occurred. The complexes have been characterized by elemental analyses, FT-IR and ³¹P-[¹H]-NMR spectroscopy and mass spectrometry.     

Synthesis and reactions of phosphido-bridged μ3-alkylidyne clusters; X-ray crystal structures of the complexes [Co2W(μ-PEt2)3(CO)5(η-C5H5)], [Co2W{μ3-C(R)C(Et)C(Et)C(O)}(μ-CO)(CO)4(PPh2{C(Et)CHEt})(η-C5H5)], and [CoW{μ-C(R)C(Et)C(Et)C(OH)}(CO)4(η-C5H5)] (R = C6H4Me-4)

Reactions of the phosphido-bridged complexes [Co₂W(μ-H)(μ₃-CC₆H₄Me-4)(μ-PR₂)(CO)₆(η-C₅H₅)] (R = Ph or Et) with PR₂H (R = Ph or Et) or RCCR (R = Me or Et) are dominated by processes involving facile PC, CC and CH bond formation. The X-ray structures of the complexes [Co₂W(μ-PEt₂)₃(CO)₅(η-C₅H₅)], [Co₂W{μ₃-C(R)C(Et)C(Et)C(O)}(μ-CO)(CO)₄(PPh₂{C(Et)CHEt})(η-C₅H₅)], and [CoW{μ-C(R)C(Et)C(Et)C(OH)}(CO)₄(η-C₅H₅)] (R = C₆H₄Me-4) have been determined.     

Synthesis and reactivity of metal-containing monomers

Optically active mixed alkoxy orthotitanates with general formula Ti(OR¹)₂(OR²)(OR³) (R¹=Et, Buⁿ; R²=CH₂CH₂OCOC(Me)=CH₂; R³=menthyl, CH(Me)CH₂Me, CH(Ph)CH(NHMe)Me, CH(C₉H₆N)(C₉H₁₄N)) were obtained for the first time by transesterification. The Ti^IV monomers synthesized were characterized by elemental analysis, ozonolysis, and¹H and¹³C NMR and IR spectroscopy. Polymer products with optical activity were obtained by liquid phase radical copolymerization of Ti^IV-containing monomers. For Part 51, see Ref. 1. Deceased. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1739–1743, September, 1999.     

Synthesis and characterization of heterobimetallic mixed-ligand complexes containing Zr(μ-OPri)2Al bridging units

Interesting varieties of heterobimetallic mixed-ligand complexes [Zr{M(OPrⁱ) _n }₂ (L)] (where M = Al, n = 4, L = OC₆H₄CH = NCH₂CH₂O (1); M = Nb, n = 6, L = OC₆H₄CH = NCH₂CH₂O (2); M = Al, n = 4, L = OC₁₀H₆CH = NCH₂CH₂O (3); M = Nb, n = 6, L = OC₁₀H₆CH = NCH₂CH₂O (4)), [Zr{Al(OPrⁱ)₄}₂Cl(OAr)] (where Ar = C₆H₃Me₂-2,5 (5); Ar = C₆H₂Me-4-Bu₂-2,6 (6), [Zr{Al(OPrⁱ)₄}₂(OAr)₂] (where Ar = C₆H₃Me₂-2,5 (7); Ar = C₆H₂Me-4-Bu₂-2,6 (8), [Zr{Al(OPrⁱ)₄}₃(OAr)] (where Ar = C₆H₃Me₂-2,5 (9); Ar = C₆H₃Me₂-2,6 (10), [ZrAl(OPrⁱ)_7-n (ON=CMe₂) _n ] (where n = 4 (11); n = 7 (12), [ZrAl₂(OPrⁱ)_10-n (ON=CMe₂) _n ] (where n = 4 (13); n = 6 (14); n = 10 (15) and [Zr{Al(OPrⁱ)₄}₂{ON=CMe(R)} _n Cl_2–n] [where n = 1, R = Me (16); n = 2, R = Me (17); n = 1, R = Et (18); n = 2, R = Et (19)] have been prepared either by the salt elimination method or by alkoxide-ligand exchange. All of these heterobimetallic complexes have been characterized by elemental analyses, molecular weight measurements, and spectroscopic (I.r., ¹H-, and ²⁷Al- n.m.r.) studies.     

Synthesis,spectral and electrochemical characterization of (dithiocarbamato)(arylazoimidazole)Palladium(II) perchlorates

The ternary complexes [Pd(RaaiX)(SS)ClO₄) where RaaiX is a N(1)-alkyl-2-(arylazo)imidazole (p-RC₆H₄N =NC₃H₂NN(1) X; X = Me, or Et, and R = H, Me or Cl) and SS = N,N-diethyldithiocarbamate or morpholinedithiocarbamate have been prepared and characterized by elemental analysis, i.r., u.v.-vis. and ¹H-n.m.r. data. Electrochemical studies show azo reduction. The complexes are thermally unstable and decompose to bis(dithiocarbamato)palladium(II) in solution. This revised version was published online in June 2006 with corrections to the Cover Date.     

Stabilisation of [Fe2(CO)9] and [Ru2(CO)9] bu substitution with bridging diphosphorus ligands

Reaction of [Fe₂(CO)₉] with a half molar amount of R₂PYPR₂ (Y = CH₂, R = Ph, Me, OMe or OPrⁱ; Y = N(Et), R = OPh, OMe or OCH₂; Y = N(Me), R = OPrⁱ or OEt) leads to the ready formation of a product which on irradiation with ultraviolet light rapidly decarbonylates to the heptacarbonyl derivative [Fe₂(μ-CO)(CO)₆{μ-R₂PYPR₂}]. Treatment of the latter with a slight excess of the appropriate ligand results, under photochemical conditions, in the formation of the dinuclear pentacarbonyl complex [Fe₂(μ-CO)(C))₄{μ-R₂PYPR₂}₂] but under thermal conditions in the formation of the mononuclear species [Fe(CO)₃{R₂PYPR₂}]. Reaction of [Ru₃(CO)₁₂] with an equimolar amount of (RO)₂PN(R′)P(OR)₂ (R′ = Me, R = Prⁱ or Et; R′ = Et, R = Ph or Me) under either thermal or photochemical conditions produces [Ru₃(CO)₁₀{μ-(RO)₂PN(OR)₂}] which reacts further with excess (RO)₂PN(R′)P(OR)₂ on irradiation with ultraviolet light to afford the dinuclear compound [Ru₂(μ-CO)(CO₄{μ-(RO)₂PN(R′)P(OR)₂}₂]. The molecular structure of [Ru₂(μ-CO)(CO)₄{μ-(MeO)₂PN(Et)P(OMe)₂}₂], which has been determined by X-ray crystallography, is described.     

Peculiarities of dissociative ionization of alkylcyclopentadienyl nitrosyl π-complexes of nickel

The decomposition of alkylcyclopentadienyl nitrosyl -complexes of nickel, (C₅H₄R)(NO)Ni (R=H, Et,i-Pr, CH₂Ph), under the action of electron impact has been studied. The nature of the nitrosyl ligand has been shown to be the factor determining the main fragmentation pathway which involves the abstraction of an NO molecule. The effect of the nature of the ligand on the ability of the molecular ion (C₅H₄R)LNi⁺ (L=C₅H₄R, C₅H₅, C₃H₅, NO) to rearrange with hydrogen atom migration from one ligand to another has been considered. The structure of the alkyl group R determines a competing fragmentation pathway involving cleavage of the -C-C bond with respect to the cyclopentadienyl ring in the substituent.Translated fromIzyestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 1985–1988, November, 1993.     

[(NHC)(NHCewg)RuCl2(CHPh)] Complexes with Modified NHCewg Ligands for Efficient Ring‐Closing Metathesis Leading to Tetrasubstituted Olefins

Imidazolium salts (NHC_ewg ? HCl) with electronically variable substituents in the 4,5‐position (H,H or Cl,Cl or H,NO₂ or CN,CN) and sterically variable substituents in the 1,3‐position (Me,Me or Et,Et or iPr,iPr or Me,iPr) were synthesized and converted into the respective [AgI(NHC)_ewg] complexes. The reactions of [(NHC)RuCl₂(CHPh)(py)₂] with the [AgI(NHC_ewg)] complexes provide the respective [(NHC)(NHC_ewg)RuCl₂(CHPh)] complexes in excellent yields. The catalytic activity of such complexes in ring‐closing metathesis (RCM) reactions leading to tetrasubstituted olefins was studied. To obtain quantitative substrate conversion, catalyst loadings of 0.2–0.5 mol % at 80 °C in toluene are sufficient. The complex with the best catalytic activity in such RCM reactions and the fastest initiation rate has an NHC_ewg group with 1,3‐Me,iPr and 4,5‐Cl,Cl substituents and can be synthesized in 95 % isolated yield from the ruthenium precursor. To learn which one of the two NHC ligands acts as the leaving group in olefin metathesis reactions two complexes, [(FL‐NHC)(NHC_ewg)RuCl₂(CHPh)] and [(FL‐NHC_ewg)(NHC)RuCl₂(CHPh)], with a dansyl fluorophore (FL)‐tagged electron‐rich NHC ligand (FL‐NHC) and an electron‐deficient NHC ligand (FL‐NHC_ewg) were prepared. The fluorescence of the dansyl fluorophore is quenched as long as it is in close vicinity to ruthenium, but increases strongly upon dissociation of the respective fluorophore‐tagged ligand. In this manner, it was shown for ring‐opening metathesis ploymerization (ROMP) reactions at room temperature that the NHC_ewg ligand normally acts as the leaving group, whereas the other NHC ligand remains ligated to ruthenium.     

Square-Planar Nickel(II) O,O′-Dialkyldithiophosphato Complexes with Triphenylphosphine of the Type [NiX(S2P{OR}2)(PPh3)] (X = Cl,Br, I and NCS)

A series of new [NiX(S₂P{O-c-Hex}₂)(PPh₃)](X = Cl^–, Br^–, I^– and NCS^–)(1)–(4) and [Ni(NCS)(S₂P{OR}₂)(PPh₃)][R =n-Pr (5), i-Pr (6)] complexes has been synthesized and characterized by elemental analyses, f.i.r., i.r., u.v.–vis., ¹H-, ¹³C{¹H}- and ³¹P{¹H}-n.m.r. spectra, magnetochemical and conductivity measurements. A single crystal X-ray analysis of [Ni(NCS)(S₂P{O-n-Pr}₂)(PPh₃)](5) reveals the molecular structure of the complex and confirms a square-planar geometry around the central atom of nickel with the NCS anion coordinated via the nitrogen atom.