Ergebnisse der umsetzung von carbonylcobaltaten mit chlordifluoracetylchlorid

We have been able to synthesize chlorodifluomethyltetracarbonyl- cobalt (1) by the reaction of chlorodifluoroacetyl chloride and sodium tetracarbonylcobaltate(-I) at low temperatures. (1) decomposes at normal temperature to yield μ-difluoromethylene-μ-carbonyl-bis(tricarbonylcobalt) (Co-Co) (2), di-μ-difluoromethylene-bis (tricarbonylcobalt) (Co-Co) (3) and μ-difluormethylene-μ-tetrafluoroethylidene-bis (tricarbonylcobalt) (Co-Co) (4). (2) proved to be an intermediate in the formation of the cluster fluoromethinyl-enneacarbonyltricobalt (5).Na[Co(CO)₃P(C₆H₅)₃] (or Na[Co(CO)₄] in presence of triphenylphosphine) and ClCF₂COCl react to form the acetyl derivative ClCF₂ CO·Co(CO)₃P(C₆H₅)₃ (6) which cannot be decomposed to give the corresponding methyl compound.     

Übergangsmetall-substituierte phosphane,arsane und stibane : XXIX. Metallierte arsane und stibane mit chiralem eisen-substituenten

The reaction of Cp(CO)₂FeEMe₂ (E  As, Sb, Bi) with Me₃P, Et₃P, Me₂PhP and (MeO)₃P leads to a CO/R₃P exchange and formation of the chiral derivatives Cp(CO)(R₃P)FeEMe₂. Cp(CO)[(MeO)₃P]FeEMe₂ rearranges already at room temperature to Cp(CO)[(Me₃E]FeP(O)(OMe)₂ which is transformed by (MeO)₃P to Cp(CO)[(MeO)₃P]FeP(O)(OMe)₂. The high nucleophilicity of the new organometallic Lewis bases is established by the easy conversion of Cp(CO)(Me₃P)FeSbMe₂ to [Cp(CO)(Me₃P)Fe(SbMe₃)]I with MeI, or to [Cp(CO)(Me₃P)FeSbMe₂Fe(CO)LCp]Hal (L  CO, Hal  Cl; L  Me₃P, Hal  Br) with Cp(CO)LFe-Hal, respectively. The new compounds are characterized by spectroscopy and elementary analyses.     

Haloalkyl complexes of the transition metals: IV. The formation of a cationic ylide complex of platinum(II) from a chloromethylplatinum(II) complex and the crystal structures of cis-[Pt(CH2PPh3)X(PPh3)2]I (X = Cl or I)

The reactions of Pt(PPH₃)₄ and Pt(C₂H₄)(PPh₃)₂ with CH₂ClI have been investigated. The product of the reaction of Pt(PPh₃)₄ with CH₂ClI is the cationic ylide complex cis-[Pt(CH₂PPh₃)Cl(PPh₃)2][I], whereas the reaction of Pt(C₂H₄)-(PPh₃)₂ gives the oxidative addition product Pt(CH₂Cl)I(PPh₃)₂. Reaction of cis- or trans-Pt(CH₂Cl)I(PPh₃)₂] with PPh₃ gives the complex cis-[Pt(CH₂PPh₃)-Cl(PPh₃)₂][I]. The structures of the complexes cis-[Pt(CH₂PPh₃X(PPh₃)₂][I] (where X = Cl or I) have been determined by X-ray crystallography. Both complexes crystalize in the monoclinic space group P2₁/n. For X = Cl a 1388.6(7), b 2026.7(10), c 1823.9(9) pm, β 96.51(2)° and R converged to 0.075 for 3542 observed reflections; structural parameters Pt-Cl 240(1), Pt-C(3) 212(2), Pt-P(2) (trans to Cl) 235(1) and Pt-P(1) (trans to CH₂PPh₃) 233(1) pm; Cl-Pt-C(3) 86.9(5), C(3)-Pt-P(2) 91.8(5), P(2)-Pt-P(1) 97.0(2) and P(1)-Pt-Cl 85.1(2)°. For X = I, a 1379.4(7), b 2044.4(10), c 1840.0(9) pm, β 96.09(2)° and R converged to 0.071 for 4333 observed reflections; structural parameters Pt-I 266(1), Pt-C(3) 212(2), Pt-P(2) (trans to I) 226(1) and Pt-P(1) (trans to CH₂PPh₃ 233(1) pm; I-Pt-C(3) 87.2(5), C(3)-Pt-P(2) 91.5(5), P(2)-Pt-P(1) 96.5(2) and P(1)-Pt-I 85.6(1)°. Some other complexes of the type cis-[Pt(CH₂PPh₃)X(PPh₃)₂]Y are also described.     

Reaktionen von Silylphosphanen mit Schwefel

Reactions of Silylphosphines with Sulphur We report about reactions of Me₂P? SiMe₃ 2 , MeP(SiMe₃)₂ 3 , (Me₃Si)₃P 4 , P₂(SiMe₃)₄ 5 , and (Me₃Si)₃P₇ 1 with elemental sulphur. Without using a solvent 2 reacts very vigorously. The reactions with 3 and 4 show less reactivity which is even more reduced with 5 and 1 . With equivalent amounts of sulphur the reactions with 2 , 3 , 4 lead to compounds with highest content of sulphur. These compounds are Me₃SiS? P(S)Me₂ 9 from 2 , (Me₃SiS)₂P(S)Me 13 from 3 and (Me₃SiS)₃P(S) 16 from 4 . Besides, the by-products (Me₃Si)₂S 8 , P₂Me₄ 7 , and Me₂P(S)? P(S)Me₂ 11 can be obtained. The reactions of silylphosphines in a pentane solution run much slower so that the formation of intermediates can be observed. Reaction with 2 yields Me₃SiS? PMe₂ 6 and Me₂P(S)PMe₂ 10 , which lead to the final products in a further reaction with sulphur. From 3 (Me₃SiS)(Me₃Si)PMe 14 and (Me₃SiS)₂PMe 12 can be obtained which react with sulphur to (Me₃SiS)₂P(S)Me 13. 4 leads to the intermediates (Me₃SiS)(Me₃Si)₂P 18 , (Me₃SiS)₂(Me₃Si)P 17 , (Me₃SiS)₃P 15 yielding (Me₃SiS)₃P(S) 16 with excess sulphur. Depending on the molar ratio (P₂SiMe₃)₄ 5 reacts to (Me₃Si)₂P? P(SSiMe₃)(Sime₃), (Me₃SiS)(Me₃Si)P? P(SSiMe₃). (Diastereoisomer ratio 10:1), (Me₃SiS)₂P? P(SiMe₃)₂ and (Me₃SiS)₂P? P(SSiMe₃)(Sime₃). With the molar ratio 1:4 the reaction yields (Me₃SiS)₂P? P(SSiMe₃)₂ (main product), (Me₃SiS)₃P(S) and (Me₃SiS)₃P. All silylated silylphosphines tend to decompose under formation of (Me₃Si)₂S. (Me₃Si)₃P₇ reacts with sulphur at 20°C (15 h) under decomposition of the P₇-cage and formation of (Me₃SiS)₃P(S). The products of the reaction of 5 with sulphur in hexane solution (molar ratio more than 1:3) undergo readily further reactions at 60°C under cleavage of P? P bonds and splitting off (Me₃Si)₂S, leading to (Me₃SiS)₃P(S) and cage molecules like P₄S₃, P₄S₇, and P₄S₁₀ and P? S-polymers. (Me₃SiS)₃P(S) isi thermally unstable and decomposes to P₄S₁₀ and (Me₃Si)₂S. Sulphur-containing silylphosphines like (Me₃SiS)P(S)Me₂ react with HBr at ?78°C under formation of Me₃SiBr (quantitative cleavage of the Si? S bond) and Me₂P(S)SH, which reacts with HBr to produce H₂S and Me₂P(S)Br.     

Diphospha-Ureas from the Phosphaketene Ph3GePCO

The phosphaketene Ph₃GePCO is shown to react with the phosphide KP(tBu)₂ to generate the anion [Ph₃GePC(O)P(tBu)₂]⁻ 1 . This species reacts with CH₃I or ClGePh₃ to give the dissymmetric diphospha-ureas (tBu)₂PC(O)P(GePh₃)(CH₃) 2 and (Ph₃Ge)₂PC(O)P(tBu)₂ 3 respectively. Sequential treatment of 2 with a base and CH₃I affords a route to (tBu)₂PC(O)P(CH₃)₂ 5 . These species are products of the first modular diphospha-urea synthesis. The subsequent thermal and photochemical reactivity of these species was also probed and described.     

Molybdenum and tungsten complexes with the heteroallyl-like Ph2P(O)C(S)NR− (R  Me,Ph) as ligand. X-ray structural analysis of Mo(CO)2(PPh3)(Ph2P(O)C(S)NPh)2 · CH2Cl2; A 4 : 3 piano-stool configuration

Ph₂P(O)C(S)N(H)R (R  Me, Ph) reacts with M(CO)₃(η⁵-C₅H₅)Cl (M  Mo, W) in the presence of Et₃N to give M(CO)₂(η⁵-C₅H₅)(Ph₂P(O)C(S)NR). The deprotonated ligand coordinates in a bidentate manner through N and S to give a four-membered ring system. M(CO)₃(PPh₃)₂Cl₂ (M  Mo, W) reacts with Ph₂P(O)C(S)N(H)R (R  Me, Ph) in the presence of Et₃N to give complexes in which the central metal atoms are seven coordinate through two ligands bonded via O and S to form five-membered ring systems, one PPh₃, and two CO groups. The complexes were characterised by elemental analyses, IR, ¹H NMR, and ³¹P NMR spectroscopy, and an X-ray structural analysis of Mo(CO)₂(PPh₃)(Ph₂P(O)C(S)NPh)₂ · CH₂Cl₂.     

Phosphino[tris(trimethylsilyl)methyl]Boranes and 2,4‐Bis[tris(trimethylsilyl)methyl]‐1,3,2,4‐diphosphadiboretanes [1]

The reaction of tris(trimethylsilyl)methylboron dihalides (Me₃Si)₃CBX₂ (X = Cl, F) with the lithium phosphides LiPHtBu and LiPHmes leads to the phosphinoboranes (Me₃Si)₃CBX‐(PHR), (Me₃Si)₃CB(PHR)₂ or the 1,3,2,4‐diphosphadiboretanes [(Me₃Si)₃CB(PR)]₂, depending on the ratio of the reagents, the reaction temperature and concentration. High dilution and low temperatures are required for the synthesis of (Me₃Si)₃CB(Hal)PHR ( 1–3 ) in order to prevent the formation of (Me₃Si)₃CB(PHR)₂ ( 4 and 5 ). The latter compounds are best prepared in a two step phosphination from (Me₃Si)₃CBHal₂ and LiPHR. At higher temperatures the four‐membered 1,3,2,4‐diphosphadiboretanes [(Me₃Si)₃CB(PR)]₂ 6 and 7 are the most stable compounds. On the other hand, compounds of type (Me₃Si)₃CB(Hal)PR₂, 8 and 9 , are thermally more stable than the monophosphinoboranes 1 – 3 . Phosphinoboranes of type (Me₃Si)₃CB(PR₂)₂ (R = tBu, mes) could not be prepared. NMR and mass spectral data are in accord with the monomeric nature of compounds 1 to 9 .     

Standard Molar Enthalpies of Formation of Ce(TCA)_3·3H_2O(s) and Ce(TCA)(C_9H_6NO)_2(s)

IntroductionBothrareearthions1and 8 hydroxyquinolineareofantibacterialfunction ,2 andtheircomplexeshavemorepowerfuldisinfection .Theirbinarycomplexeswerereport edasearlyasin 196 3.Atthesametime ,theresearchontheirternarycomplexeshavebecomeveryactiveinrecentyears,andtheyarewidelyappliedinmanyfields .3 6Dong6 reportedthesynthesisandcharacterizationofthecomplexesofrareearthtrichloroaceticacidsaltswith 8 hy droxyquinoline.Itsapplicationinleathermouldyproofshowedthatthecomplexeshavepowerfuldisinfe…     

Carbonyl and hydridocarbonyl complexes of ruthenium (II) and osmium (II) with tertiary arsines

Ruthenium halides (Cl and Br) react with monotertiary arsines-Ph₂RAs (R=Me, Et, Pr ⁿ ) in methoxyethanol, in the presence of aq. formaldehyde to give monocarbonyl complexes of ruthenium(II) of the type RuX₂(CO) (Ph₂RAs)₃. Carbonylation of an ethanolic solution containing ruthenium trichloride and the arsine at room temperature yieldtrans dicarbonyl compounds of the formula RuCl₂(CO)₂ (Ph₂RAs)₂. The osmium monocarbonyls OsX₂(CO) (Ph₂RAs)₃ (X=Cl, Br; R=Me, Et) react with NaBH₄ in methanol to yield complexes of the composition OsHX(CO) (Ph₂RAs)₃. The ruthenium analogues RuHCl(CO) (Ph₂RAs)₃ have also been made. Structures have been assigned to all these compounds on the basis of IR and NMR spectral results.     

Organometallic Lewis Acids,Part LIX[1] Pentacarbonylrhenium Complexes with Phosphorus Tricyanide and Di­cyanophosphide

The addition of Re(CO)₅⁺ [as Re(CO)₅FBF₃] to P(CN)₃ and to P(CN)₂^– affords the complexes [Re(CO)₅]₃P(CN)₃(BF₄)₃ and Re(CO)₅P(CN)₂, respectively. The spectroscopic data indicate that Re(CO)₅⁺ is coordinated to each of the three cyano groups of P(CN)₃ to give {P[C≡N‐Re(CO)₅]₃}[BF₄]₃, whereas the pseudohalide P(CN)₂^– is bonded to the rhenium cation through the phosphorus atom.     

Organometallic Reactions and Syntheses : Volume 6, E. I. Becker and M. Tsutsui,ed., Plenum Publishing Corporation., New York/ London, 1977, xii + 314 pages $47.40

The (Me₃Si)₃C group causes very large steric hindrance to nucleophilic displacement at a silicon atom to which it is attached, and (Me₃Si)₃CSiMe₂Cl is even less reactive than t-Bu₃SiCl towards base. The compounds (Me₃Si)₃CSiMe₂X (X = Cl, Br, or I) are cleaved by MeOH/MeONa to give (Me₃Si)₂CHSiMe₂OMe, possibly via the silaolefin (Me₃Si)₂ CSiMe₂, and the correspondLug (Me₃Si)₃ CSiPh₂X compounds undergo the analogous reaction even more readily. The halides (Me₃Si)₃CSiR₂X (X = Cl or Br) and (Me₃Si)₃CSiCl₃ do not react with boiling alcoholic silver nitrate, but the iodides (Me₃Si)₃CSiR₂I are rapidly attacked.     

Pseudohalogeno-Metallverbindungen. LXXV. Pentacarbonylrhenium-und Triphenylphosphangold-Komplexe mit Pseudohalogeniden: (OC)5ReX,Ph3PAuX (X = ONC(CN)2, o-MeC6H4SO2C(CN)2,o-MeC6H4SO2NCN,Ph2(S)PNCN)

Pseudohalogeno Metal Compounds. LXXV. Pentacarbonylrhenium and Triphenylphosphinegold Complexes of Pseudohalide Anions: (OC)₅ReX, Ph₃PAuX (x = ONC(CN)₂, o-MeC₆H₄SO₂C(CN)₂, o-MeC₆H₄SO₂NCN, Ph₂(S)PNCN) The pseudohalides (X^?) nitrosodicyanmethanide, o-tosyldicyanmethanide, o-tosylcyanamide and diphenylthiophosphinylcyanamide react with the Organometallic Lewis Acids (OC)₅Re⁺ (as (OC)₅ReFBF₃) and Ph₃PAu⁺ (as Ph₃PAuNO₃) to give the neutral title complexes (OC)₅Re—X and Ph₃PAu? X, respectively. X-ray diffraction shows that nitroso-dicyanmethanide is coordinated through the nitroso N-atom to the Re(CO)₅ fragment. Cyanide-N-coordination is observed for the complexes with o-tosyldicyanmethanide and o-tosylcyanamide whereas diphenylthiophosphinylcyanamide is S-coordinated to the gold atom. Spectroscopic data (IR, NMR) of 1–6 are described.     

Étude radiocristallographique des solutions solides KAuCl3,69Br0,31, KAuCl1,94Br2,06et KAuCl1,82Br2,18,2H2O

The structures of anhydrous solid solutions KAuCl_3.69Br_0.31 (a=8.687(2) b=6.420(1) c=12.290(1)Å β=95.568(3)° R=0.046) and KAuCl_1.94Br_2.06 (a=8.789(2) b=6.578(1) c=12;562(2)Å β=96.147(3)° R=0.074) have been determined by X-ray diffraction to be in the P2₁/c centrosymmetric group. The structure of the hydrous solid solution KAuCl_1.82Br_2.18,2H₂O (a=9.414(1) b=11.842(1) c=8.399(2)Å β=94.459(2)° R=0.068) corresponds to the P2₁/n group. The statistical substitution coefficient observed in the anhydrous or hydrous solid solutions with a bromine/chlorine ratio near 50% gives proof of a trans substitution. In the anhydrous solid solution KAuCl_1.94Br_2.06 the length between gold and halides (Hal) is equal to 2.330(14)Å for Au(2)-Hal(3) and 2.400(5)Å for Au(2)-Hal(4), close to the corresponding lengths Au-Cl (2.288Å) in KAuCl₄,2H₂O and Au-Br (2.427Å) in KAuBr₄,2H₂O. These results are in agreement with the existence of an intermediate trans entity [AuCl₂Br₂]⁻.     

Linkage isomerism in 5-exo thiocyanate and isothiocyanate substituted tricarbonyl(η-cyclohexa-1,3-diene)iron and tricarbonyl(η-cyclohepta-1,3-diene)iron

Nucleophilic addition to the tricarbonyl(η-cyclohexadienyl)iron cation and the tricarbonyl(η-cycloheptadienyl)iron cation by the thiocyanate ion forms initially the 5-exo-isothiocyanate (NCS) isomers, C₆H₇NCSFe(CO)₃ and C₇H₉NCSFe(CO)₃, both of which isomerise to the corresponding 5-exo thiocyanate isomers C₆H₇SCNFe(CO)₃ and C₇H₉SCNFe(CO)₃ on exposure to air.     

N,N-Bis(trimethylsilyl)dithiocarbazinsäure-S-methylester: Darstellung,Struktur und Reaktionen mit Halogenverbindungen des Titans,Niobs, Tantals und Molybdäns

N,N-bis(trimethylsilyl)-S-methyldithiocarbazate. Preparation, Molecular Structure, and Reactions with Titanium, Niobium, Tantalum, and Molybdenum Halides The reaction of Me₃SiCl with NH₂NHC(S)SMe yields as single product the title compound (Me₃Si)₂Nnhc(S)SMe ( 1 ). The Si₂NNC(S)S moiety is not planar. The Si? N-distances are in the range 176.9(8) to 178.1(9) pm. 1 does not react to hydrazido or diazenido complexes with Cp₂TiCl₂, CpTiCl₃, MCl₅ and CpMCl₄ (M = Nb, Ta). With MoO₂Cl₂(dmso)₂ the dimeric compound (dmso)₂Mo(μ-NNC(S)SMe)₂Mo(O)Cl₂ is obtained.     

The polarographic and voltammetric behaviour of acetylacetonato and hexafluoroacetylacetonato complexes in acetonitrile

The polarographic behaviour of Ce(acac)₄, Ce(acac)₃, Eu(acac)₃, Fe(acac)₃, Cr(acac)₃, Co(acac)₃, Mn(acac)₃, NaMn(acac)₃, Mn(acac)₂, Ni(acac)₂, Cu(acac)₂, VO(acac)₂, Fe(hfacac)₃, Cr(hfacac)₃ and Cu(hfacac)₂ has been studied in acetonitrile on the dropping mercury electrode. Half-wave potentials versus bisbiphenylchromium(I)/(0), the reversibility of the electrode reaction and the number of electrons participating in the electrode processes measured by coulometry are reported. Cyclovoltammetric measurements have been performed on the hanging mercury drop electrode and on the stationary platinum electrode, the data of these studies are given. quite different behaviour has been observed on the platinum electrode compared to the dropping mercury electrode. Large scale electrolysis was employed to obtain information on the reaction products. The influence of the electrode material and the reaction mechanisms are discussed.     

Chemie polyfunktioneller Moleküle. 97. Beiträge zur Komplexchemie des Lithium-bis(diphenylphosphino)amids,des Bis(diphenylphosphino)amins und des Tris(diphenylphosphino)amins

Chemistry of Polyfunctional Molecules. 97. Contributions to the Coordination Chemistry of Lithium-bis(diphenylphosphino)amide, Bis(diphenylphosphino)amine, and Tris(diphenyl-phosphino)amine (Ph₂P)₂NLi ( 1 ) forms with AuCl(PPh₃) the already known complex [Au(Ph₂P)₂N]₂ ( 2 ), which now has been proved by mass spectroscopy to possess the postulated dimeric structure. 2 gives with HCl, HClO₄, and HBF₄ the new compounds [ClAu(Ph₂P)₂NH]₂ ( 3a ) and [Au(Ph₂P)₂NH…?X]₂ [X = ClO₄ ( 3b ), BF₄ ( 3c )]. In analogy the neutral complex Fe(C₅H₅)(CO)(Ph₂P)₂N ( 5 ) os obtained from FeCl(C₅H₅)(CO)₂ and 1. 5 reacts with HCl to [Fe(C₅H₅)(CO)(Ph₂P)₂NH…?Cl] ( 6a ). The last one can also be prepared by direct reaction of FeCl(C₅H₅)(CO)₂ with (Ph₂P)₂NH ( 4 ). In the same way FeBr(C₅H₅)(CO)₂ reacts with 4 yielding [Fe(C₅H₅)(CO)(Ph₂P)₂NH…?Br] ( 6b ), which leads under metathesis with NH₄PF₆ to [Fe(C₅H₅)(CO)(Ph₂P)₂NH]PF₆ ( 6c ). With PdCl₂(NCPh)₂ the ligand 1 forms Pd[(Ph₂P)₂N]₂ ( 7 ), which also can be synthesized in another way, but is now for the first time characterized in a spectroscopically detailed manner. Cr(CO)₄(Ph₂P)₂NPPh₂ reacts with AuCl(CO) to Cr(CO)₄(Ph₂P)₂NPPh₂AuCl ( 8 ). This compound gives with Cr(CO)₄(Ph₂P)₂NLi the trimetallic complex (OC)₄Cr(Ph₂P)₂NPPh₂AuN(PPh₂)₂Cr(CO)₄ ( 9 ). (Ph₂P)₃N ( 10 ) yields with AuCl(CO) in the molar ratio of 1:3 the compound [ClAuPh₂P]₃N ( 11 ).     

[(Mes3Sn)2MoO4], ein monomeres Triorganozinnmolybdat

[(Mes₃Sn)₂MoO₄], a Monomeric Triorganotin Molybdate Mes₃SnBr (Mes = 1, 3, 5‐trimethylphenyl) reacts with (NBu₄)₂[Mo₆O₁₉] in the presence of (NBu₄)OH (in CH₃CN as solvent) to form [(Mes₃Sn)₂MoO₄]. Alternatively the title compound can be obtained from the reaction of [MoO₂(acac)₂] (acac = 2, 4‐pentadionate) with Mes₃SnOH in isopropanol. [(Mes₃Sn)₂MoO₄] forms monoclinic crystals, space group C2/c, with a = 2271.6(3) pm, b = 825.2(1) pm, c = 2739.9(5) pm, β = 90.96(2)°. The crystal structure consists of isolated molecules in which a tetrahedral MoO₄ unit is connected to two terminal Mes₃Sn groups. The Mo‐O distances range from 169.6(4) to 181.1(3) pm and the Sn‐O distance is 204.8(3) pm.     

Bildung siliciumorganischer Verbindungen. L. Untersuchungen zur Hydrierung,Methylierung und Spaltung des Octachloro-hexasila-asterans Si6Cl8C6H8

Formation of Organosilicon Compounds. L. Investigations on Hydrogenation, Methylation, and Decomposition of Octachlorohexasila-asteran Si₆Cl₈C₆H₈ Compound (a) reacts with LiAlH₄ (1:2) to form (b), respectively (c) (ratio 1:5). (b), (c) and the intermediates containing Si? H-groups can be rechlorinated to (a) by means of Cl₂. With a excess of LiAlH₄ (1:10) (a) is cleaved to compound (d) under hydrogenation. (a) is methylated to (e) resp. (f) by CH₃MgCl. (a) doesn't react with Cl₂ and Br₂; (f) is cleaved by HBr to yield (g). The different sterical conditions of the secondary and teriary Si---Cl-groups allow preparation of the partially chlorinated compounds (b) and (e).     

Komplexchemie P-reicher Phosphane und Silylphosphane. VIII. Zur unterschiedlichen Tendenz der Bildung von Chromcarbonyl-Komplexen silylierter-alkylierter Phosphane und Diphosphane

Transition Metal Complexes of P-rich Phosphanes and Silylphosphanes. VIII. Concerning the Different Tendencies of Silylated and Alkylated Phosphanes and Diphosphanes to Form Chromium Carbonyl Complexes The influence of the substituents Me₃Si tBu and Me in phosphanes and diphosphanes on the formation of complex compounds with Cr(CO)₅THF is investigated. tBu(Me₃Si)P? P(SiMe₃)₂ 1 and (tBu)₂P? P(SiMe₃)₂ 2, resp., react with Cr(CO)₅THF 4 at ?18°C by coordinating Cr(CO)₅ to the P(SiMe₃)₂ group to give tBu(Me₃Si)P? P^IV(SiMe₃), · Cr(CO)₅ 1 a, tBu(Me₃Si)P^IV? P^IV(SiMe₃)₂ · Cr(CO)₄ 1b and (tBu)₂P? P^IV(SiMe₃)₂ · Cr(CO)₅ 2a . In the reaction of 1 with 4 using a molar ratio of 1:2 at first 1 a is formed which reacts on to yield completely 1 b. In a mixture of the dissolved compounds (Me₃Si)₃P 5, (tBu)₃P 6 and (tBu)₃P? P(SiMe₃)₂ 2 only 5 and 6 react with Cr(CO)₅THF yielding (Me₃Si)₃P · Cr(CO)₅ and (tBu)₃P · Cr(CO)₅, but 2 does not yet react. In a solution of (Me₃Si)₃P 5, P₂Me₄ 7 and (Me₃Si)₂P? PMe₂ 3 only 5 and 7 react with Cr(CO)₅THF (0.25 to 1.5 equivalents with respect to 3) to give (Me₃Si)₃P · Cr(CO)₅, P₂Me₄ · Cr(CO)₅ and P₂Me₄ · 2Cr(CO)₅. The formation of complexes with Cr(CO)₅THF of the phosphanes 5 and 6 is clearly favoured as compared to the silylated diphosphanes 2 and 3 (not to P₂Me₄); the PR₂ groups (R = tBu, Me in 2 or 3 ) don't have a strong influence.