Über den Phosphandiyl‐Transfer von invers‐polarisierten Phosphaalkenen R1P=C(NMe2)2 (R1 = tBu,Cy, Ph,H) auf Phospheniumkomplexe [(η5‐C5H5)(CO)2M=P(R2)R3] (R2 = R3 = Ph; R2 = tBu,R3 = H; R2 = Ph,R3 = N(SiMe3)2)

Phosphanediyl Transfer from Inversely Polarized Phosphaalkenes R¹P=C(NMe₂)₂ (R¹ = tBu, Cy, Ph, H) onto Phosphenium Complexes [(η⁵‐C₅H₅)(CO)₂M=P(R²)R³] (R² = R³ = Ph; R² = tBu, R³ = H; R² = Ph, R³ = N(SiMe₃)₂) Reaction of the freshly prepared phosphenium tungsten complex [(η⁵‐C₅H₅)(CO)₂W=PPh₂] ( 3 ) with the inversely polarized phosphaalkenes RP=C(NMe₂)₂ ( 1 ) ( a : R = tBu; b : Cy; c : Ph) led to the η²‐diphosphanyl complexes ( 9a‐c ) which were isolated by column chromatography as yellow crystals in 24‐30 % yield. Similarly, phosphenium complexes [(η⁵‐C₅H₅)(CO)₂M=P(H)tBu] (M = W ( 6 ); Mo ( 8 )) were converted into (M = W ( 11 ); Mo ( 12 )) by the formal abstraction of the phosphanediyl [PtBu] from 1a . Treatment of [(η⁵‐C₅H₅)(CO)₂W=P(Ph)N(SiMe₃)₂] ( 4 ) with HP=C(NMe₂)₂ ( 1d ) gave rise to the formation of yellow crystalline ( 10 ). The products were characterized by elemental analyses and spectra (IR, ¹H, ¹³C‐, ³¹P‐NMR, MS). The molecular structure of compound 10 was elucidated by an X‐ray diffraction analysis.     

Bildung und Eigenschaften von Li2P7R (R = Si(CH3)3, CH3, C(CH3)3)

Formation and Properties of Li₂P₇R (R = Si(CH₃)₃, CH₃, C(CH₃)₃) The reaction of P₇(Sime₃)₃ with Li₃P₇ in the molar ratio of 2:1 yields LiP₇(Sime₃)₂, and in the molar ratio of 1:2 Li₂P₇Sime₃ is formed. Li₂P₇me and Li₂P₇Cme₃ (me = CH₃) are obtained by reaction of white phosphorus with Lime, or LiCme₃, respectively [2]. The compounds Li₂P₇R (R = Sime₃, Cme₃, me) show typical valence tautomerism, as established by ³¹P-n.m.r. spectroscopy at various temperatures. Also LiP(Sime₃)₂ transforms P₇(Sime₃)₃ to yield Li₂P₇Sime₃ but in this reaction considerable cleavage of P? P bonds occurs, too.     

Vinyl C-F cleavage by Os(H)3Cl(P(i)Pr3)2

Os(H)(3)ClL(2) (L = P(i)Pr(3)) reacts at 20 degrees C with vinyl fluoride in the time of mixing to produce OsHFCl([triple bond]CCH(3))L(2) and H(2). In a competitive reaction, the liberated H(2) converts vinyl fluoride to C(2)H(4) and HF in a reaction catalyzed by Os(H)(3)ClL(2). A variable-temperature NMR study reveals these reactions proceed through the common intermediate OsHCl(H(2))(H(2)C=CHF)L(2), via OsClF(=CHMe)L(2) and OsHCl(H(2))(C(2)H(4))L(2), all of which are detected. DFT(B3PW91) calculations of the potential energy and free energy at 298 K of possible intermediates show the importance of entropy to account for their thermodynamic accessibility. Calculations of unimolecular C-F cleavage of coordinated C(2)H(3)F confirms the high activation energy of this process. Catalysis by HF is thus suggested to account for the fast observed reactions, and scavenging of HF with NEt(3) changes the product to exclusively Os(H)(2)Cl(CCH(3))L(2). The analogous reaction of Os(H)(3)ClL(2) with H(2)C=CF(2) produces exclusively OsHFCl(=CCH(3))L(2) and HF, and the latter is again suggested to catalyze C-F scission via the observed intermediates Os(H)(2)Cl(CF(2)CH(3))L(2) and OsHCl(=CFMe)L(2).     

Synthesis and Characterizations of Ti(O‐i‐Pr)Cl3(THF)(PhCOR) (R = H,Me, Ph) and Ti(O‐i‐Pr)Cl3(PhCOR)2 (R = Me,Ph). The Molecular Structure of Ti(O‐i‐Pr)Cl3(PhCOPh)2

A series of titanium(IV) complexes Ti(O‐i‐Pr)Cl₃(THF)(PhCOR) (R = H ( 1 ), CH₃ ( 2 ), or Ph ( 3 )) is prepared quantitatively from reactions of [Ti(O‐i‐Pr)Cl₂(THF)(μ‐Cl)]₂ with 2 molar equiv. PhCOR. Treatment of Ti(O‐i‐Pr)Cl₃ with 2 molar equiv. of PhCOR affords the disubstituted complexes Ti(O‐i‐Pr)Cl₃(PhCOR)₂ (R = CH₃ ( 4 ) or Ph ( 5 )). The ¹³C NMR study of these complexes shows that the relative bonding abilities are in the order of PhCOCH₃ > PhCHO > PhCOPh. The molecular structure of 5 reveals that one of the benzophenone ligands is trans to the strongest 2‐propoxide ligand with a long Ti‐O(carbonyl) distance of 2.193(5) Å which is much longer than the other Ti‐O(carbonyl) distance of 2.097(4) Å by ?0.1 Å. All ligands cis to the alkoxide ligand are bending away from the alkoxide ligand with the RO‐Ti‐L angles ranging from 93.6(2) to 99.0(2)°.     

Synthesis of the elusive (R3P)2MF2 (M = Pd, Pt) complexes

The synthesis and characterization of previously unknown palladium(II) and platinum(II) difluoro phosphine complexes are described. These complexes can be obtained either via a halide metathesis reaction with AgF in dichloromethane or by reacting the corresponding dimethyl complexes with XeF2. While the Pt(II) complexes can be prepared with both aryl- and alkyl-phosphine ligands, the stability of the Pd(II) complexes is limited to those having cis-oriented trialkyl phosphine ligands.     

Synthesis of rhombohedral borates Ba3R(BO3)3, R = Pr-Dy

Compounds with the composition Ba₃R(BO₃)₃ (R = Pr, Nd, Sm, Eu, Gd, Tb, Dy) were obtained by solid-phase reactions at 1000°C. The compounds were studied by the methods of IR spectroscopy and X-ray and differential thermal analyses. Physicochemical properties of some of them were determined.     

Co-ordination Chemistry of ButCP,Mono-and Diphospha-allenes (R1P=C=CR2 and R1P=C=PR1) and 1,3-Diphosphacyclobutadiene

Abstract

A variety of novel coordination complexes derived from phospha-alkynes, and mono- and diphospha-allenes will be described.     

Übergangsmetallphosphidokomplexe. XVII. Reaktionen von Silylphosphanderivaten mit (R3P)2PtCl2 (R = Et,Ph)

Transition Metal Phosphido Complexes. XVII. Reactions of Silylphosphine Derivatives with (R₃P)₂PtCl₂ (R ? Et, Ph) In reactions of (Et₃P)₂PtCl₂ 1a with LiP(SiMe₃)₂ at low temperatures the substitution products (Et₃P)₂Pt[P(SiMe₃)₂]Cl 2a and (Et₃P)₂Pt[P(SiMe₃)₂]₂ 3a are formed first. At ambient temperature from 3a P(SiMe₃)₃ and PEt₃ are split off yielding a mixture of the diphosphene complex (Et₃P)₂Pt[η²-(PSiMe₃)₂] 4a and the phosphido-bridged platinum(I) complex [Et₃PPtP(SiMe₃)₂]₂(Pt? Pt) 5a . Heating 2a to 80°C in solution gives the P₂-complex [(Et₃P)₂Pt]₂P₂ 6a . 4a and 6a are also obtained reacting 1a with [(Me₃Si)₂P]₂. From 1a and [Me₃Si(Me₃C)P]₂ the diphosphene complex (Et₃P)₂Pt[η²-(PCMe₃)₂] 8a is available. In the reaction of 1a with (Me₃Si)₂P? P(CMe₃)SiMe₃ the formation of the asymmetric diphosphene complex (Et₃P)₂Pt[η²-Me₃SiP?PCMe₃] 9a can be proved n.m.r. spectroscopically. Analogous reactions of (Ph₃P)₂PtCl₂ 1b with LiP(SiMe₃)₂, and with [Me₃Si(Me₃C)P]₂ are much more difficult to survey. The complexes (Ph₃P)₂Pt[η²-(PSiMe₃)₂] 4b , [(Ph₃P)₂Pt]₂P₂ 6b , and (Ph₃P)₂Pt[η²-(PCMe₃)₂] 8b are formed in n.m.r. spectroscopically detectable amounts but could not be isolated as pure compounds. N.m.r. and mass spectral data are reported.     

Spectroscopic detection and theoretical confirmation of the role of Cr2(CO)5(C5R5)2 and .Cr(CO)2(ketene)(C5R5) as intermediates in carbonylation of N=N=CHSiMe3 to O=C=CHSiMe3 by .Cr(CO)3(C5R5) (R = H, CH3)

Conversion of N=N=CHSiMe3 to O=C=CHSiMe3 by the radical complexes .Cr(CO)3C5R5 (R = H, CH3) derived from dissociation of [Cr(CO)3(C5R5)]2 have been investigated under CO, Ar, and N2 atmospheres. Under an Ar or N2 atmosphere the reaction is stoichiometric and produces the Cr[triple bond]Cr triply bonded complex [Cr(CO)2(C5R5)]2. Under a CO atmosphere regeneration of [Cr(CO)3(C5R5)]2 (R = H, CH3) occurs competitively and conversion of diazo to ketene occurs catalytically as well as stoichiometrically. Two key intermediates in the reaction, .Cr(CO)2(ketene)(C5R5) and Cr2(CO)5(C5R5)2 have been detected spectroscopically. The complex .Cr(13CO)2(O=13C=CHSiMe3)(C5Me5) has been studied by electron spin resonance spectroscopy in toluene solution: g(iso) = 2.007; A(53Cr) = 125 MHz; A(13CO) = 22.5 MHz; A(O=13C=CHSiMe3) = 12.0 MHz. The complex Cr2(CO)5(C5H5)2, generated in situ, does not show a signal in its 1H NMR and reacts relatively slowly with CO. It is proposed to be a ground-state triplet in keeping with predictions based on high level density functional theory (DFT) studies. Computed vibrational frequencies are also in good agreement with experimental data. The rates of CO loss from 3Cr2(CO)5(C5H5)2 producing 1[Cr(CO)2(C5H5)]2 and CO addition to 3Cr2(CO)5(C5H5)2 producing 1[Cr(CO)3(C5H5)]2 have been measured by kinetics and show DeltaH approximately equal 23 kcal mol(-1) for both processes. Enthalpies of reduction by Na/Hg under CO atmosphere of [Cr(CO)n(C5H5)]2 (n = 2,3) have been measured by solution calorimetry and provide data for estimation of the Cr[triple bond]Cr bond strength in [Cr(CO)2(C5H5)]2 as 72 kcal mol(-1). The complex [Cr(CO)2(C5H5)]2 does not readily undergo 13CO exchange at room temperature or 50 degrees C implying that 3Cr2(CO)5(C5H5)2 is not readily accessed from the thermodynamically stable complex [Cr(CO)2(C5H5)]2. A detailed mechanism for metalloradical based conversion of diazo and CO to ketene and N2 is proposed on the basis of a combination of experimental and theoretical data.     

Phosphinophosphiniden-Phosphorane tBu2P?P = P(R)tBu2 aus Li(THF)2[η2-(tBu2P)2P] und Alkylhalogeniden

The Phosphinophosphinidene-phosphoranes ^tBu₂P? P = P(R)^tBu₂ from Li(THF)₂[η²-(^tBu₂P)₂P] and Alkyl Halides We report the formation of ^tBu₂P? P = P(R)^tBu₂ a and (^tBu₂)₂PR b (with R = Me, Et, ⁿPr, ⁱPr, ⁿBu, PhCH₂, H₂C = CH? CH₂ and CF₃) reactions of Li(THF)₂[η²-(^tBu₂P)₂P] 2 with MeCl, MeI, EtCl, EtBr, ⁿPrCl, ⁿPrBr, ⁱPrCl, ⁿBuBr, PhCH₂Cl, H₂C = CH? CH₂Cl or CF₃Br. In THF solutions the ylidic compounds a predominate, whereas in pentane the corresponding triphosphanes b are preferrably formed. With ClCH₂? CH = CH₂ only b is produced; CF₃Br however yields both ^tBu₂P? P = P(Br)^tBu₂ and ^tBu₂P? P = P(CF₃)^tBu₂, but no b . The ratio of a:b is influenced by the reaction temperature, too. The compounds ^tBu₂P? P = P(Et)^tBu₂ 4a and (^tBu₂P)₂PEt 4 b , e. g., are produced in a ratio of 4:3 at ?70°C in THF, and 1:1 at 20°C; whereas 1:1 is obtained at ?70°C in pentane, and 1:2 at 20°C. Neither ^tBuCl nor H₂C = CHCl react with 2 . The compounds a decompose thermally or under UV irradiation forming ^tBu₂PR and the cyclophosphanes (^tBu₂P)_nP_n.     

The coordination chemistry of selenophosphite ligands. Synthesis and characterization of heterometallic tetranuclear clusters [M{CpFe(CO)(2)P(Se)(OR)(2)}(3)](PF(6)) (M = Cu, Ag; R = (n)Pr, (i)Pr) and [Cu(mu-X) {CpFe(CO)(2)P(Se)(O(i)Pr)(2)}](2) (X = Cl, Br)

A neutral selenium donor ligand, [CpFe(CO)(2)P(Se)(OR)(2)] is used for the construction of Cu(I) and Ag(I) complexes with a well-defined coordination environment. Four clusters [M{CpFe(CO)(2)P(Se)(OR)(2)}(3)](PF(6)), (where M = Cu, R = (n)Pr, ; R = (i)Pr, and M = Ag, R = (n)Pr, ; R = (i)Pr, ) are isolated from the reaction of [M(CH(3)CN)(4)(PF(6))] (where M = Cu or Ag) and [CpFe(CO)(2)P(Se)(OR)(2)] in a molar ratio of 1 : 3 in acetonitrile at 0 degrees C. The reaction of [CpFe(CO)(2)P(Se)(O(i)Pr)(2)] with cuprous halides in acetone produce two mixed-metal, Cu(I)(2)Fe(II)(2) clusters, [Cu(mu-X) {CpFe(CO)(2)P(Se)(O(i)Pr)(2)}](2) (X = Cl, ; Br, ). All six clusters have been fully characterized spectroscopically ((1)H, (13)C, (31)P, and (77)Se NMR, IR), and by elemental analyses. X-Ray crystal structures of and consist of discrete cationic clusters in which three iron-selenophosphito fragments are linked to the central copper or silver atom via selenium atoms. Both clusters and crystallize in the noncentrosymmetric, hexagonal space group P6[combining macron]2c. The coordination geometry around the copper or silver atom is perfect trigonal-planar with Cu-Se and Ag-Se distances, 2.3505(7) and 2.5581(7) A, respectively. X-Ray crystallography also reveals that each copper center in neutral heterometallic clusters and is trigonally coordinated to two halide ions and a selenium atom from the selenophosphito-iron moiety. The structures can also be delineated as a dimeric unit which is generated by an inversion center and has a Cu(2)X(2) parallelogram core. The dihedral angle between the Cu(2)X(2) plane and the plane composed of Cp ring is found to be 24.62 and 84.58 degrees for compound and , respectively. Hence the faces of two opposite Cp rings are oriented almost perpendicular to the Cu(2)X(2) plane in , but are close to be parallel in . This is the first report of the coordination chemistry of the anionic selenophosphito moiety [(RO)(2)PSe](-), the conjugated base of a secondary phosphine selenide, which acts as a bridging ligand with P-coordination on iron and Se-coordination to copper or silver.     

Reactivity of the isolable disilene R*PhSi=SiPhR* (R* = SitBu3)

The disilene R*PhSi=SiPhR* (R* = supersilyl = SitBu3), which can be quantitatively prepared by dehalogenation of the disilane R*PhClSi-SiBrPhR* with NaR* (yellow, water- and air-sensitive crystals; decomp at ca. 70 degrees C; Si=Si distance 2.182 A), is comparatively reactive. It transforms 1) with Cl2, Br2, HCl, HBr, and HOH under 1,2-addition into disilanes R*PhXSi-SiX'PhR* (X/X' = Hal/Hal, H/Hal, H/OH), 2) with O2, S8, and Sen under insertion into 1,3-disiletanes R*PhSi(-Y-)2SiPhR* (Y = O, S, Se), 3) with Me2C=CH2 under ene reaction into the disilane R*PhRSi-SiHPhR* (R = CH2-CMe=CH2), 4) with N2O, Ten, tBuN identical to C, and Me3SiN=N=N under [2 + 1] cycloaddition into disiliranes -R*PhSi-Y-SiPhR*- (Y = O, Te, C=NtBu, NSiMe3; P4 adds 2 molecules of disilene), 5) with CO2, COS, PhCHO, and Ph2CS under [2 + 2] cycloaddition into disiletanes -R*PhSi-SiPhR*-Y-CO- (Y = O, S) as well as -R*PhSi-SiPhR*-Y-CRPh- (Y/R = O/H, S/Ph), 6) with CS2 and CSe2 under [2 + 3] cycloaddition into ethenes R*2Ph2Si2Y2C = CY2Si2Ph2R*2 (Y = S, Se), and 7) with CH2 = CMe-CMe=CH2 and Ph2CO under [2 + 4] cycloaddition into "Diels-Alder adducts". X-ray structure analyses of seven of these compounds are presented.     

Computational study of sulfur atom-transfer reactions from thiiranes to ER3 (E = As, P; R = CH3, Ph)

Computational estimates have been made for the P=S and As=S bond strengths in triphenylphosphine sulfide and triphenylarsine sulfide, on the basis of G3 calculations for the methyl analogues and isodesmic-exchange reactions. Also, with the performance of the G3 method level for related compounds taken into consideration, the best estimates are 82 and 68 kcal/mol, respectively. While the value for triphenylarsine sulfide is within 2 kcal/mol of the single experimental estimate, that for triphenylphosphine sulfide is lower by 6 kcal/mol. (Capps, K. B.; Wixmerten, B.; Bauer, A.; Hoff, C. D. Inorg. Chem. 1998, 37, 2861-2864.) Despite virtually identical electronegativities of P and As, it is found that there is greater charge separation in the P=S bond. It is found that S atom transfer from thiiranes to arsines is exothermic.     

Crystal structures and properties of SrLnCuS3 (Ln = La,Pr)

The crystal structures of SrLnCuS₃ (Ln = La, Pr) have been refined using X-ray powder diffraction data and the derivative difference minimization method in the anisotropic approximation for all atoms. The crystals are orthorhombic, space group Pnma, BaLaCuS₃ structural type, unit cell parameters a = 11.2415(1) Å, b = 4.11053(6) Å, c = 11.5990(1) Å, V = 535.97(1) ų (SrLaCuS₃) and a = 11.1171(1) Å, b = 4.09492(6) Å, c = 11.5069(2) Å, V = 523.84(1) ų (SrPrCuS₃). The crystallographic positions of strontium and lanthanides are mixed by 21 and 11%, respectively. The SrLa-S and SrPr-S bond lengths range from 2.969(3) to 3.131(3) Å and from 2.924(2) to 3.056(2) Å, respectively. Distorted CuS₄ tetrahedra form chains running along the b axis. One-capped Sr/LnS₇ trigonal prisms form a three-dimensional structure with channels accommodating copper ions. The temperatures and enthalpies of incongruent melting are, respectively, 1513 K and 18 J/g (SrLaCuS₃) and 1426 K and 34 J/g (SrPrCuS₃). The compounds are IR transparent in the region of 3000–1800 cm^?1.     

Unusual reactivity of a sterically hindered diphosphazane ligand, EtN{P(OR)(2)}(2), (R = C(6)H(3)(Pr(I))(2)-2,6) towards (eta(3)-allyl)palladium precursors

The reactivity of (eta(3)-allyl)palladium chloro dimers [(1-R-eta(3)-C(3)H(4))PdCl](2) (R = H or Me) towards a sterically hindered diphosphazane ligand [EtN{P(OR)(2)}(2)] (R = C(6)H(3)(Pr(i))(2)-2,6), has been investigated under different reaction conditions. When the reaction is carried out using NH(4)PF(6) as the halide scavenger, the cationic complex [(1-R-eta(3)-C(3)H(4))Pd{EtN(P(OR)(2))(2)}]PF(6) (R = H or Me) is formed as the sole product. In the absence of NH(4)PF(6), the initially formed cationic complex, [(eta(3)-C(3)H(5))Pd{EtN(P(OR)(2))(2)}]Cl, is transformed into a mixture of chloro bridged complexes over a period of 4 days. The dinuclear complexes, [(eta(3)-C(3)H(5))Pd(2)(mu-Cl)(2){P(O)(OR)(2)}{P(OR)(2)(NHEt)}] and [Pd(mu-Cl){P(O)(OR)(2)}{P(OR)(2)(NHEt)}](2) are formed by P-N bond hydrolysis, whereas the octa-palladium complex [(eta(3)-C(3)H(5))(2-Cl-eta(3)-C(3)H(4))Pd(4)(mu-Cl)(4)(mu-EtN{P(OR)(2)}(2))](2), is formed as a result of nucleophilic substitution by a chloride ligand at the central carbon of an allyl fragment. The reaction of [EtN{P(OR)(2)}(2)] with [(eta(3)-C(3)H(5))PdCl](2) in the presence of K(2)CO(3) yields a stable dinuclear (eta(3)-allyl)palladium(I) diphosphazane complex, [(eta(3)-C(3)H(5))[mu-EtN{P(OR)(2)}(2)Pd(2)Cl] which contains a coordinatively unsaturated T-shaped palladium center. This complex exhibits high catalytic activity and high TON's in the catalytic hydrophenylation of norbornene.     

Activation of P5R5 (R = Ph, Et) by a Rh-beta-diketiminate complex

(NacNac)Rh(C8H14))(N2) reacts with P5R5 to give complexes of formula (NacNac)Rh(P5R5) (R = Ph, Et); in the former species inversion of a P atom of P5Ph5 allows coordination to a Rh(I) centre, whereas in the later species a P-P bond undergoes oxidative addition to give a formally Rh(III) species.