Preparation,spectral characterization,and single crystal X-ray structures of cis and trans isomers of 2,4,6-trifluoroethoxy-1,3,5-triethyl-1,3,5,2λ5, 4λ5, 6λ5-triazatriphosphorinane-2,4,6-trioxide, [ETNP(O)(OCH2CF3)]3

Oxidation of the cis isomer of the λ³-cyclotriphosphazane [EtNP(OCH₂CF₃)]₃ with trimethylamine-N-oxide (TMNO) gives the cis isomer of trioxo-λ⁵-cyclotriphosphazane [EtNP(O)(OCH₂CF₃)]₃; the trans isomer of [EtNP(O)(OCH₂CF₃)]₃ is obtained by the treatment of a cis and trans mixture of [EtNP(OCH₂CF₃)]₃ with aqueous H₂O₂. The two trioxocyclotriphosphazanes have been characterized by elemental analysis, IR, and NMR (¹H, ¹³C, ¹⁹F, and ³¹P) spectroscopy. The solid state structures of both the isomers have been determined by single crystal X-ray diffraction. The six-membered P₃N₃ ring in both the isomers exhibits a twist-boat conformation; in the cis isomer, the trifluoroethoxy substituents lie on the same side of the ring, whereas, in the trans isomer, two trifluoroethoxy groups are on one side of the ring and the third on the other side of the ring. Crystal data for cis-[EtNP(O)(OCH₂CF₃)]₃: monoclinic, P 2₁/ n , a = 13.593(3), b = 9.721(2), c = 17.539(3) Å, β = 99.49(2)°, V = 2286(1) ų, Z = 4, and Final R = 0.047. Crystal data for trans-[EtNP(O)(OCH₂CF₃)]₃: monoclinic, P 2₁/ n , a = 11.685(4), b = 15.115(5), c = 13.233(5) Å, - = 102.21(3)°, V = 2284(1) ų, Z = 4, and Final R = 0.078.     

Reactions of Pyridyl‐Functionalized,Chelating λ3‐Phosphinines in the Coordination Environment of RhIII and IrIII

Rh^III and Ir^III complexes based on the λ³‐P,N hybrid ligand 2‐(2′‐pyridyl)‐4,6‐diphenylphosphinine ( 1 ) react selectively at the P?C double bond to chiral coordination compounds of the type [( 1 H ? OH)Cp*MCl]Cl ( 2 , 3 ), which can be deprotonated with triethylamine to eliminate HCl. By using different bases, the pK_a value of the P? OH group could be estimated. Whereas [( 1 H ? O)Cp*IrCl] ( 4 ) is formed quantitatively upon treatment with NEt₃, the corresponding rhodium compound [( 1 H ? O)Cp*RhCl] ( 5 ) undergoes tautomerization upon formation of the λ⁵σ⁴‐phosphinine rhodium(III) complex [( 1? OH)Cp*RhCl] ( 6 ) as confirmed by single‐crystal X‐ray diffraction. Blocking the acidic P? OH functionality in 3 by introducing a P? OCH₃ substituent leads directly to the λ⁵σ⁴‐phosphinine iridium(III) complex ( 8 ) upon elimination of HCl. These new transformations in the coordination environment of Rh^III and Ir^III provide an easy and general access to new transition‐metal complexes containing λ⁵σ⁴‐phosphinine ligands.     

Mono and Bisphosphonates from Perfluoro Olefins and Polyfunctional Fluoro Ketones. Syntheses,Molecular Structure and Derivatives

Perfluoroalkenyl phosphonates were formed along with Me₃SiF using CF₃CF=CF₂, CF₃CH=CF₂, F₅SCF=CF₂ or F₅SCH=CF₂ and silylated phosphites, (R¹O)₂POSiMe₃ (R¹=Et, SiMe₃). This straightforward method could be extended to perfluorobutadienes CF₂=C(R^F)C(R^F)=CF₂ (R^F F=F, CF₃). The formation of CF₃C(=O)P(=O)(OSiMe₃)₂ and further reactions to yield bisphosphonates will be described. Acetylphosphonates, R²C(=O)P(=O)(OSiMe₃)₂ (R²=CH₃, CF₃) reacted with the ketimine, CH₃C(=NiPr)Ph to give α-hydroxy-γ-imino phosphonates. Trifluoroacetylphenol and 2,6-bis(trifluoracetyl)-4-methyl-phenol have been proven to be versatile precursors for α-and γ-hydroxy phosphonates. Intermediates in these reactions were found to be cyclic λ⁵σ⁵P species.     

Advances in Trifluoromethylating Phosphorus Compounds

Abstract

The System CF₃I/Me₃P is re-investigated and Me₂PCF₃, Me₄P⁺γ, (CF₃)₂PMe₃, Me₃PI₂, [Me₃(CF₃)P]⁺γ are found as products. Using CF₃Br/P(NEt₂)₃ the phosphines R¹ ₂PCF₃ and R¹P(CF₃)₂ (e.g. R¹ = Me, iPr, NEt₂) can be obtained which are precursors either for phosphoranes (e.g. 1,2λ⁵σ⁵-oxaphosphetanes) or phosphonium salts (e.g. [R¹ ₂(Me)PCF₃]⁺X^? or [R¹(Me)P(CF₃)₂X^?]. The latter are deprotonated to furnish methylene phosphoranes R¹ ₂(CH₂=)PCF₃ or R¹(CH₂=)P(CF₃)₂, reactive synthons. From CF₃Br/P(NEt₂)₃/P(OPh)₃ the phosphine P(CF₃)₃ is available, which turned out to be a potent electrophile. Amido phospites ROP(NEt₂)₂ and halides R²X (R²=CCl₂CF₃, X=Cl; R²=CF=CFCF₃, X=F; R²=C₆F₅, X=Br, I; R²=C(CF₃)₃, X=Br; R²=SCF₃, X=CF₃) undergo an ARBUZOV reaction.     

Synthese von Oxovanadium(V)‐halogeno‐Komplexen der tripodalen Sauerstoffliganden LR— = [η5‐(C5H5)Co{PR2(O)}3]—, R = OMe,OEt

Syntheses of Oxovanadium(V) Halide Complexes Stabilized with Tripodal Oxygen Ligands L_R^— = [η⁵‐(C₅H₅)Co{PR₂(O)}₃]^—, R = OMe, OEt The sodium salts of the tripodal oxygen ligands L_R^— = [η⁵‐(C₅H₅)Co{PR₂(O)}₃]^— (R = OMe, OEt) react with the oxovanadium halides V(O)F₃ and V(O)Cl₃ to yield deep red compounds of the type [V(O)X₂L_R]. Halide exchange reactions with [V(O)Cl₂L_OMe] und [V(O)F₂L_OMe] aiming at the preparation of the analogous bromide complex [V(O)Br₂L_OMe] led to the isomer [VO(L_OMe)₂][V(O)Br₄]. The crystal structure of [V(O)Cl₂L_OMe] has been determined by single crystal x‐ray diffraction. The compound crystallizes in the monoclinic space group P2₁/n with a = 9.6332(8), b = 15.0312(11) and c = 15.3742(12)Å, β = 100.181(8)°. The coordination around vanadium is distorted octahedral.     

Studies of phosphazenes. Aminolysis reactions of pentachloro(2′, 2′, 2′-triphenyl-phosphazen-1′-yl) cyclotriphosphazene,N3P3Cl5(NPPh3)

The reactions of pentachloro(2′, 2′, 2′-triphenylphosphazen-1′-yl)cyclotriphosphazene, N₃P₃Cl₅(NPPh₃), with primary and secondary amines have been investigated using diethyl ether, methyl cyanid or benzene as the solvent. The structures of the products obtained, N₃P₃Cl_5minus;nR_n(NPPh₃) [n = 1, R = NHMe, NHBu^t, NMe₂, NC₅H₁₀, NEt₂; n = 2, R = NMe₂, NC₅H₁₀, NEt₂; n = 3, R = NMe₂, NHBu^t; n = 5, R = NMe₂] are elucidated by ¹H and ³¹P NMR spectroscopy. The ? NPPh₃ substituent exerts a pronounced geminal directing influence on incoming secondary amino nucleophiles; compounds containing a ≡ PCl(NPPh₃) group are not formed at the bis and subsequent stages of chlorine replacement. The reactions that involve primary amines follow the pattern established for the analogous reactions of hexachlorocyclotriphosphazene. The effect of solvent and possible mechanism(s) are discussed.     

Synthese von Fluoro-λ5-monophosphazenen und Fluoro-1, 3-diaza-2λ5, 4λ5-diphosphetidinen mittels der Staudinger-Reaktion

Synthesis of Fluoro-λ⁵-monophosphazenes and Fluoro-1,3-diaza-2λ⁵,4λ⁵-diphosphetidines by Means of the Staudinger Reaction 35 Tetrafluoro- and 2 difluorodiaza-diphosphetidines as well as 4 difluoro- and 30 monofluoro-λ⁵-monophosphazenes were prepared by the Staudinger reaction between tervalent phosphorus fluorides, R_nPF_3?n (n = 1, 2; R = R₂N, (CH₂)₅N, O(CH₂)₄N, RO, (CH₂O)₂, alkyl, aryl) and phenylazides, X? C₆H₄N₃ (X = H, 4-CH₃, 4-Cl, 4-Br, 4-NO₂, 3-NO₂). PF₃ does not react with phenylazide The influence of substituents on the structure of the reaction products is discussed. Kinetic measurements allowed to determine the constants λ^P_I of the substituents (CH₂)₅N, O(CH₂)₄N and R(C₆H₅)N (R = CH₃, C₂H₅, n-C₄H₉).     

REACTIONS OF A PHOSPHORANIMINE ANION WITH SOME ORGANIC ELECTROPHILES

Abstract

The reactions of a variety of electrophiles with the N-silyl-P-trifluoroethoxyphosphoranimine anion Me₃Sin°P(Me)(OCH₂CF₃)CH^? ₂ (1a), prepared by the deprotonation of the dimethyl precursor Me₃SiN[dbnd]P(OCH₂CF₃)Me₂ (1) with n-BuLi in Et₂O at-78°C, were studied. Thus, treatment of 1a with alkyl halides, ethyl chloroformate, or bromine afforded the new N-silylphosphoranimine derivatives Me₃SiN[dbnd]P(Me)(OCH₂CF₃)CH₂R [2: R = Me, 3: R = CH₂Ph, 4: R = CH[sbnd]CH₂, 5: R = C(O)OEt, and 6: R = Br]. In another series, when 1a was allowed to react with various carbonyl compounds, 1,2-addition of the anion to the carbonyl group was observed. Quenching with Me₃SiCl gave the O-silylated products Me₃SiN[dbnd]P(Me)(OCH₂CF₃)CH₂°C(OSiMe₃)R¹R² [7: R ¹ = R ² = Me; 8: R ¹ = Me, R ² = Ph; 9: R¹ = Me, R ² = CH[sbnd]CH₂; and 10: R ¹ = H, R ² = Ph]. Compounds 2–10 were obtained as distillable, thermally stable liquids and were characterized by NMR spectroscopy (¹H, ¹³C, and ³¹P) and elemental analysis.     

Ethylene/α‐olefin copolymerization with bis(β‐enaminoketonato) titanium complexes activated with modified methylaluminoxane

Copolymerizations of ethylene with α‐olefins (i.e., 1‐hexene, 1‐octene, allylbenzene, and 4‐phenyl‐1‐butene) using the bis(β‐enaminoketonato) titanium complexes [(Ph)NC(R₂)CHC(R₁)O]₂TiCl₂ ( 1a : R₁ = CF₃, R₂ = CH₃; 1b : R₁ = Ph, R₂ = CF₃; and 1c : R₁ = t‐Bu, R₂ = CF₃), activated with modified methylaluminoxane as a cocatalyst, have been investigated. The catalyst activity, comonomer incorporation, and molecular weight, and molecular weight distribution of the polymers produced can be controlled over a wide range by the variation of the catalyst structure, α‐olefin, and reaction parameters such as the comonomer feed concentration. The substituents R₁ and R₂ of the ligands affect considerably both the catalyst activity and comonomer incorporation. Precatalyst 1a exhibits high catalytic activity and produces high‐molecular‐weight copolymers with high α‐olefin insertion. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 6323–6330, 2005     

Ethylene–propylene copolymerization with bis(β‐enaminoketonato) titanium complexes activated with modified methylaluminoxane

Ethylene–propylene copolymerization, using [(Ph)NC(R₂)CHC(R₁)O]₂TiCl₂ (R₁ = CF₃, Ph, or t‐Bu; R₂ = CH₃ or CF₃) titanium complexes activated with modified methylaluminoxane as a cocatalyst, was investigated. High‐molecular‐weight ethylene–propylene copolymers with relatively narrow molecular weight distributions and a broad range of chemical compositions were obtained. Substituents R₁ and R₂ influenced the copolymerization behavior, including the copolymerization activity, methylene sequence distribution, molecular weight, and polydispersity. With small steric hindrance at R₁ and R₂, one complex (R₁ = CF₃; R₂ = CH₃) displayed high catalytic activity and produced copolymers with high propylene incorporation but low molecular weight. The microstructures of the copolymers were analyzed with ¹³C NMR to determine the methylene sequence distribution and number‐average sequence lengths of uninterrupted methylene carbons. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 5846–5854, 2006     

Quasi‐living copolymerization of ethylene with 1‐hexene by heteroligated (salicylaldiminato β‐enaminoketonato) titanium complexes

A series of heteroligated (salicylaldiminato)(β‐enaminoketonato)titanium complexes [3‐Bu^t‐2‐OC₆H₃CH = N(C₆F₅)] [PhN = C(R₁)CHC(R₂)O]TiCl₂ [ 3a : R₁ = CF₃, R₂ = ^tBu; 3b : R₁ = Me, R₂ = CF₃; 3c : R₁ = CF₃, R₂ = Ph; 3d : R₁ = CF₃, R₂ = C₆H₄Ph(p ); 3e : R₁ = CF₃, R₂ = C₆H₄Ph(o ); 3f : R = CF₃, R₂ = C₆H₄Cl(p ); 3g : R₁ = CF₃; R₂ = C₆H₃Cl₂(2,5); 3h : R₁ = CF₃, R₂ = C₆H₄Me(p )] were investigated as catalysts for ethylene (co)polymerization. In the presence of modified methylaluminoxane as a cocatalyst, these complexes showed activities about 50%–1000% and 10%–100% higher than their corresponding bis(β‐enaminoketonato) titanium complexes for ethylene homo‐ and ethylene/1‐hexene copolymerization, respectively. They produced high or moderate molecular weight copolymers with 1‐hexene incorporations about 10%–200% higher than their homoligated counterpart pentafluorinated FI‐Ti complex. Among them, complex 3b displayed the highest activity [2.06 × 10⁶ g/mol_Ti?h], affording copolymers with the highest 1‐hexene incorporations of 34.8 mol% under mild conditions. Moreover, catalyst 3h with electron‐donating group not only exhibited much higher 1‐hexene incorporations (9.0 mol% vs. 3.2 mol%) than pentafluorinated FI‐Ti complex but also generated copolymers with similar narrow molecular weight distributions (M _w/M _n = 1.20–1.26). When the 1‐hexene concentration in the feed was about 2.0 mol/L and the hexene incorporation of resultant polymer was about 9.0 mol%, a quasi‐living copolymerization behavior could be achieved. ¹H and ¹³C NMR spectroscopic analysis of their resulting copolymers demonstrated the possible copolymerization mechanism, which was related with the chain initiation, monomer insertion style, chain transfer and termination during the polymerization process. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55 , 2787–2797     

Chiral Fluorinated α‐Sulfonyl Carbanions: Enantioselective Synthesis and Electrophilic Capture,Racemization Dynamics,and Structure

Enantiomerically pure triflones R¹CH(R²)SO₂CF₃ have been synthesized starting from the corresponding chiral alcohols via thiols and trifluoromethylsulfanes. Key steps of the syntheses of the sulfanes are the photochemical trifluoromethylation of the thiols with CF₃Hal (Hal=halide) or substitution of alkoxyphosphinediamines with CF₃SSCF₃. The deprotonation of RCH(Me)SO₂CF₃ (R=CH₂Ph, iHex) with nBuLi with the formation of salts [RC(Me)? SO₂CF₃]Li and their electrophilic capture both occurred with high enantioselectivities. Displacement of the SO₂CF₃ group of (S)‐MeOCH₂C(Me)(CH₂Ph)SO₂CF₃ (95 % ee) by an ethyl group through the reaction with AlEt₃ gave alkane MeOCH₂C(Me)(CH₂Ph)Et of 96 % ee. Racemization of salts [R¹C(R²)SO₂CF₃]Li follows first‐order kinetics and is mainly an enthalpic process with small negative activation entropy as revealed by polarimetry and dynamic NMR (DNMR) spectroscopy. This is in accordance with a C_α? S bond rotation as the rate‐determining step. Lithium α‐(S)‐trifluoromethyl‐ and α‐(S)‐nonafluorobutylsulfonyl carbanion salts have a much higher racemization barrier than the corresponding α‐(S)‐tert‐butylsulfonyl carbanion salts. Whereas [PhCH₂C(Me)SO₂tBu]Li/DMPU (DMPU = dimethylpropylurea) has a half‐life of racemization at ?105 °C of 2.4 h, that of [PhCH₂C(Me)SO₂CF₃]Li at ?78 °C is 30 d. DNMR spectroscopy of amides (PhCH₂)₂NSO₂CF₃ and (PhCH₂)N(Ph)SO₂CF₃ gave N? S rotational barriers that seem to be distinctly higher than those of nonfluorinated sulfonamides. NMR spectroscopy of [PhCH₂C(Ph)SO₂R]M (M=Li, K, NBu₄; R=CF₃, tBu) shows for both salts a confinement of the negative charge mainly to the C_α atom and a significant benzylic stabilization that is weaker in the trifluoromethylsulfonyl carbanion. According to crystal structure analyses, the carbanions of salts {[PhCH₂C(Ph)SO₂CF₃]Li? L }₂ ( L =2 THF, tetramethylethylenediamine (TMEDA)) and [PhCH₂C(Ph)SO₂CF₃]NBu₄ have the typical chiral C_α? S conformation of α‐sulfonyl carbanions, planar C_α atoms, and short C_α? S bonds. Ab initio calculations of [MeC(Ph)SO₂tBu]^? and [MeC(Ph)SO₂CF₃]^? showed for the fluorinated carbanion stronger n_C→σ* and n_O→σ* interactions and a weaker benzylic stabilization. According to natural bond orbital (NBO) calculations of [R¹C(R²)SO₂R]^? (R=tBu, CF₃) the n_C→σ*_{S? R} interaction is much stronger for R=CF₃. Ab initio calculations gave for [MeC(Ph)SO₂tBu]Li ? 2 Me₂O an O,Li,C_α contact ion pair (CIP) and for [MeC(Ph)SO₂CF₃]Li ? 2 Me₂O an O,Li,O CIP. According to cryoscopy, [PhCH₂C(Ph)SO₂CF₃]Li, [iHexC(Me)SO₂CF₃]Li, and [PhCH₂C(Ph)SO₂CF₃]NBu₄ predominantly form monomers in tetrahydrofuran (THF) at ?108 °C. The NMR spectroscopic data of salts [R¹(R²)SO₂R³]Li (R³=tBu, CF₃) indicate that the dominating monomeric CIPs are devoid of C_α? Li bonds.     

P‐bis(trifluoromethyl) ylides: Synthesis and reactions

Bis(trifluoromethyl)phosphines RP(CF₃)₂ (R = Me, NEt₂) were methylated by MeOSO₂CF₃, yielding the respective phosphonium salts [RP(CF₃)₂Me]⁺ and CF₃SO₃⁻. Deprotonation using MeNP(NEt₂)₃ led to the phosphorus ylides RP(CF₃)₂CH₂, stable in solution at ambient temperature, which could be converted into 1,2λ⁵σ⁵‐oxaphosphetanes by adding hexafluoroacetone. © 2002 Wiley Periodicals, Inc. Heteroatom Chem 13:650–653, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10061     

F2P(NEt2)3 – Difluorphosphorane als vielseitige Fluoridierungsmittel

F₂P(NEt₂)₃ – Difluorophosphanes as Versatile Fluoridation Agent F₂P(NEt₂)₃ ( 1 ), prepared by the reaction of P(NEt₂)₃ with SF₄ (3:2) in Et₂O at –78°C, acts as fluoridation agent on Lewis acids such as AlMe₃, GaMe₃, or [Mes₃V(THF)] by transfer of a F ^– ion. The products [FP(NEt₂)₃][Me₃MF] [M = Al ( 2 ), Ga ( 3 )] and [FP(NEt₂)₃][Mes₃VF] ( 4 ) were characterized by NMR, IR and MS techniques. With 1 and 4 an X‐ray structure determination could be performed. According to them 1 consists of trigonal‐bipyramidal λ⁵‐phosphane molecules with an occupation of the axial positions by F^– ligands. In 4 the centers of the cations [FP(NEt₂)₃]⁺ and of the anions [Mes₃VF]^– are distorted terahedrally coordinated.     

Über Sn[OCH(CF3)2]2 und Sn (OCH2CF3)2 (n = 1, 2)

On S_n[OCH(CF₃)₂]₂ and S_n(OCH₂CF₃)₂ (n = 1, 2) The sulfoxylates S[OCH(R)CF₃]₂, 1 and 2 and the disulfides S₂[OCH(R)CF₃]₂, 5 and 6 (R = CF₃, H) are obtained by reacting SCl₂ or S₂Cl₂, respectively, and the lithium alcoxides LiOCH(R)CF₃. Chlorine and compound 2 give ClS(O)OCH₂F₃ and CF₃CH₂Cl, whereas the sulfur-sulfur bound is cleaved in 5 and 6 furnishing SCI₂, 1 and 2 , respectively. The ¹⁹F n.m.r. spectrum of 5 and the ¹H n.m.r. spectrum of 6 are interpreted in terms of hindered rotation about the sulfur-sulfur axis.     

First P-trifluoromethylated ylides

Trifluoromethylated phosphines R₂PCF₃ (R = NEt₂, Me, ¹Pr) were methylated by CH₄OSO₂CF₃, yielding the corresponding phosphonium salts [R₂P(CF₃)CH₃] [F₃CSO₃]. Treatment with LiN(SiMe₃)₂ at −80°C furnished the phosphorus ylides R₂P(CF₃) = CH₂ that could be trapped by use of hexafluoroacetone with formation of stable 1,2λ⁵σ⁵-oxaphosphetanes. The single-crystal X-ray structure determination of one of these oxaphosphetanes showed a distorted trigonal bipyramid at phosphorus with the P-CF₃ group in an axial position. © 1996 John Wiley & Sons, Inc.     

The reduction of Ag(I) by α‐silylamines R2NCH2SiX3

The introduction of the organosilicon substituent into the α‐position of an amino group results in cardinal change of the amine reactivity irrespective of the coordination state of silicon. Amines R₂NCH₂SiX₃ [R = Me, Et, PhCH₂, CH₂SiX₃; SiX₃ = SiMe₃, Si(OEt)₃, Si(OCH₂CH₂)₃N] easily react with AgNO₃, to give the corresponding ammonium salts (R₂NH⁺ CH₂SiX₃)·NO₃^?. At the same time, Ag(I) is reduced to Ag(0). The interaction of N‐methyl‐N,N‐bis(silatranylmethyl)amine with AgNO₃ has been investigated by EPR spectroscopy. It was proven that the reaction involved a single electron transfer stage with the formation of cation radical of this amine. A mechanism of the reaction is proposed. Copyright © 2006 John Wiley & Sons, Ltd.     

Die Reaktion der Zweikomponentensysteme P(OR)3 − x(NR2)x (x = 0–3)/CCl4 und P4/CCl4 mit HF-Donatoren

Reaction of the Two-component Systems P(OR)_{3 ? x}(NR₂)_x (x = 0–3)/CCl₄ and P₄/CCl₄ with HF-Donators The combination of organylammonium fluorides and carbon tetrachloride is a good agent for oxidative fluorination of trivalent phosphorus compounds. As oxidation products [(RO)PF₅]^? and (RO)₂P(O)F are obtained from P(OR)₃, (Et₂N)₂P(O)F and (Et₂N)₂(EtO)PF₂ from P(OEt)(NEt₂)₂ as well as (Et₂N)₃PF₂ and [(Et₂N)₃PF]⁺ from P(NEt₂)₃. In the system R₂NH/CCl₄/Et₃N · n HF P₄ is fast oxidized forming [HPF₅]^?, R₂NH · PF₅ and (R₂N)₂P(O)F. In the case of simultaneous addition of alcohols [(RO)PF₅]^?, (RO)₃PO and (R₂N)₂P(O)F are formed. The reactions are controlled by the nucleophilic power and the concentration of fluoride, the acidity of the system, and the temperature.     

Synthesis and characterization of tris(η~5-cyclopentadienyl-μ-carbonyliron)-μ_3-nitrosyl cluster:X-ray structure of[(η~5-C_5H_5)(μ-CO)Fe]_3(μ3-NO).C_4H_8O

Tris)(η 5-cyclopentadienyl-μ-carbonyl-iron)-μ3-nitrosyl cluster was obtained from the reaction of cyclopentadienyl dicarbonyliron dimer with nitrogen monoxide in xylene. The cluster was characterized by elemental analyses, IR, MS and 1H NMR. The crystal structure of [(η5-C5H5)(μ-CO)Fe]3(μ3-NO).C4H8O was determined by X-ray diffraction analysis. It crystallizes in the orthorhombic space group Pnma, a=9.053(2), 6=10.545(2), c=22.525(4) A, V=2150.3(7) A3, Z=4,Dc=1.68 g.cm-3; structure solution and refinement based on 1141 reflections with I > 3.0 (I) (MoKa, A=0.71073 A) converged at R=0.0540. The infrared absorption band at 1325 cm-1 of the μ3-NO in the cluster, which is red shifted, shows that μ3-NO is activated.     

Influence of the Counterions on the Structures of Ternary Zn/Sn/Se Anions: Synthesis and Properties of [Rb10(H2O)14.5][Zn4(μ4‐Se)2(SnSe4)4] and [Ba5(H2O)32][Zn5Sn(μ3‐Se)4(SnSe4)4]

Reactions of rubidium or barium salts of the ortho‐selenostannate anion, [Rb₄(H₂O)₄][SnSe₄] ( 1 ) or [Ba₂(H₂O)₅][SnSe₄] ( 2 ) with Zn(OAc)₂ or ZnCl₂ in aqueous solution yielded two novel compounds with different ternary Zn/Sn/Se anions, [Rb₁₀(H₂O)_14.5][Zn₄(μ₄‐Se)₂(SnSe₄)₄] ( 3 ) and [Ba₅(H₂O)₃₂][Zn₅Sn(μ₃‐Se)₄(SnSe₄)₄] ( 4 ). 1 – 4 have been determined by means of single crystal X‐ray diffraction: 1 : triclinic space group lattice dimensions at 203 K: a = 8.2582(17) Å, b = 10.634(2) Å, c = 10.922(2) Å, α = 110.16(3)°, β = 91.74(3)°, γ = 97.86(3)°, V = 888.8(3) ų; R₁ [I > 2σ(I)] = 0.0669; wR₂ = 0.1619; 2 : orthorhombic space group Pnma; lattice dimensions at 203 K: a = 17.828(4) Å, b = 11.101(2) Å, c = 6.7784(14) Å, V = 1341.5(5) ų; R₁ [I > 2σ(I)] = 0.0561; wR₂ = 0.1523; 3 : triclinic space group ; lattice dimension at 203 K: a = 17.431(4) Å, b = 17.459(4) Å, c = 22.730(5) Å, α = 105.82(3)°, β = 99.17(3)°, γ = 90.06(3)°, V = 6563.1(2) ų; R₁ [I > 2σ(I)] = 0.0822; wR₂ = 0.1782; 4 : monoclinic space group P2₁/c; lattice dimensions at 203 K: a = 25.231(5) Å, b = 24.776(5) Å, c = 25.396(5) Å, β = 106.59(3)°, V = 15215.0(5) ų; R₁ [I > 2σ(I)] = 0.0767; wR₂ = 0.1734. The results serve to underline the crucial role of the counterion for the type of ternary anion to be observed in the crystal. Whereas Rb⁺(aq) stabilizes a P1‐type Zn/Sn/Se supertetrahedron in 3 like K⁺, the Ba²⁺(aq) ions better fit to an anionic T3‐type Zn/Sn/Se cluster arrangement as do Na⁺ ions. It is possible to estimate a radius:charge ratio for the stabilization of the two structural motifs.