Etude par spectrométrie de masse de l'ionisation de benzonitriles,de phénylacétonitriles et de N,N-diméthylanilines substitués

Molecular ionization potentials for series of compounds of the type X? C₆H₄? CN, X? C₆H₄CH₂? CN and X? C₆H₄? N(CH₃)₂ have been measured using the retarding potential difference technique (RPD. technique). The effect of the various substituents X is better correlated through the electrophilic Brown σ_p⁺ constants than through Hammett's σ_p values. No meta-para orientation effect is observed. For all the disubstituted phenyl compounds studied, the effect of the second substituent is affected by the electron-releasing power of the original substituent. Ionization potentials calculated by using the semi-empirical method of equivalent orbitals are in good agreement with the experimental values.     

Darstellung und Strukturen einiger N-(Tri-t-butoxysilyl)anilin-Derivate

Formation and Structures of N-(tri-t-butoxysilyl)aniline Compounds Para-substituted N-(tri-t-butoxysilyl)anilines (t-BuO)₃SiNRC₄H₄X-p, R = H, CH₃, with substituents of high electron affinity (X = CN, NO₂) were prepared by a one-pot reaction of tri-t-butoxychlorsilane, potassium t-butanolate and substituted anilines. Corresponding compounds with substituents of low electron affinity (X = OMe, H) preferably were prepared by metalation of anilines with sodium amide. Four crystal structures were determined. N-(tri-t-butoxysilyl)-p-nitro-aniline, N-methyl-(N-tri-t-butoxysilyl)-p-nitroaniline and N-(tri-t-butoxysilyl)-p-cyanoaniline crystallize at 298 K monoclinically, N-(tri-t-butoxysilyl)aniline crystallizes orthorhombically.     

Umsetzungen des Tetrakis[bis(trimethylsilyl)methyl]dialans(4) mit Methylisothiocyanat und Phenylisocyanat – Insertion in die Al?Al-Bindung bzw. Fragmentierung

Reactions of Tetrakis[bis(trimethylsilyl)methyl]dialane(4) with Methylisothiocyanate and Phenylisocyanate – Insertion into the Al? Al Bond and Fragmentation Tetrakis[bis(trimethylsilyl)methyl]dialane(4) 1 reacts with methyl isothiocyanate under cleavage of the C?S double bond and insertion of the remaining isonitrile fragment into the Al? Al bond. As shown by crystal structure determination a three-membered AlCN heterocycle ( 4 ) is formed by the interaction of the nitrogen lone pair with one unsaturated Al atom leading to an acute angle at the aluminium center N? Al? C of 36.6°. In contrast the reaction with the hard base phenyl isocyanate yields a mixture of many unknown compounds, from which only one ( 5 ) could be isolated in a very poor yield. The crystal structure of 5 reveals only one dialkyl aluminium fragment and a chelating ligand formed by the trimerization of the isocyanate under loss of one CO group and addition of a hydrogen atom. 5 was also synthesized by the specific reaction of the chloro dialkyl aluminium compound (R = CH(SiMe₃)₂) with Li[H₅C₆? N?C(O)? N(C₆H₅)? C(O)? N(H)? C₆H₅].     

Etude par Spectrométrie de Masse de Silanes et de Stannanes Aromatiques

The mass spectra of six compounds of the type Et₃Si? C₆H₄? ZR_xR_3?x (R=Et, R′ = CI, Z = Si, Sn) have been measured. The fragmentation patterns can be interpreted on the basis of an ionized hexa-1,3-diene-5-yne intermediate.     

Recherches sur la formation et la transformation des esters LXXXI [1]. Sur la réaction d'isothiocyanates avec l'acide hydrazinoéthylphosphorique,et de l'isocyanate de phényle avec l'acide colaminephosphoreux

Hydrazinoethyl phosphoric monoester has been prepared by reacting hydrazinoethanol with polyphosphoric acid, and isolated as di-sodium salt. Sodium hydrazinoethyl phosphate reacts with phenylisothiocyanate (in H₂O+ethanol) to yield mainly the derivative thiocarbamoylated at the substituted nitrogen atom. This derivative, heated for one night at 100° in 0.5 N HCl, is cyclized to 3-amino-2-phenylimino-thiazolidine in 62% yield. Sodium hydrazinoethyl phosphate reacts with o-methoxycarbonylphenyl isothiocyanate (in H₂O+dioxane) at the unsubstituted nitrogen atom to yield mainly the corresponding quinazoline derivative (IV, X = OPO₃Na₂). This derivative, heated for one night at 100° in 0.5 N HCl, is cyclized to 2-o-carboxyphenylamino-dihydro-δ²-1, 3, 4-thiadiazine (Va) in 55% yield (hydrolysis of the lactamic function as well). Aminoethyl phosphorous monoester (colaminephosphorous acid) reacted with phenylisocyanate (in H₂0+dioxane) in slightly alkaline medium (one equivalent of NaOH) yields sodium N-phenylcarbamoylaminoethyl phosphite. Refluxed for 20 minutes in 1N NaOH, this carbamoyl derivative is not cyclized but only hydrolyzed to the open-chained N-phenyl-N′-hydroxyethylurea (VII).     

Recherches sur la formation et la transformation des esters LXXII. Aryl(ou aralcoyl ou alcoyl)amino-2-tétrahydro-m-thiazines ou aryl(ou aralcoyl ou alcoyl)amino-2-dihydro-Δ2-m-thiazines et dérivés

3-Aminopropanol reacts with aryl(or aralkyl or alkyl)isothiocyanates R? N?C?S to yield the corresponding thio-ureas R? NH? CS? NH? (CH₂)₃OH which, refluxed with hydrochloric acid, are cyclized by elimination of water. The cyclization products are identical with the hydrothiazines resulting by elimination of sulfate or phosphate from the sulfuric or phosphoric monoesters of these thio-ureas. The resulting hydrothiazines are either 2-(R-imino)-tetrahydro-m-thiazines (I) or 2-(R-amino)-dihydro-Δ²-m-thiazines (II). Their structure has been established by comparison of their spectra with those of model compounds in one of which the C?N double bond is certainly endocyclic (2-methyl-dihydro-Δ²-m-thiazine), the other presenting an exocyclic C?N double bond (3-methyl-2-phenylimino-tetrahydro-m-thiazine). When R is an aryl group, the C?N double bond is exocyclic (structure I with >C?N? Ar), and one may presume that this structure is stabilized by resonance. When R is an aralkyl or an alkyl group, the C?N double bond is endocyclic (structure II). The nmr spectra were taken with three types of solvent: CDCl₃ or CCl₄; (CD₃)₂SO; CF₃COOH. In CF₃COOH solution the benzylic protons of the hydrothiazine with R = pF? C₆H₄CH₂? couple with NH (J=5,5cps) which confirms the endocyclic position of the C?N double bond in this case.     

Etude par Résonance Magnétique Nucléaire du carbone 13 de complexes du cobalt (III) et de la diméthylglyoxime

From a carbon magnetic resonance study of several alkylcobaloximes RCo(DMG)₂B (DMG = dimethylglyoximate monoanion), it was possible to estimate the α, β and γ effects of the Co(DMG)₂B group on the chemical shifts of the carbon atoms of various alkyl groups R. The chemical shifts of the carbon atoms belonging to the equatorial ligands and to the axial base B are not significantly affected by structural modification of the R groups. Values of δ in benzylcobaloximes XC₆H₄CH₂Co(DMG)₂B agree with a donor effect of the ? CH₂Co(DMG)₂B radical. Values of ¹J(¹³C? H) coupling constants, measured in ¹³C enriched methylcobaloximes, do not vary appreciably when B is changed (J(¹³C? H) = 137 ± 1 Hz) and are close to the value obtained for methylcobalamine.     

Recherches sur la formation et la transformation des esters LXXIII Sur la préparation d'acides ω-[aryl (ou aralcoyl ou alcoyl) carbamylamino]-alcoylphosphoriques et sur leur vitesse de scission à divers pH

N-Aryl(or aralkyl or alkyl)carbamoyl-aminoalkyl phosphoric monoesters have been prepared by the reaction of isocyanates R′-N?C?O on the corresponding amino-alkylphosphoric monoesters H₂N? R? OPO₃H₂ in the presence of 2 equivalents of NaOH. The rates of scission of the phosphoric monoester group and occasionally of the phenylcarbamoylamino group of these monoesters have been studied at 100°, in solutions 0.1M in ester and at various pH.     

Synthesis of End‐Functionalized Polyacetylenes that Contain Polar Groups by Employing Well‐Defined Palladium Catalysts

A series of [(dppf)PdBr(R)]‐type complexes (dppf=1,1′‐bis(diphenylphosphino)ferrocene; R=p‐cyanophenyl ( 1 a ), o‐hydroxymethylphenyl ( 1 b ), and triphenylvinyl ( 1 c )), in combination with silver trifluoromethanesulfonate (AgOTf), were demonstrated to be active for the polymerization of monosubstituted polar acetylene monomers HC?CCONHC₄H₉ ( 2 ), HC?CCO₂C₈H₁₇ ( 3 ), HC?CCH₂OCONHC₆H₁₃ ( 4 ), HC?CCH₂OCO₂C₆H₁₃ ( 5 ), and HC?CCH(CH₃)OH ( 6 ). The yields and molecular weights of the polymers depended on the combination of the Pd catalyst and monomer that was employed. Matrix‐assisted laser‐desorption/ionization–time of flight (MALDI‐TOF) mass spectrometric analysis indicated the formation of polymers that contained the “R” and “H” groups at the chain ends. IR spectroscopic analysis supported the R‐end‐functionalization of the polymers. NMR spectroscopy and MS identified the presence of species that were formed by single, double, and triple insertion of the monomers into the Pd‐C₆H₄‐p‐CN bond, thereby giving solid evidence for an insertion mechanism for the present system. Density functional theory (DFT) calculations suggested the preference for 1,2‐insertion of the monomer compared to 2,1‐insertion.     

Hydrolyse acide du p-nitrophényl-diazométhane dans les mélanges H2O?D2O: analyse des effets isotopiques

The velocity of the hydrogen ion catalysed hydrolysis of p-nitrophenyl-diazo-methane (I) has been measured in H₂O? D₂O mixtures, giving an isotopic α_i = 0.49. The product isotope effect r = 5.1, determined from product analyses, combined with the (overall) solvent isotope effect k_H/k_D = 2.81, yields the primary kinetic isotope effect (k_H/k_D)^I = 3.8, and the secondary kinetic isotope effect (k_H/k_D)^II = 0.75. The CICH₂COOH-catalysed hydrolysis of I in H₂O? D₂O mixtures gave a straight-line plot of k_n/k_H versus the atomic fraction n of deuterium. With four carboxylic acids, as catalysts, values of about 4.3 for the kinetic (overall) isotope effects were observed.     

Mécanisme de solvolyse des cis- et trans-(p-toluènesulfonates) d'aryl-2-cyclopentyle I. Etude de la première étape de la solvolyse: effets isotopiques de l' atone de deutérium en position 2, effets de sel basique et effet spécial de sel

Solvolysis Mechanism of cis - and trans-2-Arylcylopentyl p-Toluenesulfonates. The Step: 1-Deuterium Isotope Effects, Basic Salt Effects, and Special Salt Effect We have studied the first step of the solvolysis of cis and trans-2-arylcyclopentyl p-toluenesulfonates in HCOOH, AcOH, and EtOh. All substrates show a high kinetic 1-deuterium isotope effect (k_H/k_D(1) >1.15). This fact indicates that first step leads to classical intimate ion-pair Which dissociates to a solvet-separated ion-pair, without participation either of solvent, the 2-aryl group, or a H-atom at C(2). The slight influence of added basic ions on reaction rate allows us to exclude any direct solvent attack on the covalent substrate even in the most favorable case, i.e. ethanolysis of 2-(p-nitrophenyl)cylopentyl-p-toluenesulfonates. Furthermore, solvent-separated ion pair formation is indicated by the special salt effect induced by LiClO₄.     

Recherches sur la formation et la transformation des esters LXXIX [1]. Sur la réaction de l′isothiocyanate d′o-méthoxycarbonyl-phényle avec divers acides et l′acide sérinephosphorique

Amino acids devoid of «leaving groups» on their β carbon atom (neither ? OH: serine, nor ? SH: cysteine) react with o-methoxycarbonyl-phenyl isothiocyanate (I) in the presence of one equivalent of NaOH, in water-dioxane or in ethanol, to yield the corresponding hydroquinazolinone derivatives II which were isolated as free acids. When treated with CH₃COOH + conc. HCl the hydroquinazolinone resulting from the reaction of L -serine with I undergoes a nucleophilic attack of the carbon bearing the leaving group ? OH by a lone pair of electrons of S; this attack produces the formation of an additional thiazolidine ring, yielding the thiazoloquinazolinone derivative (?)-III. In an analogous reaction DL -serine phosphoric acid treated with I at pH 8–9 yields the corresponding substituted hydroquinazolinone which, boiled in 1N hydrochloric acid, undergoes ring closure to (±)-III by the same mechanism as the serine derivative (leaving group: ? OPO₃H₂). L -Cysteine reacted with 2 equiv. of I and then treated with CH₃COOH + conc. HCl gives two products: (?)-III produced by the same mechanism as for serine (leaving group: ? SH), and the quinazolinone derivative IV where the ? SH group is also thiocarbamoylated.     

Cyclisations par l'intermédiaire de fonctions phénylthioet phénoxy-carbamyle. I. Diphényl-1,2-alcoyl-5-dioxo-3,6-hexahydro-triazines-1,2,4

The N-(p-nitrophenoxy-carbonyl) and N-(phenylthio-carbonyl) derivatives of α-amino-acyl-hydrazides cyclize in presence of diazomethane, yielding hexahydro-1, 2, 4-triazines with simultaneous formation of p-nitro-anisole or thio-anisole respectively. The molecules with a phenoxycarbonyl function such as N-(phenoxycarbonyl)-glycyl-(N, N′-diphenylhydrazide) give the corresponding ring products and anisole only in solvents with high dielectric constant (e.g. nitromethane). The phenylthio-carbonyl derivatives give the same ring products in presence of lead acetate by the intervention of HO^?. The p-nitrophenoxycarbonyl derivatives give rise to the same cyclisations in the presence of pyridine by the intermediate of carbamyle-pyridinium ion acting as electrophile. These different types of intramolecular reactions are illustrated by the formation of 1, 2-diphenyl-5-alcoyl-3, 6-dioxo-1, 2, 4-hexahydro-triazines.     

Synthèse de sucres aminès ramifiés II. Synthèse et réactions de spiro-aziridines. Communication préliminaire

Treatment of 3-C-cyano-1,2:5,6-di-O-isopropylidene-3-O-(toluene-p-sulfonyl)-α-D -allofurannose with AlLiH₄ or RMgX yields spiro-aziridines with two identical substituents on C(3′) (? H, ? CH₃, ? C₂H₅). Reactions of these products and their derivatives are briefly described. If the C(3′) substituents are protons, the aziridine ring is easily opened. In acidic media (HCl), an amino-sugar containing the branched chain ? CH₂Cl is produced; with hydrogenation, a ? CH₃ branched chain results. If the C(3′) substituents are methyl groups, the aziridine ring cannot be opened neither with HCl nor with hydrogen. The acetylated derivative of this latter compound rearranges to the corresponding allylamide with HCl. For both types of spiro-aziridine, the nitrous deamination leads to the corresponding alkene.     

Über Chalkogenolate. 196. Untersuchungen über N-(Methoxycarbimidoyl)guanidin 2. Umsetzungen mit Chlordithioameisensäureestern

On Chalcogenolates. 196. Studies on N-(Methoxycarbimidoyl)guanidine. 2. Reactions with Esters of Chlorodithioformic Acid N-(Methoxycarbimidoyl)guanidine reacts with esters of chlorodithioformic acid to produce the hitherto not known esters of N-(Methoxycarbimidoyl)guanidinedithiocarbonic acid (MCGT-R; formula see ?Inhaltsübersicht”?). By-product is the corresponding 2-amino-4-methoxy-6-alky(aryl)thio-1,3,5-triazine. MCGT-R, where R = CH₃, C₂H₅, C₆H₅, have been characterized by means of electron absorption, infrared, nuclear magnetic resonance, and mass spectra. The spectra and the related tautomeric structures of the dithioesters are discussed.     

Synthesis of 2-(2-methoxyethyl)- and 2-(2-thiomethoxyethyl)-aniline and related compounds

Summary 2-(2-Nitrophenyl)-ethanol (2) was methylated with dimethyl sulfate to give 2-(2-methoxyethyl)-1-nitrobenzene (3a) which then was reduced with hydrazine hydrate in the presence ofRaney nickel to 2-(2-methoxyethyl)-aniline (1a). Compound1a can be transformed into the N-monosilylated derivative4 by lithiation withn-butyllithium and subsequent reaction with chlorotrimethylsilane. Reaction of2 withp-toluenesulfonyl chloride yields 2-(2-nitrophenyl)-ethylp-toluenesulfonate (5), which reacts with sodium thiomethoxide to give 2-(2-nitrophenyl)-ethylp-toluenesulfonate (5), which reacts with sodium thiomethoxide to give 2-(2-thiomethoxyethyl)-1-nitrobenzene (3b).3b was reduced with hydrazine hydrate in the presence ofRaney nickel to yield 2-(2-thiomethoxyethyl)-aniline (1b). Ethyl (2-nitrophenyl)-acetate (6) could be dimethylated with methyl iodide in the presence of potassiumtert-butoxide and 18-crown-6 to give ethyl 2-methyl-2-(2-nitrophenyl)-propionate (7). Reduction of7 with lithium borohydride yields 2,3-dihydro-3,3-dimethyl-1H-indole (9) and 2-[(1-hydroxy-2-methyl)-2-propyl]-aniline (10).

---

Synthese von 2-(2-Methoxyethyl)- und 2-(2-Thiomethoxyethyl)-anilin und verwandten Verbindungen

Zusammenfassung 2-(2-Nitrophenyl)-ethanol (2) wurde mit Dimethylsulfat zu 2-(2-Methoxyethyl)-1-nitrobenzol (3a) methyliert, das sich mit Hydrazinhydrat in Gegenwart vonRaney-Nickel zu 2-(2-Methoxyethyl)-anilin (1a) reduzieren läßt. Verbindung1a kann durch Metallierung mitn-Butyllithium und anschließende Reaktion mit Chlortrimethylsilan in dasN-monosilylierte Derivat4 umgewandelt werden. Reaktion von2 mitp-Toluolsulfonylchlorid ergab 2-(2-Nitrophenyl)-ethyl-p-Toluolsulfonat (5), das mit Natriumthiomethanolat zu 1-Nitro-2-(2-thiomethoxyethyl)-benzol (3b) reagiert.3b wurde mit Hydrazinhydrat in Gegenwart vonRaney-Nickel zu 2-(2-Thiomethoxyethyl)-anilin (1b) reduziert. Ethyl-2-(nitrophenyl)-acetat (6) kann mit Methyliodid in Gegenwart von Kalium-tert-butoxid und 18-Krone-6 zu Ethyl-2-methyl-2-(2-nitrophenyl)-propionat (7) dimethyliert werden. Reduktion von7 mit Lithiumborhydrid lieferte 2,3-Dihydro-3,3-dimethyl-1H-indol (9) und 2-[(1-Hydroxy-2-methyl)-2-propyl]-anilin (10).

     

Recherches sur la formation et la transformation des esters LXVII. Note sur la scission des acides ω-(N-phénylthiocarbamylamino)-alcoyl-sulfuriques à divers pH

In aqueous solutions at 100°C varying from HCl 2N to NaOH 2N , N-phenylthiocarbamoyl derivatives of aminoalkylsulfuric monoesters C₆H₅NH? CS? R? OSO₃H are split in the following ways:

• (a) With R = ? CH₂? CH(CH₃)? or ? (CH₂)₃? the scission of the monoester group is very rapid in the hole pH-range studied, especially in alkaline medium; the resulting cyclic products, 5-methyl-2-phenylamino-thiazoline and 2-phenylimino-tetrahydrothiazine respectively, formed by nucleophilic attack of an unshared pair of the S atom on the C bearing the monoester group, have been isolated and identified.
• (b) With R = ? (CH₂)₄? , the rate of the scission in alkaline or neutral medium is very much higher than that of an alkylsulfuric monoester; in these media a cyclic product is also formed (this time by nucleophilic attack of the unshared pair of the thiocarbamoylated N atom on the C bearing the monoester function) which has been isolated after alcaline scission, and identified as N-phenylcarbomoyl-pyrrolidine. In acid medium, no special influence of the phenylthiocarbamoyl group is observed.
• (c) With R = ? (CH₂)₅? or ? (CH₂)₆? , the rate of the scission in alkaline medium is 30 to 1000 times lower than in the previous cases; no pure organic scission products have been isolated. In acid or neutral medium, these two esters behave like usual alkylsulfuric acids.

     

Acyl- und Alkylidenphosphane. XXVI. 2, 4-Bis(phenylimino)-1,3-diphosphetane aus Thiocarbamoyl- und Carbamoyltrimethylsilylphosphanen

Acyl-and Alkylidenephosphines. XXVI. 2, 4-Bis (phenylimino)-1, 3-diphosphetanes from Thiocarbamoyl- and Carbamoyltrimethylsilylphosphines . Bis(trimethylsilyl)phosphines R? P[? Si(CH₃)₃]₂ 1 (R = H₃C a, H₅C₆ b, (H₃C)₃C e, H₁₁C₉ d) and phenyl isothiocyanate give insertion compounds which were identified as [CN-phenyl, N-trimethylsilyl)thiocarbamoyl]trimethylsilylphosphines 3 ? 2 in solution as well as in the solid state [2]. In the presence of small amounts of solid sodium hydroxide the phenyl derivative 3 ? 2b eliminates bis(trimethylsilyl) sulfane, whereas the tert-butyl 3 ? 2c and the mesityl compound 3 ? 2d show the same reaction even without a catalyst. The unstable [(phenylimino)methylidene]phosphines 6 formed first, dimerize rapidly to give 2, 4-bis(phenylimino)-1,3-diphosphetanes 7 which in solution exist as mixtures of the E and Z isomers. Via a NaOH-catalyzed elimination of hexamethyldisiloxane these cyclic phosphines 7 can also be obtained from the adducts of phenyl isocyanate and bis(trimethylsilyl)phosphines 1. Taking the thermally sufficiently stable tert-butyl derivative 7 c as an example, the temperature dependence of n.m.r. spectra is discussed in detail.     

Recherches sur la formation et la transformation des esters LXXI Sur la préparation des acides ω-(phénylthiocarbamylamino)-alcoylphosphoriques et sur leur scission à divers pH

Sodium ω-phenylthiocarbamylaminoalkyl phosphates C₆H₅NHCSNH–(CH₂)_n–OPO₃Na₂ have been obtained by reacting phenylisothiocyanate with the corresponding aminoalkyl phosphoric monoester in the presence of 2 eq. of NaOH.     

Organische Phosphorverbindungen XXXVIII. Darstellung und Eigenschaften von Tris-(dialkoxyphosphonyl-methyl)-, Tris-(alkoxyphosphinyl-methyl)-und Tris-(oxophosphoranyl-methyl)-phosphinsäureestern sowie der entsprechenden Säuren [1]

Tris-chloromethyl-phosphine oxide, (ClCH₂₎₃ P?O(I), is obtained by chlorination of (HOCH₂₎₃P?O with PCl₅ or (C₆H₅₎₃PCl₂, and also by oxidation of (CICH₂₎₃P?O and (ClCh₂₎₂(CH₃)P?O. High yields of tris-(dialkyloxyphosphonly-methyl)-phosphine oxides, [RO₂(O)PCH_2]2P?O (II) (R?CH₃, C₂H₅, iso-C₃H₇, n-C₄H₉, 2- ethyl-hexyl), tris (alkyloxyphosphinyl-methyl)-phosphine oxides, [R₂(O)PCH_2]3P?O(R = C₆H₅, CH₃) are obtained by heating tris-chloromethyl-phosphine oxides, [(RO) (R′) (O)PCH_2]3P?O (R = C₄H₉, R′? C₆H₅) and tris-(oxophosphoranyl-phosphine oxides with phosphites, phosphonites and phosphinites, respectively, at 170–180°C for several hours. Compounds II possess an extraordinarily high absorption capacity. Thus a warm. 2% solution of II (R = C₂H₅) in benzene solidifies completely on cooling so that no benzene can be poured off. Tris-dihydroxyphosphonyl-methyl)-phosphine oxide, [(HO)₂(O)PCH_2]3P?O, obtained by hydrolysis of II (R ? C₂H₅) with refluxing conc. HCl or by thermal decomposition of II (R ? iso-C₃H₇) at 190°, titrates in aqueous solution as a hexabasic acid with breaks at pH = 4,4 (three equivalents) and pH = 10,7 (three equivalents). It forms crystalline salts with amines, alkali and alkaline earth metals, and is an excellent chelating agent. The ¹H- and ^31?P-NMR. spectra of all the compounds prepared are discussed.