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The tetra-carbanion formed from methyl-lithium and octamethylcyclotetraphosphazene reacts with methyl iodide and with the chlorides Me3XCl(X = Si, Ge, Sn) to give N4P4Me4(CH2R)4(R = Me, XMe3).

Crystals of hexamethylcyclotriphosphazene are monoclinic, a = 12.084(2), b = 13.426(1), c = 15.488(2) A,β = 102.92(2)°, Z = 8, space group C2/c. The structure was solved by direct methods and was refined by full-matrix least squares procedures to a final R of 0.045 and Rw of 0.060 for 1922 reflections with I ≥ 3σ(I). The six-membered phosphazene ring is slightly nonplanar and has a distorted chair conformation. Important molecular dimensions (bond lengths are corrected for libration) are: P—N, 1.599(2)–1.612(2), P—C, 1.796(3)–1.823(4) A, N—P—N, 115.7(1)–117.9(1), P—N—P, 122.1(1)–122.9(1), and C—P—C, 101.8(2)-103.1(2)°.

The tris(trimethylsilyl)amidines RC(NSiMe3)N(SiMe3)2 (R  C6H5, p-CH3C6-H4, p-ClC6H4, p-MeOC6H4, p-Me2NC6H4, p-CF3C6H4, p-C6H5C6H4 and CF3) are prepared by the reaction of the respective nitriles with (Me3Si)2NLi·OEt2 in ether to give intermediates RC(NLi)N(SiMe3)2. Heating these intermediates with ClSiMe3 in toluene affords the products, which are isolated by vacuum distillation, in high yield. With 1,4-dicyanobenzene, two equivalents of reagents affords the per(trimethylsilyl)-1,4-diamidine. Hydrolysis of the intermediates with 6N ethanolic HCl affords the unsubstituted amidine hydrochlorides RC(NH)NH2·HCl (R  C6-H5, p-MeOCh6H4, p-ClC6H4, p-O2NC6H4) in high yield.

Crystals of dodecamethylcyclohexaphosphazene are triclinic, a = 13.898(1), b = 8.690(1), c = 10.790(1) A, α = 109.84(1), β = 92.01(1), γ = 106.39(1)°, Z = 2, space group . The structure was solved by direct methods and was refined by full-matrix least-squares procedures to a final R of 0.034 and Rw of 0.042 for 4217 reflections with I ≥ 3σ(I). The unit cell contains two independent centrosymmetric molecules which are virtually identical. The 12-membered rings have the 'double tub' conformation. Bond lengths not involving hydrogen have been corrected for libration. Weighted mean bond lengths (rms deviations from the mean in parentheses) are: P—N, 1.593(6), C—P, 1.808(4), and C—H, 0.95(6) A.

Crystals of hexadecamethylcyclooctaphosphazene are tetragonal, a = 13.637(1), c = 8.215(1) A, Z = 2, space group P4/n. The structure was solved by direct methods and was refined by full-matrix leas...

The thermal decomposition of Ph3PN–S3N3 leads to the open-chain derivative Ph3PNSNSS; an X-ray crystallographic analysis of the latter shows that the five atom N–S–N–S–S sequence exists in a nearly planar, cis–trans conformation.

The reaction of bis(cyclopentadienyl)titanium dicarbonyl with tetrasulphur tetranitride yields cp2 TiS3N4(cp = cyclopentadienyl); X-ray crystallographic analysis of this compound reveals it to be based on an eight-membered TiS3N4 ring.

Cristallisation dans le systeme monoclinique, groupe P2 1 /m et affinement jusqu'a R=0,039. Conformation bateau de l'heterocycle

The reaction of benzamidine wiht S3N3Cl3 yields 1-chloro-3,5-diphenyl-1,2,4,6-thiatriazine, whose molecular structure has been determined by X-ray crystallography; reduction of Ph2C2N3SCl with triphenylantimony yields the radical species (Ph2C2N3S)· characterized by its e.s.r. spectrum.

The thermal decomposition of (Ph3P)2N+S4N5– in acetonitrile leads, sequentially, to the corresponding salt of the S3N3– and S4N– anions; an X-ray crystallographic analysis of (Ph3P)2N+ S4N– shown that the anion is a planar, cis–trans chain with nitrogen in the middle of four sulphur atoms.

Dimethyltrichlorophosphorane reacts with methylamine hydrochloride to give an oil which decomposes on heating, yielding the quaternary chloride N3P3Me6·MeCl as the principal product. The controlled pyrolysis of this salt gives N3P3Me6 in high yield. A simple method for the separation of N3P3Me6 and N4P4Me8 is described, based on the different solubilities of their salts in acetonitrile.

The reactions of triphenylphosphine and triphenylarsine with the bicyclic thiazyl heterocycle PhCN5S3 produce the corresponding 3-imino-7-phenyl-1,3,5,2,4,6,8-trithiatetrazocines PhCN4S3NEPh3(E = P or As); the exo- and endo-isomers of PhCN4S3NAsPh3 have been characterized by X-ray crystallography.

C 14 H 11 N 3 OS cristallise dans le systeme orthorhombique avec le groupe d'espace Pbca. Affinement de la structure jusqu'a 0,044. La portion N 3 C 2 du cycle est plane

Novel synthetic routes to heterocycles based on the 1,3,4,2,6-dithiatriazine framework are described; the X-ray crystal structure determination of the bicyclic derivative PhCN5S3 is reported.

The reaction of tetraphenyldiphosphine with S4N4 in toluene produces the six-membered heterocycle Ph2PS2N3, the structure of which has been determined by X-ray crystallography; the structural parameters and electronic spectrum of the PS2N3 ring are consistent with an 8-electron π-system.

On deprotonation by a sufficiently strong base, N-methylphosphazenium iodides NnPnMe2n+ 1I (n= 3,4) rearrange to phosphorins with exocyclic methylamino-groups.

The oxidation of 3,7-bis(dimethylamino)-1,5-dithia-2,4,6,8-tetrazocine yields the S-chloro salt [(Me2N)2C2N4S2Cl]+[Cl3]–, whose crystal and molecular has been determined by X-ray crystallography; the molecular structure of the cation and the cation–anion contacts are related to the stereochemistry of chlorination of transannular sulphur–sulphur interactions in cyclothiazenes.

C7HsC12N3S2, Mr=266.17, triclinic, P), a=6-028(1), b=9-985(2), c=10.157 (3) /~, ct= 117.33 (2), fl= 106.73(2), y=90.31(1) °, V= 513-3(4)/~3, Z=2, D x=1.72gcm -3, 2(MoK~t)= 0.71073 A, /1 = 9.85 cm -1, F(000) = 268, T= 293 K, R = 0.032 for 1547 unique observed reflections. The SNCNS portion of the ring is planar within 0-060 (2)/~ and the third N is displaced 0.336 (2) A from this plane on the side opposite the S-bonded C1 atoms. The S-N distances range from 1.581 (1) to 1.615 (2)/~ and the N-C distances are 1.327 (2) and 1.344 (2) ./k. Experimental. Compound prepared by the reaction of chlorine gas with PhCNsS 3 obtained from the reaction of PhC(NSiMe3) with SaNaC1 a. Crystals obtained from a 50:50 mixture of dichloromethane and hexanes. Air-sensitive parallelpiped data crystal 0.20 × 0.50 × 0.46 mm sealed in a glass capillary. Density not measured. Intensities measured with an Enraf-Nonius CAD-4 diffractometer using 09-20 scans of 4 to 16 ° min -~ in 0. Unit cell determined from least-squares analysis of angle data for 20 reflections with 22 < 20 < 40 °. Analytical absorption correction based on crystal shape varied from 0.67 to 1-00. Data collected to sin0/2 of 0-59/~-~, -7

Two novel products, (Ph3P=N)2S4N4 and (Ph3P=N)3S+S4N5−, have been isolated from the reaction of triphenylphosphine with S4N4; an X-ray structural determination of (Ph3P=N)2S4N4 shows it to consist of a 1,5-disubstituted S4N4 ring with the exocyclic substituents in an axial, equatorial configuration.

The tetra-carbanion formed from methyl-lithium and octamethylcyclotetraphosphazene reacts with methyl iodide and with the chlorides Me3XCl(X = Si, Ge, Sn) to give N4P4Me4(CH2R)4(R = Me, XMe3).

Crystals of 2,2,4,4,6,8,8-heptamethyl-6-methylamino-1,3,5-triaza-2,4,6,8(PV)-tetraphosphorin are monoclinic, a = 11.639(4), b = 11.957(7), c = 12.114(4) Å, β = 94.07(2) °, Z = 4, space group P21/n. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to R = 0.032 and Rw of 0.041 for 2012 reflections with I ≥ 3σ(I). Crystals of 2,2,4,4,6,8,8-heptamethyl-6-methylamino-7-benzoyl-1,3,5-triaza-2,4,6,8(PV)-tetraphosphorin are triclinic, a = 15.513(1), b = 8.422(1), c = 8.933(1) Å, α = 89.24(1), β = 100.18(1), γ = 107.30(1) °, Z = 2, space group [Formula: see text]. The structure was solved by Patterson and Fourier syntheses and was refined to a final R of 0.041 and Rw of 0.044 for 3654 reflections with I ≥ 3σ(I). The eight-membered P4N3C rings in both structures hâve 'tub' conformations. The mean bond lengths (corrected for libration) are: P—N(endo), 1.609(9), P—N(exo), 1.679(2), P—C(endo), 1.717(2), and P—C(exo), 1.815(8) Å for Me7(MeNH)P4N3CH and 1.595(4), 1.655(2), 1.763(4), and 1.804(5) Å respectively for Me7(MeNH)P4N3CC(O)Ph. The near-equivalence of the endocyclic P—N bond lengths in the azaphosphorins is discussed in terms of opposing changes in the in-plane and out-of-plane Π-systems.

A low-temperature (–100 °C)X-ray crystallographic analysis of S4N2 shows that it consists of a six-membered ring in a ‘half-chair’ conformation with the nitrogen atoms in the 1,3-positions.

The reaction of N-phenyl-N′-trimethylsilyl sulphur di-imide with sulphur dichloride yields benzo-1,3-dithia-2,4-diazine, a novel twelve π-electron heterocycle.

The reaction of [Ph6P3N4H2]+Cl– with sulphur dichloride affords the eight-membered 1,3,5,7,2,4,6,8-thiatriphosphatetrazocine Ph6P3N4SCl, which can be reduced by triphenylantimony to the corresponding thiatriphosphatetrazocinyl radical [Ph6P3N4S]˙; the temperature dependence of the e.s.r. spectrum of this radical provides a unique demonstration of the effects of conformational rigidity in an oligophosphazene skeleton.

The reduction of Ph4P2N3SCl by triphenylantimony in methylene chloride yields a persistent radical; molecular orbital calculations and e.s.r. spectroscopic evidence support the formulation of this species as the 1,2,4,6,3,5-thiatriazadiphosphininyl radical [Ph4P2N3S]˙.

The dimethylamino-fluorophosphonitriles NnPnF2n–x(NMe2)x(x= 1–3, n= 3–6) have been prepared by the reaction of the phosphonitrilic fluorides (NPF2)n with (a) dimethylaminotrimethylsilane at 100°(b) dimethylamine in diethyl ether at 0°. Except for n= 6, reaction (a) gives the higher yields of mono-substituted derivatives (x= 1). The 1H and 19F n.m.r. spectra show that successive dimethylamination takes place non-geminally. The dimethylaminofluorophosphonitriles react with anhydrous hydrogen chloride or hydrogen bromide at 25°(n= 4–6) or at 100°(n= 3) to give the corresponding chlorides and bromides. The i.r. and 31P n.m.r. spectra of the dimethylaminofluorophosphonitriles and the 19F n.m.r. spectra of the monohalogenofluorophosphonitriles are discussed, and the preparation of the mono-isothiocyanato-derivatives of the phosphonitrilic fluorides described.

Nitrilohexaphosphonitrilic chloride P6N7Cl9 has a condensed ring structure with comparatively weak central bonds, one of which is broken on reaction with dimethylamine.