2,4‐Bis(triphenylphosphanimino)tetrazolo[5,1‐a][1,3,5]triazine (1) was synthesized by reaction of cyanuric azide with triphenylphosphane. 1 is characterized by X‐ray structural analysis, IR, Raman, and NMR spectroscopy. The obtained spectra showed that the remaining azide group in 1 reacts with the N4 atom of the triazine ring and forms a tetrazole. An improved crystal structure for 2,4,6‐triazido‐1,3,5‐triazine (2) was determined and for the first time a 14N‐NMR spectrum was obtained. CAUTION: 2 (Cyanuric azide) is explosive! The explosive nature increases with greater purity and crystal size.

2-Triphenylphosphanimino-4-azidotetrazolo[5,1-a]-[1,3,5]triazine (6) was obtained by reaction of 2,4,6-triazido-1,3,5-triazine (1) with 1 equiv of triphenylphosphane. Raman and X-ray data revealed that only one azide group formed a tetrazole ring system whereas the second azide group did not undergo ring closure. To investigate the equilibrium between the tetrazole isomer and the open-chain azide structure for these and related species, (31)P NMR studies were carried out. The obtained spectra displayed an equilibrium between the tetrazole and the open-chain azide isomers. 2,4,6-Tris(triphenylphosphanimino)-1,3,5-triazine (4) was prepared by treatment of 1 with 3 equiv of triphenylphosphane, and its X-ray structure is discussed. On the basis of PM3 semiempirical and density functional calculations, the reaction of 1 with triphenylphosphane was studied. The thermodynamics of different isomerization reactions and the activation barriers to cyclization were estimated.

The reaction behavior of trimethylsilyl phosphanimine, Me3SiNPPh3, toward the pseudohalogen species XCN (X = Cl, Br, and I), especially the intermediate formation of [Me3SiN(PPh3)-XCN] adduct complexes, was investigated in solution. Only the ICN adduct was shown to be metastable in solution, with respect to further reaction into Ph3PNCN and Me3SiX, and can be intercepted. Raman and X-ray data of the ICN adduct revealed a very labile donor-acceptor complex with the iodine atom of the ICN moiety loosely bound to the nitrogen atom of Me3SiNPPh3. There are two distinct rather long N...I bonds with bond lengths of 2.634(1) and 2.739(14) A. The structure and bonding are discussed on the basis of natural bond orbital analysis and valence bond considerations.

Bei der Redaktion eingegangen am 5. Ma È rz 2001.Inhaltsu È bersicht. Die Kaliumkronenetherkomplexe [K([18]krone-6)(X)(OPPh 3 )], mit X = N 3 ± , OCN ± , und SCN ± , werden durch Reaktion von KX mit [18] 4,7,10,13, und Triphenylphosphan in mit UV Licht bestrahltem THF erhalten. Alle drei Kronenetherkomplexe konnten mit Hilfe der Schwingungsspektroskopie und der Ro È ntgenstrukturanalyse charakterisiert werden. Die Kronenetherkomplexe kristallisieren isotyp in der rhombischen Raumgruppe R3m mit drei Moleku È len in der Elementarzelle: [K([18]krone-6)(N 3 )(OPPh 3 )] (1): Gitterkonstanten bei 293 K: a = b = 14.213(2) A Ê ; c = 13.951(2) A Ê ; R 1 = 0.0249. [K([18]krone-6)(OCN)(OPPh 3 )] (2): a = b = 14.239(2) A Ê ; c = 13.8927(14) A Ê ; R 1 = 0.0257. [K([18]krone-6)(NCS)(OPPh 3 )] (3): a = b = 14.339(2) A Ê ; c = 14.266(2) A Ê ; R 1 = 0.0264. Abstract. The potassium crown ether complexes [K([18]-Crown-6)(X)(OPPh 3 )] (with X = N 3± , OCN ± and SCN ± ) can be obtained by reaction of KX with 18-crown-6 (1, 4, 7, 10, 13, 16-hexaoxacyclooctadecane and triphenylphosphane in THF exposed to UV light. All crown ether complexes were characterized by means of vibrational spectroscopy and Xray diffraction. They crystallize in the rhombic pointgroup R3m with three molecules in the unit cell: [K([18]crown-6) (N 3 )(OPPh 3 )] (1): lattice constants at 293 K: a = b = 14.213(2) A Ê ; c = 13.951(2) A Ê ; R 1 = 0.0249. [K([18]crown-6)-(OCN)(OPPh 3 )] (2): a = b = 14.239(2) A Ê ; c = 13.8927(14) A Ê ; R 1 = 0.0257. [K([18]crown-6)(NCS)(OPPh 3 )] (3): a = b = 14.339(2) A Ê ; c = 14.266(2) A Ê ; R 1 = 0.0264.

Key indicatorsSingle-crystal X-ray study T = 293 K Mean '(N±C) = 0.009 A Ê R factor = 0.055 wR factor = 0.131 Data-to-parameter ratio = 13.4For details of how these key indicators were automatically derived from the article, see