] with excess NaN 3 followed by precipitation with (AsPh 4 )N 3 . Compound (I) crystallizes in the monoclinic space group P2 1 /n with Z = 6 and compound (II) in the triclinic space group P1 with Z = 1 (single crystal XRD). Whereas the Pt atoms in (I) show square planar coordination they are octahedrally coordinated in compound (II). (I) is highly explosive, while (II) is of significantly greater stability.

Hydrogen Diazide – Synthesis and Crystal Structure of PPh4[N3HN3] PPh4[N3HN3] has been prepared from PPh4N3 and Me3SiN3 by the reaction with water or ethanol forming colourless nonexplosive crystal needles, which were characterized by IR spectroscopy and by a crystal structure determination. Space group C2/c, Z = 12, lattice dimensions at –70 °C: a = 3782.4(3), b = 727.8(2), c = 2512.4(2) pm, β = 110.13(1)°, R = 0.0841. The [N3HN3]– ion is characterized by an asymmetric N–H…N hydrogen bridge with a NN distance of 272(1) pm.

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Professor Kurt Dehnicke zum 70. Geburtstag gewidmet Inhaltsu È bersicht. 1,1,4,4-Tetramethyl-2,3-diazabutadien reagiert mit Dimethylaluminiumhydrid unter Hydroaluminierung nur einer C=N-Doppelbindung. Dabei entsteht das Hydrazon-Derivat [Me 2 Al±N(CHMe 2 )±N=CMe 2 ] 2 (1), das unter Bildung eines sechsgliedrigen Al 2 N 4 -Heterozyklus dimerisiert. Die zweifache Hydroaluminierung wird nicht beobachtet. Ûberschu È ssiges Di(tert-butyl)-oder Bis(trimethylsilylmethyl)aluminiumhydrid ergibt ebenfalls nur die einfache Hydroaluminierung, ein zweites Dialkylaluminiumhydrid-Moleku È l wird u È ber eine koordinative Bindung zwischen seinem Aluminiumatom und dem Stickstoffatom der C=N-Doppelbindung sowie eine 3 z±2 e±Al±H±Al-Bindung gebunden. Dadurch entstehen die Verbindungen [(Me 3 C) 2 Al]-[(Me 3 C) 2 AlH]N(CHMe 2 )NCMe 2 (2) und [(Me 3 SiCH 2 ) 2 Al]-[(Me 3 SiCH 2 ) 2 AlH]N(CHMe 2 )NCMe 2 (3), die u È ber koordinativ gesa È ttigte Aluminiumatome und fu È nfgliedrige Al 2 N 2 H-Heterozyklen verfu È gen. Durch Thermolyse von 2 bildet sich unter C±H-Aktivierung in Spuren eine bicyclische Verbindung [(Me 3 C) 2 Al] 2 [CH 2 C(Me)=N±] 2 (4), in der zwei AlN 2 C 2 -Ringe u È ber die intakte N±N-Bindung miteinander verbunden sind. Die Thermolyse von 3 ergibt dagegen unter Spaltung der N±N-Bindung in guten Ausbeuten ein dimeres Dialkylaluminium-methylidenamid (5) mit zwei terminalen C=N-Doppelbindungen. Die Insertion von C=N-Doppelbindungen in eine Al±C-Bindung wurde von uns bisher nicht beobachtet, mit Tri(tert-butyl)alan bildet sich lediglich das Addukt [(Me 3 C) 3 Al(±N=CMe 2 ) 2 ] (6).Abstract. 1,1,4,4-Tetramethyl-2,3-diazabutadiene reacted with dimethylaluminium hydride by hydroalumination of only one C=N double bond. The hydrazone derivative [Me 2 Al±N-(CHMe 2 )±N=CMe 2 ] 2 (1) was formed which gave a dimer possessing a six-membered Al 2 N 4 heterocycle. The hydroalumination of both C=N double bonds was not observed. Also an excess of di(tert-butyl)-or bis(trimethylsilylmethyl)aluminium hydride afforded only the product of a single hydroalumination step, a second dialkylaluminium hydride molecule was attached via a coordinative interaction between its central aluminium atom and the nitrogen atom of the C=N double bond and in addition via a 3 c-2 e Al±H±Al bond. Compounds [(Me 3 C) 2 Al][(Me 3 C) 2 AlH]N(CHMe 2 )NCMe 2 (2) and [(Me 3 SiCH 2 ) 2 Al][(Me 3 SiCH 2 ) 2 AlH]N(CHMe 2 )NCMe 2 (3) were formed which have five-membered Al 2 N 2 H hetero-cycles. Thermolysis of 2 gave by C±H activation compound [(Me 3 C) 2 Al] 2 [CH 2 C(Me)=N±] 2 (4) in trace amounts which possesses two anellated AlN 2 C 2 rings with a common N±N bond. In contrast, the thermal decomposition of 3 yielded by the cleavage of the N±N bond a dimeric dialkylaluminium methylideneamide (5) which has two intact C=N double bonds. Up to now our attempts to insert a C=N double bond into an Al±C bond remained unsuccessful, and only the formation of an adduct [(Me 3 C) 3 Al(±N=CMe 2 ) 2 ] (6) was observed upon treatment of tri(tert-butyl)aluminium with the diazabuta...