Accession Number:

ADA218715

Title:

Comparison of Isoelectronic Aluminum-Nitrogen and Silicon-Carbon Double Bonds Using Valence Bond Methods

Descriptive Note:

Technical rept.

Corporate Author:

RENSSELAER POLYTECHNIC INST TROY NY DEPT OF CHEMISTRY

Report Date:

1990-01-15

Pagination or Media Count:

23.0

Abstract:

Dimethyl-aluminum amide CH32AlNH2 is a postulated intermediate in the reaction between trimethyl aluminum CH33Al and ammonia to form aluminum nitride. Results of geometry optimization calculations for CH32AlNH2, H2AlNH2 and isoelectronic H2SiCH2silaethylene are presented. Each of these has a planar equilibrium skeleton with C2v symmetry. Geometry optimizations were carried out using Generalized Valence Bond Perfect-Pairing GVB-PP wave functions. AlNitrogen bond distances of 1.78 and 1.80 A are predicted for the dihydro-and dimethyl-aluminum amides, respectively, slightly longer than the optimized SiliconCarbon bond distance in silaethylene 1.74 A. AlN bond distances in these compounds are fitted into a phenomenological correlation established by Haaland which relates the covalentdative character of such a bond to the bond distance. We compare the AlN and SiC bonds in the shapes of the GVB-PP orbitals representing them and in their predicted dipole moments. aw

Subject Categories:

  • Inorganic Chemistry
  • Organic Chemistry

Distribution Statement:

APPROVED FOR PUBLIC RELEASE