The magnitudes and trends of the dipole moments of MexH3-xE and MexH3-xEBH3 (E = N, P; x = 0→3; Me = CH3) were investigated via CNDO-MO methods. Moments evaluated by the CNDO/2D approach reproduced the experimental data better than the strict CNDO/2 formalism. Transformation of the canonical CNDO/2 MO's to localized MO's (LMO's) permitted a partitioning of the total moments into bond moments, bond polarization moments, and lone pair moments. Values of the lone pair moments of the phosphines are calculated to be greater than those of the amines. Within the framework of the CNDO/2D approximation, coordination of BH3 to H3N involves a charge migration primarily between the N-bound and B-bound hydrogens (0.33e) while coordination to H3P is primarily P → B (0.27e). The covalent character of the BN and BP bonding LMO's is 46 and 61%, respectively. The CNDO molecular orbital results are in general agreement with Weaver and Parry's model for dipole moments and base strengths of amines and phosphines. © 1975.14C271280Presented at the XXV Annual Meeting of the Sociedade Brasileira para o Progresso da Ciencia. Abstract no. 27-C1, Ciěncia Cult., 25, S91 (1973). Abstracted, in part, from the M.S. thesis of F.B.T.P. b, Campinas. c) EvanstonWeaver, Parry, (1966) Inorg. Chem., 5, p. 703Kodama, Weaver, LaRochelle, Parry, Dipole Moment Studies II. The Dipole Moments of the Ethylphosphines (1666) Inorganic Chemistry, 5, p. 710Weaver, Parry, Dipole Moment Studies. III. The Dipole Moments of the Methylamine Boranes (1966) Inorganic Chemistry, 5, p. 713Weaver, Parry, Dipole Moment Studies. IV. Trends in Dipole Moments (1966) Inorganic Chemistry, 5, p. 718Morse, Parry, Dipole Moment Studies. V. The Dipole Moments of the Methylphosphine Boranes (1972) The Journal of Chemical Physics, 57, p. 5365Morse, Parry, (1972) J. Chem. Phys., 57, p. 5367Rudolph, Parry, (1967) J. Am. Chem. Soc, 89, p. 1621Foester, Cohn, (1972) Inorg. Chem., 11, p. 2590Rudolph, Schultz, (1971) J. Am. Chem. Soc., 93, p. 6821Cowley, Damasco, (1971) J. Am. Chem. Soc., 93, p. 6815Lee, Cohn, Schwendeman, (1972) Inorg. Chem., 11, p. 1917Pople, Beveridge, (1970) Approximate Molecular Orbital Theory, , McGraw-Hill, New YorkShillady, Billingsley, II, Bloor, Quantum mechanical calculations on barriers to internal rotation (1968) Theoretica Chimica Acta, 11, p. 344Shillady, (1970) Ph.D. Thesis, , University of VirginiaGiessner-Prettre, Pullman, (1968) Theoret. Chim. Acta., 11, p. 159Trindle, Sinanoglu, Semiempirical Method for the Determination of Localized Orbitals in Molecules (1968) The Journal of Chemical Physics, 49, p. 65Edmiston, Reudenherg, (1965) J. Chem. Phys., 43, p. S97Edmiston, Reudenberg, (1963) Rev. Mod. Phys., 35, p. 457England, Salmon, Reudenberg, (1971) Topics in Current Chemistry, 23, p. 31. , Springer-Verlag, BerlinWon Nicssen, Density localization of atomic and molecular orbitals (1973) Theoretica Chimica Acta, 29, p. 29. , and references thereinLabarre, Leibovici, Structure electronique des complexes acide-base de Lewis. I. Structure electronique et conformation mol�culaire des mol�cules F3P�BH3 et F2HP�BH3 (1972) International Journal of Quantum Chemistry, 6, p. 625. , CNDO, F3PBH3 and F2HPBH3Sabin, (1973) Chem. Phys. Letts., 20, p. 212. , ab initio, H3PBH3Demuynck, Veillard, (1970) J. Chem. Soc. (D), p. 873. , ab initio, F3PBH3Hillier, Marriott, Saunders, Ware, Lloyd, Lynaugh, (1970) J. Chem. Soc. (D), p. 1586. , ab initio F3PBH3Hillier, Saunders, An ab initio study of the bonding in phosphine borane, trifluorophosphine broane and trifluorophosphine oxide (1971) Journal of the Chemical Society A: Inorganic, Physical, Theoretical, p. 664. , ab initio F3PBH3 and H3PBH3Palke, (1972) J. Chem. Phys., 56, p. 5308. , ab initio H3PBH3Kroll, Shillady, (1973) J. Am. Chem. Soc., 95, p. 1422. , ab initio, aziridineboraneFujimote, Kato, Yamabe, Fukui, Molecular orbital calculations of the electronic structure of borazane (1974) The Journal of Chemical Physics, 60, p. 572. , ab initio H3NBH3Armstrong, Perkins, Calculation of the electronic structures and the gas-phase heats of formation of BH3,NH3 and BH3,CO (1969) Journal of the Chemical Society A: Inorganic, Physical, Theoretical, p. 1044. , ab initio, H3NBH3Aslangul, Veillard, Daudel, Gallais, (1971) Theoret. Chim. Acta., 23, p. 211. , ab initio H3NBH3Tinland, An ab initio SCF-LCAO-MO study of the electronic structure of borazane, BH3NH3 (1969) Journal of Molecular Structure, 3, p. 244. , ab initioPeyerimhoff, Buenker, Further Study of Umbrella vs Bridged Geometries: SCF–MO and CI Calculations for C2H6++ and Ammonia Borane (1968) The Journal of Chemical Physics, 49, p. 312. , ab initio, H3NBH3Moireau, Veillard, (1968) Theoret. Chim. Acta., 11, p. 344. , ab initio H3NBH3Veillard, Levy, Daudel, Gallais, (1967) Theoret. Chim. Acta., 8, p. 312. , ab initio, H3NBH3Kuznesof, Shriver, (1968) J. Am. Chem. Soc., 90, p. 1683. , CNDOKuznesof, (1967) Ph.D. Dissertation, , Northwestern University, preliminary study (CNDO) of the dipole moments of the methylamine boranes is presented hereHoffmann, Theoretical Investigations on Boron-Nitrogen Molecules (1964) Adv. Chem. Ser., 42, p. 78Hoffmann, (1964) J. Chem. Phys., 40, p. 2474. , Extended Hückel, H3NBH3Guest, Hillier, Saunders, (1972) J.C.S. Faraday II, 68, p. 867Rothenberg, (1971) J. Am. Chem. Soc., 93, p. 68Pritchard, Kern, (1969) J. Am. Chem. Soc., 91, p. 1631Newton, Switkes, Lipscomb, (1970) J. Chem. Phys., 53, p. 2645Evans, Huheey, (1970) J. Inorg. and Nucl. Chem., 32, p. 777. , and references thereinJolly, Perry, (1973) J. Am. Chem. Soc., 95, p. 5442University of California Lawrence Radiation Laboratory Report LBL-2565Jolly, Perry, (1974) Inorg. Chem., 13, p. 2686R.E. Bruns, Quantum Chemistry Program Exchange, Department of Chemistry, Indiana University, Bloomington Indiana program no 240Santry, (1968) J. Am. Chem. Soc., 90, p. 3309P.M. Kuznesof, submitted to QCPE. A listing is available on request. The localization procedure follows the ERTS method (refs. 7a, c) and, furthermore, is faster than a similar sub-program LOCAL currently available from QCPE (no. 191). Incorporation of ORLOC into CINDOM or CNINDO (QCPE no. 141) involves the same changes as incorporation of LOCAL into CNINDO. Another significant advantage of ORLOC is that it does not require the introduction of any additional matrices as does LOCAL. ORLOC is also available from the author as an independent program requiring as input only the CMO's and coulomb repulsion integralsP.M. Kuznesof, Quantum Chemistry Program Exchange, Departrnent of Chemistry, Indiana University, Bloomington, Indiana, program no. 94Boyd, (1972) J. Am. Chem. Soc., 94, p. 64Pople, Segal, (1965) J. Chem. Phys., 43, p. S136Odom, Barnes, Hudgens, Durig, (1974) J. Phys. Chem., 78, p. 1503. , A geometry optimized CNDO/2 calculation on Me3NBH3 gives a dipole moment in excellent numerical agreement with the experimental value. Geometry optimization of Me3N, however, yields essentially no improvement. SeeSantry, Segal, (1967) J. Chem. Phys., 47, p. 158Hillier, Saunders, (1970) J. Chem. Soc. (D), p. 316Bryan, Kuczkowski, (1972) Inorg. Chem., 11, p. 553These authors used WP's estimate for the P-=CH3 moment and they settled on the range 3.4- 4.0D for the P-BH3 moment because of an ambiguity arising in their estimate of this moment in CH3PH2BH3. For this molecule they calculated 3.92 and 3.44D depend- ing on which dipole components they selected for their analysisStamper, Trinajastic, Localised orbitals for some simple molecules (1967) Journal of the Chemical Society A: Inorganic, Physical, Theoretical, p. 782. , Values for the nitrogen lone pair moment in NH3 have been previously reported, ranging from 3.4 to 3.8D depending on the starting SCF-CMO's. SeePeters, 764. Localised molecular orbitals in self-consistent field wave functions. Part III. Hybridisations, atomic charges, and dipole moments in non-linear molecules (1963) Journal of the Chemical Society (Resumed), p. 4017Peters, Localised molecular orbitals in self-consistent field wave functions. Part X. The nature of electronegativity (1966) Journal of the Chemical Society A: Inorganic, Physical, Theoretical, p. 656. , Peters has carried out extensive studies regarding the nature and applicability of LMO's. See, and references thereinCoulson, (1961) Valence, p. 218. , 2nd ed., Oxford University Press, LondonSchaefer, III, (1972) The Electronic Structure of Atoms and Molecules, p. 197. , Addison-Wesley, Reading, MassCNDO/2 results obtained for H3PBH3 and Me3PBH3 using their experimental geometries did not significantly differ from the results presented in this workVan Wazer, Callis, Shoolery, Jones, (1956) J. Am. Chem. Soc., 78, p. 5715We define percentage covalent character as where the summation is over the atomic orbitals of atoms R, S, or bothBrauman, Blair, The bicyclo[3.2.2]nonatrienyl anion. The anionic analog of the norbornadienyl cation (1968) Journal of the American Chemical Society, 90, p. 6562Brauman, Riveros, Blair, (1971) J. Am. Chem. Soc., 93, p. 3914McDaniel, Coffman, Strong, (1970) J. Am. Chem. Soc., 92, p. 6697Holtz, Beauchamp, (1969) J. Am. Chem. Soc., 91, p. 5913Beauchamp, Ion Cyclotron Resonance Spectroscopy (1971) Annual Review of Physical Chemistry, 22, p. 527Santry, Segal, (1967) J. Chem. Phys., 47, p. 158. , phosphinesWatanabe, (1957) J. Chem. Phys., 26, p. 542. , amines