Ab Initio Computational Studies of Heterocycloalkynes:  Structures, Natural Bond Orders, Ring Strain Energies, and Isomerizations of Cyclic Iminoboranes and Iminoalanes

Abstract

Ab initio calculations of series of cyclic iminoboranes (CH 2 ) n BtN and iminoalanes (CH 2 ) n -AltN show that they adopt angularly distorted structures compared to the isoelectronic cycloalkynes. Natural bond order analyses indicate that the larger ring iminoboranes contain BN triple bonds, but the smaller ring iminoboranes and all the iminoalanes contain MN double bonds and a lone pair on the nitrogen atom. Group equivalent calculations confirm that cyclic iminoboranes and iminoalanes contain less ring strain energy than the corresponding cycloalkynes, but the data do not distinguish between doubly and triply bonded systems. Examination of the rearrangements of isomeric azacycloalkane borines to cyclic iminoboranes shows that they are exothermic, with moderate activation barriers. Thus, a way by which the heterocycloalkynes might be synthesized is suggested.

The Effect of Substituent on Molecules That Contain a Triple Bond Between Arsenic and Group 13 Elements: Theoretical Designs and Characterizations

“…Therefore, triply bonded RE 13 ≡E 15 R is the next synthetic challenge. To the best of the authors' knowledge, only R 2 BN molecules that contain a B≡N triple bond have been experimentally demonstrated to exist [30][31][32][33][34][35][36][37][38][39][40].…”

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“…Natural Bond Order analysis indicates that the larger ring iminoboranes contain BN triple bonds, the smaller ring iminoboranes BN double bonds and a lone pair on a nitrogen atom. 150 The first example of a dimeric boron azide, [(C 6 F 5 ) 2 BN 3 ] 2 , has been synthesized from 7 Boron-chalcogen species The mixed pyridine-phenol complex (dppy)BF has been synthesized and shown to show exhibit photoluminescent and novel electroluminescent properties. 165 The novel macrocyclic complex, bearing an alkoxide bridging a BF 3 and a metal centre, [Cu(LBF 4 )][BF 4 ] (Scheme 5), was formed when [Cu(HL)][BF 4 ] 2 was recrystallised from MeNO 2 -Et 2 O.…”

A Monomeric Aluminum Imide (Iminoalane) with Al–N Triple-Bonding: Bonding Analysis and Dispersion Energy Stabilization

“…1.63–1.65 Å) Al–N distances, 11 , 30 , 40 , 41 and NBO analysis of MeAlNMe by Gilbert indicated that it had an Al–N triple bond composed of one σ- and 2 π-bonds. 42 …”

“…Computations for HAlNH and MeAlNMe showed linear geometries with short (ca. 1.63–1.65 Å) Al–N distances, ,,, and NBO analysis of MeAlNMe by Gilbert indicated that it had an Al–N triple bond composed of one σ- and 2 π-bonds …”

“…1.63−1.65 Å) Al−N distances, 11,30,40,41 and NBO analysis of MeAlNMe by Gilbert indicated that it had an Al−N triple bond composed of one σand 2 π-bonds. 42 Previously, our group described the synthesis of gallium and indium imides with two-coordination at both the group 13 metal and N atoms by reaction of an m-terphenyl azide with the dimetallenes Ar iPr4 MMAr iPr4 (M = Ga, In; Ar iPr4 = C 6 H 3 -2,6-(C 6 H 3 -2,6-i Pr 2 ) 2 ), which exist in equilibrium with :MAr iPr4 monomers in solution. 43 This suggested that a similar Al species could be isolable, but the lack of an analogous Al(I) precursor (i.e., ArAlAlAr or :AlAr) precluded its synthesis.…”