An improved two-parameter omega technique (itpot) for molecular orbital calculatlons

Bond lengths are calculated for tweive aromatic hydrocarbons by way of the ITPOT and a modified Coulson's equatlon. Comparlsons are made with respect to other theoretlcal results as well as with avallable experimental data. The predlctive capabiilties of the ITPOT and the modified Coulson's equatlon are pointed out

Strain energy considerations in the photochemical [&#960;<SUP>2</SUP> + &#960;<SUP>2</SUP>] cage cyclisations. A case study en route to [6]-prismane

Six novel cases of (2+2) photocycloaddition of strained cage dienes, aiming at producing [6]-prismane and congeners, are reported and the steric criteria for the success of reaction are presented based on molecular mechanics

An improved two-parameter omega technique (ITPOT) for molecular orbital calculatlons

<span style="font-size: xx-small; font-family: Arial;"><span style="font-size: xx-small; font-family: Arial;"><span style="font-size: xx-small; font-family: Arial;"><span style="font-size: xx-small; font-family: Arial;"><p align="left">Bond lengths are calculated for tweive aromatic hydrocarbons by way of the ITPOT and a modified Coulson's equatlon. Comparlsons are made with respect to other theoretlcal results as well as with avallable experimental data. The predlctive capabiilties of the ITPOT and the modified Coulson's equatlon are pointed out.</p></span></span></span></span

1,4-Bishomo[6]prismane (garudane): molecular structure and strain analysis of reactions potentially leading to prismanes

The proposed structure of garudane (1), the face-to-face D2h dimer of norbornadiene, has been confirmed by the X-ray analysis of a single crystal of the 1,3-bis(methoxycarbonyl) derivative (2), monoclinic, space group C2/c, a= 16.570(6), b= 8.073(4), c= 12.151(4)&#197;,&#946; = 114.89(2)&#176;, final R= 0.055, Rw= 0.070. Detailed structural characteristics observed for (2) are compared with the isomeric D2d dimer (isogarudane)(3). Compound (1) is calculated to be 44 kcal mol-1 mere strained than (3). The demethylenation procedure on (1)-and the 1,4-bis homo[7] prismane (10) of similar structure-as a potential synthetic route to [6]- and [7]-prismanes (4) and (5) has advantages over the intramolecular [2+2]-photocyclization of polycyclic dienes [e.g.(12) and (13)] and the pinacolic coupling of polycyclic diketones [e.g.(14)]. These are discussed on the basis of strain analysis

Theoretical and experimental study of [2+2]-photoclosure approachtoward [7]-prismane analogs

All 39 possible intramolecular [2+2]-photocycloaddition pathways toward [7]-prismane and its homo, seco, homo-seco, bishomo and bishomo-seco analogs have been explored by MM2 .calculations. Fourteen of these are predicted to offer reasonable chance of success. Experimental support for a few of these is provided