Non‐empirical calculations of NMR indirect carbon–carbon coupling constants. Part 7—Spiroalkanes

Abstract

Carbon-carbon spin-spin coupling constants were calculated at the SOPPA level for a series of seven classical spiroalkanes, spiro[2.2]pentane, spiro[2.3]hexane, spiro[2.4]heptane, spiro[2.5]octane, spiro[3.3]heptane, spiro[4.4]nonane and spiro[5.5]undecane, with special focus upon couplings involving and/or across spiro carbons. Many interesting structural trends were investigated originating in specific geometries and unusual bonding environments at the spiro carbon.

Indirect Nuclear 77Se?77Se Spin?Spin Coupling Constants. Application of Density Functional Theory (DFT) Calculations

“…Recent progress in the calculation of isotropic spin-spin coupling constants n J(A,X) by using DFT methods is promising [7][8][9], since both the approximate 1 Anorganische Chemie II, Universität Bayreuth, D-95440 Bayreuth, Germany. 2 To whom all correspondence should be addressed; e-mail: b.wrack@ uni-bayreuth.de magnitude and the sign of coupling constants are reproduced in many cases [10][11][12][13]. Moreover, the calculations reveal the contributions from the different coupling mechanisms.…”

Non‐empirical calculations of NMR indirect carbon–carbon coupling constants. Part 10—Carbocages

“…the s-character of corresponding C-H carbon bonding hybrids. 2 -H and C sp 3 -H, whereas adamantane and diamantane have almost classical C sp 3 -H bonds and therefore possess no steric strain. A marked decrease in 1 J C,H with the corresponding carbon-hydrogen bond lengths was discovered in the title carbocages.…”

Non-empirical calculations of NMR indirect carbon-carbon coupling constants. Part 11?saturated carbocycles: a reference data set and a practical guide to structural elucidation

“…However, it can be safely assumed from their computed values of ca 30-32 Hz that the bridgehead-bridgehead bonds in 33 and 34 are essentially normal sp 3 -sp 3 bonds, showing no invertedness and/or ring strain effects characteristic of the smaller propellanes 29-32.…”

“…A number of saturated carbocycles including monocycloalkanes, 1,2 spiroalkanes, 3,4 bicycloalkanes, 5 bridged bicycloalkanes, 4,6 propellanes, 4,7 bicyclobutane-containing polycycloalkanes, 8 polyhedranes 9 and caged polycycloalkanes 10 were investigated and reported on in 10 previous papers 1 -10 in the period 2002-04. Special focus was placed on the structural behavior of carbon-carbon spin-spin coupling constants, J(C,C), in these series by means of non-empirical calculations at the SOPPA (Second-Order Polarization Propagator Approach 11 ) level.…”