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A Structural Probe for Organogold(I) Rings and [2]Catenanes

“…As part of this study, the related gold(I) complexes bearing the 4- tert -butylcyclohexylidene hinge group (X = 4- t -BuC 6 H 9 ) have been prepared. The tert -butyl substituent controls the conformation of the cyclohexyl group and provides a particularly useful probe for structure determination of the gold(I) complexes in solution by NMR. , …”

Determination of the configuration and conformation of .alpha.-, .beta.-, and isotripiperideine carbon-13 nuclear magnetic resonance spectroscopy

“…Carbon-13 NMR spectroscopy provides a simple method for assigning the configuration of a-and /3-tripiperideine by symmetry arguments. Furthermore, the dynamic behavior of the a compound (1) indicates its conformation to be B whereas the conformation of /3-tripiperideine (2) was deduced from the chemical shift data in conjunction with empirical increment calculations to be very largely F. The same procedure was applied to select the dominant structure I from the 13 possible stereoisomers of isotripiperideine (3). Determination of numeric values for the generalized anomeric effect of two nitrogen lone pairs requires knowledge of the energies of the different types14 of gauche interactions.…”

“…Experimental Section -Tripiperideine (1) and /3-tripiperideine (2) {RRR/SSS, respectively RRS/SSR racemic mixture of dodecahydro-l/i,6H,ll/i-tripyrido[l,2-a:l',2'-c:l",2"-e]-«-triazine) and isotripiperideine (3) (tetradecahydro-2.fi, ll/i-tripyrido[l,2-a:l',2/-c:3",2"-e]pyrimidine) have been prepared as described previously.7 The l:iC FT NMR spectra were recorded at 22.63 MHz using a Bruker HX 90 spectrometer equipped with a Nicolet 1083 computer and a Bruker temperature control unit; 8K data points were used resulting in a resolution of 0.03 ppm for the 2500-Hz spectra in Table I. Usually 3000-8000 FID's were accumulated; the low-temperature spectra in the exchange region required 30 000 FID's.…”

“…Registry No.-5, 60526-38-7; 5 endo-carbonate precursor, 60526-39-8; 5 exo-carbonate precursor, 60562-31-4; 6,60526-40-1; 6 exo-carbonate precursor, 60526-41-2; 6 endo-carbonate precursor, 60562-32-5; 7, 0526-42-3; 7 endo-carbonate precursor, 60526-43-4; 8, 60526-44-5; 8 carbonate precursor, 60526-45-6; 9, 60526-46-7; 9 exo-carbonate precursor, 60526-47-8; 9 endo-carbonate precursor, 60562-33-6; 10,60526-48-9; 10 exo-carbonate precursor, 60526-49-0; 10 endocarbonate precursor, 60562-34-7; dichlorovinylene carbonate, NMR spectroscopic investigations of the conformation and dynamic behavior of heterocyclic six-membered ring systems have attracted considerable interest. 3 During the last few years 13C NMR investigations have provided new information about the constitution of natural products4 and the ground state conformation5 of a number of saturated heterocycles. In connection with our interest in dynamic 13C NMR studies6 we report here our investigation of tripiperideines.…”

“…Although conformation B is asymmetric, a rapid inter- Table 1.13C NMR Spectra of -, ß-, and Isotripiperideine -Tripiperideine (1) ß-Tripiperideine (2) Isotripiperideine (3) , ppm" , ppm" , ppm"…”