13C nuclear magnetic resonance spectra. Part 10. Substituent effects on the 13C chemical shifts of adamantanes, diamantanes, and triamantanes

Abstract

The 13C n.m.r. data of a variety of substituted adamantanes, diamantanes, and triamantanes are presented. The cc-substituted chemical shifts (SCS) can be described by gauche XC interactions, the magnitudes of which decrease in the sequence BrC > HC > OC 2 CC. Similarly, gauche interactions of the types HX and CX contribute to the (3-SCS. but additionally the (3-SCS are increased, if the a-carbon atoms possess antiperplanar y'-carbon atoms. Steric interaction of the substituent with gauche y-carbon atoms seem to cause rather downfield rather than upfield shifts of the y-signals. The hyperconjugative interaction of parallel C,-Cb-and Cg-C,<-bond orbitals increase the y,,,ii-SCS of the hydroxy and, to a smaller extent, the bromine substituent.

Functionalized Nanodiamonds Part I. An Experimental Assessment of Diamantane and Computational Predictions for Higher Diamondoids

“…Column chromatography on silica gel (eluent of pentane/diethyl ether = 4:1) gave 1 (130 mg, 0.7 mmol), 1-hydroxydiamantane (12: 2.5 g, 82 %), and 4-hydroxydiamantane (13: 0.4 g, 13 %), with 1 H and 13 C NMR spectra identical to literature data. [45,64] Oxidation of 1 with dimethyl dioxirane: A 0.1 m solution of dimethyl dioxirane (18 mL, 1.8 mmol) was added to a solution of 1 (200 mg, 1.06 mmol) in acetone (20 mL) under stirring at room temperature. The reaction mixture was analyzed by GC-MS after 24 h and was found to contain unreacted 1 (32 %), 1-hydroxydiamantane (12, 52 %), 4-hydroxydiamantane ( (20).…”

“…The reaction mixture was separated by column chromatography (pentane as eluent) which gave 8 (366 mg, 39.2 %), 9 (92 mg, 9.8 %), and 16 (18 mg, 2 %), with spectral data identical to literature values. [63,64] Iodination of 1 under PTC conditions: A mixture of 1 (300 mg, 1.59 mmol), CHI 3 (1.4 g, 3.56 mmol), solid NaOH (3.5 g), and CH 2 Cl 2 (10 mL) was stirred at room temperature for 48 h, diluted with water (30 mL), and extracted with CH 2 Cl 2 (3 10 mL). The combined extracts were washed with an aqueous NaHSO 3 solution and water, and dried over Na 2 SO 4 ; excess solvents were removed in vacuo.…”

NMR spectral properties of the tetramantanes – nanometer‐sized diamondoids

“…[22,[37][38][39] Triamantane remains rare and therefore so are its NMR reports. [23,24,40] Tetramantanes occupy a position at the interface of organic chemistry and materials science. They cannot be synthesized by the carbocation methods, [41] so effective for the lower diamondoids.…”

“…1, Table 1. [23][24][25] Nuclear magnetic resonance properties of adamantane, and its derivatives, have been extensively studied [27] since Schleyer discovered high-yielding carbocation methods for lower diamondoid synthesis in 1957. [28] These studies have aided in the development of methods for describing and predicting substituent effects, in both 13 C NMR [29] and 1 H NMR, [30,31] as well as through-space effects, especially in three-dimensional systems.…”

Reactivities of the Prism‐Shaped Diamondoids [1(2)3]Tetramantane and [12312]Hexamantane (Cyclohexamantane)

“…[44] In contrast to bromination, the nitroxylation [45] of diamondoids with anhydrous nitric acid is usually less selective. [31,34,35] To probe the positional selectivities of the nitroxylation of 7 the reaction mixture was quenched with water and the mixture of mono-nitroxy derivatives was hydrogenated in the presence of PtO 2 .…”