The quest of selective catalytic reactions for direct conversion of alkanes into valued products remains to be the most important task objective of modern chemistry and metal complex catalysis. Nowadays it is adopted that the formation of metal–alkyl intermediates (MR) is a necessary condition for activation and functionalization of alkanes on metal complexes but the mechanism of subsequent reactions of metal alkyls remain obscure, so that effective catalytic systems of this kind are still rare and uncommon. Although it is widely adopted that alkane σ-complexes (M·RH) most frequently are primary hydrocarbon intermediates in these processes, low profile in the literature is given to their reactivity and these are often considered simply just as some ‘collision complexes’. Nevertheless, theoretical and experimental studies provide more and more evidence that the СН bonds in such complexes may be markedly weakened and/or polarized, thus opening wide horizons for occurrence of subsequent direct homolytic or heterolytic reactions of alkanes. This review addresses the discussion of new routes for activation and oxygenation of saturated hydrocarbons, including those via alkane σ-complexes, without formation of metal–alkyl intermediates.

对于将烷烃直接转化成有价值的产物的选择性催化反应的追求仍然是现代化学和金属络合物催化的最重要的任务目标。如今，金属-烷基中间体的形成（MR）是烷烃在金属络合物上活化和官能化的必要条件，但是金属烷基烷烃后续反应的机理仍然不清楚，因此这种有效的催化体系仍然很少且不常见。尽管人们普遍认为烷烃σ-络合物（M·RH）在这些过程中是主要的烃中间体，但文献中对它们的反应性并不重视，它们通常像某些“碰撞络合物”一样被简单地考虑。然而，理论和实验研究提供了越来越多的证据表明此类络合物中的Н键可能显着弱化和/或极化，从而为随后发生的烷烃直接均相或杂合反应打开了广阔的视野。这篇综述讨论了饱和烃活化和氧合的新途径的讨论，包括通过烷烃σ络合物而没有形成金属烷基中间体的途径。