Kudos and Renaissance of s-Block Metal Chemistry

Abstract

Abstract:In recent years, the organometallic and coordination chemistry of the alkali and alkaline earth metals has experienced tremendous progress to tackle the needs of today's society. Enhanced ecological awareness and global availability favor research on the chemistry of the essential s-block metals. Nowadays, the s-block metals are conquering new chemical fields based on sophisticated theoretical and preparative achievements. Recent investigations show a huge impact of the s-block elements on stoichiometric and catalytic processes.Keywords: s-block metals; catalysis; Grignard reagents; alkali metals; alkaline earth metals The s-block metals subsume the elements of the first two groups of the periodic table-the alkali and alkaline earth metals. The non-radioactive elements were all discovered by the middle of the 19th century [1] (Table 1), initiating a profound s-block metal-based chemistry with a very long tradition. Generally, the toxicity is low and highly toxic congeners are limited to the radioactive metals and beryllium [2], justifying the underrepresented extent of their chemistry.

Main Group Redox Catalysis of Organopnictogens: Vertical Periodic Trends and Emerging Opportunities in Group 15

“…Accordingly, the redox reactivity of the elements is usefully (even if somewhat over-simplistically) abstracted according to their periodic “block”. For elements in the s - and f- blocks, single oxidation states (+I or +II for s elements, − +III for f elements , ) tend to prevail; by contrast, numerous stable oxidation states separated by modest reduction potentials proliferate among the transition metals of the d -block . Especially for the late transition metals of the second (4 d ) and third (5 d ) rows, the prevalence of accessible two-electron redox processes provides the thermo­dynamic and mechanistic basis upon which innumerable groundbreaking discoveries in catalytic synthesis are built. − …”

Stepwise Reduction at Magnesium and Beryllium: Cooperative Effects of Carbenes with Redox Non-Innocent α-Diimines

“…Because of extreme air and moisture sensitivity, these compounds did not survive the shipping and extensive handling associated with this process. Therefore, bulk purity was assessed by IR, 1 H, 13 C, and 9 Be NMR, and/or EPR. ( Et2 CAAC)BeCl 2 (compound 3) was prepared according to a literature procedure.…”

“…1 H NMR (500.13 MHz, C 6 D 6 , 298 K) δ 7.04 (m, 6H, Aryl), 5.88 (m, 4H, Aryl), 5.24 (m, 2H, Aryl), 3.36 (s, 4H, CH 2 −backbone), 3.11 (hept, J = 6.7 Hz, 4H, CH(CH 3 ) 2 -Dipp), 1.17 (d, J = 6.9 Hz, 12H, CH(CH 3 ) 2 ), 1.10 (d, J = 6.9 Hz, 12H, CH(CH 3 ) 2 ). 13 C NMR (150.9 MHz, C 6 D 6 ) δ 185.1(C carbene ), 146.5, 138.3, 135.3, 129.9, 125.1, 122.6, 119.6, 112.1, 102.5, 54.4, 28.9, 25.0, 23.2; 9 Be NMR (84.28 MHz, C 6 D 6 ) δ 4.5.…”

“…These compounds serve as some of the most potent bases and reducing agents used in organic synthesis, , substrates in transition metal-catalyzed coupling reactions, − and templates for expanding our understanding of divalent f -block organometallic compounds . In the past two decades, as the global chemical community has made a concerted push toward more sustainable chemical practices, the earth-abundant and generally nontoxic (with the exception of Be and Ra) alkaline earth compounds have reestablished themselves as popular targets for intensive synthetic investigation. , The renewed interest in these compounds has additionally been fueled by the potential of light s -block hydrides to serve as solid-state hydrogen storage materials. − The recent resurgence in the chemistry of group 2 has precipitated several dramatic shifts in the traditional paradigms associated with the compounds, including most notably the isolation of thermally stable molecular group 2 hydrides, ,− low valent alkaline earth complexes, − and the use of these compounds as molecular catalysts in organic transformations. − …”

Structural modulation of the photophysical and electronic properties of pyrene-based 3D metal–organic frameworks derived from s-block metals

“…The alkali metals sodium and potassium are particularly attractive precursor elements due to their availability, low cost and ecological compatibility. 14 Further, the network topologies of alkali metal MOFs are typically dominated by densely packed metal-On [n = 6-10] polyhedra, forming chains or layers, interconnected by organic linkers. 15 Nevertheless, the nondirectional, ionic nature of s-block carboxylate bonds renders rational design of s-block MOFs a challenging task.…”