Stable heterocyclic stannylene: The metal, ligand‐centered reactivity, and effective catalytic hydroboration of aldehydes

Abstract

A stable O,N‐heterocyclic stannylene 1 bearing novel tetradentate 2,4‐di‐tert‐butyl‐6‐((2‐(1‐((pyridin‐2‐ylmethyl)imino)ethyl)phenyl)amino)phenolate ligand (RAPH2) was synthesized and characterized. Complex 1 is monomeric in crystal and solution due to two additional intramolecular N → Sn donor–acceptor interactions. The diverse reactivity of compound 1 towards various iron carbonyl compounds was studied. Oxidative addition of [Fe2(μ‐S2)(CO)6]2 to the tin center of 1 resulted in a new six‐coordinate Sn(IV) compound 2 containing two Sn–S bonds. The reaction of 1 with Fe2(CO)9 led to the formation of a stable tin(II) adduct 3 – RAPSn‐Fe(CO)4. The interaction between 1 and [(η5‐C5H5)Fe(CO)2]2 resulted in a transformation of the ligand skeleton. During this reaction, the tin center is oxidized to the tetravalent state, and the donor ═N–CH2–Py group is converted into an anionic one with the loss of the methylene hydrogen atom. The molecular structures of all obtained compounds were determined by single‐crystal X‐ray diffraction. The novel stannylene 1 demonstrates striking activity in benzaldehydes' hydroboration reactions down to 0.02 mole percent of the catalyst loading under mild conditions.

Efficient Hydroboration of Esters and Nitriles Using a Quinazolinone‐Supported Titanium(IV) Multitasking Catalyst

“…The experimental procedures, characterization data, crystallographic data table, and NMR spectra of all the hydroboration products are given in the supporting information. Additional references cited within the Supporting Information [3,51,56, 57–65] …”

“…Additional references cited within the Supporting Information. [3,51,56,[57][58][59][60][61][62][63][64][65]…”

Imination of Sterically Unshielded o‐Quinones in the Coordination Sphere of Zinc (II)

“…The redox activity becomes especially relevant for coordination compounds with non‐transition metals, which are not characterized by paramagnetic forms of stable ions, as it makes it possible to obtain magnetically active compounds on their basis. The various effects found on transition and non‐transition metal complexes, such as valence tautomerism, [2] fixation of small molecules, [3] selective catalysis, [4] stabilization of the metal center in the low valence state, [5] activating complexation, [6] development of new metal catalysts [7] and the ability to generate photoinduced high‐spin molecules, [8] are based on redox transformations of ligands. In this regard, the synthesis of new o ‐iminoquinone ligands in order to achieve specific geometric and redox characteristics remains an actual task.…”

Germanium Complexes with ONO Tridentate Ligands: O-H Bond Activation Control According to DFT Calculations

“…Tetrylenes [3][4][5][6][7]-heavier carbene analogs-have recently attracted significant attention [8][9][10][11][12][13][14][15][16][17][18][19][20]), primarily due to their possible application as analogs of transition metals in catalysis [21][22][23], in activation of small molecules [24][25][26][27][28][29][30], as ligands [31,32], in possible synthesis of derivatives with E-E bonds [33][34][35], reagents for synthesis [36][37][38][39] or precursors [40][41][42] in material chemistry. These species are reactive and unstable; to stabilize them, the introduction of bulky groups (kinetic stabilization) or polydentate ligands (thermodynamic stabilization) is used.…”