Magnesium Bonds: From Divalent Mg Centres to Trigonal and Tetrahedral Coordination

Abstract

wB97XD/aug-cc-pVTZ calculations were performed for MgXY complexes (X=Cl, Br; Y=Cl, Br, CH 3 , C 2 H 5 , C 6 H 5 ) with one or two H 2 O or (CH 3 ) 2 O ligands to mimic interactions of Grignard reagents in solvents. The magnesium Lewis acid centre interacts in these complexes with the Lewis base O-centre and the corresponding Mg…O link may be classified as the magnesium bond (Mg-bond). This interaction is characterized by properties similar to those of the hydrogen bond; however it also possesses few unique features. The Mg-centres of isolated MgXY species are characterized by ring regions of a positive electrostatic potential (EP) that determines their acidic properties. The linear geometry of the MgXY unit is disturbed in complexes with H 2 O or (CH 3 ) 2 O species where the Mgcentres are closer to trigonal and to tetrahedral configurations in complexes with one and two ligands, respectively; such centres also possess regions of positive EP.

Synthesis, Characterization, and Low-Toxicity Study of a Magnesium(II) Complex Containing an Isovanillate Group

“…It should be noted that when the same solution is kept in the dark for 3 days, only two complexes are present, Mg-hex and Mg-tet, in addition to a free phen ligand, indicating the transient characteristic of the high mass species. In agreement, Mg­(II) preferentially forms octahedral complexes, although tetrahedral complexes have also been reported depending on the ligand strength. , …”

“…In agreement, Mg(II) preferentially forms octahedral complexes, although tetrahedral complexes have also been reported depending on the ligand strength. 34,35 2.1.2. NMR Studies.…”

Noncovalent Bonds through Sigma and Pi-Hole Located on the Same Molecule. Guiding Principles and Comparisons

“…As work has progressed, there has been recognition of π-holes as providing a means by which an aerogen bond (involving rare gas atoms) can form [ 100 , 101 , 102 , 103 , 104 ]. Other newly introduced types of σ/π- hole directed interactions are alkali and alkaline earth bond (e.g., beryllium bond, magnesium bond) in which atoms of 1st and 2nd groups contribute [ 105 , 106 , 107 , 108 , 109 ] or regium and spodium bonds which employ transition metals from 11th (regium [ 110 , 111 , 112 , 113 , 114 , 115 ]) or 12th (spodium [ 105 , 116 , 117 , 118 , 119 ]) groups of the periodic table. The full range of these sorts of bonds, along with their designations, is summarized in Figure 1 .…”

Non-covalent bonds in group 1 and group 2 elements: the ‘alkalene bond’

“…In group 2, non-covalent bonds involving beryllium, 40–44 magnesium, 45–48 and calcium 49 have been theoretically investigated in the last decade. Beryllium bonds were identified while studying the interaction of BeD 2 (D = H, F, Cl, and OH) with different Lewis bases.…”