Poly[di-μ₂-methanolato-di-μ₂-tetramethoxyborato-disodium(I)]

Abstract

In the polymeric title compound, [Na2(C4H12BO4)2(CH4O)2]n, the two independent sodium cations are bound by five O atoms. All the O atoms of one tetramethoxyborate anion bind cations, forming a tetrameric cluster around a tetragonal inversion centre [Na-O = 2.2777 (18)-2.3907 (16) A]. Two methanol O atoms bridge the two Na atoms [Na-O = 2.3590 (15)-2.4088 (18) A] and provide the hydrogen-bonding H atoms. The second tetramethoxyborate anion provides two O atoms to one Na atom [mean Na-O = 2.31 (2) A] and two O atoms as donors for crosslinking hydrogen bonds to adjacent tetramers, which complete the three-dimensional packing. The crystal was a treated as a racemic twin.

Alkali metal alkoxyborate ester salts; a contemporary look at old compounds

“…3 and Table S1 †). 29 The layered nature of the structure results in some preferred orientation along the c-axis (Fig. S13 † 2 and Fig.…”

“…For example, the closest Na-Na distance in the highly conducting solvated Na[B(OMe) 4 ]•MeOH is 3.16 Å, compared to 5.74 Å in both Na[B(OEt) 4 ] and Na[B(OBu) 4 ]. 27,32,35 Electrostatic potential maps can give a 3-dimensional picture of charge distribution across anions and molecules. Thus, the electrostatic potential of the borate anions was analyzed to attain a better understanding of the compounds synthesized and why cationic conduction was only measurable for the sodium and potassium salts of [B(OMe) 4 ] − .…”

“…It can consequently be concluded that, rather than preventing the cation from coordinating strongly to the oxygen rich center of the anion using the bulkier alkyl groups, these alkyl groups actually obstructed the cation from migrating due to significantly increasing the distance between cation centres. 27,32,35 This was interesting as solvation was found to increase the mobility of the cation by increasing the cation/anion distance. 43 However, too much distance by using the longer chain alkyl groups decreases this mobility significantly while also decreasing the number of oxygen rich sites where the cations prefer to sit.…”

“…51 A rigid body of [B(OMe) 4 ] − , with H atoms omitted due to the low electron density, was used for the atomic structure solution of K[B(OMe) 4 ]. 29 To locate the position of H atoms, neutron diffraction should be utilized.…”

Boron

“…149 The molecular structure of the polymeric borate [Na{B(OMe) 4 }(HOMe) 2 ] n has been determined and reported. 150 The reaction of BEt 3 with the (2-dimethylaminophenyl)alcohols 1-HOX-2-NMe 2 C 6 H 4 (X ¼ CPh 2 , CCy 2 , CPh 2 CH 2 ) in 1 : 2 and 1 : 1 reaction ratios has been shown to produce a range of intramolecularly base stabilised {BEt 2 } and {BEt} derivatives. 151 Hypervalent, pentacoordinate and tetracoordinate compounds bearing an anthracene skeleton with two oxygen or nitrogen donor groups (OMe and NMe 2 respectively) in the 1,8-positions have been synthesised and reported.…”