TY - JOUR

T1 - Self-assembly of hydrogen-bonded cage tetramers of phosphonic acid

AU - Giba, Ivan S.

AU - Tolstoy, Peter M.

N1 - Publisher Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland.

PY - 2021/2/4

Y1 - 2021/2/4

N2 - The self-association of phosphonic acids with general formula RP(O)(OH)2 in solution state remains largely unexplored. The general understanding is that such molecules form multiple intermolecular hydrogen bonds, but the stoichiometry of self-associates and the bonding motifs are unclear. In this work, we report the results of the study of self-association of tert-butylphosphonic acid using low temperature liquid-state1H and31P NMR spectroscopy (100 K; CDF3/CDF2Cl) and density functional theory (DFT) calculations. For the first time, we demonstrate conclusively that polar aprotic medium tert-butylphosphonic acid forms highly symmetric cage-like tetramers held by eight OHO hydrogen bonds, which makes the complex quite stable. In these associates. each phosphonic acid molecule is bonded to three other molecules by forming two hydrogen bonds as proton donor and two hydrogen bonds as proton acceptor. Though the structure of such cage-like tetramers is close to tetrahedral, the formal symmetry of the self-associate is C2 .

AB - The self-association of phosphonic acids with general formula RP(O)(OH)2 in solution state remains largely unexplored. The general understanding is that such molecules form multiple intermolecular hydrogen bonds, but the stoichiometry of self-associates and the bonding motifs are unclear. In this work, we report the results of the study of self-association of tert-butylphosphonic acid using low temperature liquid-state1H and31P NMR spectroscopy (100 K; CDF3/CDF2Cl) and density functional theory (DFT) calculations. For the first time, we demonstrate conclusively that polar aprotic medium tert-butylphosphonic acid forms highly symmetric cage-like tetramers held by eight OHO hydrogen bonds, which makes the complex quite stable. In these associates. each phosphonic acid molecule is bonded to three other molecules by forming two hydrogen bonds as proton donor and two hydrogen bonds as proton acceptor. Though the structure of such cage-like tetramers is close to tetrahedral, the formal symmetry of the self-associate is C2 .

KW - Hydrogen bond

KW - Low-temperature NMR

KW - Phosphonic acid

KW - Self-association

KW - Tetramer

KW - self-association

KW - phosphonic acid

KW - tetramer

KW - hydrogen bond

KW - low-temperature NMR

UR - http://www.scopus.com/inward/record.url?scp=85100520964&partnerID=8YFLogxK

UR - https://www.mendeley.com/catalogue/7dcecd5b-b2ee-3b9a-8c09-dab6863482c9/

U2 - 10.3390/sym13020258

DO - 10.3390/sym13020258

M3 - Article

AN - SCOPUS:85100520964

VL - 13

SP - 1

EP - 12

JO - Symmetry

JF - Symmetry

SN - 2073-8994

IS - 2

M1 - 258

ER -