Supramolecular architecture of phenylcarbamoylated acetone oxime 1,1-diisopropyl-3-phenylurea] complex

Abstract

Carbamoylated oximes 1 form 1:1 molecular complexes 4 with N,N-dialkyl-N -phenylurea when stirred in THF or ether at room temperature for short time in good yields. The molecular complexes 4a-e were isolated and characterized by analytical and spectral means. X-ray crystallographic analysis for complex 4a was performed. In this paper, we report the use of complex 4a and its moieties as building blocks to form non-interacting polymeric zigzag chains by inter-and intramolecular hydrogen bonds along baxis, and details of supramolecular architecture of 4a. There is a intramolecular H-H interaction between hydrogen of urea NH and neighboring hydrogen of diisopropyl's CH linked to the other urea nitrogen. In addition, to obtain the most favorable orientation of the moieties of the title complex, PM3 semi-empirical quantum mechanical calculations were performed and then results from X-ray crystallography and computational modeling were compared.

Hydrogen–hydrogen bonding in biphenyl revisited

“…denote here as ''hydrogen-hydrogen'' (or H-H) bonding [4,5] is one that occurs between similar or identical hydrogen atoms, to be contrasted with the dihydrogen bonding [9][10][11][12][13][14][15][16] between a positively charged hydrogen and a negatively charged hydrogen. The Table in the Appendix contrasts H-H and dihydrogen bonding as the two extremes of a continuum. H-H bonding interactions, as defined above, have been reported in experimental [6,7,[17][18][19][20][21][22][23][24][25][26] theoretical [4,6,[26][27][28][29][30][31][32][33][34][35][36][37][38][39] and chemical informatics [40] studies, both intermolecularly [6, 19, 20, 23-26, 30, 33, 37, 38, 40] and intramolecularly [4, 6, 7, 17, 18, 21, 22, 26-29, 31, 32, 34-36, 39]. The majority of the older literature does not distinguish H-H bonding from dihydrogen bonding, but the closed-shell interaction described in the literature cited above is between similar or identical hydrogens and are, thus, not variants of the hydrogen bond, i.e.…”

“…If all close HÁÁÁH contacts were destabilizing, one would not be able to crystallize a hydrocarbon for example. For instance, recent studies have shown how the extensive and complex network of H-H bonding interactions contribute in holding the crystals of 1-phenyl-o-carborane [6] and of acetone oxime-[1,1-diisopropyl-3-phenylurea] complex [7] together. We will review some of the evidence that the presence of close contact often (not necessarily always) results in the appearance of a bond path [8] and in the characteristic hallmarks of closed-shell chemical bonding.…”

Interplay of thermochemistry and Structural Chemistry, the journal (volume 17, 2006) and the discipline

“…Coşkun et al [235] in the following article report on the use of 1,1-diisopropyl-3-phenylurea complex and its moieties as building blocks to form non-interacting polymeric zigzag chains by inter-and intramolecular hydrogen bonds along b-axis, and details of supramolecular architecture in which there is a intramolecular H-H interaction between hydrogen of a urea NH and neighboring hydrogen of an isopropyl CH linked to an other urea nitrogen. The enthalpy of formation of numerous derivatives of urea have been measured [84,236,237].…”