PMID- 3271109
OWN - NLM
STAT- MEDLINE
DCOM- 19900301
LR  - 20190516
IS  - 0108-7681 (Print)
IS  - 0108-7681 (Linking)
VI  - 44 ( Pt 3)
DP  - 1988 Jun 1
TI  - Thermal vibrations and electrostatic properties of parabanic acid at 123 and 298 
      K.
PG  - 271-81
AB  - The crystal structure of parabanic acid (1H,3H-imidazoletrione, C3H2N2O3, Mr = 
      114.1) at 123 K [monoclinic, P2(1)/n, Z = 4, a = 10.704 (2), b = 8.187 (2), c = 
      4.969 (1) A, beta = 92.32 (1)o] has been determined by neutron and X-ray 
      diffraction. Neutron reflections [1658, (sin theta)/lambda less than or equal to 
      0.78 A-1, lambda = 1.0470 (1) A, mu = 0.75 cm-1] in full-matrix least-squares 
      refinement (wR = 0.055) gave nuclear parameters with bond lengths having 
      estimated standard deviations (e.s.d.'s) of 0.001 A. X-ray reflections [3150 with 
      magnitude of F magnitude of greater than or equal to 3 sigma and (sin 
      theta)/lambda less than or equal to 1.3 A-1, Mo Ka, lambda = 0.7093 (1) A, mu = 
      1.708 cm-1] were used in full-matrix least-squares refinement (R = 0.022) 
      assuming Stewart's rigid pseudoatom model, so as to determine the charge-density 
      distribution. Sharp features near the O nuclei in the residual electron density 
      map noted by Craven & McMullan (CM) [Acta Cryst. (1979), B35, 934-945] in their 
      298 K study were absent at 123 K. New refinements using CM's 298 K data give 
      significant third-order thermal parameters for O atoms due to anharmonic 
      molecular stretching, with good agreement between probability density functions, 
      (p.d.f.'s) from X-ray and neutron diffraction. When deconvoluted from the thermal 
      vibrations in the crystal, deformation charge densities derived at 298 and 123 K 
      are in satisfactory agreement and conform closely to the 2 mm symmetry of the 
      isolated molecule. The molecular dipole moment is 2.3 (3) D [7.7 (10) x 10(-30) C 
      m]. A map of molecular electrostatic potential indicates that the carbonyl O 
      atoms in parabanic acid are weakly electronegative. This is confirmed by 
      calculation of the electrostatic energy of interaction for the two distinct 
      H-bonded pairs of molecules isolated from the crystal. Energy values are weakly 
      attractive [-7 (3) and 5 (2) kJ mol-1]. Similar calculations are less reliable 
      for pairs of molecules forming intermolecular C....O distances as short as 2.75 
      A. However, depending on the model, energy values are repulsive or negligibly 
      small. Thus the high stability of parabanic acid crystals (m.p. 516 K with 
      decomposition) cannot be explained.
FAU - He, X M
AU  - He XM
AD  - Department of Crystallography, University of Pittsburgh, PA 15260.
FAU - Swaminathan, S
AU  - Swaminathan S
FAU - Craven, B M
AU  - Craven BM
FAU - McMullan, R K
AU  - McMullan RK
LA  - eng
GR  - GM-22548/GM/NIGMS NIH HHS/United States
GR  - HL-20350/HL/NHLBI NIH HHS/United States
PT  - Journal Article
PT  - Research Support, U.S. Gov't, Non-P.H.S.
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - United States
TA  - Acta Crystallogr B
JT  - Acta crystallographica. Section B, Structural science
JID - 8403252
RN  - 0 (Hydantoins)
RN  - 0 (Imidazoles)
RN  - 3XGR439T9P (parabanic acid)
SB  - IM
MH  - Chemical Phenomena
MH  - Chemistry, Physical
MH  - *Hydantoins
MH  - *Imidazoles
MH  - X-Ray Diffraction
EDAT- 1988/06/01 00:00
MHDA- 1988/06/01 00:01
CRDT- 1988/06/01 00:00
PHST- 1988/06/01 00:00 [pubmed]
PHST- 1988/06/01 00:01 [medline]
PHST- 1988/06/01 00:00 [entrez]
AID - 10.1107/s0108768187011108 [doi]
PST - ppublish
SO  - Acta Crystallogr B. 1988 Jun 1;44 ( Pt 3):271-81. doi: 10.1107/s0108768187011108.