C2H2N20, M = 70.051; Pnma; a = 8.519(6), b = 5.427(4), c=7.235(5)A; Z=4; D x= 1.391g·cm -3 ; V=334.49A 3; (MoKa)=0.71069A; F(000) = 144. The structure was solved with direct methods and refined by least-squares analysis to an R = 0.059 including 363 observed reflections. The molecule lies on the mirror plane and must therefore be completely planar. By two intermolecular hydrogen bridges towards the oxygen and the nitrogen atom of the carbonyl and the nitrile group respectively, neighbouring molecules of the same layer are bound together

Becker, Gerd

Becker, Winfried

Drück, Ulrich

Online Publikationen der Universität Stuttgart

Zeitschrift rur Kristallographie 167, 131 - 134 (1984) 
© by R. Oldenbourg Verlag, Miinchen 1984 
Molecular and crystal structure of cyanoformamide 
U. Orlick 
Institut rur Mineralogie, Petrologie und Kristallographie, 
Philipps-Universitiit, Lahnberge, 0-3550 Marburg, Federal Republic of Germany 
W. Becker and G. Becker 
Institut rur Anorganische Chemie der Universitiit, 
PfafTenwaldring 55, 0-7000 Stuttgart 80, Federal Republic of Germany 
Received: December 9, 1983 
CyanoformamitJe / Crystal structure 
Abstract. C2H 2N 20, M = 70.051; Pnma; a = 8.519(6), b = 5.427(4), 
c=7.235(5)A; Z=4; D,,= 1.391g·cm- 3 ; V=334.49A3; (MoK(X)=O.71069A; 
F(OOO) = 144. The structure was solved with direct methods and refined by 
least-squares analysis to an R = 0.059 including 363 observed reflections. The 
molecule lies on the mirror plane and must therefore be completely planar. By 
two intermolecular hydrogen bridges towards the oxygen and the nitrogen 
atom of the carbonyl and the nitrile group respectively, neighbouring 
molecules of the same layer are bound together. 
Introduction 
Carrying on our studies on the electron density distribution of acyl ami des, 
nitriles and their derivatives, similar work on 2,4,6-tricyano-s-triazine which 
can best be prepared from the corresponding amide and diphosphorus 
pentoxide (Bailey et al., 1963), has been planned. We found, however, that the 
product of this synthesis when condensed onto a liquid-nitrogen-cooled glass 
finger, contains considerable amounts of a second more volatile compound. 
Separation can be accomplished by renewed sublimation yielding colourless, 
prismatic crystals which slowly turn yellow, when exposed to light or to X-ray 
radiation. The X-ray structure determination showed this compound to be 
cyanoformamide (ureamononitrile), formed by monomerization of the 
starting triazine; this substance, incorporated into tpany insectizides, can be 
synthesized in very high yield from cyanogen, water, formic acid, and 
acetonitrile (Welcher et al., 1959). 
132 U. Orlick et al. : Molecular and crystal structure of cyanofonnamide 
Table 1. Fractional coordinates, anisotropic temperature factors U,/ (. l()l; Al) of the non-
hydrogen atoms as well as fractional coordinates and isotropic B-values (Al) of the hydrogen 
atoms 
Atom x y z UIJ Un U33 Ull Uu U23 
C(I) 0.2406(6) 0.2500 0.6026(7) 28(3) 40(3) 24(2) 0 - 1(2) 0 
C(2) 0.1281(6) 0.2500 0.4473(8) 33(3) 42(3) 33(3) 0 - 2(2) 0 
N(l) 0.3899(5) 0.2500 0.5501(7) 28(2) 60(3) 24(2) 0 1(2) 0 
N(2) 0.0361(7) 0.2500 0.3325(7) 50(3) 60(4) 43(3) 0 -19(3) 0 
0(1) 0.1914(5) 0.2500 0.7603(6) 33(2) 81(3) 26(2) 0 5(2) 0 
Atom x y z B 
H(I) 0.406(7) 0.250 0.431(10) 1.4(10) 
H(2) 0.463(10) 0.250 0.642(11) 3.5(20) 
• The temperature factor T is given by the equation : T=exp( -2,r[Uu ·1Jl ·O·l+ ... 
+ 2 . Ul3 • k . / . b· . c·]). 
Data collection 
5624 reflections, 0.049 < sin 8/A. < 0.65 A -1, MoKer, w/28 scan mode; four-
cycle diffractometer Stoe AED, temperature of measurement + 20°C; 421 
independent reflections, internal reliability factor for 302 reflections observed 
(1)20'(1)) being 0.053; no absorption correction; scattering factors for 
neutral atoms (International Tables, 1974). The cell constants were de-
termined and refined by a least-squares calculation using the positions of a 
selected number of 18 reflections. 
Structure determination 
The structure was solved with the MUL TAN 80 program system (Main et aI., 
1980). Refinements of the non-hydrogen atoms for both possible space 
groups showed the centrosymmetric space group to be the correct solution. 
At this stage of refinement the resulting difference-density map revealed the 
positions of both hydrogen atoms. Further refinement with isotropic and 
anisotropic temperature factors for the hydrogen and all the other atoms 
respectively, gave the following results: R = O.059;Rw = O.07[w = 1/(12(Fo)], 
G.o.F. = 1.24. In Tables 1 and 2 the final parameters as well as the 
intramolecular bond lengths and angles have been listed, Figure 1 shows an 
ORTEP-plot of the molecule1• 
1 Additional material to this paper can be ordered referring to the number CSO 50747, names 
of the authors and citation of the paper at the Fachinformationszentrum Energie Physik Mathe-
matik, 0-7514 Eggenstein-Leopoldshafen 2, FRG 
U. Orlick et a!.: Molecular and crystal structure of cyanoformamide 133 
Table2. Bond lengths (A) and angles (0) with standard deviations' for ~H1N10 
C(l)-N(l) 1.327(7) N(t) -C(l) -0(1) 126.8(5) 
C(l)-O(l) 1.216(6) N(l) -C(l) -C(2) 113.9(4) 
C(1)-C(2) 1.477(8) 0(1)-C(1)-C(2) 119.3(5) 
C(2)-N(2) 1.141(8) C(t) -C(2) - N(2) 177.2(6) 
N(1)-H(l) 0.87(7) C(l)-N(l)-H(l) 116(4) 
N(I)-H(2) 0.91(8) C(1)-N(I)-H(2) 116(5) 
H(I)-N(I)-H(2) 128(6) 
• Standard deviations of bond lengths and angles were calculated taking into account 
uncertainties of cell parameters and fractional coordinates both 
N2 
Fig. I. ORTEP-plot of a molecule of cyanoformamide. The thermal ellipsoids have been scaled 
to 50% probability 
Fig. 2. Packing of molecules in solid cyanoformamide 
Discussion 
A comparison with the well known structures of urea (Guth et aI., 1980) and 
thiourea (Kutoglu et aI., 1982) reveals a good correspondence in view of the 
C(1) - N(l) bond length of the amide group [1.327(7) vs. 1.333(1) or 
1.334(2) A); the C(1) -0(1) bond, hOwever, is considerably shorter [1.216(6) 
vs. 1.246(2) A]. Probably due to less sterlc interactions on the nitrile side of 
this planar molecule the angle 0(1) -C(1) - N(l) widens [126.8(5) vs. 
134 U. Driick et aI.: Molecular and crystal structure of cyanofonnamide 
121.9(1t1, whereas the angle N(1) -C(l) -C(2) between the amide and the 
nitrile group is smaller than the corresponding N - C - N value in the urea 
molecule [113.9(4) vs. 116.2(1)°]. 
The nitrile group shows the well known 'shortening' of its bond length 
from about 1.16 to 1.141(8)A which is always observed in case of 
conventional (free atom model) refinement (Orlick and Guth, 1982). A small 
deviation from linearity [177.2(6t1 of the bond angle C(1)-C(2)-N(2) 
might be an effect of intermolecular hydrogen bonding. A C(1) -C(2) 
distance of 1.477(8)A is expected for a bond between a Sp2_ and a sp-
hybridized carbon atom. 
Figure 2 shows the crystal structure of cyanoformamide which is character-
ized by isolated layers parallel to (010). Sixteen-membered rings formed from 
four molecules each, are stabilized by two N - H ... 0 and two N - H ... N 
hydrogen bridges. With values of 2.07(8) A for H(2) - 0(1') (! + x,t - y, 
!-z) and 2.21(7)A for H(1)-N(2',) (!+x,t-y.!-z) both intermolec-
ular hydrogen bonds are considerably shorter than the sums of the van der 
Waals radii (2.70, 2.59 A: Bondi, 1964). The bond angles at the bridging 
hydrogen atoms are 153(5) and 159(4) degrees, the N(l)··· 0(1') and 
N(l)··· N(2'') contact has found to be 2.91 and 3.04 A, respectively. 
All computations were done with an IBM 370/145 computer at Mineralo-
gisches Institut der Universitat Marburg using the X-ray system (Stewart et 
aI., 1970). 
Financial support of Deutsche Forschungsgemeinschaft is gratefully acknowledged. 
References 
Bailey, A. S., Henn, B. R., Langdon, J. M. : Molecular complexes of aromatic nitnles. 
Tetrahedron 19, 161 -167 (1963) 
Bondi, A. : Van der Waals volumes and radii. J. Phys. Chern. 68,441-451 (1964) 
Driick, U., Guth, H. : A new refinement of monoclinic tetracyanoethylene (TCNE) from X-ray 
and neutron data. Z. Kristallogr. 161, 103 -110 (1982) 
Guth, H., Heger, G., Klein, S., Treutmann, W., Scheringer, c.: Strukturverfeinerung von 
HarnstolT mit Neutronenbeugungsdaten bei 60, 123 and 293 K und X - N- und 
X-X(1 sl)-Synthesen bei etwa 100 K. Z. Kristallogr. 153,237-254 (1980) 
International Tablesfor X-ray Crystallography, vol. IV, p. 99. Birmingham : Kynoch Press 1974 
Johnson, C. K.: ORTEP, A Fortran thennal-ellipsoid plot program for crystal structure 
illustrations. Oak Ridge National Laboratory, Oak Ridge, Tennessee (1965) 
Kutoglu, A., Scheringer, C., Meyer, H., Schweig, A. : Experimental and theoretical dilTerence 
densities for thiourea. Refinement of electron density distributions with charge-cloud 
models. X. Comparison of observed and calculated electron densities. XIII. Acta 
Crystallogr. B38, 2626-2632 (1982) 
Main, P., Fiske, S. J., Hull, S. E., Lessinger, L., Germain, G., Declercq, J.-P., Woolfson, M. M.: 
MULTAN 80, A system of computer programs for the automatic solution of crystal 
structures from X-ray dilTraction-data. University of York (UK), York (1980) 
Stewart, J. M., Kundel, F. A., Baldwin, J. C.: The X-ray system of crystallographic computer 
programs. Computer Science Center, University of Maryland, Maryland (1970) 
Welcher, R. P., Castellion, M. E., Wystrach, V. P.: The preparation and reactions of 1-
cyanofonnamide. J. Am. Chern. Soc. 81, 2541-2547 (1959) 


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