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288. RING: A Coordinate Transformation Program for
Evaluating the Degree and Type of Puckering of a Ring
Compound
by D. Cremer, Lehrstuhl für Theoretische Chemie,
Universität Köln, Köln, FRG
RING is a coordinate transformation program written to
provide the quantitative data which aid the
interpretation of ring conformations. These data are
termed "ring puckering coordinates," for they describe
the nonplanar character of a ring in a unique way; a
set of puckering amplitudes qm and phase angles fm
determines the amount and type of puckering
coordinates, i.e., the three-membered ring is always
planar (q1 and f1 are not defined), the four-membered
ring has just one possible puckering mode described by
the amplitude q2, the puckered five-membered ring
conformations are characterized by the amplitude-phase
pair (q2, f2), the six-membered ring forms are defined
by the pair (q2, f2) and an additional amplitude q3,
etc.
For odd-membered rings, there are 1/2(N-3) amplitude-
phase pairs (qm, fm) with m = 2,3...(N-1)/2.
For even-membered rings, there are 1/2(N-4) amplitude-
phase pairs (qm, fm) with m = 2,3...(N-2)/2 and an
additional puckering amplitude q(N/2).
FORTRAN IV (CDC)
Lines of Code: 789
Recommended Citation: D. Cremer, QCPE 11, 288 (1975).
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