A. The Crystal Structure of 9-Methyl Guanine Hydrochloride Monohydrate. B. Preliminary Studies on [C₂₇H₅₆N₂Cl]⁺•[H₁₃O₆]⁺•2 Cl⁻ : a Bicyclic Diammonium Ion Containing a Caged Chloride

Author: Bell, Robert Alan

Year: 1972

Degree: Master's thesis

Advisor: Marsh, Richard Edward

Committee Member: Unknown, Unknown

Option: Chemistry

DOI: 10.7907/GCQS-GP30

Abstract

The structure of 9-Methyl Guanine HC1 Monohydrate, C_6H_8N_5OC1•H_2O, has been determined by single crystal x-ray analysis. The whitish salt crystallizes in the monoclinic space group P2_1/c with unit cell dimensions a = 5.324(2), b = 11. 236(15) c = 15.533(10) and β = 96.11(3)°. There are four molecules in the unit cell and thus, one in the asymmetric unit. The measured density of 1.581 gm cm^(-3) is in close agreement with the calculated values of 1.578 gm cm^(-3). Three-dimensional intensity data were collected on a Datex-automated General Electric diffractometer using CoKα radiation. The structure was determined by Patterson and Fourier methods and refined by Fourier and least squares techniques to a final R index of 0.067 for 1224 reflections.

The molecules crystallize in slightly buckled planes which are parallel to and lie half way between the 104 plane of the unit cell. They are hydrogen bonded to chloride ions and water molecules between the planes and to each other within the plane. The water molecules and the chloride ions form staggered columns perpendicular to the molecular planes. The six hydrogen bonds, N(10A)-H•••N(3B), N(10A)-H•••O(2) N(1A)-H•••Cl^-, N(7A)-H•••Cl^-, O(2)-H(9)•••Cl^-, and O(2)-H(10)•••Cl^- are respectively 3.072, 2.828, 3.294, 3.191, 3.257, and 3.125 Å in length. The molecular planes are 3.17 and 3.33 Å apart.

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