An unusual example of intramolecular hydrogen bonding in a metal carbonyl cluster compound. Synthesis and crystal and molecular structure of di-.mu.-carbonylhexadecacarbonyldi-.mu.-hydroxo-.mu.4-sulfidohexaruthenium

1987 ◽  
Vol 26 (15) ◽  
pp. 2561-2563 ◽  
Author(s):  
Richard D. Adams ◽  
James E. Babin ◽  
Miklos Tasi
Keyword(s):  
Molecular Structure ◽  
Hydrogen Bonding ◽  
Crystal And Molecular Structure ◽  
Metal Carbonyl ◽  
Intramolecular Hydrogen Bonding ◽  
Cluster Compound ◽  
Carbonyl Cluster ◽  
Compound Synthesis ◽  
Intramolecular Hydrogen ◽  
Metal Carbonyl Cluster

Molecular and crystal structure of azadirachtin-H

1996 ◽  
Vol 52 (1) ◽  
pp. 145-150 ◽  
Author(s):  
T. R. Govindachari ◽  
Geetha Gopalakrishnan ◽  
S. S. Rajan ◽  
V. Kabaleeswaran ◽  
L. Lessinger
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Intramolecular Hydrogen Bonding ◽  
Hydroxyl Group ◽  
Inhibiting Activity ◽  
Nmr Studies ◽  
Rotation Axes ◽  
Intramolecular Hydrogen ◽  
Azadirachtin A

Azadirachtin-H, isolated from the seed kernels of Azadirachta indica (neem), crystallizes in space group I4, Z = 8, with disordered ethyl acetate solvent filling channels along the fourfold rotation axes. The crystal structure determination showed that the previously reported molecular structure deduced from NMR studies was correct except for the stereochemistry at C(11). Azadirachtin-H, which belongs to a group of C-seco-tetranortriterpenoids (C-seco-limonoids) of great interest for their insect antifeedant and ecdysis-inhibiting activity, has some unusual features: the absence of a carbomethoxy group at C(11); the presence of a cyclic hemiacetal function at C(11); the α-orientation of the hydroxyl group on C(11), opposite to that in all other known azadirachtins with a hydroxyl group on C(11), except azadirachtin-I. There is no intramolecular hydrogen bonding. In this crystal the rotation of the two major moieties of the azadirachtin-H molecule about the single connecting C(8)—C(14) bond is quite different from that in azadirachtin-A, whose crystal structure has recently been determined.

Molecular Structure and Photoinduced Intramolecular Hydrogen Bonding in 2-Pyrrolylmethylidene Cycloalkanones

2015 ◽  
Vol 80 (21) ◽  
pp. 10521-10535 ◽  
Author(s):  
Mark Sigalov ◽  
Bagrat Shainyan ◽  
Nina Chipanina ◽  
Larisa Oznobikhina ◽  
Natalia Strashnikova ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Hydrogen Bonding ◽  
Intramolecular Hydrogen Bonding ◽  
Intramolecular Hydrogen
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