Different hydrogen-bonded chains in the crystal structures of three alkyl N-[(E )-1-(2-benzylidene-1-methylhydrazinyl)-3- hydroxy-1-oxopropan-2-yl]carbamates

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Benzyl N-(1-{N′-[(E)-2,3-dihy­droxy­benzyl­idene]hydrazinecarbon­yl}-2-hy­droxy­eth­yl)carbamate dihydrate

The organic mol­ecule in the title dihydrate, C18H19N3O6·2H2O, adopts a twisted U-shape with the major twists evident about the chiral C atom [the C—N—C—C torsion angle is −88.2 (4) °] and about the oxygen–benzyl bond [C—O—C—C = 74.2 (4) °]. The conformation about the imine bond [1.290 (4) Å] is E and an intra­molecular O—H⋯N hydrogen bond helps to establish the near coplanarity of the hy­droxy­benzene and hydrazine groups. The crystal packing features O—H⋯O and N—H⋯O hydrogen bonds, leading to two-dimensional supra­molecular arrays in the ab plane with weak C—H⋯π connections between the arrays

Benzyl N-(2-hy­droxy-1-{N′-[(1E)-2-hy­droxy­benzyl­idene]hydrazinecarbon­yl}eth­yl)carbamate

The mol­ecule of the title compound, C18H19N3O5, adopts a curved arrangement with the terminal benzene rings lying to the same side. The hydroxyl­benzene ring is close to coplanar with the adjacent hydrazine residue [dihedral angle = 11.14 (12)°], an observation which correlates with the presence of an intra­molecular O—H⋯N hydrogen bond. The benzyl ring forms a dihedral angle of 50.84 (13)° with the adjacent carbamate group. A twist in the mol­ecule, at the chiral C atom, is reflected in the dihedral angle of 80.21 (12)° formed between the amide residues. In the crystal, two-dimensional arrays in the ac plane are mediated by O—H⋯O and N—H⋯O hydrogen bonds

Benzyl N-((S)-2-hydr­oxy-1-{N′-[(E)-2-methoxy­benzyl­idene]hydrazinecarbon­yl}eth­yl)carbamate from synchrotron data

A U-shaped conformation is found in the title compound, C19H21N3O5, with the benzene rings lying to the same side of the mol­ecule; the dihedral angle between them is 10.83 (16)°. The dihedral angle formed between the hydrazinecarbonyl and carbamate residues is 68.42 (13)°. The carbonyl groups lie approximately at right angles to each other [O—C⋯C—O pseudo torsion angle of 107.7 (3)°], and the conformation about the C12=N3 bond [1.279 (4) Å] is E. An intra­molecular Ncb—H⋯Ohy (cb = carbmate and hy = hydr­oxy) hydrogen bond occurs, generating an S(6) loop. In the crystal, inter­molecular Oh—H⋯Oca (ca = carbon­yl) and Nhz—H⋯Oca (hz = hydrazine) hydrogen bonds lead to the formation of a supra­molecular chain, two mol­ecules thick, which propagates along the a axis; these are connected by C—H⋯Oca contacts

tert-Butyl N-((1S)-2-hy­droxy-1-{N′-[(1E)-4-meth­oxy­benzyl­idene]hydrazinecarbon­yl}eth­yl)carbamate

The mol­ecule of the title compound, C16H23N3O5, is twisted about the chiral C atom, the dihedral angle formed between the amide residues being 79.6 (3)°. The conformation about the imine bond [1.278 (5) Å] is E. In the crystal, O—H⋯O and N—H⋯O hydrogen bonding between the hy­droxy, amine and carbonyl groups leads to the formation of supra­molecular layers, which stack along the c-axis direction

Benzyl N-(1-{N′-[(E)-2-chloro­benzyl­idene]hydrazinecarbon­yl}-2-hy­droxy­eth­yl)carbamate

The mol­ecule of the title compound, C18H18ClN3O4, is twisted about the chiral C atom with the dihedral angle between the two amide residues being 87.8 (5)°, but, overall, it can be described as curved, with the benzene rings lying on the same side of the mol­ecule [dihedral angle = 62.8 (4)°]. The conformation about the imine bond [1.294 (7) Å] is E. In the crystal, a two-dimensional array in the ab plane is mediated by O—H⋯O and N—H⋯O hydrogen bonds as well as C—H⋯Cl inter­actions. The layers stack along the c-axis direction, being connected by C—H⋯.π contacts

tert-Butyl N-{(1S)-1-[(2,4-dihy­droxy­benzyl­idene)hydrazinecarbon­yl]-2-hy­droxy­eth­yl}carbamate ethanol monosolvate

The mol­ecule of the title ethanol solvate, C15H21N3O6·C2H6O, adopts a curved shape; the conformation about the imine bond [N=N = 1.287 (3) Å] is E. The amide residues occupy positions almost orthogonal to each other [dihedral angle = 85.7 (2)°]. In the crystal, a network of O—H⋯O, O—H⋯N and N—H⋯O hydrogen bonds leads to the formation of supra­molecular arrays in the ab plane with the ethanol mol­ecules lying to the periphery on either side. Disorder in the solvent ethanol mol­ecule was evident with two positions being resolved for the C atoms [site occupancy of the major component = 0.612 (10)]

Benzyl N-{(1S)-2-hy­droxy-1-[N′-(2-nitro­benzyl­idene)hydrazinylcarbon­yl]eth­yl}carbamate

The carbamate and hydrazone groups in the title compound, C18H18N4O6, are approximately orthogonal [dihedral angle = 83.3 (4)°], and the carbonyl groups are effectively anti [O=C⋯C=O torsion angle = −116.2 (7)°]. The conformation about the imine bond [1.295 (11) Å] is E. The crystal packing is dominated by O—H⋯O and N—H⋯O hydrogen bonding, which leads to two-dimensional arrays in the ab plane

Benzyl N-[(S)-2-hy­droxy-1-({[(E)-2-hy­droxy-4-meth­oxy­benzyl­idene]hydrazin­yl}carbon­yl)eth­yl]carbamate

The shape of the title compound, C19H21N3O6, is curved with the conformation about the imine bond [1.291 (3) Å] being E. While the hy­droxy-substituted benzene ring is almost coplanar with the hydrazinyl residue [N—N—C—C = 177.31 (18)°], an observation correlated with an intra­molecular O—H⋯N hydrogen bond leading to an S(6) ring, the remaining residues exhibit significant twists. The carbonyl residues are directed away from each other as are the amines. This allows for the formation of O—H⋯O and N—H⋯O hydrogen bonds in the crystal, which lead to two-dimensional supra­molecular arrays in the ac plane. Additional stabilization to the layers is afforded by C—H⋯π inter­actions

LaMMos - Latching Mechanism based on Motorized-screw for Reconfigurable Robots and Exoskeleton Suits

Reconfigurable robots refer to a category of robots that their components (individual joints and links) can be assembled in multiple configurations and geometries. Most of existing latching mechanisms are based on physical tools such as hooks, cages or magnets, which limit the payload capacity. Therefore, robots re- quire a latching mechanism which can help to reconfigure itself without sacrificing the payload capability. This paper presents a latching mechanism based on the flexible screw attaching principle. In which, actuators are used to move the robot links and joints while connecting them with a motorized-screw and dis- connecting them by unfastening the screw. The brackets used in our mechanism configuration helps to hold maximum force up to 5000N. The LaMMos - Latching Mechanism based on Motorized- screw has been applied to the DeWaLoP - Developing Water Loss Prevention in-pipe robot. It helps the robot to shrink its body to crawl into the pipe with minimum diameter, by recon- figuring the leg positions. And it helps to recover the legs positions to original status once the robot is inside the pipe. Also, LaMMos add stiffness to the robot legs by dynamically integrate them to the structure. Additionally, we present an application of the LaMMos mechanism to exoskeleton suits, for easing the mo- tors from the joints when carrying heavy weights for long periods of time. This mechanism offers many interesting opportunities for robotics research in terms of functionality, pay- load and size.Comment: 14 pages, 15 figure