Bridging H bonding

In the analogous tetrahedral dinegative oxoanion cryptates a similar mix of direct and indirect water-bridged H-bonds links the encapsulated oxoanion with the NH1 donors. The direct NH+ 0" contacts are (Table 1) on average, slightly shorter than those... 

Arg-386 Salt bridge/H-bond with a-carboxylate group of substrate... 

Yokoyama, Y. and Hall, H. K. Ring-Opening Polymerization of Atom-Bridged and Bond-Bridged Bicyclic Ethers, Acetals and Orthoesters. Vol. 42, pp. 107—138. 

Fig. 8.—Packing arrangement of four symmetry-related 2-fold helices of mannan II (6). (a) Stereo view of two unit cells approximately normal to flic frc-plane. The two chains in the back (open bonds) and the two in the front (filled bonds) are linked successively by 6-0H-- 0-6 bonds. The front and back chains, both at left and right, are further connected by 0-2 -1V -0-2 bridges, (h) Projection of the unit cell along the c-axis the a-axis is down the page. This highlights the two sets of interchain hydrogen bonds between antiparallel chains, distinguished by filled and open bonds. The crossed circles are water molecules at special positions.

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