IN THE TITLE COMPOUND (SYSTEMATIC NAME 17-formyl-2,5,8,11,14-penta-oxabicyclo-[13.4.0]nona-deca-15,17,19-triene), C(15)H(20)O(6), the 15-crown-5 ring adopts a twisted conformation. The formyl group is coplanar with the benzene ring. The crystal packing is stabilized by C-H⋯O inter-actions involving the C=O group and ether O atoms as acceptors and methyl-ene CH groups as donors.

Initial attempts to make [Ni(H2O)2(15-crown-5)](NO3)2, i.e. to insert the Ni2+ ion into the 15-crown-5 macrocycle, gave the mono- (two polymorphs) and dihydrate of a co-crystal of[Ni(H2O)6](NO3)2 and 15-crown-5 (1,4,7,10,13-pentaoxacyclopentadecane=15C5). Synthetic routes designed to restrict the water available to the Ni2+ cation gave three additional compounds, [Ni(H2O)6](NO3)2-trans-[Ni(H2O)...

The reaction of MgCl(2), NiCl(2), and Na(2)(i-mnt) (i-mnt is 1,1-dicyano-thene-2,2-dithiol-ate) with 15-crown-5 (15-C-5) leads to an infinite chain polymer, {[NiMg(2)(C(4)N(2)S(2))(2)(C(10)H(20)O(5))(2)]Cl(2)}(n) or {[Mg(15-C-5)](2)[Ni(i-mnt)(2)]Cl(2)}(n), which consists of two [Mg(15-C-5)](2+) complex cations, one [Ni(i-mnt)(2)](2-) complex anion and two Cl(-) ions per formula unit. In the [Ni...

The Sn(IV) atom in the title compound, 2[Sn(CH(3))(2)(C(6)H(5))Cl(H(2)O)]·C(10)H(20)O(5), exists in a trans-C(3)SnClO trigonal bipyramidal geometry in which the organo substituents occupy the equatorial sites. The coordinated water mol-ecule forms two hydrogen bonds to the 15-crown-5 mol-ecule, which is disordered about a center of inversion.

Five structures of co-crystals grown from aqueous solutions equimolar in 15-crown-5 (or 15C5) and [M(H(2)O)(6)](NO(3))(n), M = Al(3+), Cr(3+) and Pd(2+), are reported. The hydrogen-bonding patterns in all are similar: metal complexes including the fragment trans-H(2)O-M-OH(2) alternate with 15C5 molecules, to which they are hydrogen bonded, to form stacks. A literature survey shows that this hy...