ISSN:
1572-8854
Keywords:
aminopyrimidine
;
copper
;
stacking
;
hydrogen bonding
Source:
Springer Online Journal Archives 1860-2000
Topics:
Geosciences
,
Physics
Notes:
Abstract Reaction of Cu(II) triflate with an excess of 2-aminopyrimidine (ampym) in ethanol followed by slow crystallization results in a most unusual crystal lattice, which can be considered as consisting of two interpenetrating sublattices. The compound analyzes as [Cu(ampym)2(H2O)2(CF3SO3)2(ampym)4]. Crystal data: Triclinic, P $$\overline 1$$ , a = 7.6179(5), b = 11.4311(14), c = 11.8373(13) Å, α = 84.098(9), β = 79.998(7), γ = 84.253(8)°, Vol = 1010.151(8) Å, Z = 1, Dcalc = 1.592 g/cm3. One part of the lattice consists of the unprecendented linear chain of neutral ampym molecules; the chain is built up by Watson–Crick type bis-hydrogen bonds between imine N atoms and N-H groups of the NH2. This ampym chain is apparently stabilized by the other part in the crystal lattice, which can best be described by starting from the centrosymmetric trans-CuII(ampym)2(H2O)2 ion (Cu-N = 2.01 Å; Cu-O = 1.94 Å). This Cu ion is coordinated by two monodentate ampym ligands, two water molecules and two semi-coordinating triflate oxygen atoms. The Cu chromophore is held in position by hydrogen bonding towards a triflate ion (two times for symmetry reasons), and (again two times) a free ampym ligand. The triflate ion bridges a water hydrogen to a next-neighboring free ampym ligand. The noncoordinating ampym molecule has four bonding sites, of which two are used in H-bonding with the coordinated ligand, one with the triflate and the last one with the water hydrogen atom. The noncoordination ampym molecules in this sublattice finally form aromatic stacks with coordinated ampym and with itself in pairs (ring-ring distance 3.77-3.80 Å).
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1009533729785
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