Coordination of neutral, methylene bridged bis-guanidyls at palladium.

The bis-guanidyl compound H(2)C{hpp}(2) (hppH = 1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidine) coordinates to palladium(ii) as a neutral, chelating N,N'-bidentate ligand. Structural analysis of PdMeCl(H(2)C{hpp}(2)) shows a non-planar metallacycle that is twisted relative to the square plane of the metal and an "anagostic" interaction with a C-H from the bridging methylene group. Generation of the cationic palladium complex, [PdCl(H(2)C{hpp}(2))][OTf] was achieved by halide abstraction from the dichloride PdCl(2)(H(2)C{hpp}(2)) using NaOTf.

Superbasicity of a bis-guanidino compound with a flexible linker: a theoretical and experimental study.

The bis-guanidino compound H(2)C{hpp}(2) (I; hppH = 1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidine) has been converted to the monocation [I-H](+) and isolated as the chloride and tetraphenylborate salts. Solution-state spectroscopic data do not differentiate the protonated guanidinium from the neutral guanidino group but suggest intramolecular "-N-H..

Nucleophilic activity of a linked bis{guanidine} leading to formation of a dicationic C4N4-heterocycle.

The methylene-linked bis{guanidine}, H(2)C{hpp}(2) (hppH = 1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidine), displays nucleophilic activity towards organic halides, including the activation of dichloromethane under ambient conditions affording the cyclic dication, [H(2)C{hpp}(2)CH(2)](2+)[Cl](2).

Poly{guanidinium} salts: application in the preparation of a coordinatively saturated aluminium cation.

Protonation of the linked bis(guanidine), H(2)C{hpp}(2), affords isolated guanidinium salts that have been used to prepare a coordinatively saturated aluminium cation.

Multiple coordination geometries supported by methylene-linked guanidines.

The methylene-linked bicyclic guanidine based on the 1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidine (hppH) framework provides a versatile platform able to support trigonal-planar, tetrahedral, and square-planar metal centers.

Structural consequences of the prohibition of hydrogen bonding in copper-guanidine systems.

The synthesis and structure of copper(I) complexes supported by N-substituted bicyclic guanidines is described. The N-methyl-substituted bicyclic guanidine 1,3,4,6,7,8-hexahydro-1-methyl-2H-pyrimido[1,2-a]pyrimidine (hppMe) reacted with copper(I) chloride to afford the ion-pair [Cu(hppMe)(2)][CuCl(2)] (1), a rare example of a compound containing an unsupported Cu..

Poly(guanidyl)silanes as a new class of chelating, N-based ligand.

The series of poly(guanidyl)silanes RnSi[hpp](4-n) [hpp = 1,3,4,6,7,8-hexahydro-2Hpyrimido[1,2-a]pyrimidinate; R = Me, n= 1, 2; R = Ph, n= 1] have been synthesised and their coordination behaviour at copper(I) halides investigated.

Structural diversity in the coordination of amidines and guanidines to monovalent metal halides.

A series of structurally characterised, monovalent metal-halide complexes incorporating neutral amidine and guanidine ligands is reported. N,N'-diphenylbenzamidine reacted with copper(I) chloride to afford the bis-ligand complex [CuCl(PhC[NPh][NHPh])2]2 (1), that exists as a chlorine bridged dimer in the solid state, with a non-symmetrical distribution of NH..

Structural and catalytic properties of bis(guanidine)copper(I) halides.

The neutral, bicyclic guanidine 1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidine (hppH) coordinates to Cu(I) halides via the imine nitrogen, and the complexes are stabilized by intramolecular NH...