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Resorc[4]arene octamethyl ethers have formed very stable 1:1 nitrosonoim complexes when they are treated with NOB[F.sub.4] salt in chloroform. The presence of ester carbonyl groups in these ethers have driven the N[O.sup.} cation outside the resorcarene and resorc[4]arene has showed a spectral pattern pointing out the involvement of the ester moieties in the N[O.sup.} entrapping, beside the formation of charge-transfer interactions.

The self-assembly between bidentate cavitand ligands and mono/dinuclear metal precursors to give cavitand frameworks are explored for which cavitands bearing AB and AC phenylpyridyl moieties at the upper rim are synthesized. Results reveal that predicting the outcome of self-assembly protocols of bidentate cavitand ligands with mono/ditopic metal precursors is not straightforward.

Research has been conducted on the rigid calix[4]arene cone conformers, receptors for the quaternary ammonium salts. The use of these flexible conformers in creating the heteroditopic cavitands is described.

Transmetalation (Ni/Pt system), C(sub enolate)-metal bond formation (Pd/Au system) or O(sub enolate)-metal bond formation (Ni/Co system) may occur between nickel- or palladium-coordinated phosphino enolate ligands and metal electrophiles. This was gleaned from an investigation of the reactions of phosphino enolates toward electrophilic metal reagents. The crystal structures of Pd-Au and Ni-Co complexes, which reveal a different chemoselectivity of the enolate moiety, are described.

Multifunctional, hemilabile phosphine ligands are prepared using selective P-C coupling. The reaction of Li(CH2../--C(../--O)Ph) with Ph2PCl in THF affords the ketophosphine Ph2PCH2C(O)Ph in a fully chemoselective manner. This was also true for Li(CH2../--C(../--O)NPh2), which leads to Ph2PCH2C(O)NPh2. The reactivity of the phosphino enolates of mononuclear palladium and platinum and dinuclear copper complexes toward coordinated nitrile ligands and organic isocyanates is also described.

A new series of calix(4)arenes, diametrically bridged at the upper rim with pyridino systems, were synthesized. The shape, rigidity and chemical structure of the bridge affected the host-guest complexation characteristics of these systems in solution toward several neural molecules with acidic C-H bonds. Also, selective complexation of methylammonium tosylate in comparison with other ammonium salts was noticed and the strength of this complexation was improved by electron-donor ability of the p-substituent on the pyrimidine moiety of the calixarene host.

A scheme for the one-pot synthesis of tetraaza macrocycles using benzaldehyde as the building block has been proposed. The scheme involves the Schiff base condensation of the metal-fee open-chain tetramine with benzaldehyde, formation of the Cu(II) complex and nucleophilic attack by the deprotonated nitroethane fragment to form the macrocyclic fragment. The Schiff base CuII complex and the CuII macrocyclic complex have been isolated in the crystalline form and their molecular structures were determined.

The ligand N,N'-bis(2-aminoethyl)-2-2-(4-pyridyl)ethyl malondiamide, (1b) is a building block of several supramolecular coordination compounds. The coordination of 1b and Cu(II) ion with the diamino-diamido binding unit and release of the two amido protons yields a described complex. The association of two units via their pyridine nitrogen atoms generate the supramolecular species 3 (described) which have weak interactions among the components. The complex 3 possesses exchangeable peripheral transition metal cations.

Reaction of pentaethylene glycol ditosylate with 1,3-dialkoxycalix(4)arenes produces the corresponding 1,3-alternate calix(4)arene-crown-6 conformers, which prefer Cs+ for complexation. The complexes of these conformers with Cs+ exhibit high stability constants. Preorganization of the conformers accounts for the observed entropy of complexation. X-ray studies reveal the presence of Cs+ cations between the two aromatic rings. Transportation of Cs+ cations by liquid membranes are supported by these conformers.

Syntheses of diametrical (1,3) and proximal (1,2) diformylated products involve a direct regioselective formylation of calix(4)arene tetraethers fixed in the cone conformation. A new procedure enables the conversion of 1,3-diformylcalix(4)arene derivatives into upper rim-upper rim double calix(4)arene in good yields. X-ray crystallography reveals the presence of two macrocyclic subunits of the double calix(4)arene in a flattened cone conformation.

A template reaction with the open-chain tetramine complex, (NiII(2.3.2-tet))2+, formaldehyde and a locking fragment facilitates synthesis of various functionalized azacyclam complexes of Ni(II). The low-spin (3-(4-tolylsulfonyl)-1,3,5,8, 12-pentaazacyclotetradecane)nickel(II) complex has been analyzed. Three crystallographically-independent cationic complexes are evident in the crystal structure.

Investigations were conducted to synthesize cobalt (II) complexes (CoX2(Ph2PCH2C(O)R)2) consisting of keto phosphine ligands. Single-crystal X-ray studies were used to establish the solid state structure of the fac and mer isomers.

The condensation of the associated 2- or 6-hydroxymethylated phenols yielded six dissymmetric calix (4) arenes with C4 symmetry containing four 3,4-disubstituted phenolic units. The p-methylcalix (4) arene possesses a higher energy barrier than calixarene 4a, which contains 3,4-dimethylphenol units for the gene-to-gene inversion in CDCl3. The alkylation of the phenolic hydroxyl group is used to structurally set the dissymmetric calixarenes 4. In addition to tetra derivatives, mono-acid 1, 3-di-derivatives could be used, because of the equivalence of all four phenolic units.

The binuclear complexes Rh2(mu-L)(diolefin)2 L = CA2-, DHBQ2-; diolefin = cycloocta-1,5-diene (cod), norborna-1,5-diene, tetrafluoro- (5,6)bicyclo(2.2.2)octa-2,5,7-triene were synthesized from the reaction of Rh2(mu-OMe)2(diolefin)2 with chloranilic acid (H2CA) or 2,5-dihydroxy-1,4-benzoquinone (H2DHBQ). The complex Rh4(mu-CA)2(cod)4 was also obtained and upon dissolution in a solvent and crystallization gave Rh2(mu-CA)(cod)2. The complexes were characterized by X-ray diffraction techniques.

The addition of formaldehyde and pyridine-3-carboxamide or pyridine-4-carboxamide to a (MII 2,3,2-tet)2+ complex resulted in a condensation process that facilitated the bonding of pyridines to metallocyclamsegments. Electrochemical and structural examinations were conducted to characterize the resulting complexes. The metallocyclam-pyridine complexes weresubjected to further reactions involving other metal complexes and redox systems.

The synthesis of two meso-tetrabenzoquinoxalinyl cavitands with methyl ester and hydroxymethyl functions, respectively, along with an X-ray analysis of their fluorophenyl analogue, lead to a study of their complexation behavior. The study reveals two major solid-state interactions, apart from van der Waals forces, affecting the complexation. One is dipole-dipole interaction between host and guest while the other is interactionbetweeen the methyl H-atoms and the quinoxalines' pi-electrons. In acetone solution, competition for cavity space between solvent and guest goes along with the dipole and CH3-pi interactions.

Electrophiles react with heterometallic complexes either by terminal addition to a metal center or by bridging the metal-metal bond. The reactions of three phosphido-bridged m(mu-PPh2)Pt(PPh3)2 complexes with etheric HBF4 in CH2Cl2 to yield hydrido-bridged m(mu-PPh2)(mu-H)Pt(PPh3)2-(BF4) complexes involve metal-to-metal bridging. The reaction of m(mu-PCy2)Pd(PCy2H)2 with HCl to yield m(mu-PCy2)(mu-H)Pd(PCy2H)Cl involves 1,2 mutual exchange between Cl and PCy2H as well. The substitution follows protonation and happens only with cationic compounds. Related reactions together with structural details of a heterotrimetallic tetranuclear W2AuPt complex are discussed.

The synthesis of a calixarene amino acid and the properties of self-assembly of the pseudopeptides that contain this macrocyclic unit are described. Amino acid derivatives either increase the stability of calix[4]arene tetraurea via peripheral hydrogen bonds or transfer chiral information through noncovalent molecular assemblies.