The behavior of the compound [RuCl(cym)(H2biim)][BAr'4] (cym = eta6-para-isopropylmethylbenzene, Ar' = 3,5-bis(trifluoromethyl)phenyl), synthesized from [[RuCl(cym)]2(mu-Cl)2], H2biim and NaBAr'4, has been studied as a receptor of anions both in solution and in the solid state.

The thermally stable tris(pyridyl) Al(III) complex [MeAl(2-py)3Li·THF] (1·THF), obtained from the reaction of lithiopyridine [2-pyLi] with MeAlCl2 (3:1 molar equiv, respectively), functions as a pyridyl-transfer reagent, as exemplified by the reaction of 1·THF with CuCl (1:1 molar equiv), which gives the Cu(I) organometallic [{Cu(2-py)}3]∞ (2). The solid-state structures of 1, the dimer [MeAl(2-py)3Li]2 ([1]2), and 2 are reported. Complex 2, which cannot be obtained by direct reaction of [2-pyLi] with CuCl, has a polymeric structure in which macrocyclic [Cu(2-py)]3 ring units form infinite offset stacks associated by short Cu···Cu interactions between three- and four-coordinate Cu(I) centers (2.762(3) Å).

The reaction of [ClP(mu-NtBu)]2 (1) with H2O (1 : 2 equivalents) in the presence of excess Et3N gives the new chain compound [(mu-O)[P(mu-NtBu)2P(H)=O]2] (3), consisting of two P2N2 rings linked by a mu-O atom and terminating in P(V)(H)=O groups. A similar chain species is obtained from the reaction of the lithiate of [(tBuNH)P(mu-NtBu)2P(H)=O] (5) with [ClP(mu-NtBu)2P(NHtBu)] (2), the product being [(mu-O)[P(mu-NtBu)2P(NHtBu)]2] (6). Compounds 3 and 6 are the first examples of O-bridged chain phosphazanes and potential precursors to new phosphorus-nitrogen macrocycles. The syntheses and X-ray structures of 3, 5 and 6 are reported.

The in situ reaction of the phosphazane dimer [CIP(mu-N-2-NC5H4)]2 (2) with CuCl in the presence of CsH5N/H2O gives the title complex [(P(mu-N-2-NC5H4))2(mu-O)]2(CuCl x (C5H5N)2)4 (1), containing a tricyclic [(P(mu-N-2-NC5H4))2(mu-O)]2 ligand which is isoelectronic with species of the type [(P(mu-NR))2NR]2.

Reactions of the Al(III) complex [{MeAl(2-py)3}Li·THF] (1), containing the tripodal [MeAl(2-py)3]- ligand, with [(C7H8)Mo(CO)3], CaI2, and ZnCl2 give the trimetallic and bimetallic complexes [{MeAl(2-py)3}Mo(CO)3Li(THF)3] (2), [{MeAl(2-py)3}2Ca] (3), and [{MeAl(2-py)3}ZnCl] (4), respectively. [{ n BuIn(2-py)3}Li·THF] (5), an InIII analogue of 1 containing the [ n BuIn(2-py)3]- anion, is obtained by the one-pot reaction of n BuLi with InCl3 followed by reaction with 2-Li-py. Complex 5 reacts with [(C7H8)Mo(CO)3] to give [{ n BuIn(2-py)3}Mo(CO)3Li(THF)2]∞ (6) (analogous to the AlIII complex 2). The X-ray structures of the new complexes 2, 3, 4, 5, and 6 are reported.

Compounds [Mo(CO)4(N-N)] (N-N = 4,4'-bis((4-methylphenyl)carbamoyl)-2,2'-bipyridine, bipy', 1; or 2,2'-biimidazole, H2biim, 2), [MoCl(eta3-methallyl)(CO)2(N-N)] (N-N = bipy', 3; H2biim, 4), and [Mo(eta3-methallyl)(CNtBu)(CO2)(N-N)]BAr'4 (Ar' = 3,5-bis(trifluoromethyl)phenyl; N-N= bipy', 5; H2biim, 6) were synthesized and characterized, and their behavior toward anions was investigated in solution (IR and 1H NMR) and in solid state (X-ray diffraction).

The dimeric macrocycles [[P(mu-NtBu)]2.LL]2 [LL = OCH2C(Me)2CH2O (1), 2,6-(NH)2C5H3N (2), 1,2-(NH)2C6H4(3)] have been obtained by the reactions of the appropriate diols and diamines (LLH2) with the dimeric phosph(III)azane [ClP(mu-NtBu)]2. Under different conditions the reaction of 1,2-(NH2)2C6H4 with [ClP(mu-NtBu)]2 gives the monomer [[P(mu-NtBu)]2.[1,2-(NH)2C6H4]] (4) (instead of the dimer 3). Contrary to the literature, the results illustrate that the formation of dimeric macrocycles is common in these reactions and dependent among other factors on the steric demands and length of the organic spacer (LL) as well as the reaction conditions.

The structures of the host-guest complexes [[[[P(mu-NtBu)]2(mu-NH)]5]I]-.[Li(thf)4]+ [2.I[Li(thf)4]] and [[[P(mu-NtBu)]2(mu-NH)]5].HBr.THF (2.HBr.THF) show that increased distortion of the framework of the pentameric macrocycle [[[P(mu-NtBu)]2(mu-NH)]5] (2) occurs with the larger halide ions. Theoretical studies show that the thermodynamic stabilities of the model host-guest anions [2.X]- (X=Cl, Br, I) are in the order Cl- approximately Br->I-, that is, the reverse of the templating trend observed experimentally. These studies support the view that the selection of the pentamer 2 over the tetramer [[[P(mu-NtBu)]2(mu-NH)]4] (1) is kinetically controlled, a conclusion which is also consistent with the previous observation that the frameworks of 1 and 2 are not in dynamic equilibrium with each other.