Richard A. Kowenicki

Syntheses, structures and magnetic properties of Mn(II) dimers [CpMn(μ-X)]2(Cp = C5H5; X = RNH, R1R2N, CCR)

Manganocene, Cp2Mn, has been employed as a precursor in the synthesis of a range of Mn(II) dimers of the type [CpMn(μ-X)]2 [X = 8-NHC9H6N (1), N(Ph)(C5H4N) (2), N(4-EtC6H4)(C5H4N) (3) and CCPh (4)] as well as the bis-adduct [Cp2Mn{HNC(NMe2)2}2] (5). The solid-state structures of 1–5 are reported. Variable-temperature magnetic measurements have been used to assess the extent of Mn(μ-X)Mn communication within the dimers of 1–4 as a function of the bridging ligands (X).

Targeting large phosp(III)azane macrocyles [{P(μ-NR)}2(LL)]n (n≥ 2)

The condensation reactions of the dimer [ClP(μ-NR)]2 (7) with organic diacids [LL(H)2], possessing linear orientations of their organic groups, result in the formation of phospha(III)zane macrocyles of the type [{P(μ-NR)}2(LL)]n of various sizes. The series of macrocycles [{P(μ-NtBu)}2{1,5-(NH)2C10H6}]3 (1), [{P(μ-NCy)}2(1,5-O2C10H6)]n [n = 3 (2a); n = 4 (2b)], [{P(μ-NtBu)}2{1,4-(NH)2C6H4}]4 (3), [{P(μ-NtBu)}2(1,4-O2C6H4)]3 (4), [{P(μ-NCy)}2(1,4-O2C6H4)]3 (5) and [{P(μ-NtBu)}2{(NH)C6H4OC6H4(NH)}]2 (6) can be related to classical organic frameworks, like calixarenes.

Exo-metal coordination by a tricyclic [{P(µ-N-2-NC5H4)}2(µ-O)]2 dimer in [{P(µ-N-2-NC5H4)}2(µ-O)]2{CuCl·(C5H5N)2}4{2-NC5H4= 2-pyridyl, C5H5N = pyridine)

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

Steric control in the oligomerisation of phosphazane dimers; towards new phosphorus–nitrogen macrocycles

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.

Synthesis and structure of the calixarene-like phosph(III)azane macrocycle [{P(μ-NtBu)}2{1,5-(NH)2C10H6}]3

The reaction of [ClP(mu-NtBu)]2 with 1,5-diamino-naphthalene [1,5-(NH2)2C10H6] in Et3N-thf gives the trimeric macrocycle [{P(mu-NtBu)}2{1,5-(NH)2C10H6}]3(1); the X-ray structure of the toluene solvate 1.3toluene reveals a cone-shaped (calixarene-like) arrangement in which toluene guest molecules are trapped within the cavity.

Selective formation of the [PhP(H)–PPh]− anion in the reaction of PhPHLi with MeAlCl2; synthesis and structure of the unusual tetramer [{PhP(H)–PPh}Li·thf]4

The reaction of PhPHLi with MeAlCl(2)(3:1 equivalents) gives the tetramer [(PhP(H)-PPh)Li.thf]4, and provides the first direct evidence of a link between the reactivity patterns observed for Group 14 and 15 phosphanenides and those of Group 13.

The formation of dimeric phosph(III)azane macrocycles [{P(μ-NtBu)}2·LL]2[LL = organic spacer]

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.

Pyridyl 'ring-flipping' in the dimers [Me2E(2-py)]2 (E=B, Al, Ga; 2-py=2-pyridyl).

The boron and aluminium dimers [Me2E(micro-py)]2 [E=B (1); Al (2)] are formed as mixtures of two isomers in which the group 13 centres are coordinated by the bridging 2-py ligands in a cis or trans manner, however, in contrast to previous studies, we find that simply heating the mixtures of these isomers of and gives the more thermodynamically stable (synthetically useful) trans isomers exclusively (the trans isomer being the only product in the case of the gallium analogue ).

The folded, tetrameric phosph(III)azane macrocycle [{P(μ-NtBu)}2{1,4-(NH)2C6H4}]4

The tetrameric macrocycle [(P(mu-NtBu))2(1,4-(NH)2C6H4)]4, obtained from the reaction of the phosphazane dimer [ClP(mu-NtBu)]2 with p-phenylenediamine, has an unusual folded conformation in the solid state and contains a roughly tetrahedral arrangement of endo N-H groups for the potential coordination of anions.

A one-pot synthesis to [(Me3Si)3SiSb]4; a potential precursor for Sb42−

The reaction of (Me(3)Si)(3)SiK[middle dot]18-crown-6 with SbCl(3)(3 : 1 equiv.) provides a simple route to the title complex [(Me(3)Si)(3)SiSb](4). The potassium base initially acts as a nucleophile and then as a coupling agent, forming Sb-Sb bonds.