Phosphorus V porphyrins

Absorption Spectroscopy. - UV / Visible spectroscopy has featured in the characterisation of the aryloxo derivatives of phosphorus(V) porphyrins, (42). Each new porphyrin showed a characteristic absorption spectrum indicating the presence of a P(V) ion in the porphyrin cavity. 

In our study, the oligothiophenes, which can be easily dimerized by electrochemical oxidation, were used as not only molecular wire but also coupling elements. Phosphorus(V)porphyrin, which have strong oxidizing powers and are stable to the electrochemical oxidation, were used as the photosensitizer. Since the phosphorus(V)-... 

Table 2. Absorption and emission properties of bis(thienylalko y)-and bis(oligothienylalkoxy)-phosphorus(V)porphyrin triad molecules in CH3CN...

The phosphorus(V)porphyrin derivatives 2 and 3 were polymerized by electrochemical o.xidation, whereas 1 was scarcely polymerized. The polymer showed strong photoconductivity. 

Reddy. D.R. Malya, B.G. A molecular photoswitch based on an axial-bonding type phosphorus(v) porphyrin. Chem. Commun. 2001, 117. 

Fig. 5 Schematic representation of relationships between photoinduced electron transfer and corresponding energy levels of phosphorus(V)porphyrin and oligothienyl axial groups.

P(0)(0Me)2) and at 1.5 (0P(0)(0Me)2). Aryloxo derivatives of phos-phorus(V) porphyrins (42) have been fully characterised by a combination of techniques. The proton-decoupled 831 signal (—194 to —200) suggests that an octahedral coordination around the phosphorus exists. ... 

Finally a new departure in an unusual aspect of hypervalent phosphorus chemistry has been provided by the synthesis of water-stable dialkoxy phosphorus(V)-tetraphenylporphyrins (125) from (124). The six-co-ordinate phosphorus porphyrin (125) with R=Et, has... 

Oxygen ligands form very stable complexes with hard Lewis-acid met-alloporphyrins such as Sn(IV), Zr(IV), Mn(III), Mo(V), but also with P(V)-porphyrins. Mixed-metal dimers were synthesized from Al(Me)OEP and phosphorus, arsenic or antimony porphyrins in the form of fi-oxo dimers [73]. hi most cases, polymeric structures are obtained because Sn(IV)-, Mn(III)- and Fe(III)-porphyrins can bind two axial ligands on either side of the porphyrin referred to as trans-binding. This is schematically represented in Fig. 25a. An example includes the linear trinuclear or polymers /r-frans-dioxo-MoTPP [74,75]. 

A great variety of covalently or non-covalently boimd porphyrin-terpyri-dine motifs are known to closely mimic the initial photoinduced electron transfer (PET) or excitation energy transfer (EET) events of natural photosynthetic reactions. A first example of covalent connection of a terpyridine group to the axial position of a phosphorus porphyrin as in 33 (Fig. 26b) was presented by Kumar and Maiya [81 ]. The terpy moiety itself is a strong chelator towards other transition metal ions (see also 24). Upon postirradiation, the axial terpy subimits act as a donor and P(V) porphyrin as an acceptor. In fluorescence titrations it was found that the PET and EET reactions are mod-... 

Phosphorus(V) in its most stable oxidation state forms robust chelate complexes with the porphyrin, and retains the capability of binding two oxygen ligands in a frans-axial mode as outlined in Sect. 3. This strategy was used by Maiya [81,102-104] and Tanaka and Segawa [105]. The coordination chemistry of phosphorous(V) porphyrins is similar to germa-nium(IV), tin(IV), gallium(III), and aluminium(III) porphyrin coordination chemistry [102,106]. These metalloporphyrins were shown to form multiporphyrin complexes with phenol-substituted porphyrins. Because of the... 

Slagt, V.F., van Leeuwen, P.W.N.M. and Reek, J.N.H. (2007) Supramolecular bidentate phosphorus ligands based on bis-zinc(ii) and bis-tin(lV) porphyrin building blocks. Dalton Trans., 2302-2310. 

The X-ray crystal structure of [Pv TPP(OH)2 ]OH 2H2 O has been determined.32 The porphyrin skeleton is distorted S4 symmetrically to attain short P—distance ( 1.90 A). The hydroxy groups are strongly intermolecularly hydrogen bonded, and the phosphorus atom is displaced from the N4 plane by 0.096 A. The antimony(V) ion is centred in the porphyrin plane in [Sb(OEP)(OH)2]+ with a somewhat large Sb—distance of 2.065(6) A.31 The structure of [Bi(OEP)]NO, is of interest, since the four-coordinate BiUI ion protrudes from the porphyrin N4 plane by 1.09 A with a very long Bi—Npor distance of 2.32 A.31... 

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