Three new phosphaalkenes bearing C-aryl chromophores, MesP]CPh(Ar) (1a: Ar ¼ 1-naphthyl, 1b: 9-phenanthryl, 1c: 5-dibenzosuberenyl; Mes ¼ 2,4,6-trimethylphenyl), are reported. Each phosphaalkene was characterised by multinuclear NMR spectroscopy ( 1 H, 13 C, 31 P), X-ray crystallography, mass spectrometry, UV/Visible spectroscopy and elemental microanalysis (1b and 1c). Monomers 1a and 1b were successfully polymerised using anionic methods of initiation (n-BuLi: 5 and 1.5 mol%, respectively) to afford poly(methylenephosphine)s (PMPs: 2a: M n ¼ 15 100 Da, PDI ¼ 1.14; 2b: M n ¼ 17 500 Da; PDI ¼ 1.39). Detailed NMR spectroscopic analysis of polymer 2a revealed that its microstructure is primarily composed of [P(CHPhNaph)-(4,6-Me 2 C 6 H 2 )-2-CH 2 ] n units rather than the expected [P(Mes)-CPh 2 ] n .Functional polymer 2a was oxidised to the phosphine oxide 2a$O or phosphine sulfide 2a$S, and coordinated to borane to afford 2a$BH 3 or gold(I) to afford 2a$AuCl. Significantly, 2a shows "turn-on" emission properties selectively as its oxide 2a$O (l ex ¼ 286 nm; l em ¼ 342 nm) which is prepared by treatment with hydrogen peroxide.

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New aspects of the chemistry of the phosphoranimine Cl(3)P=NMes* (Mes* = 2,4,6-tri-tert-butylphenyl) (7) and the phosphinimine ClP=NMes* (2) have been explored. A cationic derivative of 7 was prepared from the reaction between this species and DMAP (DMAP = 4-dimethylaminopyridine) in the presence of the halide abstraction agent AgOTf (OTf = OSO(3)CF(3)) which yielded the donor-stabilized cation [DMAP-PCl(2)=NMes*](+) ([9](+)). When treated with tertiary phosphines (n)Bu(3)P or Ph(3)P, 7 was found to undergo a reductive dechlorination reaction to yield 2 and dichlorophosphoranes R(3)PCl(2) (R = (n)Bu (13a), Ph (13b)). The phosphinimine 2 reacts with Cl(-) sources to form the novel dichlorophosphinamide anion [Cl(2)PNMes*](-) ([14](-)) which was characterized in solution. Treatment of [Ph(4)P][14], generated in situ, with GaCl(3) or MeOTf regenerated 2 and provided further evidence for the formation of the anion [14](-). In addition, phosphoranimine 2 was found to undergo an unexpected oxidative cyclization reaction when treated with the oxygen transfer agent pyridine-N-oxide to yield a P-chlorophosphoryl-ox-3-azoline (18).

Rigid and C2 symmetric chiral ligands are useful for crafting stereoselective catalysts. 1 Binol, binap, dpen, dach, pybox, and salen ligands 1 are just some of the 'privileged' 2 C2 symmetric ligands that have been used to construct a wide variety of interesting metal complexes as stereoselective catalysts. The C2 symmetric N2O2 salen ligand (1) forms trans octahedral complex (Scheme 1). It is uncommon to find C2 symmetric N2O2 ligands that form only one kind of cis octahedral complexes. For example, 2 (Scheme 1) can in principle form three isomers of octahedral complexes (cis-α, cis-β or trans). 3,4 In contrast, 3 and 4 (Scheme 1) should form only the C2 symmetric cis octahedral complexes (cisα) due to the connectivity of the ligand. The cis-α topology is particularly attractive for stereoselective recognition of bidentate substrates and for stereoselective catalysis that requires two free metal coordination sites in cis orientation. 3,4 Our interest in molecular recognition of small molecules 5 led us to investigate the stereoselective recognition of vicinal diamines with Zn(II) complexes of 3 and 4.Compound 3 was prepared according to a literature procedure 6 and the reaction of 3 with two equiv of acrylonitrile provided compound 4. Figure 1 shows the crystal structure of a ternary complex formed between (R,R)-dpen, Zn(ClO4)2, and the disodium salt of (S,S)-4. 7 The two phenoxy groups occupy the less favored axial positions in the Zn(II) complex allowing the phenolic oxygens to coordinate to the metal and form the highly rigid cis-α octahedral structure. In contrast, the crystal structure of a Pt(II) complex of 3 showed that the ligand binds to the metal as a bidentate ligand (N coordination) forming a square planar structure. 8 The two phenol groups in the Pt(II) complex occupy the more favored equatorial positions. Vicinal diamines generally form tetrahedral Zn(II) complexes. 9 1 H NMR was used to study the stereoselectivity of ternary complex formation between 3 or 4 with Zn(OTf)2 and 1,2diphenylethylenediamine (dpen). 10 In a typical experiment, equimolar amounts of Zn(OTf)2 (10 mM) and disodium salts of 3 or 4 (host) were mixed with two equiv of dpen (guest) in methanol-d4. 1 H NMR shows that the guest diamine does not displace the host diamines even when excess of guest diamine is used. This supports the idea that the host diamines bind tightly to the metal as a tetradentate ligand in solution as depicted in the crystal structure ( Figure 1). Figure 2a shows the chiral carbon C-H signals of the heterochiral Scheme 1. Three different octahedral complexes that can be formed by C2 symmetric N2O2 tetradentate ligands 1, 2, 3 and 4. Figure 1. Ortep representation of the Zn(II) complex formed between (S,S)-4 and (R,R)-dpen at 50% probability. Hydrogen atoms on amine nitrogens and chiral carbons are shown for clarity. Selected bond distances: Zn1-N1 = 2.130(2); Zn1-N2 = 2.144(2); Zn1-N3 = 2.222(2); Zn1-N4 = 2.213(3); Zn1-O1 = 2.094(2); Zn1-O2 = 2.109(2). Selected bond angles: O1-Zn1-O2 = 162.07(8); N1-Zn1...

In the title mol­ecule {systematic name: 3,3′‐[1,2‐bis­(2‐hydroxy­phen­yl)ethane‐1,2‐diyldiimino]propane­nitrile}, C20H22N4O2, there are three different types of intra­molecular hydrogen bonds, one of each of the types N—H⋯O [H⋯O = 2.51 (3) Å], N—H⋯N [H⋯N = 2.21 (3) Å] and O—H⋯N [H⋯O = 1.71 (3) Å]. In the crystal structure, mol­ecules are linked into one‐dimensional chains in the a‐axis direction via inter­molecular O—H⋯N [H⋯N = 1.95 (4) Å] hydrogen bonds.