The reactions of [(Me 3 Si) 2 N] 2 Ca(thf ) 2 with amidines 2-(Ph 2 P=NPh)C 6 H 4 NHC(tBu)=N(2,6-R 2 C 6 H 3 ) {R = iPr (L 1 H); R = Me (L 2 H)} afford heteroleptic calcium amido complexes (1); R = Me (2)} featuring tridentate coordination of the amidinate ligands. Complexes 1 and 2 proved to be efficient catalysts for intermolecular hydrophosphination of styrene, αmethylstyrene, divinylbenzene and phenylacetylene with Ph 2 PH and PhPH 2 . Compounds 1 and 2 exhibit high catalytic activity in the ring-opening polymerization of ε-caprolactone and enable quantitative conversion of 500 equiv. of monomer in 5 seconds [a] G. A. Razuvaev

Amido [Bu t C(NC 6 H 4 -2-OMe) 2 ] 2 LnN(SiMe 3 ) 2 (Ln = Y (3), Nd (4)) and borohydrido complexes [Bu t C(NC 6 H 4 -2-OMe) 2 ] 2 LnBH 4 (Ln = Y (5), Nd (6)) coordinated by new amidinate ligand bearing two pendant anisolyl groups are synthesized. According to X-ray analysis in complexes 3 and 4 one amidinate ligand is coordinated to the Ln 3+ cation in a bidentate fashion (κ 2 -NN), while the second one is tetradentate (κ 4 -NNOO). At the same time in borohydrido neodymium complex 6 the amidin-[a] G. A. Razuvaev

Tumor cells are well adapted to grow in conditions of variable oxygen supply and hypoxia by switching between different metabolic pathways. However, the regulatory effect of oxygen on metabolism and its contribution to the metabolic heterogeneity of tumors have not been fully explored. In this study, we develop a methodology for the simultaneous analysis of cellular metabolic status, using the fluorescence lifetime imaging microscopy (FLIM) of metabolic cofactor NAD(P)H, and oxygen level, using the phosphorescence lifetime imaging (PLIM) of a new polymeric Ir(III)-based sensor (PIr3) in tumors in vivo. The sensor, derived from a polynorbornene and cyclometalated iridium(III) complex, exhibits the oxygen-dependent quenching of phosphorescence with a 40% longer lifetime in degassed compared to aerated solutions. In vitro, hypoxia resulted in a correlative increase in PIr3 phosphorescence lifetime and free (glycolytic) NAD(P)H fraction in cells. In vivo, mouse tumors demonstrated a high degree of cellular-level heterogeneity of both metabolic and oxygen states, and a lower dependence of metabolism on oxygen than cells in vitro. The small tumors were hypoxic, while the advanced tumors contained areas of normoxia and hypoxia, which was consistent with the pimonidazole assay and angiographic imaging. Dual FLIM/PLIM metabolic/oxygen imaging will be valuable in preclinical investigations into the effects of hypoxia on metabolic aspects of tumor progression and treatment response.

Bis(alkyl) complexes [(2,6-Me 2 C 6 H 3 )NC(tBu)N(C 6 H 4 À 2-OMe)] M(CH 2 C 6 H 4 À 2-NMe 2 ) 2 (M=Sc (4), Y (5)), [(2-OMeÀ C 6 H 4 N) 2 C(tBu)] Y(CH 2 SiMe 3 ) 2 (THF) 2 (6), supported by N,N,O-tridentate (4, 5) and N,N,O,O-tetradentate (6) amidinate ligands were synthesized by the alkane elimination approach reacting tris(alkyl) rare-earth species M(R) 3 X n (R=Me 3 SiCH 2 , X=THF, n = 2; R=CH 2 C 6 H 4 À 2-NMe 2 , n = 0) with one equivalent of amidine (2,6-Me 2 C 6 H 3 ) N=C(tBu)À NH(C 6 H 4 À 2-OMe) (1) or (2-MeOÀ C 6 H 4 ) N=C(tBu)À NH(C 6 H 4 À 2-OMe) (2). The reaction of amidine 2 with equimolar amount of Y(CH 2 C 6 H 4 À 2-NMe 2 ) 3 in toluene unexpectedly results in the addition of N,N-dimethylaminobenzyl group to C=N bond of one amidinate fragment, ligand disproportionation and the formation of novel bis(amide)amidinate complex [(2-OMeÀ C 6 H 4 N) 2 C(tBu)CH 2 C 6 H 4 À 2-NMe 2 ]Y[(2-OMeÀ C 6 H 4 N) 2 C-(tBu)] (7). Complexes 4-6 were evaluated as catalysts for αolefins and isoprene polymerization.

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