Highly reactive, thermally stable, and air sensitive are three characteristics of the dark red title compound 1, which was prepared from ZrCl4·2 THF and potassium naphthalenide. The three naphthalene ligands are bound η4 to the Zr center and the co‐ordination environment has approximate C3v, local symmetry (shown on the right). Compound 1 is the first tris(naphthalene) complex and the first structurally characterized homoleptic naphthalene metalate.

Being positive about anions: Hydrocarbon complexes containing negative‐valent Hf are obtained for the first time as tris(polyarene)hafnates(2−), polyarene=anthracene (An) and naphthalene, where the latter functions as a synthon for the unknown atomic Hf2− (see scheme, cot=1,3,5,7‐cyclooctatetraene). Tris(anthracene)metalates(2−) of Ti and Zr were also accessed, which completes an unprecedented triad of tris(arene)metal complexes.

Through the use of parahydrogen-induced polarization (PHIP), conclusive evidence has been obtained that H2 addition to Pt(Ph2PCH2CH(Me)OPPh2) proceeds in a concerted, pairwise manner. PHIP has also been used in conjunction with a 2D HMQC sequence to obtain 31P and 195Pt NMR spectra from submilligram samples in 2−5 min.

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Bis(naphtha1ene)metal complexes are a highly reactive and potentially useful class of sandwich compounds as they readily undergo metal-centered substitution reactions with a variety of ligands.3 In the past, homoleptic naphthalene or substituted naphthalene complexes have been isolated only from metal-atom ligand coc~ndensation~ and potassium or magnesium atom reactions5 for vanadium, chromium, and molybdenum. Bis-(naphthalene)titanium(0)6a and bis((5-8-0)-1,4-dimethylnaphthalene)titanium(0)6balso have been prepared by the former method but could not be isolated in pure form due to their poor thermal stabilities. All of these syntheses required specialiyed equipment unavailable to most chemists. Except for bis-(naphthalene)chromi~m(O)~~~~~ and analogous molybdenum c0mplexes,5~ their properties remain poorly explored due to their relative inaccessibility.Since alkali metal naphthalenides are readily prepared by conventional methods8 and have been shown to be effective precursors to several mononaphthalene metal complexes?JO we have been exploring their possible use in the synthesis and isolation of bis(naphtha1ene)metal species. Although conventional naphthalenide reductions of metal precursors have been suggested previously to provide homoleptic naphthalene complexes, products from these reactions were not isolated and were formulated only on the basis of EPR spectroscopyll or their reaction chemistry.12(1) This paper is dedicated to the memory of Professor Paul G. Gassman, a friend and colleague who is greatly missed.(2) Highly Reduced Organometallics. 35. Part 34: Ellis, J. E.; Yuen, P. Inorg. Chem. 1993, 32,4998. (3) Kjndig and co-workers [(a) Kiindig, E. P.; Perret, C.; Spichiger, S.; Bernardinelli, G. J. Organomet. Chem. 1985, 286, 1831 have discussed in detail the electronic basis for the unusually high reactivity of coordinated naphthalene compared to that of monocyclic arenes and have compared this "naphthalene effect" with the related "indenyl effect": [(b) Basolo, F. Pure Appl. Bochkarw, M. N.; Trifonov, A. A.; Federova, E. A.; Emelyanova, N. S.; Basalgina, T. A.; Kalanina, G. A.; Razuvaev, G. A. (a) Four equivalents of KCloH8, THF, -60 OC, product was not isolated; (b) 6 equiv of KCloHs, THF, -60 OC, then 15-crown-5; (c) 2 equiv of KCloHs, THF, -60 OC, then 15-crown-5; (d) KSnMe,, 15crown-5, THF, -78 O C ; (e) MelSnC1, THF, -60 OC.We now report that the first examples of isolable bis-(naphtha1ene)titanium complexes, [Ti(C1~H8)2]2-, 1, and [Ti(CloH&SnMe3]-, 2, have been prepared by this method. Both of these compounds are stable derivatives of the very unstable Ti(CIoH8)2.6 Bright purple solutions of the latter substance, or a solvated version thereof, were readily prepared by reduction of TiC14.2THF, T H F = tetrahydrofuran, with 4 equiv of KCloH8 at -60 OC in THF, but these quickly decomposed below -20 OC to finely divided titanium metal and naphthalene. Rapid treatment of these purple solutions with an additional 2 equiv of KCloHa or 1 equiv of KSnMe3 at -60 OC caused the solutions to become dramat...