Four‐Membered 1,8‐Naphthalenediyl Transition Metallacycles

Abstract

Metallacyclobutanes form a class of compounds that has received considerable interest, mainly because of their (presumed or proven) intermediacy in several catalytic processes, such as olefin metathesis [']. Many synthetic approaches have been developed to prepare metallacyclobutanes. In our group, di-Grignard reagents are the startingpoint, and it has been shown that 1,3-di-Grignard reagents are excellent synthons for the preparation of metallacyclobutanesL2I.Recently, (1 &naphthalenediyl)magnesium (1) has been prepared and structurally chara~terizedf~]. The 1,3-relationship between the organomagnesium functions called for an investigation of the suitability of 1 as a reagent for the formation of four-membered metallacycles (Scheme 1).Scheme 1 1 2 w cyclic valence angles in the four-membered ring of 2 cause large deviations for the carbon-centered angles from the ideal 120". For that reason, the formation of dimeric compounds 4, i. e. compounds containing a 1,5-dimetallacyclooctane unit, could not be excluded beforehand. In Scheme 2, known representatives of both monomeric (3) and dimeric (4) species are listed. The only known transition metal compound is dimeric 4b; in view of the preferred linear coordination geometry of mercury(II), this is not surprising ["]. Special interest in the resulting 1,s-naphthalenediyl transition metal compounds 2 stems from the obvious strain that is imposed on the metal-carbon bonds; the small endoFrom the X-ray crystal structure analyses of 3b and 3f the severe strain in these compounds can be deduced; the naphthalene moieties are strongly distorted to accommodate the four-membered ring. Although bond lengths as well as angles deviate from the ideal values, no significant deviations from planarity have been observed. In the analogous transition metal compounds 2 (Scheme l), which are the topic of the present investigation, the metals have tetra-

[η2-8-(tert-Butylimino)-1-naphthyl]bis(η5-cyclopentadienyl)titanium(IV)

“…A solution of 1,8-naphthalenediyltitanocene (0.1 mmol), prepared according to Tinga et al (1994), in pentane (10 ml) was added to a solution of CNt Bu (0.2 mmol) in toluene (2 ml) at room temperature. After stirring for 3 h, the solvents were evaporated and the residue was extracted with cyclopentane.…”

“…The maximum deviation from the least-squares plane through this last ring system is 0.028 (3) Å for C2. The Ti1-C2 bond is elongated by 0.2 Å compared with its parent compound 1,8-naphthalenediyltitanocene (Tinga et al, 1994). The crystal packing displays a short C-HÁ Á Á contact (Fig.…”

Platinum organometallic compounds: classification and analysis of crystallographic and structural data. Part I. Monomeric Pt(0) and partly of Pt(II) with PtC4, PtA3B and PtC2A2 chromophores

“…The next 13 derivatives (Wong et al 1972, McClure and Weaver 1973, Yarrow et al 1974, Rajaram and Ibers 1978, Kemmitt et al 1983, Imran et al 1985, Hemond et al 1988, Hoover and Stryker 1989, Lai et al 1990, Tinga et al 1994, Baize et al 1995 ) have a four-membered ring with a mean C − Pt − C bite angle of 66.4 ° . Two derivatives (Hendersson et al 1986(Hendersson et al , 1989(Hendersson et al , 1990b) have a four-membered ring (-CSC-) with a mean value of 72.8 ° and in Kemmitt et al (1990) there is a four-membered ring (-CPC-) with a value of 74.9 ° .…”

“…There are 42 PtC 2 P 2 species (Wong et al 1972, Biefeld et al 1973, Evans et al 1973, McClure and Weaver 1973, Yarrow et al 1974, Norton and McDonald 1976, Rajaram and Ibers 1978, Clark et al 1979, Green et al 1979, Jason and McGinnety 1981, Kemmitt et al 1983, Imran et al 1985, Hendersson et al 1986, Grabowski et al 1986, Hemond et al 1988, de Boer et al 1989, Hoover and Stryker 1989, Alcock et al 1990a,b, Kemmitt et al 1990, Lai et al 1990, Debaerdemaeker et al 1991, Yamashita et al 1992, Fatima et al 1993, Tinga et al 1994, Baize et al 1995, Nicolaides et al 1995, Pak et al 1997, Bennett et al 1998, Edelbach et al 1998a, Shaltout et al 1998 in which a bidentate -C,C ′ donor ligand with a pair of unidentate P donor ligands form a square planar environment with a differing degree of distortion about each Pt(II) atom. Two of the species (Clark et al 1979, Pak et al 1997) are transand remaining ones have a cis -confi guration.…”

Mehrfachkoordination an Arene: die Koordination von sechs Rutheniumatomen an Naphthalin-1,8-diyl in [Ru6(μ6-C10H6)(μ3-PPh)(CO)14]

“…Sie beschränkten sich daher bisher hauptsächlich auf mono-und dinucleare Verbindungen mit Wechselwirkungen durch s-Bindungen wie in [Fe(C 10 H 7 ) 4 ][LiOEt 2 ] 2 [5] oder häufiger durch p-Komplexierung über h 2 -, h 4 -, h 6 -oder bisallylische h 3 :h 3 -Wechselwirkungen wie in den Verbindungen [Rh 2 (C 5 Me 5 ) 2 (1,2-h 2 -3,4-h 2 -C 10 H 8 )(PMe 3 ) 2 ], [6] [RhCp(h 4 -C 14 H 10 )], [7] [Ru(h 4 -C 8 H 12 )(h 6 -C 10 H 8 )] [8] und [Fe 2 (CO) 6 (mh 3 :h 3 -C 14 H 10 )]. [9] Eines unserer derzeitigen Ziele ist deshalb, [11] Kristallstrukturanalyse [13] 12 ] 4 werden an anderer Stelle beschrieben. [10] Hier stellen wir die Titelverbindung [Ru 6 (m 6 -C 10 H 6 )(m 3 -PPh)(CO) 14 ] 1 vor, die eine Naphthalin-1,8-diyl-Gruppe enthält.…”