The first stable stannanetriol and germanetriol bearing sterically congested aryl groups were synthesized by hydrolysis of the corresponding trichloro-stannane and -germane. The stannanetriol is monomeric in solution as well as in the crystalline state, as evidenced by X-ray diffraction analysis and CP-MAS NMR spectroscopy. The stannanetriol reacted with silicone grease to afford a cagelike compound having three Sn–O–Si–O–Sn linkages in the molecule. All the group 14 triols can be converted to the corresponding trihalo compounds in good yields.

DedicatedtoProfessor Norihiro Tokitoh on the occasiono fh is 60th birthdayTo explore the coordination chemistry of dibenzopentalene dianion, reactions of two dilithium dibenzopentalenides having different silyl substituents with Cr(CO) 3 (CH 3 CN) 3 were investigated. The products were unexpected anionic complexes,T he proton at the 9-position is derived from Cr(CO) 3 (CH 3 CN) 3 ,a se videnced by the use of Cr(CO) 3 (CD 3 CN) 3 .T he X-ray diffraction analysis revealed that the chromiumi sc oordinated by an anionic fivemembered ring of the pentalene skeleton, and the lithium atom is coordinated by oxygen atoms of the carbonyl groups. The complexes form ad imer or ac age-liket etramer via carbonyl-lithium interactions,d epending on the bulk of the silyl groups.T he cubic tetramer appears to retain its cage structure in nonpolarsolvents such as benzene.Benzene and cyclopentadienyl anion (Cp À )s erve as 6p-electron-donating ligandsf or transition metals to form h 6 -arene and h 5

Group 14 monolithio compounds with sterically encumbered terphenyl ligands, ArM 14 (SiHMe 2 ) 2 Li [M 14 = Si, Ge, Sn; Ar = 2,6-bis(2,6-diisopropylphenyl)phenyl and 2,6-bis(2,4,6-triisopropylphenyl)phenyl], were prepared by transmetalation reactions of ArM 14 (SiHMe 2 ) 3 with methyllithium, the structures of which were established by X-ray diffraction analysis. The