SUBVALENT GROUP 14 METAL-COMPOUNDS .15. GERMANIUM AND TIN AMIDES M(NR2)2 AS LIGANDS IN CARBONYLCHROMIUM(0) CHEMISTRY - THE CRYSTAL-STRUCTURE OF THE COMPOUNDS CIS-[CR(CO)4(SN(NR'2)2)2][M=GE OR SN, R'=SIME3 OR NR2=NCME2(CH2)3CME2]

The new crystalline complexes [Cr(CO)5{M(NR2)2)] [NR2 = NCMe2(CH2)3CMe2 and M = Ge (1) or Sn (2)] and cis-[Cr(CO)4{Sn(NR'2)2}2] (R'= SiMe3) (3) are reported. Compounds 1 and 2 were prepared from [Cr(CO5)(THF)] and M(NR2)2, while treatment of [Cr(CO)6-n(NCMe)n] [a ca. 12:6: 1 mixture of n = 1, 2 (cis), and 3, respectively] with an excess of Sn(NR'2)2 yielded a 2: 1 mixture of [Cr(CO)5{Sn(NR'2)2}] and the less pentane-soluble 3. Compounds 1-3 have been fully characterized. In crystalline 3, having l([Cr-Sn]) 2.557(1) angstrom and l[Cr-C(trans to Sn)] shorter than l[Cr-C(cis to Sn)], there is significant departure from octahedral coordination around Cr [Sn-Cr-Sn' 101.37(3)-degrees]; the N-Sn-N' bond angles [av. 105.0(2)-degrees are essentially identical to that in crystalline Sn(NR'2)2, although l([Sn-N]) in 3 is slightly shorter than in the free ligand.