Structural characterization of the dinuclear metal carbonyl anions [M2(CO)10]2- (M = chromium, molybdenum) and [Cr2(CO)10H]-. Marked stereochemical effect of a linearly protonated metal-metal bond

Abstract

The known mixed halide-phosphine (or -arsine) TBP complexes of nickel(II) are blue, green, or purple. The corresponding SPY complexes are red, brown, or purple, and if the number and kind of ligands are the same in the two geometries, as in those discussed here, the lowest energy ligand-field band occurs at lower energy in the case of the TBP. When we go to the mixed cyanidearsine, however, the result is that the lowest energy absorption maximum is found in the SPY spectrum.The lowest energy band in the SPY complex is of relatively low intensity (for [Ni(diars)2CN]+, e is 420 in 2-methyl-TBP-methanol at 300°K). If we compare the most intense ligand-field bands for the two compounds, we find that for both cyanides and halides, the intense absorption at lower energy is found in the TBP.(2) This paper is based in part on a dissertation submitted by L. B. Handy to the Graduate School of the University of Wisconsin in partial fulfillment of the requirements for the Ph.D. degree, Aug 1968.

Preparation of Cr2(CO)8(NO)2 and X-ray crystal structures of Cr2(CO)8(NO)2 and Cr2(CO)9NO−. Stereochemical comparisons to Cr2(CO)102−

“…Since the crystal structure of the PPN+ salt of the isoelectronic Cr2(C0)1~2-dianion has been reported (8), and since the isoelectronic Cr2(C0)9(NO)-monoanion (2) was also available, we obtained the X-ray structures of both 1 and 2 in order to compare the structural features of all three compounds.…”

[Pb5{Mo(CO)3}2]4−: A Complex Containing a Planar Pb5 Unit

“…The {Pb 5 Mo 2 } core of 1 can also be described as a pentagonal bipyramid with the two Mo atoms occupying the apexes and the Mo–Mo vector crossing the center of the Pb 5 ring. The Mo–Mo separation is 3.2156(8) Å, much longer than in the organometallic compound [Mo 2 (CO) 10 ] 2− (3.123 Å)23a or in [(C 5 H 5 )Mo(η 5 ‐As 5 )Mo(C 5 H 5 )] (2.764 Å) 23b…”

Dative Bonds in Main‐Group Compounds: A Case for Fewer Arrows!

“…We had followed the discovery of the carbones with interest and, despite some skepticism, we took this unusual perspective seriously and as a valid contribution to the discussion. More recently the long-known PPN cation [24,25] was presented as…”