Derivatives of manganese carbonyl with Bis(diphenylphosphino)methane and Bis(diphenylarsino)methane

Abstract

The reactions of manganese carbonyl with the ditertiary phosphorus ligand bis(dipheny1phosphino)-methane, dpm, and its arsenic analogue, dam, have been investigated. The major products are of the types Mn2(CO),(L-L), [(L-L) = dpm or dam], Mnz(C0)6(dpm)z and Mn,(CO)s(dpm)2.Mn,(C0)5(dpm), displays a carbonyl stretch at the extremely low frequency of 1645 cm-l. It has been shown that the molecule contains a carbonyl group bridging between the manganese atoms in a previously unknown manner.

The interplay between metal–metal bonds, four‐electron donor carbonyl groups, and five‐electron donor nitrosyl groups in highly unsaturated binuclear rhenium carbonyl nitrosyls

“…The very low infrared (NO) vibrational frequency for 5T-2 at 1320 cm Ϫ1 (Table III) can be assigned to this 2 --NO group. The ReORe bond distance in 5T-2 at 3.061 Å (MPW1PW91) or 3.085 Å (BP86) is reasonably close to the experimental value of 3.02 Å determined by X-ray diffraction [38] for Re 2 (CO) 10 and thus suggests a single bond. An unbridged triplet Re(NO) 2 (CO) 5 structure 5T-3 ( Fig.…”

“…Examples of compounds containing ReORe single bonds which have been characterized by X-ray diffraction include Re 2 (CO) 10 with a ReORe bond distance of 3.041 Å 38 and ( 5 -C 5 H 5 ) 2 Re 2 (CO) 4 (-CO) with a ReORe bond distance of 2.957 Å. 40 The former ReORe distance is very close to the 3.07 Å ReORe distance predicted for the triple 5T-2.…”

“…Early examples of binuclear cyclopentadienylmetal carbonyls with metal-metal multiple bonding indicated by short bond distances are the cyclopentadienyl metal carbonyls Cp 2 V 2 (CO) 5 [1,2], Cp 2 M 2 (CO) 6 (M ϭ Cr [3][4][5], Mo [6,7]), and Cp 2 MЈ 2 (CO) 3 (MЈ ϭ Mn [8], Re [9]), all of which require formal M'M triple bonds to give each metal atom the favored 18-electron configuration. A four-electron donor bridging carbonyl group is found in the stable manganese carbonyl ditertiary phosphine derivative [10] (Ph 2 PCH 2 PPh 2 ) 2 Mn 2 (CO) 4 ( 2 --CO), a substitution product of Mn 2 (CO) 8 ( 2 --CO), predicted to be the lowest energy structure for Mn 2 (CO) 9 .…”

“…Such formal orders for rhenium-rhenium bonds are not unreasonable since Cp 2 Re 2 (-CO) 3 has a Re'Re distance consistent with a formal bond order of three [9] and the Re 2 Cl 8 2Ϫ anion was the first example of a compound to be discovered with a formal metal-metal bond order of four [12]. Rhenium carbonyl nitrosyls were also chosen for this study because of the prospects for their synthesis from well-known rhenium carbonyl starting materials Re 2 (CO) 10 , HRe(CO) 5 , or Re(CO) 5 Ϫ , possibly by nitrosation followed by decarbonylation under suitable conditions. The binuclear rhenium carbonyl nitrosyls Re 2 (NO) 2 (CO) 7 as well as Re 2 (NO) 2 (CO) 6 , requiring a formal ReARe double bond to give both metal atoms the favored 18-electron configuration, are discussed in a previous paper [13].…”

Stabilization of Binuclear Chromium Carbonyls by Substitution of Thiocarbonyl Groups for Carbonyl Groups: Nearly Linear Structures for Cr2(CS)2(CO)9

“…This is a very stable molecule having a structure derived from the octahedrally coordinated Cr(CO) 6 by the replacement of one CO group with a CS group. 9 Furthermore, photolysis of Cr(CS)(CO) 5 in CH 4 matrices at 20 K has been reported by Poliakoff 10 to give two isomers of the unsaturated Cr(CS)(CO) 4 , identified by their ν(CO) frequencies.…”