Manganese complex isoelectronic

Spin complexes (Table 102). The spin-pairing has little effect on the average Cr—-N (porphyrin) distances since they are 2.033 A in Cr(TPP)-2PhMe (S = 2) and 2.027 A in Cr(TPP)(py)2 (5 = 1). However, the Cr—distances to the axial pyridine molecules (ca. 2.13 A) are considerably less than in isoelectronic high-spin manganese(III) complexes (ca. 2.4 A). This is attributed to the depopulation of the 3dz2 orbital on spin-pairing in the Cr complex. The alternative formulation of the Cr porphyrin complexes as porphyrin radical anion complexes is excluded by their visible spectra and oxidation-reduction behaviour. ... 

Manganese porphyrins also form nitrosyl complexes. Fast (ca. 10°M s ) reaction of Mn(II) with NO yields stable MnNO complexes (73) that show a linear Mn—N—0 geometry (74). Interestingly, no reductive nitrosylation is observed for the reaction of Mn(III) with NO (73). Cobalt porphyrins also form stable nitrosyl complexes. The CoNO species obtained, for example, by reaction of NO with Co(Il) porphyrins have been explored as isoelectronic... 

Under the influence of water, cationic manganese compounds decompose immediately, as in organic donor solvents such as acetone and tetrahydrofuran. In contrast to isoelectronic compounds of the chromium group, diolefin technetium and rhenium complexes have cis structures. In aqueous solution, the cation [Re(CO)4 ( 2114)2] is stable the Re —C2H4 bond in [Re(CO)5 ( 2114)] is also stable. There is no exchange between free ethylene and the ethylene in the complex. 

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