Synthesis, characterization, and structure of tri-.mu.-halogeno-hexacarbonyldirhenate(I) salts of monocationic porphyrin acids

Technetium and Rhenium

“…442 Structures of the dimeric and trimeric complexes are seen to be derived from those of the parent complexes [Re 2 Cl8p~ and Re 3 Cl9. 459 Thus, octamethyldirhenium shows eclipsed methyl groups (75) quadruple bond joining the metals in these complexes. 447 The structures of some other dimeric species are shown in Scheme 27 along with the paths by which these derivatives have been formed.…”

“…73 ' 74 An X-ray crystallography study of [OEPH3] [Re 2 Cl 3 (CO) 6 ] (OEPH2 = octaethylporphin), a by-product of the reaction of [ReCl(CO) 5 ] with OEPH 2 , has confirmed the structure of the [Re2X3(CO)6]~ anion. 75 The structure of the bromo analog has been determined as its [Re(CO) 3 2 ], respectively. 84 Unsubstituted halocarbonyls of other oxidation states are rare.…”

“…Structures of a trimeric alkyl complex and its bis(ligand) adduct are shown as (76) and (77). The trimeric complexes such as (76) undergo cleavage in the presence of phosphines to dimeric species such,as [Re2Cl2(R)2(L)4] and [Re2(R)6(L)2] that are not obtainable from the parent phosphine-substituted halides Re2X6L2- 455 The geometry of such dimeric species is believed to be similar to (75); several isomers are believed to exist in the product mixtures and no suitable single crystals have been obtained as yet.…”

Thermodynamics and Photodynamics of a Monoprotonated Porphyrin Directly Stabilized by Hydrogen Bonding with Polar Protic Solvents

“…Thep rotonation affords saddle-distorted diprotonated porphyrins (H 4 P 2 + )u nder strongly acidic conditions as shown in Scheme 1. [46,[57][58][59][60][61][62][63][64][65] Saddle-distorted H 2 Ps have been reported to form weak hydrogen bonds with polar protic solvents such as methanol (MeOH)n ot only in crystals [66][67][68] but in solutions as well. [36] The reason why H 3 P + is hard to detect in the protonation processi st hat the protonation of H 2 Pg ives much higher basicity which is much highert han that of H 2 P( K 1 !…”

“…[46][47][48][49][50][51][52][53][54][55][56] In spite of the fact that the detection of H 3 P + is indispensable for thermodynamic elucidation of an acid-base equilibrium of H 2 Pa sshown in Scheme 1, the detection and characterization have been seldom reporteds ofar. [46,[57][58][59][60][61][62][63][64][65] Saddle-distorted H 2 Ps have been reported to form weak hydrogen bonds with polar protic solvents such as methanol (MeOH)n ot only in crystals [66][67][68] but in solutions as well. [69,70] Previously,w er eported ac rystal structure of the monoprotonated form of H 2 DPP (H 3 DPP + )b yu sing 2-anthracenesulfonic acid (2-AN-SO 3 H) as ap rotons ource.…”