Electrochemical studies on [Mn(CNR)6]+ complexes

Abstract

Electrochemical Studies on [Mn(CNR),]+ Complexes derivative with Mn CO 5X X = Br or Cl) gave only with C5H5Mo(N0)2Cl in diethyl ether gave an unidentified yellow solid suggested by its NMR spectrum to contain (CH3),Sn groups but neither C5H5 nor (CH3)2C groups. Reaction of (CH3)2C=NOSn(CH3)3 with C5H5Fe(CO)2C1 in boiling benzene gave only (CH3)3SnFe(C0)2C5H5.'' No tractable products were obtained from reactions of (CH3)2-in ethereal solvents at or near room temperature. These observations suggest that the range of transition metal systems to which (CH3)2C=NOSn(CH3)3 can transfer (CH3)2CN0 groups is extremely limited and that in some cases this tin reagent instead transfers (CH3)$n or possibly (CH3),Sn0 units to the transition metal system. Acknowledgment. We are indebted to the National Science Foundation for partial support of this work under Grant CHE-75-19974. We are also indebted to M and T Chemical Co. for generous gifts of trimethyltin chloride. Registry No. MezCNOMo(CO)zCp, 61491-36-9; (CH2)&!NOMo(C0)2Cp, 61 81 3-21-6; (CHz=CH)(Me)CNOMo-(CO)zCp, 618 13-22-7; (MezC=CH)(Me)CNOMo(CO)zCp, 61813-23-8;CHz=CH(CH2)zC(Me)NOMo(CO)2Cp, 61813-24-9; (CH3)3SnMn(CO)5.' 0 ' Reaction of (CH3)2C=NOSn(CH3)3 Me2CNOW(C0)zCp, 6 18 13-25-0; (CH2)5CNOW(C0)2Cp, 618 13-26-1; (CHz=CH)(Me)CN0W(CO),Cp, 618 13-27-2; (MezC=CH)(Me)CNOW(CO)2Cp, 61 81 3-28-3; CH2=CH-(CHz)zC(Me)NOW(CO)zCp, 61813-29-4; (CH3)zC==NOSn(CH3)3, 25092-7 1-1; (CH3)zC=CHC(CH3)=NOSn(CH3)3, 61 8 12-49-5; HzC=CH(CH2)zC(CH3)=NOSn(CH3)3, 61812-50-8; CSHS-

Electron spin resonance and electronic spectroscopy of low-spin manganese(II) complexes (C5R5)(CO)2(L)Mn with L = hydrazido(1-), arylamido, anionic nitrile and purine-type ligands

“…formula (7), later] or which are too bulky to adopt the necessary conformation for II interaction in the complex. In agreement with MO calculation^^^^^^ and the structure found in a corresponding thiolate ~ornplex,~' the mirror plane of the metal fragment and the II nodal plane of the ligand must coincide, a requirement which cannot be met by diphenylamide (3). In the same vein, 1,l -diphenylhydrazine forms stable adducts with (C,Me,H,-,)-(CO),Mn, n = 0, 1, 5; however, on oxidative deprotonation the sterically encumbered pentamethylcyclopentadienyl derivative does not form an e.s.r.-detectable Mn" complex at all, whereas the smaller, less substituted metal fragments react to yield Cp(CO),(l,ldph-)Mn (4A) as rather sensitive species in low concentration.…”

“…The resulting binuclear, diamagnetic products involve p-q~inonedi-imine~~ and 4-dimethylaminophenylnitrene ligandP in the case of the p-phenylenediamine precursors and aminonitrene ligands in case of 1,l -dialkylhydrazides (5). 7 3 The mononuclear, paramagnetic intermediates could be established in most instances,66 a notable exception being 1,l -dialkylhydrazido( 1-) species which are not persistent either due to the extremely 0-and n-electron-rich character of the ligand or because of insufficient delocalization of spin. In this context, there have also been reports on the production of paramagnetic species after reduction of Cp(CO),(N,R)Mn+ with NaBH, ; however, these species were neither isolated nor identified.…”

Geometric and Electronic Structure Analysis of the Three-Membered Electron-Transfer Series [(μ-CNR)2[CpCo]2]n (n = 0, 1–, 2−) and Its Relevance to the Classical Bridging-Carbonyl System

“…Most importantly, K 2 ­[ 2 ] represents an isolable isocyano analogue of the elusive dimeric dicarbonyl dianion, [(μ‑CO) 2 ­[CpCo] 2 ] 2– . This observation is particularly significant, given the fact that isocyanide ligands are well known to decrease reduction potentials relative to CO, − and are considerably less effective π-acids. , Accordingly, we believe that the ability of the CNAr Mes2 ligands to encapsulate alkali-metal cations with π-arene interactions provides an effective pathway for the stabilization of this class of highly reduced dianions. While the presence of alkali-metal cations in solution have long been known to effect positive shifts in reduction potentials of substrates, the specific formation of π-arene/alkali-metal-cation interactions by m -terphenyl groups has been proposed to significantly contribute to the stability of highly reduced main-group element compounds. − In this respect, it is important to note that attempts to disrupt the π-arene/K + interactions in K 2 ­[ 2 ] with sequestering agents such as 18-crown-6 and dibenzo-18-crown-6, as well as traditionally non-coordinating cations such as [Ph 3 PNPPh 3 ] + , resulted rapidly in intractable mixtures.…”

A Well-Defined Isocyano Analogue of HCo(CO)4. 3: Hydride Migration to Olefins, H-Atom Transfer and Reactivity toward Protic Sources

“…Relying on the isolobal analogy between organoisocyanides and CO, − we conceived HCo­(CNAr Mes2 ) 4 as a potential structural and functional model of HCo­(CO) 4 . However, due to the fundamental differences between isocyanide and carbonyl ligation, ,, HCo­(CNAr Mes2 ) 4 also offered a potentially well-defined point of contrast to HCo­(CO) 4 from the standpoint of both electronic structure and function. To this end, in a followup report, we disclosed a complete series of well-defined mixed carbonyl–isocyanide monohydrides of the formulation HCo­(CO) 4‑ n (CNAr Mes2 ) n ( n = 1–4) such that the Brønsted acidity and spectroscopic properties attendant to both HCo­(CO) 4 and HCo­(CNAr Mes2 ) 4 could be systematically assessed as a function of carbonyl for isocyanide substitution.…”