Alkyl Isocyanide Ligands Research Articles

Aryl isocyanide derivative for one-pot synthesis of purification-free 99mTc-labeled hexavalent targeting probe

Introduction99mTc-labeled hexavalent probes can be readily synthesized by the coordination of six equivalent isocyanide ligands towards TcI, and alkyl isocyanide ligands have been extensively used for preparing such probes. However, high ligand concentration (>1 mM) is generally required due to their insufficient coordination ability to TcI. Methods and resultsIn this study, we revealed that aryl isocyanide ligands, which have greater π-accepting ability compared with alkyl ones, provided 99mTc-labeled hexavalent probes in high radiochemical yields (>95%) even at low ligand concentration (50 μM). We applied this finding to the synthesis of a 99mTc-labeled hexavalent RGD probe, targeting integrin αvβ3. This 99mTc-labeled probe was prepared in a 5 min reaction at ligand concentration of 50 μM, and exhibited high tumor localization in vivo without post-labeling purification. ConclusionThe present findings indicate that aryl isocyanide ligands would be a useful precursor to a variety of 99mTc-labeled hexavalent targeting probes for molecular imaging of saturable systems. Advances in knowledgeAryl isocyanide is a better precursor than alkyl isocyanide for preparing 99mTc-labeled hexavalent targeting probe. Implication for patient careThis work provides a straightforward method to prepare molecular imaging agents of high target uptake, which would facilitate nuclear medicine imaging in clinical settings.

ChemInform Abstract: Reductive Coupling of Carbon Monoxide and Alkyl Isocyanide Ligands in Early Transition Metal Complexes: A Review

ChemInform Abstract: Reductive Coupling of Carbon Monoxide and Alkyl Isocyanide Ligands in Early Transition Metal Complexes: A Review

Diaquatetrakis(tert-butyl isocyanide)cobalt(II) bis(perchlorate): an example of cobalt(II) coordinated by only four alkyl isocyanide ligands

The title compound, [Co(C5H9N)4(H2O)2](ClO4)2, crystallizes in the monoclinic space group C2/m. The cation has space-group-imposed 2/m symmetry, while the perchlorate ion is disordered about a mirror plane. The two slightly non-equivalent Co-C bonds [1.900 (3) and 1.911 (3) A] form a rectangular plane, with a C-Co-C bond angle of 86.83 (11) degrees, and the linear O-Co-O C2 axis is perpendicular to this plane. The C[triple-bond]N bond lengths are 1.141 (4) A and the Co-C[triple-bond]N and C[triple-bond]N-C angles average 175.5 (4) degrees. The perchlorate counter-ions are hydrogen bonded to the water molecules. The title compound is the first example of four alkyl isocyanide ligands coordinating Co(II) upon initial reaction of Co(ClO4)(2).6H2O/EtOH with alkyl isocyanide. In all other known examples, five alkyl isocyanide molecules are coordinated, as in [(RNC)5Co-Co(CNR)5](ClO4)4 (R = Me, Et, CHMe2, CH2Ph, C4H9-n or C6H11) or [Co(CNC8H17-t)5](ClO4)2. This complex, therefore, is unique and somewhat unexpected.

Cyclic voltammetric studies of tris(alkylisocyanide)bis (triarylphosphine)cobalt(II) and tris(alkylisocyanide) bis(triarylphosphine)cobalt(I) complexes exhibiting synthetic interconvertability

Nine pairs of corresponding [CoI(CNR)3(PR'3)2]X, [CoII(CNR)3(PR'3)2]X2 complexes — where X = ClO4, BF4; CNR = CNCMe3, CNCHMe2, CNC6H11, CNCH2Ph; PR'3 = PPh3, P(C6H4Me-p)3, P(C6H4OMe-p)3 — have been studied using cyclic voltammetry in CH3CN solutions. All cycles are reversible, and E1/2 for the Co(I) complexes, initially oxidized, are within experimental error identical to E1/2 values for the corresponding Co(II) complexes, initially reduced. E1/2 values are strongly dependent on the triarylphosphine ligand, decreasing in the order PPh3 > > P(C6H4Me-p)3 > P(C6H4OMe-p)3, and weakly dependent on the alkylisocyanide ligand, decreasing in the order CNCH2Ph > CNCMe3 > CNC6H11 [Formula: see text] CNCHMe2. Solution ν(-N[Formula: see text]C) IR patterns reveal that the [CoI(CNR)3(PR'3)2]X complexes do not have regular trigonal bipyramidal coordination, their structure being determined by the particular CNR ligand, while the [CoII(CNR)3(PR'3)2]X2 complexes, specifically in CF3CH2OH, appear to have regular trigonal bipyramidal coordination.Key words: cyclic voltammetry, cobalt(I) complexes, cobalt(II) complexes, alkylisocyanide ligands, triarylphosphine ligands.

Synthesis and characterization of seven-coordinate tantalum(I) and niobium(I) complexes with cis carbonyl and alkyl isocyanide ligands

A serie of seven-coordinate tantalum(I) and niobium(I) complexes of the form [M(CNR)(CO)(dmpe) 2 Cl] [M=Nb, R=Me, Cy, Bu t ; M=Ta, R=Me, Et, Bu t ; dmpe=1,2-bis(dimethylphosphino)ethane] has been synthesized by photolysis of [M(CO) 2 (dmpe) 2 Cl] in the presence of CNR. The bis(isocyanide)complex [Ta(CNMe) 2 (dmpe) 2 Cl] was prepared by reduction of [TaCl 4 (dmpe) 2 ] in the presence of CNMe.

Synthesis and complexation to ruthenium(II) and iron(III) meso-tetraphenylporphyrins of two new fluorinated alkyl isocyanides: 2-monofluoroethyl isocyanide and 2,2,2-trifluoroethyl isocyanide

New 2-monofluoroethyl isocyanide and 2,2,2-trifluoroethyl isocyanide ligands have been complexed to TPPRu(II) and TPPFe(III)OSO 2CF 3 in order to provide information on the fluorine effect on alkyl isocyanide binding. The comparison of IR and NMR data indicates a great similarity between the bonding properties of the fluorinated isocyanide and alkyl isocyanide ligands.

Mechanistic studies of the reductive coupling of isocyanides in seven-co-ordinate molybdenum complexes; X-ray crystal structures of [Mo(CNBut)6] and [Mo{CN(But)(SiMe2But)}(CNBut)5][O3SCF3

Aspects of the mechanism for reductive coupling of alkyl isocyanide ligands in seven-co-ordinate molybdenum(II) complexes of general formula [Mo(CNR)6X]+(X = halide) have been elucidated. The chemistry is analogous to that previously reported for reductive coupling of adjacent CO ligands in [M(CO)2(dmpe)2Cl] molecules (M = Nb or Ta, dmpe = Me2PCH2CH2PMe2). Reduction of [Mo(CNBut)6l]+ with 1% Na/Hg yields the six-co-ordinate molybdenum(0) species, [Mo(CNBut)6]. An X-ray crystal structure determination of this molecule revealed considerable bending at the isocyanide nitrogen atoms indicative of substantial charge delocalization onto the ligands. Addition of trifluoroacetic acid to [Mo(CNBut)6] results in reductive coupling of two isocyanide ligands to form [Mo(ButHNCCNHBut)(CNBut)4(O2CCF3)]+. Although additional intermediates in this coupling reaction were not isolated, an alkylaminocarbyne is suggested to be another likely species along the mechanistic pathway, by analogy to the CO reductive coupling mechanism. In support of this hypothesis, addition of SiMe2But(O3SCF3) to [Mo(CNBut)6] resulted in the formation of the stable cation [Mo{CN(But)(SiMe2But)}(CNBut)5]+. The structure of this new aminocarbyne complex was elucidated in an X-ray crystal structure determination. When 1 equivalent of trifluoroacetic acid was added to [Mo(CNBut)6] the interesting doubly protonated species [Mo(CHNHBut)(CNBut)5]2+ was obtained, as revealed by solution NMR spectroscopic analyses. The possible mechanistic implications of these results are discussed.

Reductive Coupling of Carbon Monoxide and Alkyl Isocyanide Ligands in Early Transition Metal Complexes: A Review

Israel Journal of ChemistryVolume 30, Issue 4 p. 331-341 Article Reductive Coupling of Carbon Monoxide and Alkyl Isocyanide Ligands in Early Transition Metal Complexes: A Review Raymond N. Vrtis, Raymond N. Vrtis Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USASearch for more papers by this authorStephen J. Lippard, Corresponding Author Stephen J. Lippard Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USADepartment of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USASearch for more papers by this author Raymond N. Vrtis, Raymond N. Vrtis Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USASearch for more papers by this authorStephen J. Lippard, Corresponding Author Stephen J. Lippard Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USADepartment of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USASearch for more papers by this author First published: 1990 https://doi.org/10.1002/ijch.199000035Citations: 42AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Citing Literature Volume30, Issue4Special Issue: Organometallic Models and Mechanisms (Part A)1990Pages 331-341 RelatedInformation

Preparation of the isocyanide complexes trans-[ReCl(CNR)(dppe)2](R = Me or But) and their reactions with acid to give carbyne complexes. X-Ray crystal structure of trans-[ReCl(CNHMe)(dppe)2][BF4

The complexes trans-[ReCl(CNR)(dppe)2](1, R = Me or But) have been prepared by replacement of dinitrogen in trans-[ReCl(N2)(dppe)2]. The alkyl isocyanide ligands in complexes (1) undergo electrophilic attack at the nitrogen atom by mineral acid (HBF4), forming the carbyne complexes trans-[ReCl(CNHR)(dppe)2][BF4](2, R = Me or But) and spectroscopic data for these complexes are given.The X-ray structure of trans-[ReCl(CNHMe)(dppe)2][BF4] has been determined and shows that the CNMe angle is 123(2)°, the Re–C (carbyne) bond length is 1.80(3)A, and the C(carbyne)–N bond length is 1.35(3)A.

13C nuclear magnetic resonance studies of the binding of alkyl isocyanides to soybean leghemoglobin; comparison with animal myoglobins

13C NMR of labelled alkyl isocyanide ligands has been used with a view to probe the protein environment around the heme site of Soybean leghemoglobin, and comparatively, those of sperm whale myoglobin and monomeric Glycera hemoglobin. The terminal carbon of the isocyanide, which is known to be highly sensitive to change in hybridization of the nitrogen, could be expected to reflect the movement of the alkyl group through steric interactions. Three alkyl isocyanides (alkyl = methyl, ethyl & n-butyl) have therefore been used and the 13C0 chemical shift values were measured for each ligand bound to the various proteins studied. In all cases, the 13C0 resonance of the bound ligand were shifted considerably down-field with respect to those of the free unbound species, but the pattern of these displacements revealed more pronounced steric hindrance in the case of some proteins compared to others. The modifications of the chemical shift values of binding delta delta = delta bound -- delta free) were least in the case of leghemoglobin; moreover, the delta delta values were insensitive to the length of the alkyl chain (methyl to n-butyl) when bound to leghemoglobin, in contrast to the other proteins examined. The results are interpreted as arising from a diminished steric hindrance to isocyanide binding with leghemoglobin, in conformity with the recently published X-ray structure which reports the existence of a large heme pocket on the distal side.