Molybdenum carbonyl complexes with pyridylimino acidato ligands

Reactions of [Mo(CO)4(pip)2] with pyridine-2-carbaldehyde and the appropriate amino ester or amino acid produce complexes with chelated pyridylimino ligands bearing, respectively, an ester (1) or carboxylate (2a,b, 4, 5a,b) pendant arm, the structures of which have been determined by X-ray crystallography. In the case of alpha-amino acids, the resulting imino carboxylate complexes are unstable towards decarboxylation, this being complete for (R)-2-phenylglycine. The products of decarboxylation 3a-c were isolated and characterized, including X-ray structure determinations for and . In contrast, the derivatives of beta-alanine (4) and 3- and 4-aminobenzoic acids (5a,b) are stable towards decarboxylation. The structure determinations show that the pyridyliminocarboxylate complexes crystallize as salts with piperidinium cations, forming hydrogen-bonded ion-pair dimers featuring twelve- or eight-membered rings. Protonation of carboxylate complexes with 2 M HCl in CH2Cl2/water yields the corresponding neutral complexes 6a,b containing a free carboxylic acid functionality.     

Phthalazine iron carbonyl complexes

Reaction of phthalazine with diiron enneacarbonyl in benzene at room temperature and with triiron dodecacarbonyl in hot benzene gives mono- and binuclear complexes where the nitrogen atoms behave as two- or three-electron donor ligands. 1,2-Dihydrophthalazine and a binuclear iron carbonyl derivative are formed when the triiron dodecacarbonyl reaction is effected in methanolic benzene.     

Reactions of iron carbonyl complexes with dimethylthiocarbamoyl chloride

The reactions of dimethylthiocarbamoyl chloride with a number of neutral and ionic iron carbonyl complexes in tetrahydrofuran are described. A variety of unusual products were obtained, viz. Fe(CO)₂(S₂CNMe₂)₂ from Fe(CO)₅; Fe(CO)₂(S₂CNMe₂)(CSNMe₂) from Fe₂)CO)₉, Fe₃(CO)₁₂, and Fe(CO)₄^2?; [Fe-(CO)₂(S₂CNMe₂)(CNMe₂)(CNMe₂)₂S]⁺ from Fe(CO)₄^2?, and Fe₄(CO)₁₂S(CSNMe₂)-(CNMe₂) from Fe₂(CO)₈^2?, as well as Fe₂(CO)₆(CSSEt)₂ from Fe₂(CO)₉ and ClCSSEt. The structures and behavior and some reactions of these complexes are described.     

The first carbonyl iron complexes with dihydroacepentalene ligands

1,4-Dibromo- (8) as well as 1,4,7-trichloro- (11a) and 1,4,7-tribromotriquinacene (11b) react with Fe₂(CO)₉ in THF to yield (dihydroacepentalene)hexacarbonyldiiron complexes 9 and 10, the first representatives with a 7,10-dihydroacepentalene ligand. By reaction with Fe₂(CO)₉, the readily accessible 4,7-bis (dialkylamino)tricyclo[5.2.1.0^4.10]deca-1(10),2,5,8-tetraenes 14, derivatives of the unknown 4,7-dihydroacepentalene, were transfomed into their tricarbonyliron complexes 15. Upon reduction with sodium in THF, the η⁴-(diene)tricarbonyliron 15 selectively gave the novel 1,10η²-(olefin)tricarbonylferrates(-2)17 as a result of a twofold electron transfer. The intermediate green radical anion 16, which is persistent in the absence of excess sodium, was characterized by its ESR signal. Complexes 17 are the first of their class with complete structural characterization by ¹H- and ¹³C-NMR spectroscopy.     

Mass spectra of cobalt carbonyl complexes

The mass spectra of the following acetylenic derivatives of Co₂(CO)₈ are reported: Co₂(CO)₆C₂H₂Co₂(CO)₆C ₂,(CH₃)₂, Co₂(CO)₆ C₂(CH₂Cl)₂, Co₂(CO)₆C₂ (CF₃)₂, Co₂(CO)₂C₂(C₆H₅)₂ and Co₂(CO)₆C₂(COOCH₃)₂. The effect of different C₂RR′ on fragmentation modes is investigated. When R and R′ are aromatic groups, the major controlling factor is the stability of charged fragments; in other cases, it seems to be the loss of a stable neutral moiety. Transfer processes of alkoxylic groups are observed in Co₂(CO)₆C₂(COOCH₃)₂, as well as in Co₃(CO),₉CCOOCH₃, and Co₃(CO)₉CCOOC₂H₅. It is suggested that both cobalt and carbon atoms may be the migration sites.     

Two-dimensional bimetallic carbonyl cluster complexes with new properties and reactivities

The new electron-rich, anionic, planar cluster complex [IrRu(6)(CO)(23)](-), 5, isolated as a PPN salt, PPN = [Ph(3)PNPPh(3) ](+), has been synthesized and characterized crystallographically. The complex exhibits unusual absorption and emission properties. Computational analyses have been performed to explain its metal-metal bonding and electronic properties. Anion 5 reacts with [Ph(3)PAu][NO(3)] to yield the uncharged planar complex Ru(5)Ir(CO)(20)AuPPh(3), 6, by metal atom substitution.     

Polynuclear nitrosyl carbonyl ReI complexes with thiolate and sulfide bridges

The reaction of the complex Re₂(CO)₄(NO)₂Cl₄ (1) with NaSCMe₃ (2) (in THF or MeCN, 65–80°C, 24 h) was studied at different ratios of the reagents (from 1∶2 to 1∶6). At the reagent ratio of 1∶2, the binuclear complex Re₂(CO)₄(NO)₂Cl₂(μ-SCMe₃)₂ (3) was obtained as a mixture ofsyn andanti isomers (3a and3b, respectively) containing Re₂S₂ fragments with different structures (the butterfly-like structure in3a and the planar fragment in3b). When the initials were taken in ratios from 1∶4 to 1∶6, two compounds were isolated: the binuclear complex Re₂(CO)₄(NO)₂(μ-SCMe₃)₂(μ-S)4 (cocrystallized as a mixture ofsyn andanti isomers,4a and4b, respectively) and the triangular cluster Re₃(CO)₃(NO)₃(μ-SCMe₃((μ₃-S)(μ₃-Cl) (5). Apparently, complex4 is formed in the course of isolation as a result of elimination of SR₂ from the unstable tetrathiolate dimer Re₂(CO)₄(NO)₂(SCMe₃)₂(μ-SCMe₃)₂ (6). Cluster5 is the product of the reaction between compounds3 and4. Products of interaction of compound6 with silica gel upon column chromatography of the reaction mixture were studied. Four complexes containing hydroxy and oxo bridging groups, (CO)₂(NO)Re(μ-SCMe₃)₂(μ-OH)Re(SCMe₃)(CO)(NO) (7), (CO)₃(NO)₃RE₃(μ-SCMe₃)₃(μ₃-SCME₃)(μ₃-O) (8), [(CO)₂(NO)₂Re₂(SCMe₃)₂(μ-SCMe₃)₂(μ-OH)][Na(THF)(Et₂O)] (9), and [(CO)₂(NO)₂Re₂(SCMe₃)₂(μ-SCMe₃)₂(μ-OH)]₂−[Na(H₂O)₆][H₅O₂] (10), were isolated. The structures of complexes3, 4, 5, 7, 8, 9, and10 were established by X-ray diffraction study. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1030–1044, May, 1998.     

Polarizability effect in transition metal carbonyl complexes

The literature date on substituent influence on the carbonyl stretching frequencies (ν), CO stretching force constants (k), as well as ¹³C NMR carbonyl chemical shifts (δ) have been analyzed for 19 series of the transition metal carbonyl complexes. It was established for the first time that the ν, k and δ values depend not only on the inductive and resonance effects but also on the polarizability of substituents. The polarizability contribution ranges up to 37%.     

Hydrogen bonding in transition metal carbonyl complexes

Conclusions The formation of a previously unknown type of hydrogen bonding OH...OC-M involving the oxygen atom of the CO group at the metal atom was observed upon the interaction of CpMn(CO)₂-P(i-Pr)₃ with (CF₃)₃COH in liquid xenon solution at low temperatures.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2605–2608, November, 1986.     

Platinum and rhenium phosphine carbonyl thiolate complexes

The heterometallic complex (CO)₃(PPh₃)Re(μ-SPr)Pt(PPh₃)(CO) (I) was formed in the reaction of Re₂(μ-SPr)₂(CO)₈ with (PPh₃)₂Pt(C₂Ph₂), together with (CO)₃(PPh₃)Re(μ-SPr)₂Re(CO)₄ (II), which was also prepared by an alternative synthesis. Compounds I and II were characterized by X-ray diffraction. In I, the Re-Pt single bond, 2.7414(5) Å, is supplemented by a thiolate bridge with shortened bonds: Pt-S (2.336(2) Å) and Re-S (2.449(2) Å). The Re-P (2.469(2) Å) and Pt-P (2.329(2) Å) bonds are also shortened. Complex II resulting from replacement of one CO group in the starting rhenium complex by triphenylphosphine has no M-M bond, and the Re-S and Re-P bond lengths (2.511(2)–2.527(2) and 2.517(3) Å) are close to the length of single bonds. It is assumed that the platinum atom in I is attached to the formally double bond Re ? SPr arising upon dissociation of Re₂(μ-SPr)₂(CO)₈.