S.S. Sandhu

Diorganotin(IV) derivatives of N-phthaloyl amino acids

Twentyfour complexes of the general formulae (R2SnL2 and R2(L)SnOSn(L)R2 (L = N-phthaloyl derivative of l-leucine, dl-alanine and l-phenylalanine; R = CH3, C5H5, n-C4H9) and n-C8H17) have been prepared by reacting ligand and dialkyltin(IV) oxide in 2/1 and 1/1 (ligand/metal) molar ratio. These complexes have been characterised by elemental analysis and structures assigned with the help of infrared, 1H NMR and 119Sn Mossbauer spectroscopy. These data support six-coordinated distorted octahedral structures with two alkyl groups in trans positions.

Diorganotin(VI) complexes of N-acetylamino acids

Abstract Sixteen complexes of general formula R2SnL2 and R2(L)SnOSn(L)R2 (where L = N-acetyl-L-leucine or N-acetyl-L-phenylalanine) R = CH3, C2H5, n-C4H9, or n-C8H17) have been prepared by interaction between the ligand and R2SnO in 2:1 or 1:1 molar ratio. The complexes were characterized by IR, 1H NMR and 119Sn Mossbauer spectroscopy. All the 2:1 complexes are assigned six-coordinate, distorted octahedral geometry with chelating carboxylate groups, while the 1:1 complexes have oxygen-bridged binuclear five-coordinate, trigonal-bipyramidal configurations. The amido −CO and −NH groups are hydrogen bonded in the solid state.

Diorganotin(IV) complexes of N-protected dipeptides

Abstract Eight new diorganotin(IV) complexes of general formula R 2 Sn(DP) 2 and [R 2 Sn(DP)] 2 O (DP = anion of N -benzoyl- dl -alanylglycine; R = CH 3 , C 2 H 5 , n-C 4 H 9 , n-C 8 H 17 ) have been prepared and characterised by IR, and 119m Sn Mossbauer spectroscopy. However, only two complexes, (DP) 2 Sn(n-C 4 H 9 ) 2 and (DP) 2 Sn(n-C 8 H 17 ) 2 were sufficiently soluble for NMR ( 1 H and 13 C) studies. The 2 : 1 complexes are monomeric with distorted trans -octahedral structures. The 1 : 1 complexes are dinuclear with Sn-O-Sn bridges and trigonal bipyramidal geometry about tin. In both cases the dipeptide acts as an O,O -bidentate ligand.

Chemistry of iron complexes—IV. Spectroscopic, magnetic and other properties of complexes of iron(II) iodide and iron(II) tetracarbonyl iodide with b

Abstract Bis(tertiaryphosphine/arsine oxides), Ph 2 E(O) (CH 2 ) n E(O)Ph 2 react with iron(II) iodide and iron(II) tetracarbonyliodide forming com

Arylarsonates of diorganotin(IV)

Arylarsonates of diorganotin(IV) of the general formula X-C6H4AsO3SnR2 (R = CH3, n-C4H9, n-C8H17, C6H5CH2; X = H, p-CH3, p-Cl, p-Br, p-OH, p-COOH, o-COOH, o-NH2, o-NO2) and [CH2As(C6H5)O2Sn(C8H17)2 have been prepared. The complexes are high melting solids, insoluble in the common organic solvents, and have been characterized by elemental analysis, molecular-weight determination, and infrared and Mossbauer spectroscopy. Five- and six-coordinate structures are postulated.

Synthesis, spectroscopic, and magnetic studies of copper(II) with N-protected amino acids: crystal and molecular structure of diaquatetrakis(µ-N-benzoyl-α-alaninato)-dicopper(II)

Eighteen complexes of copper(II) having the general formula CuL2·nH2O (n= 1–4) with N-protected amino acids (HL) have been prepared and characterized by spectroscopic methods and magnetic susceptibility measurements. These complexes belong to three types: binuclear species having bridging bidentate co-ordination through the carboxylate group, mononuclear species having symmetrical chelating bidentate co-ordination or bridging bidentate co-ordination with no Cu–Cu interaction, and mononuclear species having highly unsymmetrical chelating bidentate or non-chelating unidentate co-ordination through the carboxylate group. The complex [{Cu(Bz-α-AlaO)2(H2O)}2] crystallizes in the triclinic system with space group P, and unit-ceil parameters a= 9.421 (2), b= 9.549(2), c= 12.618(3)A,α= 74.31(2), β= 79.21(2), γ= 88.69(2)°, and Z= 1. Full-matrix least-squares refinement using 2 842 independent reflections converged to a final R= 0.038 and R′= 0.052. The complex has a typical copper(II) acetate monohydrate type structure with mean Cu–O(carboxylate), Cu–O(water), and Cu–Cu distances of 1.968(3), 2.138(4), and 2.664(1)A, respectively.

Synthesis, spectroscopic and magnetic properties of nickel(II) with N-protected amino acids: crystal and molecular structure of bis(N-acetylglycinato)tetraaquonickel(II)

Abstract Nickel(II) complexes of the general formula NiL2·nH2O have been prepared with various N-protected amino acids and characterized by thermogravimetric, magnetic susceptibility, IR and UV spectroscopy. The crystal structure of bis(N-acetylglycinato) tetraaquonickel(II) has been determined. The coordination around nickel is octahedral with two acetylglycine ligands trans to each other. Acetylglycine coordinates with nickel through a single oxygen of the carboxylate group, and the remaining four coordination sites are occupied by four water molecules. The structure is held together by strong intermolecular hydrogen bonding. Spectroscopic studies indicate that all complexes are octahedral in structure.

Chemistry of iron complexes—II. Spectroscopic, magnetic and other studies of new complexes of iron(III) with bis(tertiary phosphine/arsine oxides)

Abstract Spectroscopic (i.r., far i.r., ESR, u.v.-vis) magnetic, TGA, molar conductance and X-ray diffraction studies of new complexes of iron(III) halides with bis(tertiary phosphine/arsine oxides) Ph 2 E(O)(CH 2 ) n E(O)Ph 2 (LL) have been reported. The complexes are of the types: (a) [Fe(LL) 2 Cl] [FeCl 4 ] 2 ( n = 2,4; E = As) and (b) [Fe(LL) 2 Br 2 ] [FeBr 4 ] [E, n :P (1,2,4,6); As(2,4)]. The cations [Fe(LL) 2 Br 2 ] + were assigned a trans octahedral structure. The far i.r. data support chloro-bridged octahedral structures for the cations [Fe(LL) 2 Cl] 2+ .

Ligating properties of model bioheterocyclics. Ill. Synthesis and characterization of the palladium(II) and platinum(II) Complexes with 3,6-disubstituted-2,7-dihydro-1,4,5-thiadinzepine derivatives

Abstract Palladium(II) and platinum(II) halides with 3,6-disubstituted-2,7-dihydro-1,4,5-thiadiazepine derivatives (L) form complexes of general formula, [MX 2 ·L′] (L′ = monohydrazone, VII). During the formation of these complexes, the thiadiazepine ring underwent hydrolytic cleavage at the carbon- nitrogen double bond, the nitrogen of which is involved in coordination with the metal ions These complexes have also been obtained from mono. hydrozones of 2,2″-thiodiacetophenones. These are diamagnetic and non-electrolytes. From their it, n.m.r., electronic spectra, T.G.A., D.T.A., magnetic susceptibility and conductivity measurements, these complexes have been assigned a square planar structure.

X-ray diffraction (powder), e.s.r. and other spectral studies oftris[methylenebis(diphenylphosphine oxide)]iron(III) perchlorate

SummaryBifunctional methylenebis(diphenylphosphine oxide) (mdpo) on reaction with iron(III) perchlorate forms the complex, [Fe(mdpo)3](ClO4)3 · H2O. This has been characterized through elemental analysis, i.r., far-i.r., u.v. and visible spectroscopy and by x-ray diffraction, magnetic moment, molar conductance and e.s.r. data. The e.s.r. spectrum consists of five lines with transitions from: ¦−5/2〉→¦−3/2〉¦−3/2〉→¦−1/2〉, ¦−1/2〉→¦+1/2〉¦+1/2〉→¦+3/2〉 and ¦+3/2〉→¦+5/2〉 centred at a g-value of 2.00. On the basis of these studies, a chelated octahedral structure has been assigned to the cation, [Fe(mdpo)3]3+.