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Metal-mediated coupling of one isocyanide in cis-[PdCl2(CNR1)2] (R1 = C6H11 (Cy) 1, tBu 2, 2,6-Me2C6H3 (Xyl) 3, 2-Cl-6-MeC6H3 4) and various carbohydrazides R2CONHNH2 [R2 = Ph 5, 4-ClC6H4 6, 3-NO2C6H4 7, 4-NO2C6H4 8, 4-CH3C6H4 9, 3,4-(MeO)2C6H3 10, naphth-1-yl 11, fur-2-yl 12, 4-NO2C6H4CH2 13, Cy 14, 1-(4-fluorophenyl)-5-oxopyrrolidine-3-yl 15, (pyrrolidin-1-yl)C(O) 16, 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propane-1-yl 17, EtNHC(O) 18] or sulfohydrazides R3SO2NHNH2 [R3 = Ph 19, 4-MeC6H4 20] led to a series of (hydrazido)(amino)carbene complexes cis-[PdCl2{ C (NHNHX) N(H)R1}(CNR1)]; X = COR2, SO2R3 (21–48, isolated yields 60–96%). All prepared species were characterized by elemental analyses (C, H, N), HR ESI+-MS, IR, 1H and 13C{1H} NMR spectroscopy, and by a single-crystal X-ray diffraction for 38. Complexes 21–48 demonstrated excellent activity as catalysts in copper-free Sonogashira coupling of aryl iodides and a variety of aromatic terminal alkynes. Catalytic system runs in environmentally benign EtOH ensuring product yields of up to 75–96% and TONs of up to 104. Mechanism of the copper-free Sonogashira catalytic cycle involving 21–48 as catalysts was proposed upon identification of key intermediates using HRESI-mass.

The metal-mediated coupling between cis-[PdCl2(CNR1)2] [R1 = cyclohexyl (Cy) 1, t-Bu 2, 2,6-Me2C6H3 (Xyl) 3, 2-Cl-6-MeC6H3 4] and hydrazones H2NN CR2R3 [R2, R3 = Ph 5; R2, R3 = C6H4(OMe-4) 6; R2/R3 = 9-fluorenyl 7; R2 = H, R3 = C6H4(OH-2) 8] provided carbene complexes cis-[PdCl2{C(N(H)N CR2R3) N(H)R1}(CNR1)] (9–24) in good (80–85%) yields. Complexes 9–24 showed high activity [yields up to 99%, and turnover numbers (TONs) up to 3.7 × 104] in the Sonogashira coupling of various aryl iodides with a range of substituted aromatic alkynes without the need of copper co-catalyst. The catalytic procedure runs at 80 °C for 1 h in EtOH using K2CO3 as a base. No formation of homocoupling or acetylene decomposition products was observed. Designed copper-free Sonogashira system can also run at room temperature giving target products with yields up to 87% and TONs up to 87.

Aminocarbene complexes cis-[PtCl2{ C (N(H)N = CR2R3)=N(H)R1}(CNR1)] (7–15) prepared via the nucleophilic addition of hydrazones H2N–N=CR2R3 [R2, R3 = Ph 4; R2/R3 = 9H-fluorenyl 5; R2 = H, R3 = 2-(OH)C6H4 6] to cis-[PtCl2(CNR1)2] [R1 = cyclohexyl (Cy) 1, 2,6-Me2C6H3 (Xyl) 2, 2-Cl-6-MeC6H3 3] were evaluated as catalysts for the hydrosilylation of terminal alkynes with trisubstituted silanes giving vinyl silanes. The optimized catalytic system runs at 80–100 °C in dry toluene for 3–6 h with a typical catalyst loading of 0.1 mol%. A range of substrates with different steric hindrance and activity (Et3SiH, Pr3SiH, iPr3SiH, and PhMe2SiH as silanes; PhC CH, tBuC CH, and 4-(tBu)C6H4C CH as alkynes) were successfully transformed into the target silylated products in 83–99% yields attesting the versatility of our catalytic system. Decreasing the catalysts loading to 10−3 mol% guaranteed the maximum TONs of 4.0 × 104 and TOFs of 1.7 × 103 (h−1) that were accomplished within 24 h of the reaction.

A reaction of isocyanide complex cis-[PdCl2(CNAr)2] with hydrazones H2N-N=CR1R2 proceeded at the carbon atom of one of the isocyanide groups and gave the corresponding diaminocarbene isocyanide palladium(ii) complexes. These complexes showed high catalytic activity in the Sonogashira and Suzuki cross-coupling reactions.

Two complexes [KLa(HL(1))2{(CH3)2NCHO}2(H2O)3] (1) and [Sm(H2O)9](E-H2L(2))3·2H2O (2) were synthesized by the reaction of lanthanum(III) and samarium(III) nitrates with potassium 3-(2-(2,4-dioxopentan-3-ylidene)hydrazinyl)-2-hydroxy-5-nitrobenzenesulfonate (KH2L(1)) and potassium (E,Z)-5-chloro-3-(2-(1,3-dioxo-1-phenylbutan-2-ylidene)hydrazinyl)-2-hydroxybenzenesulfonate (KH2L(2)), respectively. Both complexes were fully characterized by elemental analysis, IR, (1)H and (13)C NMR spectroscopy, ESI-MS and single-crystal X-ray diffraction. Cooperative E,Z→E isomerization of KH2L(2), induced by resonance assisted hydrogen bonding and ionic interactions, occurs upon the interaction with Sm(III). Catalytic activities of KH2L(1,2) and their lanthanide derivatives were evaluated in the Henry reaction of nitroethane with a variety of aromatic and aliphatic aldehydes. Good yields (up to 91%) and diastereoselectivities (syn/anti 3 : 1) were observed in the reactions catalyzed by 1 in water.